Plasticity Lecture 5

Food for thought What does it mean that the brain is “plastic” Are there “critical periods”? How important are they? Are there parts of the brain that are predestined for some behavior? Think about the neurobiology of brain development and how that might contribute to plasticity.

Types of plasticity Experience independent

Types of plasticity Experience independent Experience dependent

Types of plasticity Experience independent Experience dependent Experience expectant

Experience Independent Plasticity Experience is not required to “wire” up the system

Experience Independent Plasticity Experience is not required to “wire” up the system Systems that are similar across species

Experience Independent Plasticity Experience is not required to “wire” up the system Systems that are similar across species Examples?

Experience Independent Plasticity Experience is not required to “wire” up the system Systems that are similar across species Examples? Brainstem

Experience Independent Plasticity Experience is not required to “wire” up the system Systems that are similar across species Examples? Brainstem Some aspects of the visual system

Experience Independent Plasticity Experience is not required to “wire” up the system Systems that are similar across species Examples? Brainstem Some aspects of the visual system Mechanism

Experience Independent Plasticity Experience is not required to “wire” up the system Systems that are similar across species Examples? Brainstem Some aspects of the visual system Mechanism Gene expression

Experience Dependent Plasticity Specific to experience

Experience Dependent Plasticity Specific to experience Different by individual

Experience Dependent Plasticity Specific to experience Different by individual Based upon individual experience

Experience Dependent Plasticity Specific to experience Different by individual Based upon individual experience Examples?

Experience Dependent Plasticity Specific to experience Different by individual Based upon individual experience Examples? Memory

Experience Dependent Plasticity Specific to experience Different by individual Based upon individual experience Examples? Memory Stressful life events?

Experience Dependent Plasticity Specific to experience Different by individual Based upon individual experience Examples? Memory Stressful life events? Formation of new connections?

Experience Dependent Plasticity Specific to experience Different by individual Based upon individual experience Examples? Memory Stressful life events? Formation of new connections? Mechanism

Experience Dependent Plasticity Specific to experience Different by individual Based upon individual experience Examples? Memory Stressful life events? Formation of new connections? Mechanism Likely LTP or similar mechanism

Experience Expectant Plasticity A particular experience that is expected in the environment contributes to wiring of system.

Experience Expectant Plasticity A particular experience that is expected in the environment contributes to wiring of system. Most members of the species have that experience

Experience Expectant Plasticity A particular experience that is expected in the environment contributes to wiring of system. Most members of the species have that experience Examples? Language

Experience Expectant Plasticity A particular experience that is expected in the environment contributes to wiring of system. Most members of the species have that experience Examples? Language Ocular Dominance Columns

Experience Expectant Plasticity A particular experience that is expected in the environment contributes to wiring of system. Most members of the species have that experience Examples? Language Ocular Dominance Columns Mechanism

Experience Expectant Plasticity A particular experience that is expected in the environment contributes to wiring of system. Most members of the species have that experience Examples? Language Ocular Dominance Columns Mechanism Redundant connections in the brain

Transplantation Studies Taking visual cortex and moving it to auditory cortex

Transplantation Studies Taking visual cortex and moving it to auditory cortex Takes on some characteristics of auditory (e.g., responds to sound)

Transplantation Studies Taking visual cortex and moving it to auditory cortex Takes on some characteristics of auditory (e.g., responds to sound) Takes on other characteristics of visual (e.g., the way cells are organized).

Transplantation Studies Taking visual cortex and moving it to auditory cortex Takes on some characteristics of auditory (e.g., responds to sound) Takes on other characteristics of visual (e.g., the way cells are organized). Mechanism

Transplantation Studies Taking visual cortex and moving it to auditory cortex Takes on some characteristics of auditory (e.g., responds to sound) Takes on other characteristics of visual (e.g., the way cells are organized). Mechanism Redundant connections maintained or reformed when cortex is moved.

Recovery from early lesions Examples

Recovery from early lesions Examples Language and the left hemisphere

Recovery from early lesions Examples Language and the left hemisphere Spatial abilities and the right hemisphere

Recovery from early lesions Examples Language and the left hemisphere Spatial abilities and the right hemisphere Mechanism

Recovery from early lesions Examples Language and the left hemisphere Spatial abilities and the right hemisphere Mechanism Redundant connections

Mechanism for Recovery from lesion: Example

Mechanism for Recovery from lesion: Example

Negative experience Children raised in impoverished environments (e.g., orphanages)

Negative experience Children raised in impoverished environments (e.g., orphanages) Reduced brain size?

Negative experience Children raised in impoverished environments (e.g., orphanages) Reduced brain size? Reduced blood flow?

Negative experience Children raised in impoverished environments (e.g., orphanages) Reduced brain size? Reduced blood flow? Animal analogues – Rearing studies

Negative experience Children raised in impoverished environments (e.g., orphanages) Reduced brain size? Reduced blood flow? Animal analogues – Rearing studies Effects on brain

Negative experience Children raised in impoverished environments (e.g., orphanages) Reduced brain size? Reduced blood flow? Animal analogues – Rearing studies Effects on brain Effects on behavior

Negative experience Children raised in impoverished environments (e.g., orphanages) Reduced brain size? Reduced blood flow? Animal analogues – Rearing studies Effects on brain Effects on behavior Abused children

Negative experience Children raised in impoverished environments (e.g., orphanages) Reduced brain size? Reduced blood flow? Animal analogues – Rearing studies Effects on brain Effects on behavior Abused children Responses to emotional expressions

Experiments of Nature People born deaf

Experiments of Nature People born deaf What happens?

Experiments of Nature People born deaf What happens? Visual areas increase in size and “jobs”

Experiments of Nature People born deaf What happens? Visual areas increase in size and “jobs” Auditory areas may be “taken over” for visual function

Experiments of Nature People born deaf What happens? Visual areas increase in size and “jobs” Auditory areas may be “taken over” for visual function Improved attention to movement in the periphery

Experiments of Nature People born deaf What happens? Visual areas increase in size and “jobs” Auditory areas may be “taken over” for visual function Improved attention to movement in the periphery Specific to deafness: Not sign language

Experiments of Nature People born deaf What happens? Visual areas increase in size and “jobs” Auditory areas may be “taken over” for visual function Improved attention to movement in the periphery Specific to deafness: Not sign language Language is visual-spatial, but still in the left hemisphere

Experiments of Nature People born deaf What happens? Visual areas increase in size and “jobs” Auditory areas may be “taken over” for visual function Improved attention to movement in the periphery Specific to deafness: Not sign language Language is visual-spatial, but still in the left hemisphere (for anyone who learns a visual/spatial language).

Plasticity in adulthood Experience Dependent plasticity

Plasticity in adulthood Experience Dependent plasticity Rats in enriched environments have more cortical connections

Plasticity in adulthood Experience Dependent plasticity Rats in enriched environments have more cortical connections Can be rearing

Plasticity in adulthood Experience Dependent plasticity Rats in enriched environments have more cortical connections Can be rearing But also occurs in aged rats

Plasticity in adulthood Experience Dependent plasticity Rats in enriched environments have more cortical connections Can be rearing But also occurs in aged rats ED Plasticity can occur throughout the lifespan

Plasticity in adulthood Experience Dependent plasticity Rats in enriched environments have more cortical connections Can be rearing But also occurs in aged rats ED Plasticity can occur throughout the lifespan String Instrument players

Plasticity in adulthood Change in cortical representation due to amputation

Plasticity in adulthood Change in cortical representation due to amputation Mechanism

Plasticity in adulthood Change in cortical representation due to amputation Mechanism Formation of new connections?