neuro lec 4 Flashcards

1
Q

what are the 3 parts of the basal ganglia?

A
  1. caudate nucleus
  2. putamen
  3. globus palidus
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2
Q

what is the caudate nucleus + putamen called? what about putamen + globus pallidus?

A
  • caudate nucleus + putamen = “striatum”
  • putamen + globus pallidus = “lenticular nucleus”
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3
Q

functions of the basal ganglia? (4)

A
  • facilitating desired movements and Inhibiting competing/undesired movements.
  • cognitive functions.
  • timing of automatic movements.
  • contains motor homunculus in motor regions.
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4
Q

if the basal ganglia is a facilitator, which part of the brain is the initiator?

A

superior motor area

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5
Q

name 3 disorders of the basal ganglia

A
  1. parkinson’s disease (difficulty initiating movements).
  2. huntington’s disease (difficulty inhibiting involuntary movements).
  3. tourette syndrome (inhibiting undesired movements, tics, verbal, and thoughts)
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6
Q

describe the DIRECT pathway of the basal ganglia-thalamic-cortical system (4)

A
  • the thalamus excites the cortex (more motor activity).
  • GPint inhibits the thalamus.
  • striatum inhibits the GPint.
  • net result: more excitation of the cortex.
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7
Q

describe the INDIRECT pathway of the basal ganglia-thalamic-cortical system (4)

A
  • subthalamic neurons are firing, increasing GPint neurons.
  • net result: inhibition on cortex.
  • firing of GPext neurons inhibits the subthalamic neurons, making the GPint neurons less active.
  • net result: inhibiting the thalamus.
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8
Q

which pathway does parkinson’s disease affect? what about huntington’s disease?

A
  • parkinson’s: direct pathway (net result of inhibition = difficulty initiating movements, slowness…)
  • huntington’s: indirect pathway (net result = difficulty inhibiting movements…)
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9
Q

what are the 3 nuclei related to the basal ganglia?

A
  1. substantia nigra
  2. subthalamic nucleus
  3. nucleus accumbens
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10
Q

where is the substantia nigra located? what does it produce? what does a loss of these cells result in?

A
  • midbrain
  • dopamine
  • parkinson’s disease
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11
Q

T or F: the nigrostriatal pathway only excites the direct pathway.

A

false – has the dual effect of exciting the direct pathway while simultaneously inhibiting the indirect pathway.

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12
Q

what brain part is the subthalamic nucleus part of? what does it play a role in?

A
  • diencephalon
  • movement regulation
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13
Q

what is deep brain stimulation? who is it used on? what are its benefits?

A
  • pulse generator sends impulses to subthalamic nucleus
  • medically intractable parkinson’s patients
  • may alleviate side effects of medication + increase medication tolerance
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14
Q

where is the nucleus accumbens? what does it mediate?

A
  • between caudate and putamen
  • mediates goal-directed behaviour and plays a role in addiction
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15
Q

what are the 5 subcortical tracts?

A
  1. superior longitudinal fasciculus
  2. arcuate fasciculus (part of SLF?)
  3. corpus callosum
  4. internal capsule
  5. corona radiata
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16
Q

what is the function of the arcuate fasciculus?

A
  • connects broca’s with wernicke’s area
  • basically language processing
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17
Q

what is the function of the corpus callosum? what are its 2 main parts? by what age is it developed?

A
  • integrates info between two hemispheres
  • forceps major (“splenum” near occipital lobe) and forceps minor (“genu” near frontal lobe)
  • complete by age 4 but growth continues until 30
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18
Q

what is the function of the internal capsule? is it afferent or efferent?

A
  • separates caudate from lenticular nucleus and connects cortex with subcortical structures/brain stem/spinal cord
  • bidirectional (efferent AND afferent)
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19
Q

what is the corona radiata?

A
  • fibers of internal capsule radiate to various parts of the cerebral cortex and BG
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20
Q

why is the cerebellum called “little brain”?

A

bc it has its own cortex and subcortical structures

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21
Q

what are the parts of the cerebellum (3)? which part of the brain is the cerebellum part of?

A
  • vermis (worm): separates cerebellar hemispheres
  • primary fissure
  • horizontal fissure
  • metencephalon
22
Q

what are the 3 cerebellar nuclei? describe the function of each + what happens when there is a lesion.

A
  1. fastigial nucleus: vestbiular, motor, gait, and posture. lesions = loss of balance and involuntary movements.
  2. interpositus nucleus: motor coordinating agonist and antagonist muscles. lesions = tremor.
  3. dentate nucleus: fine motor control of voluntary movements. lesions = ataxia.
23
Q

what are the 3 cerebellar peduncles? what kind of input is each related to?

A
  1. superior: output from Cb.
  2. middle: input to Cb via pons (movement + cognition).
  3. inferior: input to Cb via pons (vestibular).
24
Q

unlike the cerebral cortex, the cerebellum receives input from, and controls output to, the____ side of the body, and damage to the cerebellum therefore results in deficits to the ____ side of the body.

A

ipsilateral
ipsilateral

25
Q

which output zone is each cerebellar nucleus related to?

A
  • fastigial nucleus = medial zone (vestibular spinal cord and thalamus)
  • interpositus nucleus = intermediate zone (midbrain and thalamus)
  • dentate nucleus = lateral zone (cortex and thalamus)
26
Q

function of the brainstem? what is it made of? what are its main 3 structures?

A
  • connects spinal cord + cerebrum
  • external = white matter, internal = gray matter
  • midbrain, pons, medulla
27
Q

which -cephalon is the midbrain, pons, and medulla related to?

A
  • midbrain = mes
  • pons = met
  • medulla = mye
28
Q

what makes up the ventral part of the midbrain? (1)

A
  • cerebral peduncles/crus cerebri (white matter)
29
Q

what makes up the dorsal part of the midbrain? (2)

A
  • superior colliculi: integrates visual, auditory and somatosensory info for eyes and head
  • inferior colliculi: relays auditory stimuli from cochlea to cortex
30
Q

what is the function of the rostral part of the midbrain?

A

merges with diencephalon

31
Q

what are the components of the internal part of the midbrain? (3)

A

1.substantia nigra
2. cerebral aqueduct
3. periaqueductal gray (involved in involuntary vocalization and pain sensation)

32
Q

what makes up the dorsal part of the pons? (2)

A
  • 4th ventricle which widens into medulla
  • pineal gland (epiphysis) and produces melatonin
33
Q

what makes up the lateral part of the pons? (1)

A

large root of trigeminal nerve (CN V)

34
Q

what makes up the internal part of the pons? (2)

A
  • lateral lemniscus: auditory pathway… connects to inferior colliculus
  • medial lemniscus: touch, vibration, proprioception… connects to thalamus and cortex
35
Q

what makes up the ventral part of the medulla? what is crucial about this part?

A
  • pyramids (white matter)
  • crucial: 85-90% or the fibres cross the midline in the decussation of the pyramids
35
Q

what makes up the internal part of the medulla?

A

cranial nerve nuclei (9, 10, 11, 12)

36
Q

what makes up the dorsal part of the medulla?

A
  • fourth ventricle
  • fasciculus gracilis (legs)
  • fasciculus cuneatus (arms)
  • olive (sound)
  • central pattern generator (chewing, swallowing, respiration)
37
Q

T or F: the spinal cord is longer than the vertebral column

A

false – shorter!

38
Q

spinal cord ends at the ____ and nerves continue to the ____

A
  • conus medullaris
  • cauda equina
39
Q

in the spinal cord, ___ matter is on the periphery, ___ matter is centrally

A
  • white
  • grey
40
Q

what input does the dorsal vs ventral horn receive?

A
  • dorsal = afferent (sensory)
  • ventral = efferent (motor)
41
Q

what white matter connects dorsally and ventrally?

A
  • dorsally = dorsal columns (afferent)
  • ventrally = corticospinal tract (efferent)
42
Q

motor nerves have their cell body in the ___.

A

spinal cord

43
Q

sensory nerves have their cell body in the ____.

A

spinal ganglion (outside of spinal cord)

44
Q

damage to upper motor neurons (eg strokes, tumors) can influence the pyramidal tract or extrapyramidal tract. how do symptoms differ?

A
  • pyramidal: impact voluntary movements… increases spasticity, stronger reflexes, hypertonia
  • extrapyramidal: reduced reflexes, hypotonia
45
Q

what does damage to lower neurons do to muscles?

A

loss of muscle innervation, muscle atrophy

46
Q

corticospinal/pyramidal tract: where is the upper vs lower neuron located?

A
  • upper: cortex
  • lower: spinal cord
47
Q

corticospinal/pyramidal tract:
fibers that do cross control the ____.
fibers that do not cross control the ____.

A
  • arms/legs
  • trunk/head
48
Q

whats a dermatome vs myotome?

A
  • Dermatome: area inervated by Dorsal root neurons
  • Myotome: Muscle innervated by ventral root neurons
49
Q

what are some health conditions that manifest themselves along dermatomes? (3)

A
  • sciatica
  • chickenpox
  • shingles
50
Q

what is referred pain?

A

when CNS perceives pain coming from one part of the body as pain coming from its associated dermatomes/myotomes