Psych 311 Exam 2

What is learning?

* an enduring change in behavior as a result of experience
* encoded by changes in the brain

What are the two types of learning?

non-associative and associative

What is non-associative learning?

When a stimulus is not paired with a behavior

What are two types of non-associative learning?

* habituation
* sensitization

What is associative learning?

when a response becomes associated with a stimulus

What are the two types of associative learning?

* classical conditioning
* operant conditioning

What is habituation?

* decreased response to the same, repeated stimulus
* tends to be toward non-threatening stimulus

what is sensitization?

* Increased response to the same, repeated stimulus
* tends to be toward a threatening or arousing stimulus

What is an animal commonly used to test habituation and sensitization?

Aplysia california and their Gill-Withdrawl Reflex

What is classical conditioning?

* AKA Pavlovian conditioning
* Learned response (CR) to a neutral stimulus by pairing the neutral stimulus (CS) with one (US) that evokes a natural response (UR)

What is associative learning?

* Operant conditioning
* Consequences of an action will determine how likely it is to happen again
* Behaviors that lead to good outcomes will be repeated
* Behaviors that lead to negative outcomes are less likely to occur again
* Use of reinforcement or punishment to shape behavior
* positive
* negative

What is an example of positive reinforcement?

add appetitive stimulus following correct behavior

What is an example of negative reinforcement?

remove noxious stimulus following correct behavior

What is an example of positive punishment?

add noxious stimulus following behavior

What is an example of negative punishment?

remove appetitive stimulus following behavior

What is memory?

Internal records of past experience as a result of learning

What is short term memory?

Working memory: short term, active storage

What are the two types of long-term memory?

Declarative and non-declarative

What is declarative memory?

* memories that can be recalled
* semantic: facts or events that did not happen to you;
* episodic: things that happened to you

What is non-declarative memory?

procedural: remembering how to do things like ride a bike

What type of memory does the hippocampus store?

* declarative memory
* episodic memory
* semantic memory

What type of memory does the prefrontal cortex store?

working memory

What type of memory does the cerebral cortex store?

perceptual memory, semantic memory, priming

What type of memory does the amygdala store?

emotional memory

What procedure was performed on patient H.M.?

had 2/3 of his hippocampus removed at age 27

What were the effects of patient H.M.’s procedure?

* he still had working memory and procedural memory
* he could not convert new declarative memories into long term memories
* he could not remember the years just before surgery

What were H.M.’s deficits?

anterograde amnesia and some retrograde amnesia

What did H.M.’s deficits tell us?

* Memory has many facets, each facet does not necessarily rely on the hippocampus.
* The hippocampus may be involved in converting/storing new memories into long term storage, but likely doesn’t store memories long term

What is the pathway for memory consolidation in the hippocampus?

sensory cortices → dentate gyrus → CA3 → CA1 → association cortices

What stage in memory consolidation are the sensory cortices active?

sensory information

What stage in memory consolidation are the dentate gyrus, CA3, CA1 active?

short-term memory

What stage in memory consolidation are the association cortices active?

long-term memory

What part of the brain are place cells located?

in the hippocampus

What are place cells?

* networks of cells that fire when rat is in a specific place in the environment
* silent when they are anywhere else

Where does long-term potentiation occur?

occurs in the hippocampus and amygdala

what is long-term potentiation?

persistent strengthening of synapses based on recent patterns of activity

What are ways to test memory?

* radial arm maze
* delayed t-maze
* barnes maze
* delayed matching to position (DMTP)
* morris water maze

What does the radial arm maze test?

working and reference memory

What is the resting membrane potential in mV?

\-60 and -80 mV

What 3 ions contribute to the resting membrane potential?

Sodium (Na+), Potassium (K+), Chloride (Cl-)

How does the neuron maintain resting membrane potential?

sodium-potassium pumps and potassium leak channels

Do sodium-potassium pumps or potassium leak channels use ATP?

sodium-potassium pumps

what are the properties of ion channels (Na+ and K+)

* voltage-gated
* use passive diffusion
* no energy
* ion channels only let molecules that are small enough to pass through

What are the characteristics of the resting potential?

* Open passive K+ channel
* creates the resting potential
* Closed gated K+ channel
* Closed Na+ channel

What are the characteristics of depolarization to the threshold?

* Open passive K+ channels
* Open Na+ channel
* some Na+ channels open, depolarizing cell to threshold
* Closed gated K+ channel

What are the characteristics of depolarizing after threshold?

* Open passive K+ channels
* Na+ channels are inactivated
* Gated K+ channels open
* re-polarizing and even hyper polarizing the cell (after potential)

What are characteristics of returning to resting potential

* all gated channels close
* the cell return to its resting potential

What are the two types of refractory periods?

Relative and absolute

What is absolute refractory?

* Another action potential cannot occur
* v-gated Na+ channels inactivated

What is relative refractory?

* Another action potential can occur if a super strong stimulus is present
* V-gated K+ channels open

What are two ways to improve conduction in a neuron?

increase myelination and increase diameter of axon

What sensation does the primary sensory neuron, Aα, perceive?

proprioception

What sensation does the primary sensory neuron, Aβ, perceive?

touch

What sensation does the primary sensory neuron, Aδ, perceive?

pain (mechanical and thermal)

What sensation does the primary sensory neuron, C, perceive?

pain (mechanical, thermal, chemical)

What are the characteristics of EPSP?

* Small depolarization (+) of the membrane
* Brings the neuron a bit close to threshold → more likely to fire action potential
* Excitatory neurotransmitter action
* glutamate

What are the characteristics of IPSP?

* Small hyperpolarization (-) of the membrane
* Bring neuron farther away from threshold → less likely to fire action potential
* inhibitory neurotransmitter action
* Gaba

What is summation?

when EPSPs and IPSPs add together

What are glutamate receptors?

NMDA, AMPA, mGluR

What happens when glutamate binds to glutamate receptors?

allows cations (Na+ and Ca2+) to enter cell

What happens when the presynaptic cells releases GABA and GABA binds to GABA receptors

Cl- channel opens, negative charge spreads throughout cell. This is IPSP

What happens when a positive action potential makes it to the axon terminal?

voltage gated calcium channels open. the calcium bind to vesicles causing them to reach neurotransmitters

what is synaptic plasticity?

change in strength (or number) of synaptic connections

how long is short term synaptic plasticity?

seconds, minutes

What presynaptic changes can happen in relation to synaptic plasticity?

* **Facilitation:** increased NT release
* **Depression:** decreased NT release

What specific presynpatic changes occur due to short term synaptic plasticity?

* Number of release/docking sites
* Ca2+ channel conductance
* Amount of NT per vesicle
* Number of vesicles = size of ready-releasable pool

How long is long term synaptic plasticity?

hours to days

What are the two types of long term synaptic plasticity?

* Long-Term potentiation
* increased EPSP after high frequency stimulation
* AMPA receptors insertion
* Long-Term depression
* Decreased EPSP following low frequency stimulation
* AMPA receptors internalization

What can we learn from in vivo electrophysiology?

* Which cell populations fire during behavior
* how certain cells are firing
* frequency, temporal aspects

What can we learn from in vitro electrophysiology?

* How ions are moving through the membrane
* voltage clamp: holding the voltage constant to see how ions move
* at a particular voltage, what ions are moving in and out of the cell
* How certain ions moving through the membrane influence membrane voltage
* current clamp: injecting a specified amount of a particular ion and seeing how it changes the voltage of a cell
* can measure action potentials, and show which ions contribute to action potential firing

What are the long term effects of drinking?

* substance use disorder
* co-users were at 3/38 greater odds of having an AUD but not CUD
* behavioral
* decreased academic performance
* SAM doubled the odds of drunk driving, social consequences, and harms to self
* neuro-cognitive
* poorer selective attention accuracy
* greater discounting of future rewards

What is non-contingent exposure

* experimenter-adminstered, animal does not choose to take the drug
* intraperitoneal injection, subcutaneous injection, oral gavage

what does the animal model of drug self-administration

* operant task: response required for reinforcement
* routes: I'.V/, oral ingestion, inhalation
* dose, reinforcement schedule, cues can all be manipulated
* what this can tap into:
* cumulative intake
* patterns of intake
* increase in intake (escalation)
* motivation to receive the drug

what are self-administration caveats?

animals dont like many of the drugs humans do: THC and LSD

What happens in the brain when you consume alcohol and THC together?

* both bind to cannabinoid receptor type 1 (CB1R)
* located on membrane of presynaptic axon terminal
* inhibit presynaptic neuron
* increase or decrease neurotransmitter release

How does combined exposure to alcohol and THC affect the current frequency in a CB1R-dependent manner?

reduces miniature excitatory postsynaptic

In control rats, 40 Hz stimulation inhibits local field potential in prefrontal cortex

LFP: firing of a group of neurons; extracellular recording

CB1R agonist injection increased LFP2, i.e., reduced the magnitude of the initial inhibition

CB1R stimulation ___ PFC inhibition under 40 Hz

reduces

GABAaR stimulation ____ that inhibition

restores

What does GABA facilitate?

LTD

What are classical hormone receptors?

* nuclear receptors
* directly influence genetic expression

What are non-classical hormone receptors?

* cell-surface receptors
* indirectly influence genetic expression via second messengers

What are peptide hormones?

* lipophobic
* act through non-classical signaling
* Ex. angiotensin, gherkin, insulin, leptin, oxytocin, somatostatin, vasopressin, growth hormone

What are different sex hormones?

* estrogens
* primary type: estradiol (E)
* androgens
* testosterone (T)
* dihydrotestosterone

What is the HPG Axis: sex hormone signaling for males

* luteinizing hormone (LH) stimulated T production in testes
* follicle-stimulating hormone (FSH) and T promotes sperm production

What is the HPG Axis: sex hormones for females

* follicle-stimulating hormone (FSH) stimulates E production in ovaries
* lutenizing hormone (LH) stimulates P production - prepare for ovulation

What are the two major phases of the human menstrual cycle

follicular phase: before ovulation, egg is maturing, endometrium is being built up

luteal phase: after ovulation, egg is dying, endometrium reaches peak thickness

What are the coordination of hormones in the human menstrual cycle?

LH surge triggers ovulation

progesterone stimulates endometrial shedding

What issues can occur with the humans menstrual cycle?

* endometrial cancer
* polycystic ovary syndrome
* infertility

What are the four phases of rat estrous cycle?

* destroys 1
* sometimes called metestrus
* diestrus 2
* proestrus
* peak E and P
* ovulation
* sex behavior
* estrus
* sex behavior

How do you determine stages of the estrous cycle?

* vaginal lavage
* wash out vaginal cells, stain, visualize
* cornification
* terminal differentiation and programmed cell death
* cells look different depending on the day of estrus cycle
* diestrus: cells dies and leukocytes clear debris
* proestrus: high E, healthy cells with nuclei
* estrus: lower E and P, cornfield epithelial cells (dying)

What are the characteristics of the estrous cycle?

* sex behavior is dependent on sex hormone levels
* females are only receptive to copulation when estrogen and progesterone are high

What are the characteristics of the menstrual cycle?

* humans and primates
* sex behaviors is independent of sex hormones
* females are receptive to copulation regardless of hormone levels

What are sexual behaviors of male rat?

* mounts
* intromission
* ejaculation

What are sexual behaviors of female rats?

* proceptive behaviors
* hopping, darting, ear wiggling
* lordosis

What brain regions are involved in sexual behavior in rats?

* medial pre optic area
* basolateral amygdala
* mediobasal hypothalamus

How is the medial preoptic area involved in sexual behavior in rats?

* in anterior hypothalamus
* for masculine sexual behaviors, ex. mounting
* lesions inhibit copulation

How is the basolateral amygdala involved in sexual behavior in rats?

* lesions reduce rates of responding to receive a sexual reinforcer
* used male rats as subjects
* sexual activity is normally rewarding

How is the mediobasal hypothalamus involved in sexual behavior in rats?

* for female rat sexual receptivity

What are the the two chemicals involved in sex behavior?

dopamine and opioids