Educated guess cog bio

Substance Use Disorder

Compulsive substance use despite negative consequences; severity based on number of symptoms (mild 2–3, moderate 4–5, severe 6+)

Neuropharmacology

The study of how drugs affect the nervous system and behaviour

Endogenous substances

Substances produced naturally within the body

Exogenous substances

Substances from outside the body (e.g., drugs)

Mesocorticolimbic pathway

Dopamine pathway (VTA → nucleus accumbens → cortex) responsible for reward and addiction

Role of dopamine in addiction

Drugs increase dopamine activity, mimicking natural reward signals

Ventral striatum vs dorsal striatum

Ventral = reward; Dorsal = habit formation

Insula function in addiction

Interoception and conscious urge/craving to take drugs

Ventromedial prefrontal cortex

Controls impulses and inhibits drug-seeking behaviour

Ligand

A substance that binds to a receptor

Agonist

Activates a receptor and increases neurotransmission

Antagonist

Blocks receptor and decreases neurotransmission

Inverse agonist

Produces effect opposite to normal receptor function

Ionotropic receptors

Fast receptors that directly open ion channels

Metabotropic receptors

Slow receptors that act via second messenger systems

Dopamine pathways

Mesostriatal (movement) and mesolimbocortical (reward)

Cocaine mechanism

Blocks dopamine reuptake, increasing dopamine in synapse

Serotonin function

Mood, sleep, sexual behaviour, anxiety

SSRI effect

Blocks reuptake of serotonin to increase its activity

Glutamate

Main excitatory neurotransmitter

GABA

Main inhibitory neurotransmitter

Tolerance

Decreased drug effect with repeated use

Sensitisation

Increased drug effect with repeated use

Downregulation

Fewer receptors after agonist exposure

Upregulation

More receptors after antagonist exposure

Wanting vs Liking theory

With repeated drug use: liking decreases, wanting/craving increases

Stress and addiction

Stress increases vulnerability and relapse risk by altering reward systems

Attention

Limited capacity system that selects relevant information and filters irrelevant stimuli

Top-down attention

Goal-directed attention controlled by cognitive processes

Bottom-up attention

Stimulus-driven attention triggered by salient events

Cognitive control components

Inhibition, shifting, updating

Inhibition

Suppressing irrelevant information or responses

Shifting

Switching between tasks or mental sets

Updating

Refreshing and manipulating working memory information

Congruency effect

Slower and more error-prone responses on incongruent vs congruent trials

Anterior cingulate cortex (ACC)

Detects conflict in cognitive tasks

Dorsolateral prefrontal cortex (DLPFC)

Implements cognitive control

Alpha oscillations

Reflect inhibition of irrelevant information

Theta oscillations

Signal need for cognitive control and coordinate brain networks

Olfaction

Ability to perceive smells

Functions of olfaction

Hazard detection, social bonding, memory, wellbeing, eating behaviour

Flavour vs taste

Taste = basic (sweet, salty, etc.); Flavour = includes smell + taste

Proust effect

Odours trigger vivid, emotional autobiographical memories

Peripheral olfactory system

Olfactory structures in the nose (epithelium and receptors)

Central olfactory system

Brain regions processing odour (e.g., piriform cortex)

Piriform cortex

Processes odour identity and perception

Amygdala role in olfaction

Links smells to emotional responses

Hippocampus role in olfaction

Strongly involved in odour memory

Quantitative olfactory dysfunction

Loss or reduction of smell sensitivity

Qualitative olfactory dysfunction

Distorted or altered smell perception

Parosmia

Distorted perception where familiar smells become unpleasant

Sensorimotor hierarchy

Cortex (highest), brainstem, spinal cord (lowest)

Posterior parietal cortex (PPC)

Processes spatial information and attention

Dorsolateral prefrontal cortex (movement)

Selects and initiates goal-directed actions

Primary motor cortex (M1)

Controls movement and encodes action endpoints

Mirror neurons

Neurons that fire during both action execution and observation

Ideomotor apraxia

Inability to perform or imitate gestures (linked to parietal damage)

Cerebellum

Coordinates movement and corrects motor errors

Basal ganglia

Regulates movement, habit learning, and reward

Hormones

Chemical messengers released into bloodstream affecting target tissues

Pituitary gland

The “master gland” controlling other endocrine glands

Cortisol

Stress hormone that increases glucose and suppresses non-essential functions

Cortisol behavioural effect

Shifts behaviour from goal-directed to habitual control

Oxytocin

Hormone involved in social bonding and affiliation

Oestrogen

Influences mood, cognition, and brain plasticity

Testosterone

Linked to dominance motivation and social status (not direct aggression)

Interaural time difference (ITD)

Difference in time of sound arrival between ears

Interaural level difference (ILD)

Difference in sound intensity between ears

Duplex theory

ITD used for low frequencies; ILD used for high frequencies

Sound localization cues

ITD, ILD, spectral cues, reverberation

Precedence effect

First-arriving sound determines perceived location and suppresses echoes

Looming bias

Sounds increasing in intensity are perceived as closer and more urgent

Cortisol receptors

Highly present in hippocampus, amygdala and prefrontal cortex

Stress effect on brain

Increases sensitivity to drug reward and relapse risk

ACC role in attention

Conflict monitoring

DLPFC role in attention

Top-down control and decision making

Insula interoception

Perception of internal bodily states (e.g., heart rate, thirst)

Ventromedial PFC in addiction

Inhibits impulsive drug-seeking behaviour

Dopamine in nucleus accumbens

Signals reward and reinforcement

Goal-directed behaviour

Actions based on expected outcomes

Habitual behaviour

Automatic responses independent of outcomes

Stress effect

Shifts behaviour towards habitual responding

Testosterone and competition

Increases after winning and motivates future competition

Oxytocin function

Enhances social bonding and emotional salience

Attention (William James)

The focusing of the mind on one object or thought while excluding others

Attention (key property)

Limited capacity system where some inputs are processed and others are ignored

Types of attention

Focused (selective), sustained, divided

Limited resource model

Attention is required because the cognitive system cannot process everything at once

Spotlight model of attention

Spatial attention enhances processing of items within its focus

Effect model of attention

Stimuli representations compete, and attention selects the dominant one

Early selection theory

Filtering occurs before semantic processing, based on physical features

Broadbent’s filter model

Only attended information is processed semantically; unattended input is filtered out early

Dichotic listening task

Task where different messages are presented to each ear to test selective attention

Evidence for early selection

Unattended stimuli only processed for physical features, not meaning

Cocktail party effect

Personally relevant information (e.g., your name) can break through attentional filter

Problem with early selection

It cannot explain why meaningful unattended information is sometimes detected

Treisman attenuation model

Unattended information is weakened (not blocked) and can be processed if important

Late selection theory

All stimuli are processed semantically, but only selected stimuli guide responses

Deutsch & Deutsch model

Semantic processing occurs for all stimuli before selection

Stroop effect

Slower responses when word meaning conflicts with ink colour (semantic interference)