Neuroscience Exam 2: Gates Of Delirium

Front 1

prosencephalon components

Back 1

a. Telencephalon (lateral ventricles)
b. Diencephalon (3rd ventricle)

Front 2

telencephalon components

Back 2

i. Cerebral cortex
ii. Basal ganglia
iii. Rhinencephalon
iv. Semioval center

Front 3

diencephalon components

Back 3

i. Thalamus
ii. Hypothalamus
iii. Epithalamus
iv. Subthalamus

Front 4

Rhombencephalon (4th ventricle) components

Back 4

a. metencephalon
b. myelencephalon

Front 5

metencephalon components

Back 5

i. Pons
ii. Cerebellum

Front 6

myelencephalon components

Back 6

i. Medulla oblongata

Front 7

prosencephalon characteristics

Back 7

a. Separated into R and L hemispheres by longitudinal fissure.
b. Lateral ventricles are located in each hemisphere – no one knows which is #1 or #2
c. Each hemisphere- 5 anatomical lobes
d. Cerebral hemisphere is made of gyri and sulci
e. Gyri – convolutions of tissue – all have names
f. Sulci – grove found between gyri – they also have names
i. Fissure is a big sulcus

Front 8

5 lobes of Cerebral hemispheres (all bilateral):

Back 8

a. Frontal: occurs between frontal poles to the central sulcus posterior, and the lateral fissure laterally
b. Parietal: extends from central sulcus to parieto-occipital sulcus posteriorly
c. Occipital: posterior to parieto-occipital sulcus
d. Temporal: inferior to the lateral fissure (also called Sylvian fissure) and extends back to the level of the parieto-occipital sulcus
e. Insula: (Island of Reil/Hidden lobe) lies deep to lateral fissure and comprised of 4-5 gyri.

Front 9

white matter contains the

Back 9

the cellular processes (axons- myelinated)

Front 10

grey matter contains the

Back 10

cell bodies of neurons (not myelinated, thus grey) – makes up the cerebral cortex (Grey matter = cerebral cortex)

Front 11

cerebral contex (grey matter) characteristics

Back 11

i. 4-5mm thick; 2.5 sq ft. when flattened out
ii. Thickness varies and depends on the gyrus
1. 4.5 mm in precentral gyrus (in frontal lobe)
2. 1.5 mm in calcarine gyrus (in occipital lobe)
iii. About 14 billion neurons have cell body in cortex
iv. Neurons of the cortex are amitotic; they are permanent (a few exceptions)

Front 12

6 Histological layers of cells in cortex- what occurs here?

Back 12

neurons

Front 13

6 Histological layers of cells in cortex communication characteristics

Back 13

b. Each layer communicates with another adjacent layer
d. If layers are normal, then communication is normal
e. Messed up cyto-architecture impairs communication = symptoms

Front 14

6 Histological layers of cells in cortex order (superficial to deep)

Back 14

organized horizontally
i. Molecular
ii. External granular
iii. External pyramidal
iv. Internal granular
v. Internal pyramidal
vi. Polymorphic

Front 15

6 Histological layers of cells in cortex order is based on

Back 15

i. Type of neuron present
ii. Density of cells
iii. Arrangement of cells

Front 16

Functional Cortical Mapping- pathological data characteristics

Back 16

crude approach, made assumptions based on area of the brain that is injured and the behavior that ensued.

Front 17

Functional Cortical Mapping- Electro-stimulation data

Back 17

tap areas of the brain with current and see what happens; often used in neurosurgery to make sure the right spot is operated on.

Front 18

Functional Cortical Mapping- blood flow data characteristics

Back 18

functional MRI (fMRI); there is an increase or decrease in blood flow as a result of a task; during fMRI, pt does a task while in MRI tube and physicians observe which area of the brain has a “hot spot.”

Front 19

Functional Cortical Mapping- blood flow data limitations

Back 19

1. The lighting up does not occur in real time
2. Do not know if area is excitatory or inhibitory

Front 20

d. Metabolic data: pet scan characteristics

Back 20

pt. is injected with radioactive isotope with a short half-life that binds to oxygen and glucose; pt. performs a task and the area active has a greater emission of photons.

Front 21

metabolic data: SPECT definition

Back 21

single photon emitted CT scan

Front 22

Historical Maps characteristics

Back 22

these were based on pathological and electro-stimulation data

a. Campbell (1905) mapped 20 areas
b. Broadmann (1909) mapped 47 areas – most famous – still in use today
c. Economo (1929) mapped 97 areas

Front 23

Primary motor cortex (cerebral motor cortex location)

Back 23

-located in the pre-central gyrus of the frontal lobe, in front of the central sulcus

-Also includes anterior to pre-central gyrus; is an association motor cortex

Front 24

Primary pre- motor cortex controls

Back 24

Voluntary skeletal muscle activity on the contralateral side

Front 25

pyramidal system definition

Back 25

Motor system controlling skeletal muscle activity

Extrapyramidal system controls involuntary

Front 26

Pre-central gyrus cortex contains

Back 26

cell bodies of Upper Motor Neurons (i.e., one of the six layers; axons cross to the other side and tell LMN what to do)

Front 27

Pre-central gyrus is organized how?

Back 27

somatotopically organized (specific areas of the cortex control specific parts of the body) (homunculus)

large amount of cortex dedicated to finesse movements when compared to gross movements

Finesse control = more neurons involved.

Front 28

Motor unit definition

Back 28

ratio of LMN to number of extrafusal fibers being innervated

Front 29

Damage to pre-central gyrus cortex causes

Back 29

lose voluntary skeletal muscle activity to contralateral side of the body

Front 30

Primary sensory cortex (primary somatosensory area, somatosethic area, cerebral sensory) location

Back 30

post-central gyrus (behind central sulcus) of the parietal lobe

Front 31

Primary sensory cortex allows for discrimination and location of general sensations:

Back 31

1. Pain
2. Temperature
3. Pressure
4. Crude touch
5. Vibration
6. Fine touch (2 point discrimination, texture etc)
7. Proprioception

Front 32

Post-central gyrus organization

Back 32

ii. Left post-central gyrus controls the right and vice versa (contralateral side of the body).
iii. same somatotopic organization as primary motor cortex
iv. More sensitive parts of your body have a larger portion of the cortex devoted to them
v. Damage impacts contralateral perception
vi. If info does not reach cortex, then you do are not consciously aware of it – cannot consciously become aware of your environment

Front 33

If info does not reach primary sensory cortex, then:

Back 33

then you do are not consciously aware of it – cannot consciously become aware of your environment

Front 34

If post-central gyrus is removed/damaged, then patient can still perceive pain from the:

Back 34

thalamus

Front 35

Primary visual cortex location

Back 35

located in the occipital lobe, adjacent to the calcarine fissure.

Broadmann’s terminology “area #17”

Front 36

Primary visual cortex characteristics

Back 36

ii. Calcarine fissure region interprets as upside down and black and white image
iii. Images are received inverted, then the visual cortex flips them right side up to make sense of them.
iv. Damage to this area will cause blindness (Visual agnosia), despite intact eyes, nerves, aqueous humor, etc. Nothing is perceived until it reaches the cortex
v. Hit to the back of the head -> distortion -> See stars (not fun)
vi. Develops by sensing light as a kid

Front 37

Primary auditory cortex characteristics

Back 37

located in the superior temporal gyrus of the temporal lobe
i. Helps us to perceive sound.
ii. Damage to this area can cause deafness (if both sides damaged)

Front 38

Intellectual, personality, psychic, abstract, self-control, cognition: location

Back 38

located in the anterior portion of frontal lobe
i. Primarily anterior 1/5 of frontal lobe
ii. Injuries to the frontal lobe result in malfunctioning
iii. Phineas Gage (see textbook)

Front 39

Olfactory cortex fxn and location

Back 39

perceive smell
i. Involves 2 areas, both located in inferior temporal lobe (lateral olfactory area and medial olfactory area)

Front 40

lateral olfactory area (aka. stria) characteristics

Back 40

passes lateral to the optic chiasm and terminates at the uncus (medial bulging in the parahippocampal gyrus). Most significant area in terms of conscious olfactory response.

Front 41

Medial olfactory area location

Back 41

medial to optic chiasm and under; becomes anterior perforated substance.

Front 42

gustatory cortex characteristics

Back 42

-perceive taste
-3 locations of the brain involved with taste:
1. Most ventral portion of post-central gyrus
2. Insular cortex (insula) – deep to lateral fissure
3. Frontal operculum (frontal lobe)

Front 43

Association areas location and fxn

Back 43

-Surround the major cortical areas previously described
-refinement and/or interpretation of the major functions (auditory, visual, motor, primary somatosensory)

Front 44

association areas effects on vision

Back 44

-Helps visual cortex to see depth perception and other internal visual calculations.
-Adds color, movement, 3D perception, etc to primary vision
-Damage to the association area may cause loss of color, movement, depth perception, even though vision remains
-Important to keep in mind with patient’s with neurological insults – may have intact primary area, but lesion in association area
1. Will present with abnormal symptoms

Front 45

Motor speech cortex fxn

Back 45

allows a person to initiate speech by influencing portions of pre-central gyrus that control skeletal muscle for speech (larynx, pharynx, tongue, facial muscles/mastication muscles, and mouth)

Front 46

Broca’s area characteristics

Back 46

-located in the inferior frontal gyrus of the frontal lobe
-Primary cortex for motor speech – also known as Broadmann’s classification areas 44 and 45.
-Also considered part of the association area of the pre central gyrus
a. Technically an association area of frontal lobe that finesses info and sends it to the precentral gyrus

Front 47

Broca’s aphasia often caused by

Back 47

often done w L sided stroke

Front 48

Aphasia definition

Back 48

general term for language disorders to include reading, writing, speaking, or comprehension of written and spoken words, generally due to cerebral cortex or conduction dysfunction

Front 49

broca's aphasia definition

Back 49

(Motor aphasia, non-fluent aphasia) caused by damage to Broca’s area, generally in stroke of middle cerebral artery; patient cannot or has difficulty forming words even though vocal cords and innervations are normal

Front 50

Broca’s aphasia characteristics

Back 50

i. Speech is slow and elaborate, deliberate; pts. must concentrate. Applies to speech and writing.
ii. VERBALLY COMPROMISED (can’t speak)
iii. GRAPHICALLY COMPROMISED (can’t write)
iv. 90% of humans are left hemisphere dominant, with Broca’s area strongest on the left hemisphere. Therefore, a pt. presenting with stroke and affected left-side will have severe damage to Broca’s area. Patients with right-side stroke will have some symptoms but it will be less dramatic
v. Non-fluent: words do not flow, despite the ability to perceive language and organize thought processes.
vi. Pts. are usually aware that they cannot get words out, and they get very frustrated.
vii. Can perceive and understand language

Front 51

Hemianopia characteristics

Back 51

-(loss of half a visual field) and paralysis of facial mm on the right accompany Broca’s aphasia.
-3 symptoms usually appear together – Broca’s aphasia, hemianopia, paralysis of facial mm on right
1. Because optic pathway and internal capsule are close to Broca’s area
2. Vascular supply contributes to this too.

Front 52

Language cortex: Wernicke’s area location characteristics

Back 52

i. 90% Located in the posterior part of the superior temporal gyrus
1. 10% extends into parietal lobe
a. Though still considered a function of the temporal lobe
iii. Left hemisphere is more dominant over the right in 90% of the population (same as Broca’s area).

Front 53

Language cortex: Wernicke’s area fxn

Back 53

Controls comprehension of spoken words and written and auditory language.

Front 54

Wernicke’s aphasia characteristics

Back 54

(fluent aphasia, receptive aphasia)
-involved with comprehension of spoken and written language
-Able to speak and write words but the sequence is not normal
-patient is not aware they are not making sense
-1. LINGUISTICALLY COMPROMISED (Can say words, but out of sequence)
2. If large lesion, then visual and linguistic ability is compromised.
3. Wernicke’s area must be able to receive input from other areas of the brain

Front 55

receptive aphasia of wernicke's area definition

Back 55

when it is not receiving visual or auditory information properly

Front 56

empty speech characteristics

Back 56

a. Paraphasia: substitute one word for another.
b. Neologisms: create new and meaningless words and put them into sentences.
c. Jargon aphasia: speech is incomprehensible but seems logical to the patient

Front 57

blood supply for broca and wernicke's areas

Back 57

Same artery feeds Broca’s and Wernicke’s areas – middle cerebral artery

Front 58

Conduction aphasia definition

Back 58

-lesion impairs the conduction from Wernicke’s to Broca’s
-two areas are not specifically damaged, but the lesion destroys the arcuate fasciculus (efferent connection from Wernicke’s to Broca’s areas)

Front 59

Conduction aphasia characteristics

Back 59

i. Less fluent in language than patients with Wernicke’s aphasia.
ii. May make periphrastic errors (substituting words)
iii. Comprehension is good but ability to repeat is limited/poor.
iv. Naming is impaired
v. Reading aloud is impaired, but pt. can read silently with good comprehension.
vi. Writing (function of Broca’s) is abnormal with misspelled and omitted words.

Front 60

Global aphasia definition

Back 60

-Most severe form of aphasia: inability to use language in any form due to extensive damage to Broca’s, Wernicke’s, and arcuate fasciculus; -LINGUISTICALLY and VERBALLY compromised – unable to read/write well, unable to comprehend speech, unable to produce intelligible speech (language of any form)

Front 61

global aphasia generally occurs where?

Back 61

Generally occurs in the left hemisphere
a. Broca’s is damaged,
b. Wernicke’s area is damaged
c. Arcuate fasciculus is damaged

-A stroke this catastrophic has low survival rates, so this is an uncommon presentation

Front 62

Memory cortex: processing areas; occurs in which 2 areas in the temporal lobe?

Back 62

hippocampus

amygdala

Front 63

Hippocampus of temporal lobe location and importance

Back 63

-located deep to the parahippocampus

-Damage to hippocampus results in anterograde amnesia. Would remember previous events (that occurred before damage) but not events that happened after damage

Front 64

Amygdala (Amygdaloid nuclear complex) characteristics

Back 64

1. Deeply seated group of nuclei in the telencephalon
2. Initial processing and storage of memory; if it doesn’t pass through here, it doesn’t get remembered.
3. If you’re going to remember something consciously, hippocampus and amygdala must process that information

Front 65

UMN paralysis (spastic paralysis) to the contralateral side of the body caused by

Back 65

-Damage to the pre-central gyrus: contains UMN that feed LMN on the opposite side of the body – as well as the association motor cortex areas
-These structures are all fed by the middle cerebral artery, so stroke in that region can cause

Front 66

UMN paralysis (spastic paralysis) to the contralateral side of the body- spastic characteristics

Back 66

b. Spastic: wiped out UMN and LMN is still intact; muscles are still innervated due to sensory input; reflexes still occur, but there is no control b/c the UMN is not working to influence LMN.
i. Due to damage to internal capsule that contains axons of UMN (posterior limb of internal capsule?)

Front 67

Loss of general sensation (perception and discrimination) to contralateral side of the body caused by

Back 67

-Damage to post-central gyrus of the parietal lobe

Front 68

Loss of general sensation (perception and discrimination) to contralateral side of the body characteristics

Back 68

i. Instantaneous spatial coordination of all parts of the body is integrated at the posterior parietal lobe.
b. LMN doesn’t know what to do and becomes non-functional.
c. Right parietal lobe is primarily involved in spatial organization
d. Right parietal lobe is more dominant than left parietal lobe

Front 69

i. Damage in posterior part of right parietal lobe causes deficits in

Back 69

perception of person and spatial relationships

Front 70

Right side damage of parietal lobe results in

Back 70

-Left sided neglect/personal neglect/neglect occurs on contralateral side to lesion. (It’s as if that side of the body does not exist)
-Neglect can occur for whole side, regions, or body parts on the contralateral side of the body

Front 71

Hemi-inattention definition

Back 71

ignoring due to a lack of integration of senses with the rest of the body

Front 72

Hemi-inattention examples

Back 72

i. Non-movement of left extremities
ii. Lack of awareness of sensory stimuli
iii. Lack of personal hygiene and grooming
iv. Pt plans movement around the right side of the body

Front 73

Bilateral spatial neglect characteristics

Back 73

-also damage to right parietal lobe.
-Lack of understanding of spatial relationships; pt does not include the left side in anything (painting only on right side of paper as an example)

Front 74

Right sided spatial neglect characteristics

Back 74

occurs as a severe damage of left parietal lobe – must be substantial damage. Survival is unusual.
a. Because right parietal lobe is dominant

Front 75

apraxia definition

Back 75

inability to carry out or regulate a complex or skilled movement when there is no LMN paralysis, no ataxia (loss of coordination), loss of sensory input, and the pt is not confused.
a. Example: “Tie your shoe.” Pt understands what you’ve requested, but cannot carry out task.
b. Cerebral cortex is not processing.

Front 76

apraxia caused by

Back 76

i. Due to a lesion in the premotor and supplemental motor cortexes.
1. When these are not working, the pre-central gyrus does not get correct instructions.

Front 77

agraphia definition

Back 77

inability to write

Not due to LMN paralysis, ataxia, or sensory input

Front 78

Transmissive apraxia definition

Back 78

inability to carry out a sequence of skilled motor movements
i. Supramarginal gyrus in the parietal lobe

Front 79

Agnosia definition

Back 79

: inability to perceive sensations through otherwise normally functioning sensory pathways.
a. Dysfunction in cortex applies to general sensation and special senses.
b. The information is not consciously integrated.

Front 80

Tactile Agnosia (Asterognosis) definition

Back 80

inability to recognize familiar object through touch and proprioception; due to a lesion in the posterior parietal lobe of the dominant hemisphere

Front 81

agnosia- Disturbance of body image characteristics

Back 81

due to a parietal lobe lesion; pt may not recognize their thumb from their pinky finger, they can confuse right and left

Front 82

Depth agnosia definition

Back 82

inability to appreciate depth and thickness of objects due to a lesion in the occipital lobe

Front 83

Movement agnosia definition

Back 83

inability to recognize stationary and moving objects due to a lesion in the occipital lobe.

Front 84

Prosopagnosia definition

Back 84

inability to recognize faces due to a temporal lobe lesion; pt can see the face, but not know who it belongs to until they hear the voice of the face

Front 85

In general, which hemisphere do we consider dominant?

Back 85

Left side

Dominant in most humans because that is the hemisphere that controls language (Broca’s and Wernicke’s) in 90% of the population

Front 86

Cerebral hemispheres connected by:

Back 86

connected via the corpus callosum
ii. Info presented to the left visual field is not perceived because it cannot transfer to the left side dominant language area.
iii. Info presented to the right visual field will be perceived because it is already on the right and does not have to cross.

Front 87

Seizure's effects on corpus callosum

Back 87

i. In seizure pts, the corpus callosum can be split to prevent the hemispheres from communicating.

Front 88

Left hemisphere (characteristics)

Back 88

a. Contains Broca’s and Wernicke’s areas
b. Logical and analytical abilities
c. General math ability
d. Processing large volumes of information
e. Ability to be rational and pragmatic
f. What we think versus what we feel
g. Doing-consciousness – you are aware (or want to be) about what is going on…

Front 89

Right hemisphere (characteristics)

Back 89

a. Geometric spatial orientation
b. Musical perception and skills (singing, playing an instrument)
c. Artistic talent
d. Formation of ideas (non-verbal ideation)
e. Perception and processing of emotions
f. Coordination of sensory information
g. What we feel versus what we think
h. Being conscious of our environment and emotion
i. Prosody- emotions and feelings that go with saying something

Front 90

connectivity definition

Back 90

1. The ability of specific parts of the nervous system to communicate with each other through established pathways and systems of pathways
2. Pathways may involve one or multiple neurons
3. Accounts for how various parts of the NS become involved with functional systems or processes

Front 91

Connectome definition

Back 91

– the highly organized connection matrix of the human brain. Defining how information flows through a complex system to do a complex task
a. Uses Diffusion Tensor Imaging (DTI) (functional MRI) to diagnose communication links
i. Mapping of movement of water in neurons in brain and spinal cord.
ii. Basis of visualization is that water molecules bump into other molecules in the neuron as they diffuse. Measured by MRI

Front 92

Human Connectome Project characteristics

Back 92

Trace and map the major neural pathways that link approximately 500 major regions in the brain, which are the neural substrates for mental processes. Will become the blueprint for the human brain connectivity (connectome)

Front 93

Semioval center of telencephalon definition

Back 93

white matter within cerebral hemispheres; made of cellular processes (myelinated axons and dendrites); extends between the cerebral cortex, basal ganglia, and ventricular system

Front 94

3 types of fibers in the semioval center

Back 94

commissural fibers
association fibers
projection fibers

Front 95

commissural fibers fxn

Back 95

connect corresponding cortical regions of the two hemispheres; crosses midline

Front 96

Corpus callosum characteristics

Back 96

1. ‘Overturned canoe’
2. Largest of the 3 commissures
3. Millions of fibers that are a primary means of communication between right and left hemispheres.

Front 97

Parts of corpus callosum and their connections

Back 97

a. Rostrum: connects frontal lobes
b. Genu: connects frontal lobes.
c. Body: (largest portion) connects frontal and parietal lobes.
d. Splenium: connects temporal and occipital lobes.

Front 98

Anterior commissure characteristics

Back 98

(telencephalon) crosses midline rostrally through the fornix to connect portions of the temporal lobe; part of the olfactory pathway

Front 99

Posterior commissure characteristics

Back 99

(diencephalon) visual reflexes that rely on optical information; interconnects superior calliculi and pretectum of the midbrain [reciprocal pathways].

Front 100

Association fibers definition

Back 100

connect cortical regions in the same hemisphere

Front 101

2 types of association fibers

Back 101

short association fibers (arcuate)

long association fibers

Front 102

Short association fibers: (arcuate) definition

Back 102

not specifically named; arch the floor of each sulcus to connect adjacent gyri (think about nosy neighbors)

Front 103

Long association fibers definition

Back 103

cables, always reciprocal (runs both directions); connect cortical regions in different lobes within the same hemisphere

Front 104

Fasciculus definition

Back 104

named long association fibers that form bundles – Reciprocal structures

Front 105

Uncinate fasciculus connects

Back 105

frontal lobe to temporal lobe

Front 106

Arcuate (Sup Longitudinal) fasciculus connects

Back 106

frontal, temporal, and occipital lobes; major fasciculus that connects Broca’s and Wernicke’s area

Front 107

Cingulum fasciculus characteristics

Back 107

-primary association bundle on medial side of the hemisphere of the brain
-connects parietal, temporal, and frontal lobes
-can be surgically removed to decrease pain.

Front 108

2 association areas deep to the insula

Back 108

external and extreme capsules (white matter structures that contain association fibers)

Front 109

Superficial to deep, association areas from insula

Back 109

insula-> extreme capsule-> claustrum (grey matter, part of the basal ganglia)-> external capsule-> corpus striatum (basla ganglia)-> internal capsule

Front 110

projection fibers characteristics

Back 110

i. Mostly axons that converge on the brainstem
ii. Connect one specific part of the cerebral cortex and another specific part of the CNS [reciprocating];
iii. Afferent and efferent fibers. (Reference point is SC cortex)
1. Afferent – towards cortex
2. Efferent – away from cortex

Front 111

corona radiata definition

Back 111

radiating mass of afferent and efferent fibers b/c everything has to narrow when passing through the brain stem.; contains projection fibers

Front 112

internal capsule definition

Back 112

compact band of projection fibers formed rostrally to midbrain (appears as a white “H” in the corpus striatum in a transverse section of the brain). Contains the anterior limb, the genu, and the posterior limb

Front 113

boundaries of internal capsule

Back 113

flanked medially and laterally by the basal ganglia

Front 114

2 limbs of internal capsule

Back 114

anterior and posterior limb

Front 115

anterior limb of internal capsule characteristics

Back 115

i. Afferent sensory
ii. Partially separates the caudate nucleus and the putamen (both are basal ganglia).
1. Specifically – medially it IS the caudate nucleus of the basal ganglia and laterally it IS the putamen of the basal ganglia
iii. Both afferent and efferent fibers (90% afferent)

Front 116

Thalamocortical projection fibers characteristics

Back 116

originate in the thalamus, pass through anterior limb, and are projected to various parts of the cortex.
b. If damaged, sensation is affected.

Front 117

efferent fibers of anterior limb of internal capsule characteristics

Back 117

a. Remaining 10%
b. Frontopontine; come from frontal lobe (cortex) and travel to pons

Front 118

boundaries of anterior limb of internal capsule

Back 118

1. Medially by the head of the caudate nucleus.
2. Laterally by the putamen.

Front 119

damage to anterior limb of internal capsule causes

Back 119

sensory issues

Front 120

Posterior (motor) limb of internal capsule boundaries

Back 120

1. Medially by the thalamus.
2. Laterally by the globus pallidus

Front 121

organization of internal capsule

Back 121

somatotopically organized

Front 122

fiber make up posterior limb of internal capsule

Back 122

1. Afferent (sensory) are thalamocortical. About 10%
2. Efferent motor fibers: About 80-90% originate from cerebral cortex to nuclear masses in brain, brain stem, and spinal cord) Corticofugal fibers (fugal means just kind of spread out):

Front 123

damage to posterior limb of internal capsule causes

Back 123

Damage to posterior limb: Motor issues; paralysis

Front 124

4 types of corticofugal fibers of posterior limb of internal capsule

Back 124

a. Corticothalamic: go to thalamus.
b. Corticopontine: go to the pons
c. Corticobulbar: motor nuclei of CN of brainstem
d. Corticospinal: to ventral horns of the spinal cord

Front 125

fornix characteristics

Back 125

made up of commissural and projection fibers; connects telencephalon and diencephalon; 2 way reciprocal movement of information

Front 126

fimbria of fornix characteristics

Back 126

i. Formed from the axons of the pyramidal neurons of the hippocampus.
ii. Fibers spread over the ventricles to form the fimbria
iii. Axons proceed forward until they reach the posterior end of the hippocampus.
iv. They then arch beneath the splenium of the corpus callosum where they become the crura of the fornix.

Front 127

Crura (leg) of the Fornix characteristics

Back 127

i. Bilateral structure
ii. Converge and form the body of the fornix.
iii. Between the two converging crura is a thin sheet of tissue called the fornical commissure (hippocampal commissure)

Front 128

Body of the fornix characteristics

Back 128

i. Runs forward under the corpus callosum to the rostral margins of the thalamus
ii. It then bifurcates and forms the two anterior columns of the fornix

Front 129

Anterior columns of the fornix charcteristics

Back 129

i. Arch ventrally;
ii. Half of the fibers descend behind (caudally) the anterior commissure and are called the postcommissural fibers.
1. These fibers terminate in the thalamus and the mammillary bodies of the hypothalamus.
iii. Half of the fibers descend in front (rostral) of the anterior commissure and are called precommissural fibers.
1. These fibers terminate in the thalamus

Front 130

function of the fornix

Back 130

major input/output structure associated with the limbic system [lobe]

Front 131

limbic system definition

Back 131

cortical and subcortical structures which are active with emotions and the visceral (physiological) and behavioral responses associated with those emotions

Front 132

limbic lobe structures

Back 132

a. Hippocampal formation: (temporal lobe)
i. Dentate gyrus
ii. Hippocampal gyrus
iii. Parahippocampal gyrus
b. Amygdaloid nuclear complex: (temporal lobe)
c. Anterior nucleus of thalamus (diencephalon)
d. Hypothalamus (diencephalon)

Front 133

connecting pathways of the limbic system

Back 133

a. Fornix (telencephalon to diencephalon)
b. Stria terminalis: lateral border of diencephalon; reciprocal connection between amygdala and hypothalamus.
c. Mammilothalamic tract: connects mammillary nuclei of hypothalamus and thalamus.

Front 134

ganglia definition

Back 134

a collection of cell bodies outside the CNS

Front 135

corpus striatum components

Back 135

caudate nucleus

lenticular nucleus

Front 136

caudate nucleus structure

Back 136

i. Head, body, and tail:
1. Head lies rostral (front) to thalamus.
2. Body extends along the dorsal lateral border of the thalamus.
a. Stria terminalis: separates the body from the thalamus. Supracelamic structure (Above the thalamus)
3. Tail descends and terminates in an associated with the amygdaloid.

Front 137

lenticular nucleus charcteristics

Back 137

buried in semioval center and surrounded by white matter; in close contact with internal capsule (which separates it from the thalamus)
a. About the size of a walnut
b. Divided into 2 parts (putamen and globus pallidus)

Front 138

Putamen location

Back 138

larger of 2 halves and more lateral; lies between external capsule and the lateral medullary lamina.

Front 139

globus palliduc location

Back 139

medial and smaller; lateral boundary is lateral medullary lamina and medial boundary is posterior limb of the internal capsule.

1. Lateral medullary lamina: seperates putamen from globus pallidus

Front 140

basal ganglia components

Back 140

corpus striatum
amygdaloid nuclear complex
claustrum

Front 141

amygdaloid nuclear complex characteristics

Back 141

oldest (one of the first to develop); in temporal lobe
a. Internal to the uncus;
b. Nuclear structure divided into subnuclear structures.
c. Makes afferent and efferent connections:
i. Hypothalamus
ii. Thalamus
iii. Olfactory regions (reincephalon)
d. Classified as basal ganglia, not part of the extra pyramidal systems

Front 142

amygdaloid nuclear complex involved in

Back 142

Involved with limbic system, memory processing , fear, reward, addictions

Front 143

claustrum characteristics

Back 143

small; gray matter; thin plate that lies between lenticular nucleus and insular cortex.
a. Lateral border is extreme capsule, medial border is external capsule.
b. Not involved with the extrapyramidal system
c. Memory and consciousness processing

Front 144

function of basal ganglia

Back 144

(only extrapyramidal system - corsus striadum)

Principal component of extrapyramidal system responsible for involuntary skeletal muscle contractions.

Front 145

extrapyradmidal system components

Back 145

i. Corpus striatum
1. Caudate nucleus
2. Putamen
3. Globus pallidus
ii. Subthalamus (diencephalon)
iii. Substantia nigra (mesencephalon)
iv. Red nucleus (mesencephalon)

Front 146

Function of the extrapyramidal system

Back 146

i. Controls involuntary muscle activity (in contrast to pyramidal system which controls voluntary activity. They always work together)
ii. Helps inhibits involuntary movement that gets in the way of desired voluntary movement
iii. Helps inhibits co-contraction of antagonistic muscles of the limbs
iv. Adjusts body position appropriately for a given task – involuntary (muscle memory)
v. Subconscious reflexive system
vi. Basil ganglia needs to utilize inhibitory processes
vii. Works in contrast to pyramidal system (voluntary)

Front 147

why will injury to basal ganglia not cause paralysis?

Back 147

-Neurons from the basal ganglia do not project directly into the SC, they project into structures within the brainstem-which then indirectly influence activity in the SC.
-Basal ganglia indirectly influences skeletal muscle; injury will not cause paralysis.

Front 148

categories of basal ganglia damage

Back 148

i. Dyskinesisas: abnormal involuntary movement (Parkinson’s static tremor)
ii. Disturbance of muscle tone: rigidity (hypertonicity), some may show hypotonicity

Front 149

Rhinencephalon characteristics

Back 149

(still a part of the telencephalon): olfactory system. CN I

Front 150

Olfactory bulbs characteristics

Back 150

a. Outgrowth of the brain that lies on the cribriform plate (that is part of the ethmoid bone of the skull).
b. Receives neurons from nasal mucosa (1st order sensory) that synapse with 2nd order sensory neurons in olfactory bulbs.
c. Olfactory nerve/tract is made of the 2nd order sensory neurons
d. 2nd order sensory neurons (cell bodies in the bulb) then travel through the olfactory nerve.

Front 151

olfactory bulbs enter rhinencephalon and bifurcates where?

Back 151

i. Left - Lateral stria- Terminates in the temporal lobe to the uncus of the parahippocampus.
ii. Right - Medial stria- Heads towards anterior perforated substance (which is technically cortex)
iii. Some neurons may desiccate (cross over) may cross over the anterior commissure to go to the uncus

Front 152

smell information processing characteristics

Back 152

-Smell information coming into the right nostril goes to both lobes to be perceived.
-Any general sensation or general sense has to reach cortex
-involved in limbic system

Front 153

only sensation not first processed by thalamus before going to cortex?

Back 153

Smell

Goes DIRECTLY to the cortex. Responds to danger quickly

Front 154

Diencephalon: (2nd vesicle of the forebrain) boundaries

Back 154

a. Between the posterior commissure caudally to the interventricular foramen rostrally
b. Laterally bounded by posterior limb of internal capsule, tail of caudate nucleus, and stria terminalis
c. 3rd ventricle separates the diencephalon into right and left halves, making it a bilateral structure.

Front 155

Epithalamus location

Back 155

most posterior aspect of the diencephalon

Front 156

habenecular trigone characteristics

Back 156

triangle shaped nuclei that belong to the diencephalon; have both afferent and efferent connections to other parts of the brain (i.e., hypothalamus, thalamus, and basal ganglia).
1. These fibers are reciprocating.
2. Connections occur in the stria medullaris.
a. Stria medullaris: Afferent and efferent fibers to Hypothalamus, Thalamus, basal ganglia (amygdala, habenular trigone
3. Function is not clear - Plays a minor role in the limbic system

Front 157

pineal body characteristics

Back 157

(gland) attached to the roof of the 3rd ventricle in the region of the posterior commissure.
1. Between the two Habendular Trigons
2. Plays a major role in the onset of puberty by producing melatonin
3. Pineal body quits functioning once puberty has been triggered and begins to calcify around age 40.
4. Plays a role in circadian rhythm

Front 158

Epithelial Roof of 3rd ventricle definition

Back 158

epithelial lining the roof is the choroid plexus producing CSF

Front 159

largest portion of diencephalon?

Back 159

Thalamus

Front 160

thalamus boundaries

Back 160

1. Ventrally: hypothalamic sulcus.
2. Caudally: level of the posterior commissure and the cerebral aqueduct.
3. Rostrally: interventricular foramen.
4. Dorsally: stria medullaris of epithalamus.
5. Lateral: posterior limb of internal capsule.
6. Medial: helps form lateral wall of 3rd ventricle

Front 161

massa intermedia (interthalamic mass) fxn

Back 161

iv. Thalamus is divided into right and left halves that are connected by the massa intermedia (interthalamic mass) which crosses the 3rd ventricle

Front 162

thalami internally composed of?

Back 162

-numerous nuclei (40-50):
-Nomenclature of the nuclei is complex and inconsistent
-anatomical and functional classification

Front 163

Specific Relay Nuclei (R Nuclei) of thalamus fxn

Back 163

i. Project and receive fibers from well-defined cortical areas related to specific functions.
ii. Receive from ascending tracts such as spinothalamic and dorsal column

Front 164

Association Nuclei (A Nuclei) of thalamus fxn

Back 164

i. Do not receive fibers from ascending systems but project to association areas of brain

Front 165

Subcortical Nuclei (SC Nuclei) of thalamus fxn

Back 165

i. Project to subcortical areas (basal ganglia, red nucleus, etc)

Front 166

Diffuse Cortical Connection Nuclei (DC) of thalamus fxn

Back 166

i. Relays to various areas of the cortex
ii. Destinations not as specific as R Nuclei

Front 167

most common nuclei of thalamus

Back 167

4. R and A nuclei most common

Front 168

Pulvinar Nucleus characterisitics

Back 168

a. Anatomically, it belongs to the lateral nuclear group.
i. Functionally, it is an R (relay) nucleus.
ii. Very large
iii. It has two smaller nuclei: medial and lateral geniculate bodies

Front 169

Medial geniculate body characteristics

Back 169

a. R-type nucleus
b. Involved with perception of hearing and auditory reflexes

Front 170

Lateral geniculate body characteristics

Back 170

a. R-type nucleus
b. Involved with perception of vision and visual reflexes

Front 171

vii. General functions of the Thalamus:

Back 171

1. Great relay station of the brain.
2. Plays a dominant role in the maintenance and regulation of consciousness, alertness, and attention
3. Is involved with subcortical perception of pain and temperature
4. Some of the nuclei may serve as integrative areas for motor function (i.e., pain and the reflexive increase in muscle tone).
5. The thalamus is not purely a sensory structure as once thought.

Front 172

Thalamus, great relay station of the brain characteristics

Back 172

a. All sensory information (except olfaction) is processed by the nuclei of the thalamus
b. Includes all internal and external stimuli
c. Can have secondary input back to the olfactory cortex.
d. The thalamus processes sensory information and sends to appropriate areas via projection fibers (thalamocortical fibers: corona radiata and internal capsule).
e. Primary sensory intergrating structure of the brain

Front 173

thalamus involvement with subcortical perception of pain and temperature

Back 173

a. Post central gyrus allows you to discriminate where pain is coming from and what kind of pain it is.
b. The thalamus is where the actual appreciation of pain is.

Front 174

hypothalamus boundaries

Back 174

1. Lies ventral to the hypothalamic sulcus.
2. Lies beneath the thalamus.
3. Extends from the region of the optic chiasm to the caudal borders of the mammillary bodies.

Front 175

supraoptic Region (anterior hypothalamus) characteristics

Back 175

a. Located just btwn the optic chiasm & the 3rd ventricle
b. Contains two distinct nuclei which project to the posterior lobe (neurohypophysis) of the pituitary gland
i. paraventricular nucleus
ii. supraoptic nucleus
c. Controlling seat of the PARASYMPATHETIC NS
d. Has one not distinct nucleus which receives direct projections from the retina. Note relationship from eye to hypothalamus visual stimulation can stimulate visceral responses such as nausea

Front 176

Preoptic Region (medial hypothalamus) characteristics

Back 176

a. Superior to the supraoptic region
b. Contains 3 nuclei
i. Preoptic periventricular nucleus most important
c. Involved with the PARASYMPATHETIC NS

Front 177

Tuberal Region (middle hypothalamus) characteristics

Back 177

a. In the middle
b. Largest
c. Contains 4 nuclei
d. Involved with the SYMPATHETIC NS
e. In this region the fornix is passing through on its way to terminate with the mammillary bodies

Front 178

Mammillary Region (caudal hypothalamus) characteristics

Back 178

a. Most caudal aspect of the hypothalamus
b. Contains the two prominent MAMMILLARY BODIES (Nuclei)
c. Recall the fornix terminates by synapsing with these nuclei (receives fibers from fornix)
d. Where fornix terminates (connects to limbic system)

Front 179

hypothalamus connections

Back 179

extensive afferent & efferent connections
1. The connections are usually reciprocal
2. Prominent areas
a. Reticular formation
b. amygdaloid nuclear complex
c. Hippocampal formation
d. Fornix
e. Retina
f. Olfactory regions

Front 180

hypothalamus fxn in general

Back 180

involved with visceral, autonomic, and endocrine

Front 181

hypothalamus fxns

Back 181

-Controls the activity of the ADENOHYPOPHYSIS (anterior lobe) and neurohpophysis (posterior lobe) of pituitary gland
-Synthesizes hormones which are stored in the NEUROHYPOPHYSIS (posterior lobe)
-Involved with the supraspinal control of the ANS
-Involved with
1. Thirst & water uptake
2. Temperature regulation
3. Hunger
4. Emotional states (rage, hate, aggression)
5. Libido

Front 182

hypothalamus controls anterior lobe of pituitary gland by

Back 182

synthesizing RELEASING FACTORS (RF)

For every hormone released in the pituitary, there are releasing factors from the hypothalamus

Front 183

Releasing factors (RF) journey to anterior pituitary gland characteristics

Back 183

RF reach the anterior lobe via the infundibulum (connected hypothalamus to pituitary gland)
i. Infundibulum contains the axons of the neurons in the hypothalamus which synthesize the RF
ii. The RF are picked up by capillaries of the cardiovascular system located in the infundibulum (pituitary portal system): normal cardiovascular system to the hypothalamus
iii. They are carried to the anterior lobe via the capillaries and then leave & enter the anterior lobe tissue

Front 184

fxn of releasing factors (RF)

Back 184

stimulate synthesis & secretion of hormones from the anterior lobe into the cardiovascular system

Front 185

8 major hormones that are synthesized & released from the anterior lobe and go to cardiovascular system to stimulate target organs to release their hormones

Back 185

i. thyrotrophic hormone
ii. growth hormone
iii. prolactin
iv. Lutenizing
v. Melatonin
vi. Follicle stimulating
vii. Glandotrophic (male & female)
viii. ardenocorticotrophic

Front 186

anterior lobe of pituitary gland characteristics

Back 186

-Controls the endocrine system
-Anterior lobe of pituitary is under CHEMICAL CONTROL not neurological
-Called the “master gland” of the body
-synthesizes and releases hormones to CV system

Front 187

hormones stored in NEUROHYPOPHYSIS (posterior lobe) of pituitary gland characteristics

Back 187

1. Hormones are synthesized by neurons located in the preoptic & supraoptic regions
2. They are transported to the posterior lobe by the axons of the same neurons which synthesized them via axonal transport system
3. Axons are in the infundibulum
4. Hormones are stored in the posterior lobe
5. Upon neurological stimulation from the same neurons which synthesized them, they are released into the cardiovascular system
6. Under neurological control ( bc action potentials tell it when to release hormones)

Front 188

2 hormones involved in NEUROHYPOPHYSIS (posterior lobe) of pituitary gland

Back 188

a. Oxytocin: causes smooth muscle cells to contract during “birthing” and emotions like love, affection, bonding
b. Vasopressin:
i. Vasoconstrictor (raises BP)
ii. Antidiuretic

Front 189

Sympathetic system is influenced by what portion of hypothalamus?

Back 189

TUBERAL portion

Front 190

Parasympathetic system is influenced by what portion of hypothalamus?

Back 190

PREOPTIC & SUPRAOPTIC regions

Front 191

Subthalamic Region location

Back 191

i. Ventral to the thalamus
ii. Medial to the internal capsule & lateral & caudal to the hypothalamus

Front 192

subthalamic region contents

Back 192

1. Several distinct nuclei
2. Subthalamic nucleus, zona incerta, nuclei of the tegmental fields of forel
3. Has extensive afferent & efferent connections
4. Functionally they are involved with MOTOR INTEGRATION ACTIVITIES (Part of the extrapyrimidal system)

Front 193

Extensive afferent and efferent connections of subthalamic region characteristics

Back 193

a. Most important is the PALLIDOSUBTHALAMIC FIBERS from the globus pallidus (afferent)
b. Other afferent & efferent are associated with the substania nigra, tegmentum, & cortex

Front 194

clinical significance of subthalamus

Back 194

1. Destruction of the subthalamus nucleus will result in hemballism
a. Violent, forceful, involuntary, movements of the extremities on the contralateral side of the lesion. More violent than choreoid like movements
b. Usually follows bleeding events

Front 195

Optic Nerves (CNII) characteristics

Back 195

i. Embryonically they are outgrowths of the diencephalon
ii. Thus they are not true nerves but tracts of the brain (neurons are outside the brain)

Front 196

2 parts of midbrain (mesencephalon)

Back 196

a. Dorsal surface: tectum or quadrigeminal plate
b. Ventral portion: cerebral peduncle

Front 197

Tectum (Quadrigeminal Plate): Dorsal Aspect made up of

Back 197

a. Made of 4 rounded swellings called colliculi

Front 198

inferior colliculi characteristics

Back 198

i. Two nuclei and within brain (so include cell bodies of neurons)
ii. Part of auditory pathway and auditory reflexes
iii. Relay auditory information to medial geniculate body of pulvinar nucleus of the thalamus. Thalamus receives sensory info to send to cortex so we can hear.
iv. R/L Brachium of inferior colliculi: lateral structure, contains neurons from inferior colliculi to medial geniculate body

Front 199

superior colliculi characteristics

Back 199

i. Two Nuclei and within brain
ii. Involved with visual pathway and visual reflexes
iii. Relay visual info to lateral geniculate body of thalamus
iv. R/L Brachium of superior colliculi: contain neurons for communication btwn superior colliculi and Lateral Geniculate body

Front 200

Tectum forms roof of

Back 200

cerebral aqueduct

Front 201

sensory nuclei characteristics

Back 201

o Cell bodies of the initial sensory neurons (1st order) are located in various ganglia of the head & neck
o the cell bodies of the 2nd order sensory neurons are located in the sensory nuclei of the brain stem
o 1st order & 2nd order synapse somewhere in the sensory nucleus

Front 202

motor nuclei characteristics

Back 202

o Contain cell bodies of the LMN (alpha & gamma motor neurons) which are going to exit via cranial nerves & innervate skeletal muscle fibers (extrafusal)

Front 203

Cerebral Peduncles: (Ventral Structures) 3 major parts

Back 203

i. Crus Cerebri: (Part of the peduncle! Don’t mix up w Cerebral penduncle!)
ii. Tegmentum
iii. Substantia Nigra

Front 204

Tegmentum characteristics

Back 204

1. Most dorsal portion of peduncle
2. Continuous elongated mass of gray matter extending from upper midbrain caudally through pons and medulla
3. Contains CN nuclei and ascending sensory systems
4. Forms floor of cerebral aqueduct

Front 205

Tegmentum of Cerebral Peduncle: Structures

Back 205

i. Motor nucleus of trochlear nerve (IV)
ii. Tegmental Nuclei:
iii. Mesencephalic Nucleus (V)
iv. Oculomotor Nuclear Complex (III)
v. Edinger-Westphal Nucleus (CN 3)
vi. Red Nucleus
vii. Reticular Formation
viii. Decussation of Superior Cerebellar Peduncles
ix. Lateral lemniscus
x. Trigeminal lemniscus
xi. Medial Lemniscus
xii. Spinal Lemniscus
xiii. Medial longitudinal fasciculus (MLF

Front 206

i. Motor nucleus of trochlear nerve (IV) characteristics

Back 206

1. Located in tegmentum
2. Innervates superior oblique extrinsic eye muscle

Front 207

tegmental nuclei characteristics

Back 207

1. Small diffuse nuclei that surround cerebral aqueduct
2. Part of limbic system communication

Front 208

mesencephalic nucleus characteristics

Back 208

1. Sensory nucleus that technically belong to CN 5 (trigeminal)
2. Located in caudal midbrain and rostral pons
a. Two parts of brainstem
3. Involved with proprioceptive pathway of muscles of mastication (head and neck)
a. Receives sensory input from muscle spindles

Front 209

mesencephalic nucleus exception to the rule

Back 209

this nucleus contains the cell bodies of 1st order sensory neurons
5. Only cranial sensory cell bodies 1st order all from NS, normally ganglia

Front 210

iv. Oculomotor Nuclear Complex (III) characteristics

Back 210

1. Several nuclear structures within it
2. Each extrinsic eye muscle innervated by CN III has own nucleus.
3. Innervates 4 of the 6 extrinsic eye muscles
4. Innervates levator palpebral superioris- eyelid muscle
a. Also has own nucleus in complex

Front 211

4 of the 6 extrinsic eye muscles the Oculomotor Nuclear Complex (III) innervates

Back 211

a. Inferior oblique
b. Medial rectus
c. Superior rectus
d. Inferior rectus

Front 212

v. Edinger-Westphal Nucleus (CN 3) characteristics

Back 212

1. Belongs to CN III
2. Parasympathetic motor nucleus
3. Contains cell bodies of pre-ganglionic parasympathetic neurons
4. 2 neuron pathway: pre communicate with postganglionic neurons
5. Fxns (next slide)

Front 213

v. Edinger-Westphal Nucleus (CN 3) fxns

Back 213

a. Causes pupilla sphincter muscle constriction: part of iris
i. Miosis: pupil smaller
b. Innervates ciliary body: surrounds lens of eye
i. Causes shape of lens to change- accommodation
ii. You lose the elasticity of the ciliary body as you age. Results in people squinting, which changes the shape of the lens

Front 214

vi. Red Nucleus characteristics

Back 214

1. Most conspicuous structure in midbrain
2. Encapsulated by connective tissue
3. Histologically: oval column of cells, tube runs up and down
a. Starts level superior colliculi, extends up into diencephalon
4. Functionally part of extrapyramidal system
5. In the midbrain
6. Communicates with structures as part of extrapyramidal

Front 215

Red Nucleus Communicates with these structures as part of extrapyramidal

Back 215

a. Cerebellum
b. Cerebral Cortex
c. Basal ganglia
d. Spinal cord

Front 216

damage to red nucleus causes

Back 216

7. If damaged causes various forms of involuntary skeletal muscle activity

Front 217

vii. Reticular Formation characteristics

Back 217

1. In tegmentum of brainstem
2. Made up of diffuse small nuclei
3. Communicates with ascending sensory pathways and descending motor pathways
4. Deals with sleep, consciousness, alertness, arousal, pain inhibition, Limbic activity, refinement of motor activity

Front 218

viii. Decussation of Superior Cerebellar Peduncles characteristics

Back 218

1. Three sets of peduncles that attach cerebellum to brain stem
a. Superior Peduncles: attach cerebellum to midbrain
b. Middle: attach to pons
c. Inferior attach to medulla
2. Peduncles have information that cross over in the tegmentum of midbrain (R cerebellar fibers go through the peduncle to the L side, vice versa)

Front 219

ix. Lateral lemniscus characteristics

Back 219

(collection of axons-ascending) – lemniscus is a band of fibers
1. Part of ascending sensory pathway- auditory pathway
2. Contains 2nd and 3rd order sensory neurons of the auditory pathway

Front 220

x. Trigeminal lemniscus characteristics

Back 220

- ascending
1. Part of ascending general sensation pathway of head and neck
2. Contains 2nd order sensory neurons associated with trigeminal n (CN5)

Front 221

xi. Medial Lemniscus

Back 221

ascending (Part of midbrain, pons, and medulla tegmentum)
1. Contains 2nd order sensory neurons of the ascending dorsal column pathway
a. Nuclear structures in the medulla w the cell bodies
i. Nucleus cuneatus and nucleus gracillus
2. Synapses w 3rd order in the thalamus
3. Involved with conscious proprioception, fine touch, 2 pt discrimination, discriminative touch—part of pathway of which this involve will ascend

Front 222

Spinal leminiscus characteristics

Back 222

ascending
1. Collection of 2nd order sensory neurons of the Spinothalamic pathway
2. Involved in pain, temp, crude touch conduction

Front 223

xiii. Medial longitudinal fasciculus (MLF) characteristics

Back 223

Ascending sensory pathways of controlling eyeball movement
2. Descending pathways involved with equilibrium reflexes
a. 3 major descending pathways (next slide)

Front 224

3 major descending pathways of medial longitudinal fasciculus

Back 224

i. Tectospinal tract:
ii. Reticulospinal Pathway
iii. Medial vestibulospinal tract

Front 225

tectospinal tract characteristics

Back 225

tectum of midbrain descends through MLF toward spinal cord
1. Auditory and visual reflexes

Front 226

reticulospinal pathway characteristics

Back 226

reticular formation through spinal cord
1. Motor activities

Front 227

Medial vestibulospinal tract characteristics

Back 227

vestibular system toward spinal cord
1. Skeletal muscle reflexes

Front 228

d. Substantia Nigra of Cerebral Peduncle characteristics

Back 228

i. Gray matter (cell bodies of neurons), located btw crus cerebri and tegmentum
ii. Extends full length of midbrain
iii. Part of extrapyramidal system- involved w/ involuntary skeletal muscle activity
1. Primarily, communicates with basal ganglia (dopamine transported to basal ganglia through projection neurons)

Front 229

e. Crus cerebri of cerebral peduncle characteristics

Back 229

i. Most ventral portion of peduncle
ii. Contains corticofugal fibers (UMN) thus motor structure. Synapse w many things
iii. If Synapse with LMN, synapses at brain stem (motor nuclei) or ventral horns of spinal cord.

Front 230

e. Crus cerebri of cerebral peduncle organization

Back 230

iv. Somatotopically organized, collectively called corticofugal (all UMN)
1. Lateral, middle, and medial third. Middle part is also divided into three.

Front 231

2. Somatotopic organization of middle 3rd of crus cerebri:

Back 231

a. Lateral 3rd of middle 3rd- corticofugal/corticospinal tract going to LMN of skeletal muscle of lower extremities ; form corticospinal tract
b. Middle 3rd of middle 3rd: corticospinal fibers on way to LMN innervate skeletal muscle of upper extremities ; part of corticospinal tract
c. Medial 3rd of middle 3rd: corticobulbar fibers on way to motor nuclei of cranial nerves w/ motor functions; skeletal muscles of head and neck

Front 232

3. Lateral 3rd of crus cerebri connections

Back 232

a. Occipital pontine fibers: occipital lobe to pons
b. Temporal pontine fibers: temporal lobe to pons

Front 233

4. Medial 3rd of crus cerebri connection

Back 233

Frontopontine fibers, frontal lobe to pons

Front 234

Anatomy of pons

Back 234

1. Middle portion of brain stem
2. most rostral part of the hindbrain
3. ventral surface has horizontal striations
4. attached indirectly to the cerebellum by the middle cerebellar peduncles
5. separated from the medulla by the Inferior Pontine Sulcus
6. separated from the midbrain by the Superior Pontine Sulcus
7. on ventral surface, right on midline, is the basilar sulcus (which contains the basilar artery)
8. between the dorsal surfaces of the pons & cerebellum is the 4th ventricle

Front 235

2 parts of the pons

Back 235

1. Dorsal Pons (tegmentum) smaller
2. Ventral Pons (pons proper) larger – has the transverse fibers

Front 236

3 types of things found in Dorsal Pons: Tegmentum (as it passes through the pons)

Back 236

-ascending sensory pathways (same as midbrain)
-pontine reticular nuclei
-cranial nerve nuclei- V, VI, VII, VIII (III, VII, IX,X CNs that have parasympathetic functions – associated w motor nuclei)

Front 237

b. Pontine Reticular Nuclei characteristics

Back 237

(formation)(arousal, sleep)
i. Contains diffuse small, nuclear structures, see midbrain

Front 238

i. facial motor nucleus (VII) fxn

Back 238

1. Muscles of facial expression

Front 239

ii. salivatory nuclei (VII & IX) characteristics

Back 239

superior is in the pons, and inferior is in salivatory nuclei (in superior portion of medulla)
2. innervates sublingual, mucus, lacrimal, & submadibular glands
3. motor nucleus – efferent response
4. contains cell bodies of preganglionic parasympathetic nerves

Front 240

iii. solitary nucleus (VII, IX, &X) characteristics

Back 240

1. located in tegmentum of the medulla
2. involved with sensory function: taste innervation for anterior 2/3 of the tongue, CN VII

Front 241

iv. spinal nucleus of V (V, VII, IX, &X) characteristics

Back 241

1. located in both pons & mostly the medulla (at the transition)
2. sensory function: involved with pain, temperature, pressure, & crude touch (CN V)
3. sensory function: pain, temperature, pressure, & crude touch in a small area behind the external ear (CN VII)

Front 242

v. motor nucleus of the trigeminal nerve (V) characteristics

Back 242

1. Trigeminal: motor and sensory
a. involved with perceiving general sensations from the face, head, & neck
b. innervates muscles of mastication
c. uses 3 nerves: opthalmic (V-1), maxillary (V-2), & mandibular (V-3) only one that is mixed

Front 243

vi. mesencephalic nucleus of V characteristics

Back 243

1. sensory nucleus which receives proprioceptive information of head &neck
2. contains 1st order sensory neurons
3. Located in midbrain

Front 244

vii. chief sensory nucleus of V (V, VII, IX, & X) characteristics

Back 244

1. involved with discrimination of fine touch (2pt. discrimination)

Front 245

viii. Abducent Motor Nucleus (VI) characteristics

Back 245

1. innervates lateral rectus extrinisic eye muscle
2. strictly motor
3. Located in tegmentum of pons

Front 246

ix. Vestibulocochlear Nerve (VIII) characteristics

Back 246

1. Cochlear involved with perception of hearing
a. originated in cochlea of inner ear
b. where we find the dorsal & ventral cochlear nucleus
c. involved with equilibrium

Front 247

x. Vestibular Nuclei (VIII) characteristics

Back 247

1. Vestibular nerve
a. involved with equilibrium
b. comes from semicircular canals of the inner ear
c. communicated with vestibular nuclei located in the tegmentum of the pons

Front 248

iv. Pons Proper (ventral pons) components

Back 248

1. Pontine nuclei (very small & numerous)- give pons striated appearance
2. Transverse Fibers (originate with pontine nuclei)
3. Longitudinal Fibers

Front 249

Transverse Fibers (originate with pontine nuclei) of ventral pons characteristics

Back 249

a. Take information into the cerebellum from the pons
b. When an UMN goes through the pons on their way to the SC, the UMNs send off collateral neurons. These collateral processes synapse with the transverse fibers, and then the signal travels into the cerebellum
c. Communicate with pontine nuclei
d. Both give rise to the middle cerebellar peduncles:
i. superficial transverse fibers:
ii. deep transverse fibers

Front 250

Longitudinal fibers of ventral pons characteristics

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a. in between superficial & deep transverse fibers
b. two major groups of fibers
i. corticospinal tract: made up of UMN, they are on their way to the central horns of the SC on the contralateral side.
ii. corticobulbar tract: follows the same pathway as the corticospnal tract, synapse w/ LMN cell bodies in the brain stem with motor nuclei of CNs.
c. UMN that synapse with LMN in motor nuclei of cranial nerves

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General functions of the pons

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1. relay station btw the midbrain & the medulla (acts like bridge)
2. allows cerebellum to communicate with/coordinate the influences of the cerebrum (Middle cerebellar peduncle)
3. very important with functions of reticular formation (having to do with sleep, arousal, alertness, circadian rhythms, consciousness, etc)
4. involved with cranial nerve activity
5. secondary respiratory system
6. primary sleep center

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2. Cerebellum (metencephalon of rhombencephalon) location and appearance

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a. has a laminated, layered appearance
i. each of the folds are called folia
b. overlies the posterior aspect of the pons & medulla
c. sits in posterior cranial fossa
d. covered and protected superiorly by tentorium cerebelli
e. right & left hemispheres separated by the falx cerebelli
f. right & left hemispheres connected by the vermis

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g. Cerebellar connections to the brains stem:

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connections to the brains stem:
i. superior peduncle (to midbrain) is predominately an efferent structure of the cerebellum (sends out cerebellar messages)
ii. middle (to pons) & inferior (to medulla) peduncles are predominately afferent structures (take info into the cerebellum)

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3 lobes of cerebellum

Back 254

i. Anterior Lobe (spinocerebellum/paleocerebellum)
ii. Posterior Lobe (middle lobe/pontocerebellum & neocerebellum)
iii. Flocculonodular Lobe (archicerebellum)

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i. Anterior Lobe (spinocerebellum/paleocerebellum) fxns

Back 255

1. Muscle tone maintenance (hypotonia)
2. Maintenance of posture
3. gross voluntary movement (gait)

Front 256

ii. Posterior Lobe (middle lobe/pontocerebellum & neocerebellum) characteristics

Back 256

1. coordination of fine voluntary movements
2. damage: ataxia & intentional tremor
3. largest of three cerebellar lobes

Front 257

iii. Flocculonodular Lobe (archicerebellum) fxn

Back 257

maintenance of equilibrium

Front 258

Damage to cerebellum causes

Back 258

-Fibers don’t project directly from the cerebellum to the spinal cord, therefore if the cerebellum is damaged, the person won’t be paralyzed
-Influences everything indirectly.

Front 259

j. Cerebellar Cortex - Gray matter 3 layers

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i. 5 types of cells
ii. 3 Layers (superficial to deep)
1. Molecular
2. perkinje layer
3. granular layer

Front 260

k. Cerebellar cortex - White Matter- deep cerebellar nuclei (medial to lateral) – bilateral structures

Back 260

1. Fastigal-equilibrium
2. globose
3. emboliform
4. dentate nuclei – most lateral

Front 261

information travels from cortex to nuclei characteristics

Back 261

1. Afferent cerebellar input
a. Primarily via middle and inferior peduncles
2. Cerebellar cortex (Gets here via primary afferent peduncles- Middle and inferior cerebellar peduncles). Then sends info to..
3. Deep cerebellar nuclei
a. Make decisions – send efferent cerebellar output via efferent cerebellar peduncle

Front 262

b. To carry out functions, Cerebellum needs

Back 262

i. Constant proprioceptive info (position sense from mm spindles)
ii. equilibrium info (from semi-circular canals)
iii. muscle tone
iv. skeletal muscle activity
1. from corticospinal and corticobulbar

Front 263

4. Efferent cerebellar peduncle- Superior cerebellar peduncle characteristics

Back 263

i. Most dominate 80-90% of information from cerebellar nuclei passes through to leave cerebellum
1. Remember all peduncles are mixed
ii. Most of this efferent info goes to red nucleus in midbrain
iii. All of this info is coming from 3 of the 4 deep cerebellar nuclei
1. Dentenate, globose, emboliform
iv. Red nucleus involved w motor tone, influences skeletal mm

Front 264

b. Fastigial efferent connections (Not part of superior peduncle) characteristics

Back 264

i. Used by fastigial nuclei
ii. Group of neurons located below superior cerebellar peduncle
iii. Fastigial efferent neurons project to vestbular nuclei in pons
1. Involved w equilibrium issues

Front 265

Information flow in cerebellum in a nutshell

Back 265

l. All this information enters cerebellum through two peduncles, cortex makes decisions, deep cerebellar nuclei makes decisions then pedulcles send info.

Front 266

Medulla Oblongata anatomy

Back 266

i. Most caudal portion of brain stem
ii. Rostral continuation of spinal cord
1. No anatomical start and stop point: anything above magnum foramen is medulla
iii. Forms part of floor of 4th ventricle
iv. Divided into columns by anterior and posterior median fissures
v. Obex: On the dorsal aspect it is a V-shaped structure formed where the 4th ventricle narrows into the central canal of the spinal cord.
vi. Anterolateral Sulcus: marks the lateral limits of the Pyramids

Front 267

4 of the cranial nerves associated with medulla in anterolateral sulcus

Back 267

1. Glossopharyngeal (IX)
2. Vagus (X)
3. Spinal Accessory (XI)
4. Hypoglossal (XII)

Front 268

contents of the medulla

Back 268

1. Cranial Nerve Nuclei
2. Nucleus Gracilis and Nucleus Cuneatus
3. Ascending sensory tracts
4. Descending Motor Tracts

Front 269

a. Spinal Nucleus of V characteristics

Back 269

i. Sensory nucleus, which belongs to Trigeminal Nerve but descends from pons into the medulla. Shared by fourt cranial nerves which have general sensation capabilities.
1. Trigeminal (V)
2. Facial (VII)
3. Glossopharyngeal (IX)
4. Vagus (X)

Front 270

b. Inferior Salivatory Nucleus characteristics

Back 270

i. Motor nucleus of parasympathetic system shared by Facial nerve (VII) and Glossopharyngela (IX)
ii. Contains preganglionic parasympathetic neurons involved with innervating salivary and mucus glands

Front 271

c. Nucleus Ambiguus characteristics

Back 271

i. Motor nucleus
ii. Contains cell bodies of LMN involved with innervation of pharynx, larynx, and soft palate.
iii. Three cranial nerves share this nucleus:
1. Glossopharyngeal (IX)
2. Vagus (X)
3. Spinal Accessory (XI)

Front 272

d. Dorsal Motor Nucleus characteristics

Back 272

i. Motor nucleus belongs to Vagus Nerve (X)
ii. Contains cell bodies of preganglionic parasympathetic neurons involved with innervating visceral structures (those with smooth muscle) of thorax, abdomen, and pelvis
1. Lungs, GI, gallbladder, etc.

Front 273

e. Hypoglossal motor nucleus characteristics

Back 273

i. Motor nucleus associated with hypoglossal nerve (XII).
ii. Contains cell bodies of LMN involved with innervating the intrinsic and extrinsic muscles of the tongue

Front 274

f. Solitary Nucleus characteristics

Back 274

i. Sensory nucleus involved with taste utilizing CN VII, IX, and X.
1. See early notes (VIII ant. 2/3 of tongue for taste; IX posterior 1/3 of tongue for taste

Front 275

2. Nucleus Gracilis and Nucleus Cuneatus characteristics

Back 275

a. Pass through pons and tegementum as medial lemniscus
i. Tegmentum of medulla is where 2nd order sensory neurons located.
b. Bilateral nuclei, located in inferior medulla, which contain cell bodies of 2nd order sensory neurons which form medial lemnisci
c. Part of conscious proprioception pathway (dorsal column)

Front 276

3. Ascending sensory tracts of medulla characteristics

Back 276

a. All ascending tracts originating in spinal cord and those which originate in medulla pass through the tegmentum of the medulla

Front 277

v. Anterior and Posterior Spinocerebellar Tracts fxn

Back 277

1. bring unconscious proprioception to cerebellum (conversely to dorsal column pathway which involves conscious proprioception)
2. spinal cord to cerebellum
3. what info do they conduct: proprioception (body position sense)

Front 278

Descending Motor Tracts of medulla characteristics

Back 278

a. All descending motor tracts going to the spinal cord and the medulla or pass through medulla. Thus, they may stop at midbrain, pons, or medulla. Major ones previously discussed in relation to Pons and Midbrain

Front 279

corticospinal descending motor tract characteristics

Back 279

1. Begins at precentral gyrus of cortex with UMN
2. Pons: longitudinal fibers
3. Passes through medulla on way to ventral horns of spinal cord

Front 280

Corticobulbar descending motor tract characteristics

Back 280

UMN descend enter brain stem and stop at some point at a motor nucleus

Front 281

iii. Rubrospinal descending motor tract characteristics

Back 281

1. Red nuclei into ventral horns of spinal cord
2. Involved with skeletal muscle activity

Front 282

reticospinal descending motor tract characteristics

Back 282

1. Has both motor and sensory function
2. Mainly motor
3. Neurons from reticular formation of brain stem
a. Reticular formation is in Midbrain, pons, and medulla
4. Descend into spinal cord

Front 283

5. Corticospinal Decussation happens where?

Back 283

a. R/L Corticospinal tract decussation occurs at pyramids in medulla (ventral surface

Front 284

6. Decussation of Medial Lemniscus happens where?

Back 284

a. Where 2nd order sensory neurons originating from Nuclei Cuneatus and Nuclei Gracilis decussate and form medial lemniscus which ascends

Front 285

7. Medullary reticular formation characteristics

Back 285

a. Small diffuse nuclei full length of brainstem
b. Part of overall reticular formation associated with tegmentum of brain stem

Front 286

8. Inferior Cerebellar Peduncle characteristics

Back 286

a. Structure which attaches the cerebellum to the brain stem. Contains both afferent and efferent fibers

Front 287

9. Inferior Olivary Nuclear Complex characteristics

Back 287

a. Large nuclear complex involved with cerebellar coordination activites.
b. Contains both afferent and efferent fibers

Front 288

10. Specific Areas within the Medulla are involved with regulation of major physiological activities to include

Back 288

a. Respiratory center: instigates phrenic nerves to control diaphragm
b. Cardiovascular Center: controls heart rate and blood pressure
i. Receives info from multiple system including endocrine system
c. Vomiting: reverse peristalisis