use dependent plasticity Flashcards
what is a common task to understand how we adapt mvmts to novel forces
create systematic mvmt errors by modifying the mapping between muscle activity and limb motion
what areas do force field and visuomotor learning involve
cerebellum
parietal cortex (area 5 and 7)
M1
what is use dependent plasticity
changes in the cortical representation of actiosn and/or effectors caused by repeated use or familiarity
the more use, the more plasticity
what changes are seen in the brain with plasticity
thickness of tracts
number of synapses
amount of size used by areas
what is the benefit of expansion of fingertip representation in S1 (area 3b)
improved sensation
what are the disadvantages to expanded representation of fingertips in S1 (area 3b)
area of S1 is finite therefore increased rep of the fingertips takes away from other areas
- reduction in sensitivity and acuity of other digits / body parts
what selective increase in fingertip representation is seen
only the digits receiving repeated stimulation show increased rep in S1
expansion of rep for distal pads of fingers and decreased rep of hands
what happens to the receptive fields on fingers receiving repeated stimulation
smaller size
more numerous (increase in total number)
increase in number of neurons dedicated to that area
= finer spatial acuity
where does the median nerve innervate on the palmar surface
digits 1, 2, 3, and half of 4
where does the ulnar nerve innervate on the palmar surface
half of digit 4 and 5
what happens after surgical transection of the median nerve
large silent region present in S1
- areas in S1 represented by the median nerve are innervated by the ulnar and radial nerves
(collateral spreading - nerve endings spread and take over)
what is syndactyly
incomplete separation of skin between the fingers
how is syndactyly a model of cortical plasticity
alters somatotopic map in S1
some neurons respond to stimulation of either digit (at the borders)
shows hebbian learning
- neurons that fire together wire together (have common sensory and motor input/output
what is a neurons muscle field
the M1 neuron and the resulting activity in muscle after stimulation
what is involved in use dependent reorganisation of M1
training improves behavioural performance and increases rep of the trained fingers in M1
as performance increases, fewer mvmts are required to complete the task
