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PSYC 3240 Exam 2 Review

Terms in this set (78)

Spinal Cord
- cable of neurons (gray matter & white matter)
- carries signals from the brain to muscles and glands (periphery)
- carries sensory info from the periphery (sense organs) to the brain
- "hub" for reflex arcs
Reflex arc
- neural pathway that controls a reflex act
Reflex act
- simple, automatic response (muscle contraction or gland secretion) to a sensory stimulus
Cerebrospinal fluid & meninges
- provide structural support
- protect CNS from trauma
vertebrae
spinal column (outside-cartilage, inside-jellylike substance) -- *skeletal system, NOT nervous system
Blood-brain barrier
- prevents harmful substances (toxins) from entering the brain
- Capillary membrane cells so tightly packed together that they form a barrier to most molecules
- Fat soluble substances freely pass through the barrier (i.e. psychiatric medications and other drugs)
- Other substances use special transport proteins to get through (amino acids, glucose)
- some areas of the brain are NOT protected by blood-brain barrier
the area postrema (in medulla)
- induces vomiting when certain toxins are in bloodstream
Peripheral Nervous System
Cranial nerves (12 pairs), Spinal nerves (31 pairs)
Somatic
motor neurons, sensory neurons
motor neurons
carry signals from CNS to skeletal muscles
sensory neurons
bring info from sensory organs into CNS
Autonomic
- regulates body's general activity level
- controls smooth muscles, heart, glands, etc.
Sympathetic branch
- speeds up bodily processes such as heart beat, respiration, blood pressure, sweat glands
- originate from middle of spinal cord
- passes through sympathetic ganglion chain (simultaneous activation of organs -- works as a unit; connected)
Parasympathetic branch
- slows bodily processes back down
- originates from ends of spinal cord -- isolated (not connected like ganglion chain)
Sympathetic and Parasympathetic...
are both active to some degree all the time -- body's activity reflects balance between the two
Proliferation (development of nervous system)
neurons divide & multiply at extreme rate
Migration (development of nervous system)
neurons migrate to final location by climbing radial glial cells
Circuit Formation
- neurons send developing axons to make synapses with their target cells
- growth cone develops at tips of developing axons and move toward final targets using chemical/molecular signals
Circuit Pruning
- extra neurons that have developed die
- eliminates large numbers of extra synapses --refines the organization
Plasticity
- ability of synapses to be modified by experience (learning)
- decreases with age; cortical association areas are more likely to return their plasticity
Drugs
chemical substance that changes the body or its functioning
psychoactive drugs
have psychological effects (anxiety relief, hallucinations, etc)
agonist
- mimics or enhances the occurrence of a neurotransmitter (NT)
- having some effect on receptor as NT
- increasing effect of NT on receptor
- blocking reuptake or degradation of NT
antagonist
- blocks or reduces the effect of a NT
- binding to a receptor without activating it; prevents NT from binding to receptor and opening the related ion channel
- reducing the availability of the NT
addiction
- preoccupation with obtaining drug
- compulsive use of drug
- high tendency to relapse after quitting
withdrawal
- negative reaction when drug use is stopped
- symptoms often the opposite of effects of drug (withdrawal from elation producing drug -- depression)
tolerance
- increasing amounts of the drug are required to produce the same results
- mostly due to reduction in number and/or sensitivity of receptors to the drug
Opiates
- derived from opium poppy
- opium has been abused since around 4000 BC
- morphine
*early 1800s - effective treatment of intense pain
heroine
opiate - late 1800s - initially sold as an over-the-counter analgesic
codeine
opiate - cough suppressant
effects of opiates
- analgesic (pain relieving)
- hypnotic (sleep inducing)
- produce euphoria (intense sense of happiness)
- addictive (heroine): highly soluble in lipids (crosses blood-brain barrier easily), major danger in overdose b/c drug is too pure & tolerance
- bind to opiate receptors; act as agonists of endogenous (generated within the body) opioids known as endorphins (pain reliever)
Depressants
-reduce activity of CNS
-includes sedative, anxiolytic, and hypnotic
Ethanol (alcohol)
- depressant; produced from fermented fruits, grains, etc (waste product of bacteria)
- complex action: high doses= sedative (calming, hypnotic), low doses=stimulant
- addictive (oldest of abused drugs)
- withdrawal involves tremors, anxiety, mood, and sleep disturbances (delirium tremors in worst case - hallucinations, seizures, even death)
- acts as an *antagonist of glutamate (most prevalent excitatory NT)
- acts as an *agonist of GABA by binding to GABAa receptors; facilitates opening of Cl- channels -- hyperpolarization of postsynaptic membrane
Barbiturates
- derivatives of barbituric acid
- complex action: low doses=inhibits cortical centers that inhibit behavior (i.e. talkative); high doses=sedative and hypnotic
- acts as antagonist of glutamate
- agonist of GABA; in high doses can open Cl- channels even without GABA -- potentially very dangerous (even coma or death)
Benzodiazepines
- similar to barbiturates but safer -- cannot open Cl- channels on their own
- produce anxiolytic (anxiety reducing), sedative, anti-seizure, and muscle relaxing effects
- addictive
Stimulants
activate or increase activity of CNS
cocaine
- stimulant that produces euphoria, increased alertness, relief from fatigue
- used to be legal as an ingredient in over-the counter medications and Coca Cola (1 part in 50 million - trace amounts)
- acts as agonist of dopamine and serotonin by blocking their reuptake
- Addictive, withdrawal symptoms include depression and anxiety
- Can cause brain damage, seizures, and psychotic symptoms (kills neurons over time)
amphetamines
- stimulant; synthetic drugs (methamphetamine: speed, crank, crystal)
- produce euphoria, increase in confidence, alertness & concentration
- acts as agonist of dopamine and norepinephrine by increasing their release in the synaptic cleft
- in high doses can cause hallucinations, delusions, and other psychotic-like symptoms
nicotine
- stimulant; primary psychoactive and addictive agent in tobacco
- complex action: short puffs=stimulating effect; long puffs=depressant effect
- acts as agonist of acetylcholine (activates muscles, increases alertness)
- addictive, withdrawal symptoms include nervousness, anxiety, drowsiness, lightheadedness, headaches
caffeine
- stimulant; primary psychoactive agent in coffee
- produces arousal, alertness, and decreased sleepiness
- acts as agonist of dopamine and acetylcholine by increasing their release in the synaptic cleft
- withdrawal symptoms include headaches, fatigue, anxiety, shakiness, craving
Psychedelics
cause perceptual distortions (of objects, time, self, often accompanied by euphoria)
LSD
psychedelic drug similar to serotonin -- binds to serotonin receptors
Ecstasy (MDMA)
psychedelic drug that causes release of dopamine and serotonin -- destroys serotonergic neurons in monkeys
Angel dust (PCP)
- produces schizophrenia-like symptoms in humans
- inhibits glutamate receptors
- increases activity (agonist) of dopamine pathways
- addictive (developed as an anesthetic)
Marijuana
- dried and crushed leaves and flowers of Indian hemp plant
- Major psychoactive ingredient: THC - particularly concentrated in the dried resin of the plant -- hashish
- THC acts as agonist of neurotransmitters anandamide and 2-AG by binding to their receptors (two known cannabinoid receptors); widely distributed in CNS
- Anandamide and 2-AG may play important role in the regulation of mood, memory, appetite, and pain perception (effects of marijuana)
- withdrawal symptoms are associated with stopping use (e.g. anxiety, irritability, stomach cramps)
Addiction
- preoccupation with obtaining drug
- compulsive use of drug
- high tendency to relapse after quitting
Withdrawal Avoidance Hypothesis
- addiction is caused by desire to avoid withdrawal symptoms (does not explain use of drug before dependence develops)
withdrawal
negative reaction when drug use is stopped
Different areas of the brain seem to be involved in...
withdrawal and addiction
Periventricular/Periaqueductal gray
-responsible/involved in withdrawal
ventral tegmental area
-involved in establishment of addiction (along with medial forebrain bundle, nucleus accumbens, and mesolimbocortical dopamine system)
Mesolimbocortical dopamine system
- the whole responsible for signaling reward leading to addiction (whole being ventral tegmental area, medial forebrain bundle, and nucleus accumbens)
- may be part of a general reward system *(location for major drug reward system)
- electrical stimulation of the medial forebrain bundle is rewarding in rats; increases dopamine level in NAcc
- Involved in rewarding effects for behaviors of basic importance (e.g. sex, feeding, etc); increase dopamine level in NAcc (both humans and non-humans)
Nucleus Accumbens (NAcc)
- rich in dopamine receptors
- nearly all abused drugs increase dopamine levels in NAcc
- reducing dopamine level in NAcc decreases rewarding effects of drug
*Increase in dopamine in NAcc may be the 'neural basis' for rewarding effect of drugs (but not only drugs)*
Apparent paradox:
- lower number of dopamine receptors in drug users; possible innate trait; "reward deficiency syndrome" - vulnerability to drug use
- Dopamine activity in MDS cannot account for all addictions: benzodiazepines affect glutamate and GABA levels; many continue to use drugs even when the effects are no longer pleasurable (possibly due to withdrawal avoidance)
- possible important role in learning: just seeing drug paraphernalia can evoke craving in drug addicts; dopamine levels in MDS may act as "teaching signals" emphasizing importance of relevant stimuli
Overcoming withdrawal symptoms...
- difficult w/ nicotine or opiates
- potentially life threatening w/ alcohol
Agonist treatments
replace addicting drug with another that has similar effect (nicotine gum; methadone for heroine addict)
Antagonist treatments
involve drugs that block effects of addicting drug (GABAa receptor blocker limits effect of alcohol)
Aversive treatments
- cause negative reaction when person takes an addicting drug
- Antabuse prevents breakdown of alcohol by-products, makes you ill if you drink alcohol
Antidrug vaccines
- stimulate immune system to produce antibodies that break down the drug: longterm action; avoid side effects of other medicines
**pharmacological treatments for drug addiction are still somewhat controversial
Motivation
- set of factors that initiate, sustain and direct behavior
- useful concept for organizing ideas about the sources of behavior
*inability to explain behavior solely in terms of external stimuli
Instinct
(theoretical approach to motivation)
- complex behavior
- automatic
- unlearned
- occurs in all members of a species
- not the same as reflex*
- ex: spiders ability to build webs
- does not apply to humans*
drive theory
(theoretical approach to motivation)
- the body actively maintains physiological systems in a condition of balance (homeostasis - Greek term)
- departure from homeostasis=aroused condition (drive) ((e.g. lack of nutrients, drop in temperature))
- drive motivates the organism to engage in appropriate behavior (e.g. eating, drinking, seeking warmth, etc.) which restores homeostasis
*applies to behaviors directly involved in restoring basic tissue needs
Incentive theory
individuals are motivated by external stimuli, not just internal needs (e.g. money, grades=incentives)
Arousal theory
individuals are motivated to maintain a preferred level of arousal -- different people have different "optimal" levels of arousal
Drive theory (revised)
- drives=conditions of tissues
- drives=states of the brain -- better accounts for sexual behavior, even eating behavior
Simple homeostatic drives...
many physiological systems maintain a given condition within a narrow range (e.g. body temperature, energy reserves)
Control systems
operate on negative feedback loop
feedback
process whereby some proportion of output of a system is passed (fed back) to the input --> influences the output
**see slides on BB
Negative feedback loop
feedback stabilizes the system at a given set point
**see BB slides
Temperature regulation
heterothermic and homeothermic
Heterothermic animals (reptiles)
externally regulated body temperature; adjust body temperature by sunning, finding shade, etc
Homeothermic (endothermic) animals (mammals)
adjust body temperature internally; sweating vs shivering

****where is the thermostat? = hypothalamus (see BB slides)
Thermostat *see slide*
hypothalamus, anterior commisure (connects left and right side of brain ((except birds))), optic chiasm, pituitary gland, mamillary body (resemble breasts), preoptic area (contains warmth-sensitive and cold-sensitive cells (neurons) that produce heat-reducing responses (sweating, panting) and heat-conserving responses (shivering)
Thirst
osmotic and hypovolemic
Osmotic thirst
water content decreases inside the cell --> eating salty food --> higher concentration of NaCl in blood than inside cell --> H2O drawn out of cell by osmotic pressure

*regulated by OVLT; Median PreOptic Nucleus (Hypothalamus) to make you feel thirsty ***see BB slides****
Hypovolemic thirst
blood volume decreases due to loss of extracellular water (e.g. sweating, vomiting, diarrhea, bleeding)

**regulated by heart (contains baroreceptors), to nucleus of the Solitary Tract (medulla), then to Median PreOptic Nucleus

*regulated by kidney (produces chemical hormone renin -- angiotensin II -- released into blood, to SubFornical Organ, to Median PreOptic Nucleus ***see BB slides****
Hunger
-more complex drive than temperature regulation and thirst
-set point can undergo dramatic and prolonged shifts (e.g. obesity)
-involves the need for variety of different and specific kinds of nutrients --> dietary selection: must distinguish between nutritious and non-nutritious (or toxic) foods -- role of TASTE
5 Primary Tastes
sweet, salty, sour, bitter, umami -- more complex taste sensations are combinations of the 5 primaries *See BB slides*
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