Behavioral neuroscience exam 3

difference between neural plate, neural groove, and neural crest

- neural plate: A thickened, flat sheet of ectoderm induced by the notochord to become the neuroectoderm. It is the very first stage, representing the precursor to the entire nervous system.

- neural groove: Formed when the center of the neural plate invaginates (dips down) and the sides rise to form neural folds. forms neural tube

- neural crest: a column of ectodermal cells settling on either side of the neural tube, will migrate to form the peripheral nervous system

What structure in the CNS can the neural tube turn in to and what happens with a defect to neural tube development?

develops in to the brain (anteriorly) and spinal cord (posteriorly). defect to brain or spinal cord.

function of apical radial glia and what happens if they are defected

they produce all the neurons in the cortex and divide symmetrically to. make more radial glia or assymmetrically to make future neurons. Defects in aRGs impair neurogenesis and neuron guidance, leading to severe brain disorders

what is the function of growth cones in synaptogenesis

grows from the cell body to make the axon. it is attracted to its final target by chemoattraction and is repelled by chemoorepulsion. at the tips of developing axons and dendrites that drive axon guidance, target recognition, and synapse formation.

chemoattraction vs chemorepulsion

cells or organisms move toward (attraction) or away from (repulsion) specific chemical signals

physiological brain changes in aging

brain volume declines with age. around 60, whole brain volume can be lost more. human brain volume declines steadily by about 5% per decade after the age of 40. synaptic density declines with age. hippocampus declines after 60 otherwise is variability.

what happens to sleep architecture as you grow older?

the total amount of sleep declines and the number of awakenings increases. less stage 3 sleep.

what happens to your sleep as you grow older?

we sleep less and less until we hit adolescence. we sleep less as we age. early in life we have lots of REM sleep. by adulthood, we average 8 hours and 20% is REM sleep. most people sleep a lot less in old age.

what is a critical period?

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

what is the importance of early life experiences in critical periods? what happens to your brain structure with these experiences?

early life experience shapes the wiring of neural circuits. active/effective synapses are strengthened. ineffective synapses are pruned.

ocular dominance

most cortical cells become binocular as the two eyes are stimulated by experience. monocular deprivation can lead to blindness in that eye.

what is a hormone?

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

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

they receive synaptic signals from other neurons and produce action potentials. they secrete a hormone into the bloodstream INSTEAD of releasing neurotransmitters into synapse.

anterior pituitary vs posterior

anterior secretes (makes its own) tropic hormones while posterior stores and releases hormones from two hypothalamic regions

HPG axis function

starts in the hypothalamus that releases hormones to the anterior pituitary which stimulates release of two more hormones. Goes to ovary and testis. Negative feedback: output of the hormone feeds back to inhibit the drive for more of that same hormone.

role of aromatase in masculinization vs feminization

Aromatase is an enzyme that converts testosterone into estrogen and then the estrogen is binded to a receptor and shows gene expression and cell survival. brain is masculinized by estrogen (made from testosterone). females need low estrogen/aromatase for a female brain.

role of estrogen receptors in masculinization vs feminization. corresponding effect on the SCN?

brain organization neonatal vs adulthood. giving injection of testosterone during critical period vs adulthood.

during neonatal: hormones have organizational effects. they physically shape brain circuits. Effects are permanent or long-lasting.

during adulthood: In adulthood, hormones mainly have activational effects. They activate or modulate already-built circuits. Effects are temporary and reversible.

- When the developing brain is exposed to androgens, the animal's brain is organized in a masculine fashion, so,

as an adult, it is more likely to show male-like behaviors, and less likely to show female-like behaviors.

what is social behavior?

interactions between 2 or more members of a species

what is a social decision making network?

a set of brain regions implicated in detecting, evaluating, and responding to the presence and behavior of other members of the species

calcium imaging vs lesion studies. purpose and function.

Measure real-time neural activity. (Neurons fire → calcium levels inside the cell rise) vs. observing behavioral or cognitive changes resulting from damaged brain tissue (determines what brain region is necessary for a function)

gene silencing vs receptor autoradiography. purpose and what does it do?

Reduce or "turn off" the expression of a specific gene to study what that gene does (by RNA interference) vs. telling us where a specific receptor is located in the tissues

what does oxytocin do?

hormone that regulates uterine contractions and milk letdown. acts on the brain to regulate maternal care and prosocial behavior.

what is the point of prairie voles and why do we study them?

Patterns of oxytocin receptor expression in voles may tell us about neural mechanisms of pair bonding. shows stable pair-bondings and oxytocin infusions in the brain of females to help them bond to their mates.

prairie voles vs montane voles

PV- monogamous and loyal to partner

MV- polyamourous, not loyal to partner

PV have more oxytocin receptors and MV have little to no oxytocin receptors

what is homeostasis?

The state of steady internal physical and chemical conditions despite changing external conditions

what is the general principle of mammalian homeostasis?

sensor--> control--> effector

- The sensor detects a shift from the set point (or zone), detects deviation

- The control center processes the information and determines a response

- The effector carries out the response to restore balance (can be behavioral)

what is thermoregulation?

the physiological process that maintains a set body temperature

what are the functions of TRPM2 and how does the animal react when activated?

TRPM2 is activated by moderately warm temperatures. Especially important in the hypothalamus (body temperature control center). Helps detect when the body/environment is getting too warm.

Typical responses:

- seek cooler environments

- reduce heat production

- increase heat loss behaviors (spreading out, reduced activity)

hunger vs. satiety? what is the different hormone response for each?

hunger (grhelin) vs. fullness (leptin).

NPY/AgRP → hunger, feeding

POMC/CART→ satiety, fullness, cessation (stopping) of feeding

hormonal communication vs neuronal communication when hungry. specific nerve for neuronal communication to the brain?

hormonal is through bloodstream and neural is through nerves. the body communicates with the brain vis nerves AND hormones to regulate appetite. vagus nerve innervates the gut.

hypothalamus neurons sensing hunger vs satiety?

- The arcuate nucleus of the hypothalamus contains two types of neurons that have opposing effects on feeding and appetite

- POMC/CART→ satiety, fullness, cessation (stopping) of feeding

- NPY/AgRP → hunger, feeding

what does leptin regulate and how does it regulate in the body?

regulates satiety. more fat means more leptin. then the stomach release grhelin when empty. body communicates with brain through nerves and hormones.

types of biological rhythms and their differences

- circadian rhythm: occurs within one day

- ultradian: more frequently than just one day

- infradian: occurs over multiple days

- circannual: happens yearly

endogenous circadian rhythms vs entrainable

persist even in the absence of external cues vs. when you do you have a cue (such as light/time) it can realign the body's internal

purpose of electroencephalogram (EEG) and why we use it

used to measure the brain's electrical activity by recording signals from the scalp. studies sleep and circadian rhythms.

what are characteristics of sleep stages (esp rem sleep and stage 3 sleep)

- stage 3: slow-wave sleep is recognized by large, slow delta waves. most restorative.

- REM sleep: despite deep muscle relaxation, activity in REM sleep resembles that of waking. high brain activity, vivid dreaming, rapid eye movement, and muscle paralysis.

what is jet lag?

a disruption of circadian rhythms due to crossing time zones

during a period of jet lag, what happens to your circadian clock?

they become desynchronized from the local day-night cycle, causing body rhythms to fall out of sync. need one day per time zone to get back on track.

explain the different brain regions regulating sleep

Basal forebrain: slow wave sleep

Brain stem: arousal, wakefulness, alertness

Subcoerulerus: REM sleep

Hypothalamus: coordination of the above regions

intrinsically photosensitive retinal ganglion cells (ipRCGs) what are their functions and how do they work for sleep?

specialized retinal cells. they express melanopsin which absorbs blue wavelengths of light, triggering cation channels. stops melatonin release if light is present.