Part 2 - Olfactory Limbic Hypothalamus Thalamus

Front 1

olfactory pathway

Back 1

- olfactory nerves through cribriform plate to mitral cells in olfactory bulb to anterior olfactory nucleus (AON) to medial olfactory stria and lateral olfactory stria to primary olfactory cortex and amygdala

Front 2

olfactory cortex components and projections

Back 2

components:

- pyriform lobe

- entorhinal cortex (parahippocampal gyrus)

projections:

- primary olfactory cortex and amygdala to dorsomedial thalamic nucleus to orbitofrontal cortex

Front 3

anosmia

Back 3

- loss of sense of smell

- early sign of neuropathological disease

Front 4

Kallmann syndrome

Back 4

- lack of sense of smell and reproductive function

Front 5

limbic system function, clinical application, components

Back 5

- involved in emotions and memory

- plays a part in: schizophrenia, autism, anxiety disorders, dementias

- components: limbic lobe (cingulate, subcallosal, parahippocampal gyri); subcortical centers (amygdala, septal nuclei, basal forebrain); diencephalic nuclei (anterior thalamus, mammillary bodies)

Front 6

cingulate cortex

Back 6

- cingulum (fiber bundle) sends info to parahippocampal gyrus

- mediates interactions of cognition and emotion associated with empathy, conflict resolution, decision-making

- role in chronic pain syndromes

Front 7

hippocampus regions

Back 7

- 3-layered cortex, 3 regions

- dentate gyrus = major input for hippocampus

- hippocampus proper = input from dentate, entorhinal cortex, septum

- subiculum = major output zone; contains fimbria that forms the fornix

- fornix = to septum via precommissural fornix; to mammillary bodies and anterior nucleus of thalamus via postcommissural fornix

Front 8

hippocampus function

Back 8

- convers short-term memories into long-term memories

- lesions = anterograde amnesia

Front 9

Papez circuit

Back 9

- oversimplification, but:

- cingulate cortex to hippocampus to mammillary bodies to anterior thalamus to cingulate cortex

Front 10

Korsakoff syndrome

Back 10

- caused by thiamine deficiency in alcoholism

- memory deficits, confabulation, confusion

- affects mammillary bodies, anterior and dorsal medial thalamic nuclei

Front 11

septum

Back 11

- labels sensory stimuli as pleasurable or positive

- optiate and dopamine receptors found here

- send info to hippocampus via the fornix

- lesion = produce hyperemotional states and impaired learning, esp perseveration (repetition of incorrect response)

Front 12

amygdala

Back 12

- focuses attention

- labels stimuli as negative/harmful

- receives direct olfactory information

Front 13

Kluver-Bucy syndrome

Back 13

- associated with amygdala

- tameness, hyperoral, hypersexual behaviors

- psychic blindness (agnosia)

Front 14

Urbach-Wiethe syndrome

Back 14

- bilateral lesions of amygdala

- can't read emotions of others

- does not exhibit fear to dangerous situations

Front 15

nucleus accumbens

Back 15

- location: ventral striatum, @ junction of cuadate and putamen

- role in drug and alcohol addiction

Front 16

basal forebrain

Back 16

- location: ventral to anterior commissure

- nucleus basalis of Meynert = cholinergic = basis of dementia

Front 17

hypothalamus

3 functions and locations affected

Back 17

- regulates/coordinates autonomic, behavioral, endocrine responses

- autonomic = brainstem, spinal cord

- behavioral = cerebral cortex, hippocampus, amygdala

- endocrine = pituitary

Front 18

hypothalamus pituitary gland connections

Back 18

1. hypothalamo-neurohypophysial tract

- posterior lobe of pituitary

2. tuberhypophysial tract

- orginates in arcuate nucleus

- stress response pathway

- hypophysial portal system (capillaries)

- anterior lobe of pituitary

Front 19

parasympathetic control of ANS

- structures

- input

- output

- function

- clinical significance

Back 19

- structures: anterior, medial hypothalamus

- input: autonomic brainstem, amygdala, cerebral cortex, viscerosomatic center, insula

- output: vagus nerve, sacral parasympathetic innervation

- function: parasympathetic control

- clinical: decrease HR, increase vasodilation, increase GI

Front 20

sympathetic control of ANS

- structures

- input

- output

- function

- clinical significance

Back 20

- structures: lateral, posterior hypothalamus

- input: autonomic brainstem, amygdala, cerebral cortex, insula

- output: brainstem, spinal cord

- function: activates intermediolateral cell column neurons at T1-L2/L3

- clinical: increase HR & BP, decrease GI, pupil dilation

Front 21

emotional behavior coordination

- structures

- input

- output

- function

- clinical significance

Back 21

- structures: cerebral cortex, hippocampus, amygdala

- input: cerebral cortex, limbic system

- output: limbic system, brain stem (arousal, attention)

- function: rage and flight/fight/freeze behavior

- clinical: lesions = sham rage reactions

Front 22

stress response pathway

- input

- hypothalmic output

- pituitary output

- adrenal output

- glucocorticoid effects

Back 22

- input: cortical and limbic systems (threats)

- hypothalmic output: cortico-releasing factor (CRF) in PVN

- pituitary output: adrenocorticotropic hormone (ACTH)

- adrenal output: glucocorticoids

- glucocorticoid effects: liver gluconeogenesis; decrease immune and inflammation, negative feedback to CRF and ACTH

Front 23

fluid balance

- structure

- input

- output

- function

- clinical significance

Back 23

-structure: supraoptic and PVN; hypothalamus; synthesizes vasopressin (antidiuretic hormone)

- input: circumventricular organs = osmolality; brain stem = BP

-output: post. pituitary; secretes vasopressin

- function: raises BP, inhibits urine formation

- clinical significance: damage = diabetes insipidus; increase urine output; dehydration, heat stroke, hemorrhagic shock

Front 24

reproductive & affiliative behaviors

- structure:

- input

- output

- function

- clinical significance

Back 24

- structure: hypothalamo-neurohypophysial system (PVN and supraoptic nucleus); synthesizes oxytocin

- input: brainstem, spinal cord (uterus), somatosensory (suckling)

- output: posterior pituitary; secretes oxytocin

- function: mediates parturition in childbirth, milk letdown reflex for nursing

Front 25

circadian rhythms

- structure:

- input

- output

- function

- clinical significance

Back 25

- structure: suprachiasmatic nucleus

- input: irradiance-responsive neurons in retina

- output: other hypothalamic nuclei to brainstem for ANS control of endocrine glands (pineal=melatonin; adrenal = glucocorticoids; liver=glucose)

- function: controls biological functions

- clinical significance: jet lag; SAD

Front 26

temperature regulation

- structure:

- input

- output

- function

- clinical significance

Back 26

- structure: anterior & posterior hypothalamus

- input: thermoreceptors on skin for temp

- output/function:

heat reduction: vasodilation and sweat gland activation; increase blood flow to skin and sweat evaporation

heat production: preoptic neurons release TRH to thyroid for hormone release; shivering; vasodilation

Front 27

fever

- input

- output

- function

- clinical significance

Back 27

- input: exposure to pyrogens (toxic substances that affect brain's temperature regulation)

- output: hypothalamus releases prostaglandins to induce fever

- function; elevates temp set point

- clinical significance: asprin = anti-pyretic; inhibits prostaglandin synthesis; decreases set point

Front 28

5 functions of thalamic nuclei

Back 28

1. receive all ascending sensory info except olfaction

2. receive motor activity (ventral)

3. receive cerebellar output

4. receive ARAS

5. limbic system circuitry (anterior nucleus, dorsal medial)

Front 29

dorsal medial nucleus of thalamus

Back 29

input: substantia nigra, amygdala, olfactory

output: frontal eye fields, prefrontal cortex; olfactory cortex

function: visual, emotion, memory, pain, stress of amygdala input

Front 30

medial geniculate body (thalamus)

Back 30

input: inferior colliculus

output: primary, secondary auditory cortex

- tonotopically organized: low=rostral; high=caudal

Front 31

lateral geniculate body (thalamus)

Back 31

input: superior colliculus

output: primary, visual cortex

layers 1,4,6 = contralateral visual field

layers 2, 3, 5 = ipsilateral visual field

Front 32

pulvinar nucleus (thalamus)

lateral posterior nucleus (thalamus)

Back 32

input: association cortex, superior colliculus

output: visual association cortex, widespread

Front 33

intralaminar nuclei (thalamus)

Back 33

diffuse connection

input: reticular formation via CTT and spinothalamic tract

output: cerebral cortex

function: modulates pain

damage: thalamic pain syndrome

Front 34

ventral anterior nuclei (thalamus)

Back 34

diffuse connection

input: intralaminar nucleus

output: cerebral cortex

function: ARAS - control of consciousness

Front 35

reticular nucleus (thalamus)

Back 35

subcortical

- inhibitory nucleus

- controls cortical activity