psych 210 exam 3

neural groove vs neural plate vs neural crest

neural plate: formed by thickening of the ectoderm

neural groove: formed by neural plate folding in on itself

neural crest: top corners of neural groove

what structure within the CNS can the neural tube turn into and what happens when you have a defect in the neural tube development?

neural tube will become the brain and spinal cord, if there’s a defect CNS will not correctly form

what is the funciton of the apical radial glia and what happens if they’re defective?

radial glia are bipolar progenitor cells that produce all the neurons in the cortex

• divide symmetrically to make more radial glia

• divide asymmetrically to make intermediate progenitors

• newborn progenitors climb up the processes of the radial glia

what are growth cone functions?

growth cones in synaptogenesis grow from the cell body to make the axon, attracted to its final target via chemoattraction and chemorepulsion

what are some of the physiological brain changes in relation to brain structure? what occurs in sleep architecture as we age?

• brain continues to mature throughout early life and into adulthood

• synaptic density and brain density decline with age

• synatogenesis occurs, myelination occurs, synaptic pruning continues for years after the first year of life

• as we age, there is a severe reduction in stage three sleep and more frequent wakings

what is a critical period? what is the importance of early life experiences in critical periods? if you lack these early life experiences, what happens to your brain structure?

critical period: a period of maximal brain plasticity during which sensory experience is necessary to establish optimal cortical representations

• active/effective synapses are strengthened and ineffective synapses are pruned, active synapses more efficiently compete for neurotrophic factors

• if you lack early life experiences, brain shape will change to accommodate (neuroplasticity), won’t develop properly for portion deprived

ocular dominance critical periods, what does the histogram look like for normal monocular development and then for monocular deprivation?

normal monocular development: number of cells normally distributed with peak in middle (equal)

monocular development: side with closed eye has no cells and side with open eye has almost all of the cells

what is a hormone?

a chemical messenger that travels through the blood to act upon a distant target

what is the function of a neuroendocrine cell and why is it different than a normal neuron?

neuroendocrine cells receive synaptic signals from other neurons and produce action potentials, yet secrete a hormone into the bloodstream, thus electrical signals are converted into hormonal signals

anterior vs posterior pituitary, structure and hormonal differences

anterior: produce releasing hormones, released from axons that terminate on the portal system, travel via portal to anterior pituitary, anterior pituitary cells respond by secreting tropic hormones which travel through bloodstream and regulate endocrine glands

posterior: produce oxytocin or vasopressin, axons from neurons pass through pituitary stalk, terminates in capillaries of posterior pituitary, hormone released from terminal directly into bloodstream

HPA axis, hypothalamic pituitary gonadal axis

hypothalamus (GnRH) → anterior pituitary (LH and FSH) → gonads (testosterone, estrogen and progesterone)

demonstrates negative feedback loop, when testosterone/estrogen/progesterone are released, they go back to anterior pituitary and hypothalamus to tell it to stop producing more of themselves

what is the role of aromatase in masculinization vs feminization?

male: testes → testosterone → into SDN-POA neuron → aromatase → estrogen receptor → gene expression and cell survival → masculinization of the brain

female: ovaries → aromatase is present in SDN-POA but no testosterone → no gene expression and cell death → feminization of the brain

what is the role of estrogen receptors in masculinization vs feminization?

a critical period for sex hormone effects organization of the brain

males: shows peak of testosterone perinatally (just before birth), and a second rise of testosterone at puberty, large SDN POA, estrogen receptors present and active

females: lacks both perinatal and pubertal rises in testosterone, small SDN POA, no estrogen receptors

brain organization neonatally vs adulthood, giving an injection of testosterone during critical period vs adulthood, what happens?

critical period: female injected with testosterone perinatally will result in large SDN-POA (typical of males)

adulthood: female injected with testosterone during adulthood/puberty show no effect on SDN POA size

what is social behavior?

essential, engages a conserved set of brain regions

parenting, friendship, reproduction, communication, aggression, and prosocial behavior

what is a social decision making network?

a set of brain regions for detecting, evaluating and responding to the presence and behavior of others

calcium imaging vs lesion studies

what does it do and what is the purpose

calcium imaging: Ca²+ floods into cell, binds to indicator, to see for neural activity, inject virus into brain

lesion studies: destroy region of brain, then you can see what deficits there are in behavior to determine function of that brain region

gene silencing and receptor autoradiography

gene silencing: mess with the RNA to prevent protein translation, decreases number of whatever was being translated, essentially removing/silencing/knocking down that gene

receptor autoradiography: radiolabeled ligand put on radioactive tracer, ligands bind to receptors, then film or imaging plate creates image, tells us where a specific receptor is located in the tissue

• high binding → dark

• low binding → light

function of oxytocin in brain?

hormone that regulates uterine contractions and milk letdown, also a neuropeptide that acts on the brain to regulate maternal care and prosocial behavior

prairie voles

patterns of oxytocin receptor expression in voles indicates neural mechanism in pair bonding

prairie voles are monogamous as opposed to montane voles, which are promiscuous

oxytocin receptor autoradiography shows high binding in nucleus accumbens of prairie voles, but low binding in montane voles

homeostasis and thermoregulation

homeostasis: the state of steady internal physical and chemical conditions despite changing external conditions

thermoregulation: physiological process that maintains a set body temperature

general principle of mammalian homeostasis: sensor (detects shift) → control (determines response) → effector (executes action to restore balance)

thermoregulation in homeostasis:

• if body temp rises → blood vessels dilate, sweat glands secrete fluid, heat is lost

• if body temp falls → blood vessels contract to conserve heat, shivering to generate heat

TRPM2, warm sensing neurons

neurons in preoptic area (POA) sense warmth and express TRPM2

when TRPM2 are activated, induces cold-seeking behavior in animals

if TRPM2 are knocked out, what does animal do? not display cold seeking behavior, impaired ability to detect warmth

hormones responsible for hunger and satiety

hunger: ghrelin (also LH)

satiety: leptin and GLP-1 (also VMH)

neuronal communication to brain when feeling hungry, what is the nerve responsible for neuronal communication to brain

vagal nerve

hypothalamic neurons for hunger and satiety

hunger: NPY/AgRP, GABAergic

satiety: POMC/CART

leptin

regulates satiety, produced by white adipose tissue, gets regulated by fat mass (adipose tissue)

biological rhythms

circadian: about a day

infradian: more than a day (menstrual cycle)

ultradian: less than a day (sleep cycles)

circannual: about a year

endogenous vs entrainable circadian rhythms

endogenous: persist in absence of external cues

entrainable: a cue, like light, can realign the body’s internal clock

EEG

a test that measures electrical activity in the brain using electrodes attached to the scalp, can see scan of brainwaves, used to characterize different stages of sleep

characteristics of sleep stages

stage 1: alpha rhythms and vertex spikes

stage 2: sleep spindles and K complexes

stage 3: large, slow delta waves

REM sleep: rapid eye movement, resembles that of waking

jet lag

when shifting to a different time zone with different lighting, internal clock gets shifted by present of light cue and you experience fatigue, insomnia, digestive problems etc, look at brain waves and presence of light

brain regions for regulating sleep

basal forebrain: slow wave sleep

brain stem: arousal, wakefulness and alertness

subcoeruleus: REM sleep

hypothalamus: coordinates above regions

ipRGC

• in response to sleep

• express melanopsin, which absorbs blue wavelengths of light, which triggers opening of cation channels, specialized retinal cells

• retinohypothalamic tract conveys information from ipRGCs to SCN

what are their purposes of each technique and what does the result tell you, in terms of sleep?