Quiz4

Question 1

what is a homunculus

Answer 1

• discovered by epilepsy surgery
• representation of the human body, but mapped out onto the brain
• divided into motor and somatosensory
• organized contralaterally (on opposite sides, ex. right temporal lobe controls left foot)
• parts depicted larger are of greater importance

Question 2

explain brain plasticity and reorganization

Answer 2

• brain changing based on experience

ex. after amputation of finger, no longer input from missing digit to brain so other digits overtake that

Question 3

explain phantom limb syndrome

Answer 3

• when someone misses a limb it is common for them to still perceive sensations in that missing limb
• explained by somatosensory homunculus because reorganization of the somatosensory strip could lead to neurons previously devoted to receiving certain tactical information now being devoted to receiving other tactical info as well

Question 4

what is perceptual reorganization

Answer 4

• experts in music or sports can experience this
• ex. study with people blindfolded for a week-occipital lobe still activated so it tried to help out other parts of the brain on task completion

Question 5

what are the main pieces of motor control

Answer 5

• basal ganglia
• cerebellum
• motor cortex
• supplementary motor area and premotor area

Question 6

explain the supplementary motor area in motor control

Answer 6

selecting order of movements

Question 7

explain the premotor area in motor control

Answer 7

selecting the types of movements

Question 8

explain the cerebellum in motor control

Answer 8

timing patterns of muscle activation

Question 9

explain the basal ganglia in motor control

Answer 9

switching between different patterns of movement starting or stopping

Question 10

explain the motor cortex in motor control

Answer 10

initiation of motor execution of the force and/or direction of movement

Question 11

explain damage to the cerebellum

Answer 11

cerebellar ataxia: coordination problems
dysarthria: speech problems
action/intention tremors: jerky, staggered movements when starting a movement (not spontaneously)

Question 12

what is the structure of basal ganglia and some examples of what it can control

Answer 12

five distinct loops from basal ganglia structures to/from cortical regions

ex. regulating posture, switching between tasks, motor learning with reward, suppressing unwanted movements

Question 13

explain alien limb syndrome

Answer 13

• a limb appears to have its own personality, not controlled voluntarily
• caused by contralateral damage or corpus callosum restriction (split brain)
• two limbs can fight with eachother

Question 14

explain parkinson’s disease

Answer 14

• caused by damage to the substantia nigra, stopping production of dopamine
• tremors-involuntary shaking movements caused because putamen without dopamine cannot inhibit movements
• cogwheel rigidity: stiffness: movements are resisted, but then jerk to another location that is then resisted
• akinesia/bradykinesia: lack of movement or slowness of movement, including even parkinsonian mask (expressionless face)
• difficulty with posture and gait (walking)

Question 15

what is a demylenating disease

Answer 15

multiple sclerosis

Question 16

what is epilepsy

Answer 16

a disease where seizure activity is recurrent

Question 17

what is the primary motor cortex

Answer 17

cortical region that is the final exit point for neurons responsible for fine motor control of the body’s muscles

Question 18

what is the primary sensory cortex

Answer 18

cortical region that initially receives information about a particular sensory modality