PSY2061 Lecture Notes - Lecture 1: Adult Stem Cell, Olfactory Bulb, Neurogenesis
15 May 2018
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experience & postnatal development
-Neurodevelopment is a dependant on the environmental experiences
-Critical periods (Window of opportunity)
*specific periods (i.e. time dependent) in which brain systems are dependent on
environmental exposures, e.g. : binocular vision - 3 to 8 months
-Sensitive periods of development (when environmental exposures have greater
influences
environmental deprivation & enrichment
Studies have focused on sensory and motor systems
Deprivation:
-Rats reared in dark develop vision deficits and fewer synapses (dendritic spines)
-Human infants with cataracts develop severe vision deficits, but vision restores if
removed 1-9 months
enrichment:
-Rats raised in group enclosures have thicker cortex, more dendritic spines and
synapses than those raised in isolation
Competitive Real estate
- Depriving one eye of input during a sensitive period of development, has a life long
effect on the functioning of that eye
*ability of the eye to activate visual cortex is reduced, while the ability of the other eye is
increased
Neurogenesis in Adults
•Historically, neurogenesis was considered a phase that only occurred early in
development!
- excess cells produced initially which then die if served its purpose or inactive!
- lost cells never replaced
•Since 1980s, evidence emerged demonstrating adult neurogenesis
•Non-human primate adult neurogenesis:!
- Hippocampus!
- Olfactory bulb
•Human primates!
- hippocampus!
- striatum
Adult Stem Cells
Olfactory bulb and striatum neurones
-adult stem cells at the sub-ventrical zone of the lateral ventricles
-migrate to olfactory bulb or striatum
Reorganisation of the adult cortex
Substantial evidence states that adult cortex can be re-organised
-Adult stringed musicians who play with left hand have enlarged finger hand
representation area in their right somatosensory cortex
-Anaesthetising specific fingers reduced their representation in contralateral
somatosensory cortex!
Document Summary
Neurodevelopment is a dependant on the environmental experiences. *speci c periods (i. e. time dependent) in which brain systems are dependent on environmental exposures, e. g. : binocular vision - 3 to 8 months. Sensitive periods of development (when environmental exposures have greater in uences environmental deprivation & enrichment. Studies have focused on sensory and motor systems. Rats reared in dark develop vision de cits and fewer synapses (dendritic spines) Human infants with cataracts develop severe vision de cits, but vision restores if removed 1-9 months enrichment: Rats raised in group enclosures have thicker cortex, more dendritic spines and synapses than those raised in isolation. Depriving one eye of input during a sensitive period of development, has a life long effect on the functioning of that eye. *ability of the eye to activate visual cortex is reduced, while the ability of the other eye is increased. Neurogenesis in adults: historically, neurogenesis was considered a phase that only occurred early in development.
