Psychology Chapter 5 Quiz

Psychobiology Pre-lecture Work 1

• Psychobiology is the study of biological mechanisms of normal and abnormal behavior. Behavior is influenced by bodily function, with the brain playing a key role.

Organisation of the Brain

• The brain is divided into lobes (frontal, parietal, occipital, temporal), the central sulcus, Sylvian fissure, pons, cerebellum, medulla, and spinal cord. These structures are interconnected.

The Hemispheres

• Left hemisphere: controls speech and abstract thinking, and the right side of the body.
• Right hemisphere: responsible for image processing, spatial thinking, and movement in the left side of the body.
• The two hemispheres communicate via nerve fibres.

Neurons Structure

• Neurons have dendrites (receivers), a cell body, an axon (conducting fibre), a myelin sheath (insulating layer), nodes of Ranvier, and axon terminals (transmitters). The myelin sheath speeds transmission.

Main Neurotransmitters

• Glutamate
• Dopamine
• GABA

Lecture Notes: What is Learning?

• Learning is the acquisition of behavioral information.
• Memory is the retention of information.
• Learning is crucial for adaptive behavior.
• Memory improves with more learning

Law of Diminishing Returns

• The same effort put into learning yields progressively less additional improvement over time.

The Rescola-Wagner Rule

• Learning occurs most strongly when outcomes are surprising.
• The amount learned is proportional to the amount of surprise in the outcome.
• As learning progresses, the prediction error (surprise) decreases.

Supporting Evidence - Pavlovian Blocking

• Blocking occurs when a new stimulus accompanied by a well-established conditioned stimulus (CS) does not lead to new learning.
• The pre-existing CS blocks the new information about the accompanying stimulus

Hollerman & Schultz: Monkey Study

• Monkeys learn to associate a visual cue with a reward (in this case a banana milkshake)
• Brain activity using neurons that release dopamine in the ventral tegmental area (VTA) is observed.
• This highlights the importance of prediction error and reward signals in learning

Plot 3: Dopamine Neurons and Prediction Error

• Monkey shown an image, but no reward given. This results in a lack of dopamine neuron activity.
• This illustrates that dopamine neurons respond to prediction errors (differences between what was expected and what actually happened).

Plot 1 & 2: Dopamine and Reward Prediction

• Plot 1 (first time): Shows unpredictable activity in the VTA - this is because there was no prior expectation of a reward.
• Plot 2 (later trial): The VTA demonstrates a predictive response to the image.

Conclusion: Prediction Error and VTA Firing

• If the monkey doesn't predict the reward, the VTA fires.
• When prediction is correct (reward is expected), VTA does not fire.

Prediction Error in Humans

• Experiments using predictable (water and juice) and unpredictable stimuli show that activity in the Nucleus Accumbens is greater in response to the unexpected.
• Dopamine (from VTA) is crucial for this (reinforcement learning).

Supporting Evidence - Inhibition of the Orbitofrontal Cortex

• Inhibition of the orbitofrontal cortex in animals demonstrates that the VTA is necessary for learning.

Learning in Babies: Prediction Error

• Babies react when they don’t predict an outcome (e.g., a cart not making a sound stopping).

Timescales: Visual Memory

• Visual memory has two stages; immediate or iconic memory (less than a second) and visual short-term memory.

Pavlovian Fear Conditioning (Rats)

• An experiment testing how long it takes rats to forget the sound/shock association
• An experiment using sound, shock, and freezing behavior.

Memory Consolidation (Pavlovian Fear Conditioning)

• Consolidation creates lasting memories from short-term memory.
• Protein synthesis is involved in memory consolidation
• The use of Anisomycin to inhibit protein synthesis.

Arc Protein and Memory Consolidation

• Scientists discovered that the Arc protein is involved in memory consolidation by using antisense technology to limit its production.

NMDA Receptors and Learning

• NMDA receptors are essential for learning – they directly bind to glutamate and can affect memory formation (or lack of memory).

Neuroscience Implications of Epilepsy

• Epilepsy is linked to altered BDNF expression.
• Met supplementation may offer a way to improve memory in people with epilepsy.

Learning and Memory (Energy Use)

• Learning and memory are energy intensive processes; the brain prioritises important information.
• Memory can be categorized for easier recall

Synaptic Plasticity

• Synaptic plasticity is the ability of synapses to adjust their strength. It results from differences in neuron activation.

Long-Term Potentiation (LTP)

• High-frequency stimulation increase synaptic strength.
• Was discovered in rabbits' hippocampus by Bliss and Lomo.

Two Types of LTP

• Non-associative LTP: activity in the presynaptic neuron alone can increase the synaptic strength.
• Associative LTP: coincident activity in the pre-and post-synaptic neurons is required for the increase in synaptic strength.

LTP and Fear Conditioning

• LTP plays a critical role in fear conditioning; this process occurs mainly in the amygdala.

Making an Artificial Fear Memory (Optogenetics)

• Optogenetics can induce fear memory without a foot shock stimulus when light is used.

Long-Term Depression (LTD)

• LTD decreases synaptic strength with low-frequency stimulation.
• This mechanism may underlie motor learning (processes that happen in the cerebellum)

Coexisting LTD and LTP

• LTD and LTP co-exist and can both affect increased responding.
• In an inhibitory synapse, weakening it excites the neurons.

Neural Communication: Resting Membrane Potential

• The electrical potential difference inside and outside a neuron when it is at rest. It is normally -70 mV
• Sodium-potassium pump maintains a negative charge inside a cell.

Neural Communication: Action Potential

• The rapid depolarization and repolarization of a neuron's membrane potential in response to a stimulus.
• The change happens in rapid sequence of opening and closing of sodium and potassium voltage-gated channels.

Synapses and Synaptic Transmission

• Chemical transmission where the neurotransmitter in the synaptic cleft is converted to an electrical signal.

Postsynaptic potentials: Hyperpolarization and Depolarization

• Excitatory postsynaptic potentials (EPSPs) : decrease the negative resting potential.
• Inhibitory postsynaptic potentials (IPSPs) : increase the negative resting potential

Spatial and Temporal Summation

• Spatial summation: summing of EPSPs from multiple synapses
• Temporal summation: summing of EPSPs from a single synapse over time

Neurotransmitter Receptors: Ionotropic and Metabotropic

• Ionotropic receptors: directly alter ion channels.
• Metabotropic receptors: cascade effect using G-proteins .

Binding of Ligands to Receptors

• Selectivity to different shapes
• Can have several receptor types

Neurotransmitters: Amino Acid Derivatives and Monoamines

• Glutamate, GABA, Glycine
• Dopamine, serotonin, noradrenaline
• Peptides (neurotransmitters that are chains of amino acids, complex and diverse set of functions.

Psychopharmacology: Key Terms

• Pharmacology: study of drugs
• Drugs: a substance that produces a physiological effect.
• Psychopharmacology: study of psychoactive drugs' effect on behavior and psychological processes.

Pharmacokinetics

• How the body deals with drug (absorption, distribution, metabolism, and excretion)
• Routes of administration: oral ingestion, rectal, nasal, sublingual, transdermal, inhalation, injection

First Pass Metabolism

• Early breakdown of drugs in the stomach and liver (before systemic circulation).

Drug Absorption

• How drugs move through cell membranes into blood stream.
• Lipid solubility and ionization affect absorption.

Drug Distribution & Target for Action

• Drugs reach various parts of the body, including the brain (but not all compounds cross the blood-brain barrier).

Drug Metabolism

• Conversion of a drug into another compound; often done by the liver.

Drug Elimination

• Different routes for drug elimination: urine, breath, sweat, faeces.

Drug Response: Time Course

• Onset of action: time to reach peak effect.
• Duration of action: time until the drug wears off; half-life is how long for levels to be reduced in half

Pharmacodynamics

• Agonists (mimic or enhance effects of neurotransmitters)
• Partial agonists (weak agonists): only partially activate receptors.
• Antagonists (block or reduce effect of neurotransmitters)

Direct and Indirect Mechanisms

• Direct agonists: mimic effect of neurotransmitter.
• Indirect agonists: enhance the effect of neurotransmitter via other mechanisms.
• Inverse agonists: opposite effect to agonists.
• Direct antagonists block receptor binding.
• Indirect antagonists: interfere with neurotransmitter release or production.

Allosteric Modulators

• Effect on receptors not related to the normal ligand
• Can increase or decrease likelihood of agonist binding.

Quantifying Drug Effects (Dose-Response Curve)

• Dose-response curve analyses to measure drug potency and efficacy
• ED50 = amount of drug that has half of maximum response.
• Potency = dose needed for a certain response (efficacy).
• Efficacy = maximum response reached.
• Therapeutic index tells us how safe a drug is.

Action of Psychoactive Drugs: Alcohol

• Effects vary based on dose. Typical depressant effect on the brain.

Alcohol on the Brain

• Enhances GABA activity (GABA receptors)
• Inhibits glutamate activity (NMDA receptors)
• Affects neurotransmission of serotonin, opioids, dopamine, cannabinoid receptors.

Alcohol Biotransformation

• Conversion to acetaldehyde and then acetic acid.
• Food slows absorption, men metabolise alcohol more slowly than women.

Factors Affecting Alcohol Metabolism

• Food in stomach
• Gender (sex)
• Ethnicity

Cocaine

• Psychoactive drug (extracted from coca plants)
• Routes of administration (nasal, inhaled)
• Effects: increased alertness, pupils dilation, psychological affects.

Cocaine Effects on the Brain

• Blocks dopamine transporter.
• Prolongs dopamine in synapse

Amphetamines

• Synthetic stimulant.
• similar mechanism as cocaine (increase neurotransmission of dopamine and noradrenaline)

Nicotine ,Caffeine

• Direct agonists of acetylcholine
• Increased neurotransmission (especially dopamine)

Opiates

• Natural/synthetic opioid drugs (morphine, codeine, heroin, fentanyl, oxycodone).
• Targets opioid receptors in the brain, affecting dopamine release.

Cannabis

• Main active component: THC
• THC is a direct agonist at CB1 and CB2 receptors resulting in dopamine release.

Factors Contributing to Differences in Drug Effects

• Individual differences in physical factors like metabolism or size (liver mass/blood volume) can affect drug response.
• Differences in age, sex, and sociocultural factors play a role.
• Genetic factors affect drug responses.

Drug Tolerance

• Tolerance reflects how less effective a drug becomes with repeated use.
• There are metabolic and cellular/systemic tolerance mechanisms

Placebo Effect

• Placebo effect can demonstrate physiological and behavioral effects due to belief of a treatment.

Emotion:

• A complex interplay between physiological (autonomic, muscular, hormonal), cognitive(appraisal of event, context, and memory), and expectation processes
• Amygdala plays a crucial role in emotional memory and responding to fearful stimuli
• Prefrontal cortex (PFC) involved in emotional control
• Implict racial bias: there is a greater amygdala response to Black faces.

PTSD:

• Trauma and Stressor-related Disorder
• Characterised by re-experiencing, avoidance, negative thoughts/beliefs, and arousal.
• Amygdala excessively active in individuals with PTSD.
• PFC function and ability to resolve fear responses are hampered.

Motivated behaviors

• Motivations not as simple as reflexes (can be influenced by many factors).
• Preparatory behavior is goal-directed (e.g, preparing to eat or mate).
• Consummatory behavior is achieving a goal (e.g., eating or mating).

Drive Theory

• States that deviations from homeostasis leads to a need state or physiological deprivation state resulting in a drive state which activates behaviour towards a goal.
• Negative feedback systems are part of homeostasis.

Liking vs Wanting

• Liking: Sensory pleasure (unconscious).
• Wanting: Motivational incentive value (can be conscious or unconscious).

Development of the Nervous System

• Birth of neurons (migration, differentiation, formation of the cerebral cortex)
• Neuronal connections
• Synapse formation (synaptogenesis)
• Myelination of neurons
• Importance of critical periods for development

Neurodegeneration and Recovery

• Types of neurodegeneration (stroke, neurodegenerative diseases)
• Brain shrinkage and loss of synapses (neurons)
• General causes of neuron death (e.g., hypoxia, excitotoxicity)
• Huntington's disease (genetic link, basal ganglia degeneration)

Alzheimer's Disease

• Neurological disorder causing memory loss, executive issues, and personality changes.
• Associated with the accumulation of amyloid-beta plaques and neurofibrillary tangles
• Several types and subtypes
• Causes: genetic factors (e.g. APOE4) and environmental factors such as diet & inactivity.

Test your knowledge on key concepts in psychobiology and cognitive functions. This quiz covers topics such as the Rescola-Wagner Rule, neurotransmitter roles, and learning phenomena like blocking. Perfect for psychology students looking to reinforce their understanding of brain functions and learning processes.