Neuroscience: Chapter 11

Front 1

neuritis

Back 1

-an inflammation of the nerves that is often caused by a viral infection

Front 2

proprioception

Back 2

the sense that collects information from our muscles and tendons and joints to tell us where our hands are and what movements our feet and legs are making

Front 3

we get information about our body from the ____ and from the ____

Back 3

-somatosensory system
-vestibular system

Front 4

somatosenses includes...

Back 4

-proprioception
-interoceptive system
-vestibular system

Front 5

proprioception

Back 5

the skin senses, which tell us about conditions at the surface of our body

Front 6

proprioception

Back 6

-"belonging to one's self"
-is the sense that informs us about the position and movement of our limbs and body
-its sensors report tension and length in muscles and the angle of the limbs at the joints
-very important in controlling movement

Front 7

without proprioception we would have a lot of difficulty with...

Back 7

maintaining posture, moving our limbs, and grasping objects

Front 8

skin senses

Back 8

-are touch, warmth, cold and pain
-the range is limited to the surface of our body
-changes in those areas are often due to external stimulation so the skin senses inform us about our body and the world

Front 9

two general types of skin senses receptors

Back 9

1. free nerve endings
2. encapsulated receptors

Front 10

free nerve endings

Back 10

skin senses receptors that are simply processes at the ends of neurons; they detect warmth, cold and pain

Front 11

encapsulated receptors

Back 11

skin senses receptors that are more complex structures enclosed in a membrane; their role is to detect touch

Front 12

Meissner's corpuscles

Back 12

-in the superficial layers of the skin
-respond with a brief burst of impulses
-detect the texture and fine detail of objects
-detect movement and come into play when you explore an object with gentle strokes of your hand or when a blind person reads Braille

Front 13

Merkel's disks

Back 13

-in the superficial layers of the skin
-give a more sustained response compared to the Meissner's corpuscles
-detect the texture and fine detail of objects
-detect movement and come into play when you explore an object with gentle strokes of your hand or when a blind person reads Braille

Front 14

Pacinian corpuscles and Ruffini endings are located____

Back 14

in the deeper layers where they detect stretching of the skin and contribute to our perception of shape and grasped objects

Front 15

Body senses are remarkable for their ___

Back 15

neural separation

Front 16

cold receptors

Back 16

which are near the skin's surface have peak firing rates at 25 celsius

Front 17

warmth receptors

Back 17

are deeper than cold receptors and have peak firing rates at 45 degrees celsius

Front 18

warmth receptors

Back 18

-stop firing at 50 degrees celsius

Front 19

painful and nonpainful heat activate different areas in the ____

Back 19

somatosensory cortex

Front 20

vestibular sense

Back 20

-helps us maintain balance, and it provides information about head position and movement

Front 21

The organs of the vestibular sense

Back 21

-semicircular canals
-the utricle
-saccule

Front 22

Why is the physical arrangement of the semicircular canals especially responsive to movement of the head?

Back 22

-at the base of each canal is a gelatinous mass called a cupula which has a tuft of hair cells protruding into it. during acceleration, the fluid shifts in the canals and displaces the cupula; bending the hair cells in one direction depolarizes them and being in thee other direction hyperpolarizes them, increasing or decreasing the firing rate in the neuron

Front 23

the system only responds to _____, and stops responding when speed ____

Back 23

acceleration
stabilizes
(just as the coffee sloshes out of your cup when you start up from a traffic light and then levels off in the cup when you reach a stable speed, the fluid in the canals also returns to its normal position)

Front 24

the utricle and saccule monitor____

Back 24

-head position in relation to gravity
-the receptors (hair cells) are covered with a gelatinous material. when the head tilts, gravity shifts the gelatinous mass and the hair cells are depolarized or hyperpolarized, depending on the direction of tilt.

Front 25

the hair cells in the utricle are arranged in a _____, while the saccule's receptors are on its ____; thus the two organs can detect tilt in any direction

Back 25

urticle - horizontal patch
saccule- vertical wall

Front 26

what would happen without a vestibular system

Back 26

-a patient who lost his vestibular system, when he walked he body tilted a full 20 degrees to the left but he wasnt aware of his tilt.

Front 27

vestibular sense' use for picking up things

Back 27

-it helps us with the position of our body and the relation of our arm to our body.
-the brain combines information about the object's spatial location with inputs from the vestiular sense and from proprioception to tell us what arm movements are required

Front 28

______ also triggers reflexive eye movements that keep returning our gaze to the scene as we turn our head

Back 28

proprioception

Front 29

parieto insular vestibular cortex

Back 29

-the vestibular system sends projections to the cortex in this area
-likely location where stimulation that produces excessive body movements that causes dizziness and nausea

Front 30

dermatomes

Back 30

-segments that the body is divided into
-each served by a spinal nerve
-each dermatome overlaps he next by one third to one half because if one nerve is injured then the area will not lose all sensation

Front 31

Body sense information enters the spinal cord or the brain and travels to the ____ which then goes to the ___

Back 31

thalamus
somatosensory cortex

Front 32

somatosensory cortex

Back 32

-the body sense neurons go to their projection area
-located in the parietal lobes just behind the primary motor cortex and the central sulcus

Front 33

How does pain begin?

Back 33

-when certain free nerve endings are stimulated by intense pressure or temperature or by damage to tissue

Front 34

3 types of pain receptors

Back 34

1. Thermal
2. Mechanical
3. Polymodal

Front 35

Thermal pain receptors

Back 35

respond to extreme heat and cold

Front 36

mechanical pain receptors

Back 36

react to intense stimulation like pinching and cutting

Front 37

polymodal pain receptors

Back 37

are activated by both thermal and mechanical stimuli as well as by chemicals released when tissue is injured

Front 38

Pain information travels to the spinal cord over large, ______and small, lightly ______

Back 38

-myelinated A-delta fibers
-lightly myelinated or unmyelinated C fibers

Front 39

A-delta fibers

Back 39

-transmit rapidly- it is the reason why you feel sharp pain almost immediately when you are injured

Front 40

In the spinal cord, pain neurons release ____ and ____

Back 40

glutamate and substance P

Front 41

Substance P

Back 41

-a neuropeptide involved in pain signaling (neuropeptides enhance the effect of a neurotransmitter at the synapse)
-Substance P is released only during more intense pain stimulation

Front 42

gate control theory

Back 42

-Ronald Melzack and Patrick Wall came up with it
-hypothesized that pressure signals arriving in the brain trigger an inhibitory message that travels back down the spinal cord, where it closes a neural "gate" in the pain pathway
-they believed that this gate mechanism is also involved when emotion increases or decreases pain

Front 43

endorphins

Back 43

-function both as neurotransmitters and as hormones, and act as opiate receptors in many parts of the nervous system.

Front 44

How do we know that analgesia of inescapable sock is endorphin based?

Back 44

because, an injection of naloxone eliminated the analgesia induced by inescapable shock but not the milder analgesia that followed escapable shock; since naloxone blocks opiate receptors by occupying them

Front 45

stimuli like pain and stress cause the release of endorphins in the ____

Back 45

periaqueductal gray

Front 46

periaqueductal gray

Back 46

-endorphins are released here when you are stressed or there is pain
-a brain stem structure with a large number of endorphin synapses

Front 47

endorphin release inhibits the release of _____, closing the pain gate in the spinal cord

Back 47

substance p

Front 48

activation of the endorphin circuit apparently has multiple neural origins, including the ....

Back 48

cingulate cortex during placebo analgesia and the amygdala in the case of fear induced analgesia

Front 49

blocking cannabinoid receptors in the periaqueductal gray

Back 49

-reduces the analgesia produces by brief foot shock, but naloxone does not this suggests that cannabinoids are also internal pain relievers and they share the neural gating system used by endorphins

Front 50

opiorphin

Back 50

-a peptide in human saliva that blocks enzymes that degrade morphine and other opiates; opiorphin reduced pain in rats as much as morphine, apparently by enhancing endorphin functioning

Front 51

MDAN

Back 51

-a new drug that blocks the delta receptor
-50 times greater pain relief than morphin, with no signs of addiction or development of tolerance to the pain relieving effects

Front 52

what the the organizational and functional similarities of the sensory system with the visual cortex

Back 52

-it contains a map of the body
-some of the cortical cells have complex receptive fields on the skin
-the somatosensory processing is hierarchical

Front 53

somatosensory neurons with complex fields:

Back 53

-have sensitivities for orientation, direction of movement, shape surface curvature, or texture
-these neurons combine input from neurons with simpler functions, just as complex visual cells integrate the inputs of multiple cells

Front 54

example of one type of receptive field

Back 54

-includes multiple fingers; the cells' firing rate depend on how many fingers are touched, so they give an indicate of the size of the held object.

Front 55

primary somatosensory cortex

Back 55

-consists of four areas, each of which contain a map of the body and plays a role in processing sensory information from the body
-the thalamus sends its output to two of these subareas which extract some information and pass the result onto the to other two areas, which in turn send their output to the secondary somatosensory cortex

Front 56

secondary somatosensory cortex

Back 56

-receives input from the left and the right primary somatosensory cortices, so it combines information from both sides of the body.
-neurons in this area are particularly responsive to stimuli that have acquired meaning by association with reward
-connects to the part of the temporal lobe that includes the hippocampus, which is important in learning, so it may serve to determine whether a stimulus i committed to memory

Front 57

the primary somatosensory cortex projects to the ____ cortex as well as to the ___ cortex

Back 57

posterior parietal cortex
secondary cortex

Front 58

posterior parietal cortex

Back 58

-is an association area that brings together the body senses, vision, and audition
-here the brain determines the body's orientation in space the location o the limbs, and the location in space of objects detected by touch, sight, and sound
-it integrates the body with the world
-it is composed f several subareas which are responsive to different sense modalities

Front 59

posterior parietal cortex and its neurons

Back 59

-its function is not solely perceptual because many of its neurons fire before and during a movement
-it passes its information on to frontal areas that do.

Front 60

blocking a type of ____ channel that occurs in high numbers in pain neurons might be another way of relieving pain

Back 60

sodium channel

Front 61

when tissue is injured it becomes a bit more acidic; a compound called ____, which reduces pain by blocking glutamate receptors, becomes 62 times more effective when ti encounters this slight change in pH level

Back 61

NP-A

Front 62

phantom pain

Back 62

-70% of amputees experience this
-its pain that is experiences as located in the missing limb
--the cut ends of nerves generate impulses that are registered in the part of the brain that once served the missing limb

Front 63

reasons that explain why phantom pain originates in the brain

Back 63

-people with a break in the spinal cord high in the upper body sometimes experiences phantom legs
-the presence of unusually high spontaneous activity in the thalamus in some phantom limb patients

Front 64

three types of muscles

Back 64

-skeletal muscles
-smooth muscles
-cardiac muscles

Front 65

skeletal muscles

Back 65

-they move the body and limbs
-also called striated muscles because their striped appearance

Front 66

smooth muscles

Back 66

-produce the movement of the internal organs
-for instance, moving food through the digestive system

Front 67

cardiac muscles

Back 67

-are the muscles that make up the heart

Front 68

muscle cells

Back 68

-are controlled by motor neurons that synapse with a muscle cell at the neuromuscular junction
-the number of cells served by a single axon determines the precision of movement possible

Front 69

a muscle fiber is made up of ____ and ____

Back 69

myosin filaments and actin filaments

Front 70

when a motor neuron releases acetylcholine in the muscle fiber

Back 70

-the muscle fiber is depolarized, whcih opens calcium channels; the calcium influx initiates a series of actions by the myosin that contract the muscle.
-a myosin filament essentialy climbs along the surrounding actin filaments, using small protrusions that it attaches to the actin. movement of myosin filaments relative to the actin filaments shortens the muscle fibers and contracts the muscles

Front 71

antagonistic muscles

Back 71

-muscles that produce opposite movement at a joint
-ex: the biceps muscle flexes the arm and the triceps extend it
-it creates a smoother movement, allows precise stopping and maintains a position with minimal tremor

Front 72

when a doctor taps the patellar tendon which connects the quadriceps muscles to the lower leg bone, it stretches the muscle which is detected by muscle stretch receptors called ___ and relay to the spinal cord

Back 72

muscle spindles

Front 73

benefits of stretch reflex

Back 73

-enables a muscle to resist very quickly if the muscle is stretched by activity in its antagonistic partner
-allows a muscle to respond quickly to an increased external load (ex: if you are holding a stack of books and a friend drops another book on top of it)

Front 74

Golgi tendon organs

Back 74

-are receptors that detect tension in a muscle, trigger a spinal reflex that inhibits the muscle
-this prevents muscles from contracting so much that they might be damaged

Front 75

central pattern generators

Back 75

-neuronal networks that produce a rhythmic pattern of motor activity such as those involved in walking, swimming, flying and breathing
-located in the spinal cord or in the brain
-might be useful in restoring some function after paralysis

Front 76

the motor cortex consists of ___

Back 76

primary motor cortex and two major secondary motor areas, the supplementary motor area and the premotor cortex

Front 77

role of prefrontal cortex

Back 77

-plans actions with regard to their consequences
-it receives information from the ventral visual stream about object identity which is useful in identifying targets of motor activity
- most of all its role is planning for movements

Front 78

what happens when monkeys perform some variation of a delayed match to sample task (given visual task, must pick correct one)

Back 78

-some cells in the prefrontal cortex start firing when the first stimulus is presented and continue to fire throughout the delay, suggesting that they are "remembering" the stimulus
-at response time another group of prefrontal cells start firing before activity starts in the premotor areas; this indicates that the prefrontal cortex selects the target of behavior and the appropriate motor response

Front 79

premotor cortex

Back 79

-begins programming a movement by combining information from the prefrontal cortex and the posterior parietal cortex

Front 80

supplementary motor area

Back 80

-output from the prefrontal cortex flows into this
-assembles sequences of movements such as those involved in eating or playing the piano

Front 81

primary motor cortex

Back 81

-is responsible for the execution of voluntary movements
-its cells fire most during the movement instead of prior to it
-contributes control of movement's force and direction

Front 82

the primary motor cortex is able to put complex movement sequences together with the help of

Back 82

input from the secondary motor areas and somatosensory cortex and the posterior parietal area

Front 83

basal ganglia

Back 83

-the caudate nucleus, putamen, and globus pallidus- use information from the primary and secondary motor areas and the somatosensory cortex to integrate and smooth movements
-sends output to the primary motor cortex, supplementary motor area and the premotor cortex via the thalamus
-involved in learning movement sequences

Front 84

cerebellum

Back 84

-receives information from the motor cortex about an intended movement, it determines the order of muscular contractions and their precise timing
-uses information from the vestibular system to maintain posture and balance, refine movements, and control eye movements that compensate for head movements
-once an intended movement has been modified, the cerebellum sends the information back to the primary cortex
-necessary for motor skills, nonmotor learning, in making time and speed judgments about auditory and visual stimuli

Front 85

parkinson's disease

Back 85

-is characterized by motor tremors, rigidity, loss of balance and coordination, and difficulty in moving, especially in initiating movements

Front 86

substantia nigra

Back 86

-symptoms of parkinson's disease are caused by the deterioration of this
-its neurons send dopamine releasing axons to the straitum which is composed of the ganglia's caudate nucleus and putamen and the nucleus accumbens

Front 87

familial

Back 87

meaning that it occurs more frequently among relatives of a person with disease than it does in the population

Front 88

lewy bodies

Back 88

-abnormal clumps of protein that form within neurons
-found in several brain locations in some parkinson's patients and Alzheimer's disease
-contibribute to the cognitive deficits and depression that often accompany parkinson's disease

Front 89

environmental influences that have been implicated in parkinson's disease

Back 89

-subtle brain injury
-a variety of toxins, including industrial chemicals, carbon monoxide, herbicides, pesticides

Front 90

Levodopa (L-dopa)

Back 90

-used to treat parkinson's disease
-is the precursor for dopamine
-dopamine will not cross the blood brain barrier but L-dopa will, and in the brain it is converted to dopamine
-its not that helpful though

Front 91

Huntington's disease

Back 91

-is a degenerative disorder of the motor system involving cell loss in the striatum and cortex
--begins with jerky movements that result from impaired correction then involuntary movement appear, first as fidgeting and then as movements of the limbs and then writhing of the body and facial grimacing
-death usually follows within 15 to 30 years

Front 92

Huntington's disease deficits:

Back 92

impaired judgement, difficulty with a variety of cognitive tasks, depression, and personality changes
-the motor symptoms are due to the degeneration of neurons in the striatum, while defective or degenerated neurons in the cortex probably account for psychological symptoms

Front 93

What causes Huntington's disease?

Back 93

-results from a mutated form of the huntingtin gene, the loss of neurons is due to the accumulation of the gene's protein.
-in normal person, the gene has between 10 to 34 repetition of the bases cytosine, adenine, and guanine but the more repeats the person have beyond 37 the earlier in life the person will get the disease

Front 94

How can we treat Huntington's disease?

Back 94

transplant of fetal striatum cells

Front 95

myasthenia gravis

Back 95

-is a disorder of muscular weakness caused by reduced number or sensitivity of acetylcholine receptors
-patients have 70 to 90% less receptors than normal individuals

Front 96

what drug gives temporary relief from the symptoms of myasthenia gravis?

Back 96

drugs that inhibit the action of acetylcholinesterase because acetylcholinesterase breaks down acetylcholine at the synapse; these inhibitors increase the amount of available neurotransmitter at the neuron muscle junction

Front 97

what is a standard treatment for myasthenia gravis?

Back 97

the removal of the thymus
-the thymus is the major source of lymphocytes that produce antibodies; the thymectomy eliminates symptoms completely in almost 80% of patients

Front 98

multiple sclerosis

Back 98

-is a motor disorder with many varied symptoms caused by deterioration of myelin and neuron loss in the central nervous system
-is an autoimmune disease

Front 99

process of multiple sclerosis in life

Back 99

-demyelination reduces the speed and strength of movements
-impuses traveling in adjacent neurons, whcih should arrive simultaneously become desynchronized because of differential loss of myelin
-as disease progresses, unmyelinated neurons die leaving areas of sclerosis

Front 100

symptoms of multiple sclerosis

Back 100

muscular weakness, tremor, impaired coordination, urinary incontinence, visual problems