brain and behavior test 2

define cross tolerance

exposure to one drug can produce tolerance to drugs that act on the same receptors

what are some examples of cross tolerance drugs?

heroin and morphine; alcohol and benzodiazepines

define metabolic tolerance

when your body has repeated exposure to a drug and you need more of that drug to make an impact; less gets to the cite of action

define functional tolerance

drug doesn’t react with the site of action it needs to reach

what are some reasons for functional tolerance?

fewer receptors (downregulation), decreased efficiency of binding at receptors, receptors are less responsive

what is conditioned drug tolerance?

conditioned tolerance response to repeated situations (same place, same people, same album)

dopamine release _________

in the nucleus accumbens

what does the mesolimbic part of the brain signal?

to pay attention

what are the 2 natural reinforcers of the mesolimbic pathway

food and whoohoo time

give examples of how drugs of abuse harness the reinforcement pathway

nicotine binds to nicotinic Ach receptors on dopaminergic neurons in VTA; cocaine blocks dopamine transporters (DaT) in nucleus accumbens; amphetamine causes dopamine to leak out the vesicles and reverse dopamine transporters (DaT) in nucleus accum.

is GABA inhibitory or excitatory

inhibitory

Describe, compare and contrast the autonomic and somatic branches of the peripheral nervous system.

somatic: external environment; conscious movements

autonomic: regulates internal environment, managing involuntary function (stay alive functions)

name specific functions of the autonomic nervous system

regulates internal organ functions (heart rate, digestion, respiration rate, blood pressure)

what neurotransmitter does the somatic system use

acetylcholine

what neurotransmitter does the autonomic system use

Ach and norepinephrine

Describe, compare and contrast the parasympathetic and sympathetic branches of the autonomic nervous system

parasy: rest and digest system (conserves energy)

symp: flight or fight

Describe the general function of the cranial nerves

handle the sensory and motor functions of the head, neck, and facial region

how many cranial nerves are there

12 pairs

explain the twin studies

monozygotic (MZ) twins: identical twins who develop from a single fertilized egg and share 100% of their genes.

Dizygotic (DZ) Twins: Fraternal twins who develop from two separate eggs and share roughly 50% of their genes (the same as ordinary siblings).

• all behavioral traits are heritable

Differentiate between DNA and mRNA and between transcription and translation

trabscript: RNA polymerase reads a strand of DNA and builds a complementary single-stranded messenger RNA (mRNA) molecule; inside the nucleus

transl: Ribosomes read the mRNA sequence in sets of three bases using transfer RNA (tRNA) molecules to assemble a chain of amino acids, which folds into a functional protein; in cytoplasm

t/f: if MZ>DZ theres a greater heritability? (more shared genes & more shared trait)

t

t/f: if MZ=DZ theres a lower heritability? (difference in shared genes but not in shared trait)

t

define biochemical methods for studying heritability

certain genes linking to behaviors or disorders

define epigenetics

how gene expression changes w/o altering the DNA sequence

Define, compare, and contrast sex-limited genes and sex-linked genes

sex-linked genes are located on the sex chromosomes (X or Y)

sex-limited genes are located on non-sex chromosomes (autosomes) and are expressed in only one sex due to physiological or hormonal differences.

name the steps of gene expression

DNA transcription in nucleus, makes mRNA, translation in cytoplasm, makes protien

difference between transcription and translation

transcript: DNA segment copied into mRNA strand by RNA polymerase in the nucleus

translatio: mRNA read by ribosome to build amino acid chain, which then folds into a protein, in the cytoplasm

How do mRNA vaccines work?

teach your cells how to make a harmless piece of a protein from a virus, which triggers an immune response

What are some epigenetic modifications that can occur?

Epigenetic modifications are reversible, heritable changes in gene activity that happen without altering the underlying DNA sequence

!!!! YOUTUBE VIDHow does methylation, demethylation, acetylation affect gene activity?

meth: a transcriptional off-switch; Methyl groups block transcription factors from binding to the DNA.

deme: a transcriptional on-switch;

ace: turns genes on promoting gene expression

What kinds of experiences can cause epigenetic modifications?

stress, trauma, toxins, nutrition

whats a psychoactive?

chemical that crosses the blood-brain barrier to directly modify central nervous system activity, perception, mood, consciousness, or cognition

Which route of administration would get a drug to the brain the fastest?

inhaling it

Define and provide examples of agonists

A molecule that mimics or enhances the action of a natural ligand (such as a neurotransmitter or hormone) by stimulating a receptor

(morphine, heroin)

Define and provide examples of antagonists

A molecule that mimics/enhances the action of a neurotransmitter or hormone by stimulating a receptor

(antipsychotic meds, narcan)

what is this and what does it show?

A dose-response curve is a graphical representation that shows the relationship between the dose of a drug (or concentration) on the x-axis and the magnitude of the biological response (or percentage of a population responding) on the y-axis

what receptor do benzodiazepines and barbiturates bind to?

GABA

are benzodiazepines and barbiturates agonists or antagonists?

agonists

what are the effects of benzodiazepines and barbiturates

inhibition/IPSPs; behaviorally, they are anxiloytics and sedatives

out of benzodiazepines and barbiturates, which has the wider therapeutic index

benzos (its harder to overdose on)

give an example of a benzodiazepines

xanax, valium

what is cross tolerance

developing a tolerance to one drug also results in a reduced response to a different (chemically or pharmacologically simila) drug

define metabolic tolerance

the body becomes more efficient at breaking down something, so that less of it reaches its target site in the body

define functional tolerance

adaptation to a substance allowing someone to show fewer outward signs of intoxication and perform daily tasks more normally despite having a high concentration of the substance in their body

define conditioned drug tolerance

connecting drug effects to environment

What is this pathway called VTA --> Nucleus Accumbens pathway

mesolimbic, or reward/reinforcement pathway

Other than drugs of abuse, what else activates the mesolimbic pathway

food, whoohoo time, socialism

What is the perception generated by dopamine release in the nucleus accumbens? In other words, what does it signal to us?

"Pay attention, this is highly important and worth pursuing right now.”

for cocaine, THC, opioids, nicotine, ecstasy, and amphetamine/methamphetamine:

• What is their site of action (to what do they bind on the neuron), and how do they affect it (do the activate it or block it?)?

What drugs of abuse are ritalin, adderall, and concerta similar to, and in what way?

similar to illicit and licit central nervous system stimulants such as cocaine

What is the effect of opiate action in the locus coeruleus (pons), PAG (midbrain), medulla, and spinal cord?

blocks pain signals from reaching the brain

What drugs are used to treat opiate use disorder and how do they work?

methadone: agonist that binds to receptors in the brain, hitting the need without the effects

buprenorphine: agonist that binds to receptors and partially activates them

Where does nicotine act in the nervous system?

binding to nicotinic acetylcholine receptors (nAChRs) in the CNS and PNS

What are some cognitive effects of nicotine?

increased attention and alertness

By what neural mechanism is alcohol a stimulant? By what neural mechanisms is it a depressant?

it releases dopamine;

enhances inhibitory signaling by binding to GABA hyperpolarizing the neurons and making response time slow

What neurotransmitter systems are responsible for alcohols (1) reinforcing and (2) pleasureful effects?

1. dopamine, GABA, glutamate

2. dopamine, GABA, serotonin

What are some neural and cognitive effects of heavy, chronic use?

white matter alterations: communication between hemispheres

How do antabuse, naltrexone, and acomprosate work?

antabuse: blocks enzyme needed to break down alcohol; acts as a psychological and physiological deterrent

naltrexone: antagonist; binds to opioid receptors in the brain and blocks them without activating them blocking euphoric effects reducing desire to continue

acomprosate: GABA agonist and glutamate antagonist; restore and stabilize this baseline chemical balance in the brain during post-detox recovery

What neurotransmitter system do LSD, ecstasy, and psilocybin all affect?

serotonin

What hormones does ecstasy stimulate? In the context of ecstasy, which of those deals mainly with water balance and which deals mainly with social interactions?

serotonin, dopamine, and norepinephrine, oxytocin, vasopressin

oxy= social

vaso= water

Describe the 4 main models of addiction, as well as their weaknesses

1. addiction is a personal choice; promotes shame

2. addiction is a chronic disease; gives off powerlessness

3. addiction is a learned behavior; places alot of weight on their psychology forgoing dependence

4. addiction is based on social structures; overlooks fact that two people in the same environment can have different paths

Describe the conditioned place preference test and the self-administration test

CPP: rat in room with 4 other rooms and one room has drugs and is restricted to that room on designated days; if rat chooses to go to drug room unwarrented, drug considered rewarding, if avoided its considered aversive.

SA: rat has a catheter connected to an intravenous line, or a cannula for intracranial injections; rat presses trigger to get drug; either rat gets drug after a certain number of presses or number of presses goes up each dose; measures abuse liability

Define agonist and antagonist and provide an example of each

agonist: binds to a cell receptor and activates it to produce a biological response (turning on) (ex. morphine, heroin)

antagonist: binds to a cell receptor without activating it, blocking natural substances or agonists from attaching (turning off) (ex. narcan)

What are the 3 ways to remove a neurotransmitter from a synapse?

diffusion: Molecules move away from the synaptic cleft down their concentration gradient into the surrounding extracellular fluid, lowering their local concentration so they stop binding to receptors

enzymatic degradation: enzymes in the synaptic cleft break down the neurotransmitter into inactive pieces

reuptake: presynaptic neuron absorbs the molecules back into its axon terminal for recycling; neighboring glial cells (like astrocytes) absorb the neurotransmitters

Can a neuron respond to more than 1 neurotransmitter?

yes

Can a neuron release more than 1 neurotransmitter?

yes

What neurotransmitters go into the group “monoamines”?

Dopamine, Norepinephrine, Epinephrine, Serotonin, Histamine

What neurotransmitters share a pathway of synthesis? Collectively what are they called?

Dopamine, norepinephrine, and epinephrine; catecholamines

Where do the initial precursors for dopamine, norepinepherine, epinepherine, serotonin and acetylcholine come from

diet

what is norepinepherine made by

the locus coeruleus of the pons

What nuclei are responsible for (a) serotonin, (b) dopamine, and (c) acetylcholine?

a. raphe

b. substantia nigra

c. basal forebrain complex

What is the most common excitatory neurotransmitter?

glutamate

What is the most common inhibitory neurotransmitter?

GABA

What is the difference between ionotropic and metabotropic receptors?

ion: ligand-gated ion channels composed of multiple protein subunits that form a central pore; When a neurotransmitter binds directly to the receptor, it triggers an immediate physical change that opens or closes the pore, allowing ions (Na⁺, K⁺, Ca²⁺, or Cl⁻) to rush across the cell membrane

meta: G-protein-coupled receptors; When a neurotransmitter binds, the receptor activates an intracellular G-protein, which dissociates and triggers a biochemical cascade of second messengers, this can indirectly open or close ion channels, alter enzyme activity, or modify gene transcription