Ch 23 , 25: Plasticity Flashcards
Stage 1: Neurogenesis
Neural stem cells produce neuro blast and glial blast from progenitor cells. Neurons and glia also produce in hippocampus and olfactory bulb.
Stage 2: Cell Migration
Cells migrate along radial glial fibers
continues to 8 mo after birth
Stage 3: Cell Differentiation
Specialization of the blast cells.
Neural-> interneuron and projecting neurons
Glial-> Oligodendroglia and Astrocyte
Complete at birth
Stage 4; Neural Maturation
Development of dendrites in 2 step;
dendritic arborization and growth of dendritic spines (slow process)
Development of axons are faster and mechanisms (structure, distance, signals, and branches) Continues after birth
Stage 5 and 6; Synapse formation and pruning
Gene, biochemical, and electrical signaling guide formation of synapses.
Experience expectant
Depend on the presences of certain sensory experiences for organization
Experience dependent
refer to generation synapses that are unique to and individual organism
Myelogenesis
Cerebral Maturation throughout lifespan
Piaget: stages of cognitive development
Sensorimotor(birth-18-24mo) Object permanence
Preoperational (2-6yrs) can represent things with words and drawings
Concrete operation(7-11 yrs) conservation, mathematical transformation
Formal operation (>12 yrs) abstract reasoning
Growth Spurts
Large increase in mass of brain in irregular periods due to increase in metabolism, synapse, blood volume to brain
Environmental Deprivation
Structure can be molded into different forms. Influenced by external and internal factors (more disruption after 18 mo)
brain injury and plasticity
effects depend on behavior, speech, extent and location of the damages and age during the time the injury occur
Effects of early brain lesions on brain structure later in life
plastic changes in brain that support recovery; intact circuits of the brain re-orgainze, new circuitry is generated, and neurons and glial are generated to replace the lost neurons
Evidence of plasticity on brain structure later in life
cortical connectivity; abnormal connection after day 1, hemidecortications-> connection expand and improve function
Neural Plasticity can be studied through
chapter 25
observable behavior, cerebral maps, synaptic organization, physiological organization, molecular structure, and mitosis.
Somatosensory Plasticity
Motor and sensory maps can be altered by experience - not alway adaptive
Plasticity in synaptic organization
dendritic arborizations; synapse number and size
Plasticity in physiological organization: Long-term potentiation
enhanced synaptic transmission after electrical stimulation of a cell
Hippocampus
Plasticity in physiological organization; Kindling
development of persistent seizure activity after repeated exposure to an initially subconvulsant stimulus
Amygdala
Plasticity in Molecular Structure Epigenetics
allows researcher to see what genes are affected by certain experiences
Plasticity in Mitotic Activity
Olfactory bulb and hippocampus produce new neurons in adults
examples of functional restitution
Recovery from aphasia;
Head-injury pt (vs stroke) show most rapid and most complete recovery
Deficits are least severe in anomic(naming object) pt and most severe in global aphasic(every aspect)
Rate of recovery similar in all patients
During recovery, progress to other stages
Recovery from Aphasia
Most recovery in first 3 mo
Younger pt better recovery
Right hemisphere is more resistant to damage
Function restitution; return to daily life
when employment is used as a measure of recovery
sibling relationship suffer more along with social and leisure activities
Measure of recovery often overlook the strategies the person is using
Variable affecting recovery
Young age
female and left handedness
Higher iq intelligence
and optimistic/positive personality
Plasticity in the injured brain
functional imaging after cerebral injury-
post stroke changes; reorganization take place bilaterally
capacity for reorganization declines with increases in stroke size and age
considerable variability exists between patients
