Behavioral Neuroscience Final Exam

Gender

The behaviors and attitudes that a given culture considers to be masculine, feminine, or an alternative

Sex

A trait that determines whether a sexually reproducing organism produces male or female gametes

Testosterone and estradiol

What are two gonadal hormones?

Gonadal hormones

Two hormones that mediate early changes in the developing brain to assure that activation of the same circuits by the same hormones in adulthood will produce appropriate reproductive behaviors?

Early in development

When are sex differences established?

sex; gender

Humans are unique from other animals in that we distinguish ___ from ___.

Reproductive behavior

A broad term encompassing behaviors for attracting and finding a mate, copulation for exchange of gametes, and care and nurturing of offspring after they are born

Behaviors for attracting a mate, copulation, and care and nurturing of offspring

3 components of reproductive behaviors

Gonads

Sex hormones are excreted from this term.

testes; ovaries

What are the male and female gonads called?

Steroid

What type of structure do sex hormones have?

Androgens

Gonadal steroids synthesized in the testes

Estrogens

Gonadal steroids synthesized in the ovaries

Sex determination

The process by which the decision is made for a fetus to develop as a male or female

Sry

What is the gene on the Y chromosome called that directs the formation of testes?

Sex-determining region of the Y chromosome

What does Sry stand for?

Bipotential gonad

What is the gonad precursor known as?

Developmental program is female

What occurs in the absence of Sry or if there is a loss-of-function mutation in Sry?

Wolffian and mullerian ducts

What are the two ducts that connect the indifferent gonads to the body wall?

Mullerian ducts

What structure develops into the female reproductive organs?

Wolffian ducts

What structure develops into the male reproductive organs?

Neonatal period

The period of development directly following birth

Puberty

What can be viewed as a secondary sensitive period in mammals?

Sensitive period

When do steroids have an organizational effect?

Organizational/Activational hypothesis

A framework used to describe the two sensitive periods for gonadal steroid influences in sexual differentiation.

William Young

Who is the OAH based on?

Organizational

The first part of the OAH hypothesis in which onset of testosterone secretion in males defines the sensitive period in the brain and the start of masculinization.

When females are no longer sensitive to the effects of androgens

When does the organizational period end?

Activational

The second part of the OAH hypothesis in which a later surge of gonadal hormones in puberty serves to turn on previously organized brain networks

Proceptive behaviors

Female behaviors that encourage or maintain sexual interactions

Lordosis

An arched-back posture

Intromission

The active process of inserting the penis into the vagina

Only testosterone

How many signals masculinize the body, brain, and behavior?

True

True or False: Full masculine behavior require testosterone during development and adulthood

False

True or False: Female rats exposed to testosterone at birth will show lordosis

Sexual dimorphism

A term that refers to marked sex differences in appearance

Sexually dimorphic nucleus of the preoptic area (SDN-POA)

A small region in the hypothalamus in rats that is larger in many males relative to females

SDN-POA

Lesions in what brain structure disrupt ovulatory and copulatory behaviors in females and males?

SDN-POA (sexually dimorphic nucleus of the preoptic area), AVPV-POA (anteroventral periventricular nucleus of the preoptic area), pBST (Principal nucleus of the bed nuclei of the stria terminalis), SNB (spinal cord, nucleus bulbocavernosus)

What are the 4 Key CNS structures altered by organizing effects of gonadal steroids?

False

True or False: There are different neural circuits for male and female reproductive behavior

Hippocampus and amygdala

Two brain regions with sex differences not involved in reproduction

Emotionality, aspects of learning of memory, stress responsiveness, affiliative behaviors

Sex difference sin the hippocampus and amygdala show differences that affect (4):

Simon LeVay

The researcher who discovered a morphological difference in the brain of homosexual men

Third interstitial nucleus of the anterior hypothalamus (INAH-3)

The region of the brain located in the preoptic area that is larger in heterosexual men than in homosexual men

Homeostasis

Regulation of biological processes that keep certain body variables within a fixed range

Set point

A single value that the body works to maintain

Negative feedback

Processes that reduce discrepancies from the set point are known as

33% lost to digestion, 55% consumed by basal metabolism, 12% used for active behavioral processes

Energy Breakdown

Calories/day = 70 x weight^0.75

The basic equation for basal metabolism

Kleiber

The researcher that creator a basic equation for basal metabolism

Insulin

The pancreatic hormone that promotes glucose uptake into cells, and promotes conversion of glucose to glycogen

Glycogen

The form of glucose that is stored in the body

Glucagon

The pancreatic hormone that increases blood levels of glucose; mediates breakdown of glycogen back to glucose

Yes, brain cells. Glucose is actively transported across the blood-brain barrier

Can any cells in the body bring glucose take in glucose without insulin?

Type I

Diabetes that is juvenile onset and the pancreas does not produce insulin

Type II

Adult onset diabetes associated with obesity and a reduced sensitivity to insulin

Low

Are insulin levels high or low in people with diabetes mellitus?

Ventromedial hypothalamus

Lesions of which area of the brain could cause obesity in rats

Lateral hypothalamus

Lesions of which area of the brain could cause lack of appetite in rats

Lesions change the set point

How do lesions of VMH or LH change intake and body weight?

Arcuate nucleus of the hypothalamus

A region of the hypothalamus known as the appetite control center, that is governed by a variety of circulating hormones in the periphery

Leptin

A hormone produced by the body's fat cells when amount of fat stored reaches a certain level.

Leptin

A hormone that signals the arcuate nucleus to increase appetite

Ghrelin

A hormone released into the bloodstream by endocrine cells in the stomach. Levels rise during fasting and drop upon eating

PYY 3-36

A hormone released into the bloodstream from the gut with the opposite effect of ghrelin

PYY 3-36

A hormone that has low levels at fasting and rises right after eating, that is also associated with feelings of satiety

NPY/AgRP neurons (neuropeptide Y/Aghouti-related protein neurons)

The type of neurons in the arcuate nucleus that are sensitive to hunger signals (appetite enhancing)

POMC/CART neurons (pro-opiomelanocortin/cocaine-and -amphetamine-related transcript neurons)

The type of neurons in the arcuate nucleus that are sensitive to satiety signals (appetite-supressing)

Inhibit POMC/CART neurons, activate PVH, activate LH

3 Effects of NPY/AgRP neurons

Inhibit NPY/AgRP neurons, inhibit LH

2 Effects of POMC/CART neurons

Paraventricular Hypothalamus

Activating this structure stimulates appetite. This structure is a control center of hormones by projecting to the pituitary, and also has projections to brainstem neurons important for energy balance and food intake

Nucleus of the solitary tract

A brain structure that is part of a central pathway for feeding behavior, that receives signals from the PVH and LH.

Stomach distention, change in glucose levels in liver, other signals from vagus nerve

What type of signals would be sent to the NTS?

Cholecystokinin (CKK)

A hormone peripheral signal that is released by the gut after ingestion of good high in protein or fat

Feelings of satiety, activates vagus nerve receptors to signal satiety by inhibiting NPY/AgRP and exciting POMC/CART neurons

Characteristics of CKK

NTS System

Drugs like Ozempic and Wegovy act on which brain system?

Leptin and insulin

Two hormones where appetite/satiety regulation is on a longer time scale

Ghrelin and PYY 3-36

Two hormones where appetite/satiety regulation is a shorter time scale

Over-eating

Does lesioning of the ventromedial hypothalamus lead to over-eating or under-eating?

Ultradian rhythms

A biological rhythm with a frequency more than once per day

Infradian rhythms

A biological rhythm with a frequency less that once per day

Endogenous circannual rhythms

Internal mechanisms that operate on an annual or yearly cycle

Endogenous circadian rhythms

All animals (and life) produce which kinds of biological rhythms?

Free-running rhythm

A biological rhythm that occurs when no stimulus resets it

Phase shift

A shift of activity due to a shift in a synchronizing stimulus

Zeitgeber

A term used to describe any stimulus that entrains the circadian rhythm to the Earth's 24hour light/dark cycle (mainly light)

Suprachiasmatic nucleus (SCN)

A part of the hypothalamus that is the main control center of the circadian rhythms, it is located dorsal to the optic chiasm

The pattern is more erratic but still functions in light/dark; the pattern does not function at all without external cues

Can circadian rhythms work in rats with SCN lesions if light/dark is present? If light/dark is not present?

Damage the endogenous rhythms

What do SCN lesions do?

Retinohypothalamic tract

The small branch of the optic nerve that transmits light signals to the SCN

Melanopsin

The photopigment found in ganglion cells that transmit signals to the retinohypothalamic tract

No; the cells respond directly to light

Do ganglion cells going to the retinohypothalamic tract need input from rods or cones?

Clock and Cycle

The two proteins in the dimer that bind to DNA, enhancing transcription of Period and Cryptochrome

Function as a dimer that inhibit the activity of the Clock/cycle dimer, slowing transcription of Per and Cry genes, and therefore, Per and Cry proteins

What do Per and Cry proteins do?

Retinal ganglion cells with melanopsin send signals via the retinohypothalamic tract and release glutamate into the SCN. Increased glutamate leads to increased transcription of per gene causing synchronization

How does light act on the molecular steps of circadian regulation?

False

True or False: Mutations of Clock disrupt circadian rhythm if light is present?

Pineal gland

An endocrine gland located posterior to the thalamus that is regulated by the SCN

Melatonin

What hormone is primarily released from the pineal gland in the evening?

Jet lag

A term that refers to the disruption of circadian rhythms due to crossing time zones

Phase-delays

Traveling west does what to our circadian rhythms