Plasticity

Question 1

4 traits of normal hand map in 3b

Answer 1

1. Individual variations
2. Medio-lateral topography of body parts
3. Distal to proximal shift of RF as electrode moves caudally
4. Interpolated islands representing hairy skin

Question 2

If medial nerve is transected

Answer 2

Ulnar and and radial take over cortex

Question 3

Unmasking is

Answer 3

immediate map changes

Question 4

2 things implied by progressive changes to somatosensory cortex

Answer 4

1. Axonal sprouting

2. Synaptic reorganization

Question 5

Progressive topographic reorganization does what to RF size?

Answer 5

decreases in size

Question 6

Example of visual plasticity?

Answer 6

Perceptual fill in of scotomas

Question 7

Example of auditory plasticity?

Answer 7

Tinnitus

Question 8

3 subcortical regions that reorganize after amputation

1 that doesn’t

Answer 8

Spinal cord dorsal horn
Cuneate nucleus
Cortico-cortical connections

Doesn’t: thalamo-cortical connections

Question 9

When axon is cut (like in Pons study) atrophy is seen in 2 regions
Expansion in 1`

Answer 9

Cuneate nucleus
Thalamic VPL nucleus

Expansion of face in VPM thalamic nucleus

Question 10

Hypothesis behind finger amputation repurposing

Answer 10

Hebbian plasticity:temporal coincidence of inputs

Question 11

What developed with 3 finger bar training

Answer 11

2-3 digit receptive fields

Supports Hebbian plasticity

Question 12

Transplanting skin, nerves and blood supply is called

Answer 12

Neurovascular pedical flap transplant

Question 13

3 good things about crushed nerve regeneration

Answer 13

1. RFs are small
2. Topographic map is conserved
3. More correct localization

Question 14

3 bad things about crushed nerve regeneration

Answer 14

1. Imperfect and haphazard
2. Not all original territory is recaptured
3. RFs are scattered and representations of skin are fractured

Question 15

Vibration training on skin caused 2 things

Answer 15

1. Expanded representation of S1 3b for trained skin region

2. Enlarged RFs for whole finger

Question 16

Moving stimuli training on skin caused 2 things

Answer 16

1. Expanded representations of stimulated skin region

2. Shrinkage of RFs (maybe greater acuity)

Question 17

Vibration vs moved stimuli training implies

Answer 17

they are very different physiological processes

Question 18

3 examples of somatosensory or motor reorganization of topographical maps

Answer 18

1. Braille- reading finger
2. Musicians with string instruments
3. Motor maps after amputation

Question 19

2 traits of reorganization after scotoma

Answer 19

1. Blind spot persists in LGN but is filled in in V1

2. Increased cortico-cortical connections

Question 20

3 major categories of mechanisms of neural plasticity

Answer 20

1. Sprouting
2. Substitution
3. Synaptic changes

Question 21

3 types of sprouting

Answer 21

1. Regenerative: to replace lost axon (only in PNS)
2. Collateral: intact axons help neighbors
3. Compensatory: in reponse to printing axonal tree

Question 22

Recruitment means

Answer 22

intact neural tissue to perform novel functions (like crosstraining)

Question 23

2 types of synaptic changes

Answer 23

1. Unmasking latent synapses

2. Hebbian plasticity

Question 24

2 neurogenic zones

Answer 24

1. Subventricular zone of the lateral ventricles

2. Subgranular zone

Question 25

What promotes hippocampal neurogenesis?

Answer 25

Aerobic exercise