Plasticity & recovery

Question 1

Plasticity

Answer 1

Brain’s capacity for continuously changing its structure, & ultimately its function, throughout a lifetime

Question 2

Metaplasticity

Answer 2

Idea that many factors that result in changes in the brain interact with one another to produce different kinds of changes under different combinations of factors

Question 3

Recovery for what cognitive function is most extensive?

Answer 3

Language functions

Question 4

3 possible outcomes of behavioral fx following brain injury

Answer 4

Compensation, diaschisis, recovery assoc. w/ neuro changes

Question 5

3 neurological implications of brain damage

Answer 5

Cell death
Survival with reduced total input
Reinnervation (whole or in part)

Question 6

Spontaneous recovery is due to

Answer 6

Resolution & absorption from hematomas, decrease in swelling, return of electrolyte & neurochemical balance

Question 7

What area of the CNS is most likely to be plastic?

Answer 7

Cortex

Question 8

Significant recovery in behavior is associated with

Answer 8

Growth in the dendritic trees & thus number of connections

Question 9

Synapse supersensitivity

Answer 9

Compensates for loss of presynaptic elements; remaining dendrites become hypersensitive to incoming stimuli

Question 10

Sprouting

Answer 10

Remaining nerve fibers develop branches that occupy sites left empty by damaged neurons, thus reinnervating unoccupied areas

Question 11

Denervation supersensitivity

Answer 11

In areas of damage, postsynaptic processes may become supersensitive to NT substance leaking from pre-lesion neurons thus allowing activation of post-lesion pathways & restitution of normal functioning

Question 12

Substitution

Answer 12

Existing intact brain structures assume functions previously held by lesioned areas

Question 13

More complete & rapid recovery from aphasia is seen in closed head injuries or stroke?

Answer 13

Closed head injuries

Question 14

Neural competition hypothesis

Answer 14

Following cerebral insult in early stages of development, there occurs a relocation of fx, resulting in a decrease in synaptic sites available for mediating behaviors; leads to “crowding” phenomenon; in longer term, there remain fewer synaptic sites available to be taken up by new, emerging skills, leading to cumulative deficits & increased problems w/ development progressions

Question 15

Effects of early brain injury on development

Answer 15

Development may lag with later emergence of skills than peers; impairments may emerge as the impact of poor skill acquisition results in increasing discrepancies with peers; info processing & exec fx may fail to mature

Question 16

How does the severity of the lesion impact plasticity in children?

Answer 16

Small lesions & very large unilateral lesions may cause interhemispheric reorganization; moderate or bilateral focal lesions fail to cause interhemispheric reorganization; in diffuse injuries, there is a dose-response relationship between severity & outcome

Question 17

How does gender impact plasticity following childhood injury?

Answer 17

Possibly more diffuse organization of function & in females & earlier LH maturation, so there is evidence of greater likelihood of transfer of fx to the less specific RH

Vulnerability more common in males, greater for RH

Question 18

How does psychosocial context impact plasticity in childhood injury?

Answer 18

Plasticity is associated with high SES, access to rehab, early intervention

Question 19

Effects of hemidecortication on language function

Answer 19

After the complete removal of LH most people are capable of some language & do not experience the dense global aphasia seen in pts with large LH strokes

Question 20

How may the phenomenon of diaschisis help to account for functional recovery after a focal brain injury?

Answer 20

As the functional continuity between various areas of the brain is disrupted following a lesion, & as this disruption extends beyond the direct effect of the lesion, resolution of these disruptions may help account for recovery of fx

Question 21

Why might symptoms of early brain injury return with aging?

Answer 21

As pts age, the mechanisms that promoted recovery earlier in life may be called on to compensate for neuronal deterioration