Development of Brain Continued Flashcards
continues throughout adulthood, guided by experience
synapse rearrangement
typically weaker or inactive synapses are pruned away and the stronger ones remain, this allows for:
more efficient neural communication and signaling
the cortical thinning process continues from caudal to rostral throughout maturation reaching the … last, which may contribute to teenagers impulsivity
prefrontal cortex
is the most frequent inherited cause of intellectual disability, which ranges from mild to severe
Fragile X
in humans and mice with this disorder, cortical neurons have excessive immature … so normal elimination of synapses doesn’t occur
dendritic spines
(the extra inefficient synapses interfere with cognition and behavior)
impairment of vision in one eye with inability to see clear forms; lazy eye
- if h=this eye isn’t strengthened, the brain will ignore the image coming in from the weaker eye
amblyopia
is when one eye is misaligned, which results in double-vision
strabismus
if not realigned in childhood, the individual will not have good visual acuity (or accuracy) or
depth perception
preventing sight in both eyes, results in a loss of dendritic spines and a reduction in synapses in the visual cortex
binocular deprivation
- if deprivation lasts long enough, sight can never be restored
the … of development is when experience or treatment can make permanent alterations
sensitive period
during this period causes significant reorganization throughout the brain (from the eye to the thalamus and cortex) and permanently impairs vision in the deprived eye
monocular deprivation
- normally most neurons in the visual cortex respond equally to light presented to either eye, with md, most cortical neurons respond only to input from the non-deprived eye
grow stronger or weaker depending on their ability to affect a postsynaptic cell
hebbian synapses
- cells that fire together, wire together
together these findings demonstrate…
importance of early experience in organizing the visual system
the sum of an individuals intrinsic, genetic information; constant (that is, your genes)
genotype
the sum of an individual’s physical characteristics; changes constantly based on extrinsic effects on genes, including environment, experience, etc.
phenotype
genes are intrinsic factors that develop WITHIN the cell – all other influences are extrinsic
differences in experiences produce different phenotypes and behaviors
identical twins
an example of the effect of genetics combined with experience can be seen in individuals with …
phenylketonuria (PKU)
PKU causes inability of the individual to … an amino acid present in many foods
metabolize phenylalanine
is the study of the factors that change gene expression without changing the gene sequences
epigenetics
- genes code for proteins
- changing gene expression changes the amount of protein that is produced
- proteins code for things like hormone receptors: the level of hormone receptors can significantly change behavior
why does changing gene expression matter?
experiences and environment can add or remove things to the DNA (without changing the DNA sequence itself) to make it more or less capable of being transcribed and producing proteins
how can you change gene expression?
one example is … where a methyl group (CH3) is added on to the DNA and reduces gene expression
methylation
neither! it depends on the environment in which they live
which phenotype is better? one that is more anxious or less anxious?
