Psychology Theories, Research, and Biological Foundations

Psychoanalytic Perspective

Sigmund Freud develops psychoanalytic approach to treat patients with psychological problems, focusing on how unconscious factors (drives, conflicts from childhood) impact human development and behaviour.

Behaviourist Perspective

Emphasizes scientific study of observable action, founded by John Watson (1920) building off of Ivan Pavlov who studied classically conditioned fear. BF Skinner studied impact of reinforcement and punishment on behaviour in studies on operant conditioning.

Humanistic Perspective

Takes holistic approach of individual, emphasizing higher aspects of nature. Abraham Maslow proposed that humans are motivated to achieve needs in a hierarchy of importance, with the highest level being self-actualization (fulfilling one's greatest potential). Carl Rogers introduced the concept of unconditional positive regard (acceptance and support).

Hypothesis

Testable explanation for a phenomenon.

Alternative Hypothesis

Based on prior evidence and assumes that a significant relationship or difference exists between variables, predicting the nature of that relationship or difference.

Null Hypothesis

The inverse of the alternative hypothesis, stating that there is no significant difference or relationship between variables.

Independent Variable

Manipulated by the experimenter to determine if changes to it impact the dependent variable.

Dependent Variable

The outcome that is measured in an experiment.

Correlational Studies

Studies that examine the relationship between variables but cannot demonstrate cause and effect as no variables are manipulated.

Experimental Studies

Researcher manipulates the independent variable to determine its impact on the dependent variable or outcome, showing a cause and effect relationship.

Placebo

A substance or treatment with no active therapeutic effect, often used in clinical trials to compare against the actual treatment.

Reliability

Extent that experiment can consistently produce similar results.

Validity

Accuracy of study or measure.

Internal validity

Extent to which measure of experiment produces true result.

External validity (generalizability)

Extent to which study results can be applied to real life situations.

Informed consent

Process of instructing potential research participants about study, risks, and rights (ex: to withdraw).

Descriptive statistics

Describes dataset with measure of central tendency (mean, median, mode) and variation (IQR, SD).

Mean

Average data point.

Median

Middle value when data organized in numerical order.

Mode

Most frequently occurring data points.

Range

Difference between lowest and highest data points.

Inferential statistics

Used to draw conclusions that reach beyond sample dataset.

Pearson correlation

Describes linear relationship between two variables.

Positive correlation

Variables increase/decrease together.

Negative correlation

As one variable increases, other decreases.

Zero correlation

Lack of linear relationship between variables.

Afferent neurons

Send signals towards brain.

Efferent neurons

Carry messages away from brain.

Gray matter

Unmyelinated axons, neuronal cell bodies, dendrites.

White matter

Consists of myelinated axons that allow for long distance communication between neurons.

Somatic Nervous System

Sensory neurons that relay information from body to CNS and motor neurons that relay command from CNS.

Autonomic Nervous System

Controls subconscious, not subject to voluntary control.

sympathetic

helps body prepare for stressors

parasympathetic

allows body to return to homeostasis

Functions of sympathetic

Dilates pupil, inhibits salivation, accelerates heartbeat, dilates bronchi, inhibits digestion, stimulates glucose release, inhibits gallbladder, secretes epi and norepi, inhibits intestinal activity, relaxes bladder, promotes ejaculation and vaginal contraction

Functions of parasympathetic

Constrict pupils, stimulates salivation, slows heartbeat, constricts bronchi, stimulates digestion, inhibits glucose release, stimulates gallbladder, stimulates intestinal activity, contracts bladder, promotes erection of genitals

neurons

send chemical or electrical signals to other cells

Glial cells

support functions to neurons and nervous system

Parts of the nerve cell

cell body, dendrites, axon terminals

neuron soma (cell body)

stores nucleus which has DNA

dendrites

branches that extend from cell body and receive input from other neurons when neurotransmitters bind to postsynaptic receptors on dendrites

Axon terminal

end of axon at synapse

action potential

electrical signal that travels down axons and causes release of neurotransmitters from axon terminal

Neuron myelination

layer wrapped around axons; Myelin is lipid, multilayered continuous along length of axon, interrupted at nodes of ranvier

What happens when action potential reaches axon terminals?

neurotransmitters release into synaptic cleft

Synaptic cleft

junction formed between axon terminal of presynaptic neuron and dendrites of postsynaptic neuron

Role of glial cells

structural and chemical buffering support for neurons, make CSF, immune cells

Communication between neurons

involves action potential

Membrane potential

unequal concentration of charged ions between inside and outside of all living cells

Resting membrane

high concentration of potassium ions and low concentration of sodium ions inside neurons

Result of ionic movement

postsynaptic depolarization (excitation) or hyperpolarization (inhibition)

excitatory postsynaptic potential (EPSP)

binding membrane potential closer to threshold increases likelihood of action potential

inhibitory postsynaptic potential (IPSP)

brings membrane potential further from threshold and decreases likelihood of AP

Components of an action potential

At rest: postsynaptic Na+ channels closed but if stimulus opens, Na+ ions enter cell, causing membrane to depolarize. If depolarization is enough to reach certain threshold, action potential initiated in neuron. If threshold reached, additional Na+ channels open causing rapid depolarization. Repolarization: Na+ channels inactivate and K+ channels open allowing K+ to rush out of cell and membrane potential becomes negative. Resting membrane potential: restored when K+ and Na+ channels.

Absolute refractory period

Time when no new action potentials can be generated regardless of strength of stimulus because Na+ channels inactive.

Neural transmission rate

Larger diameter axons and axons that are myelinated transmit neural impulses faster than smaller and unmyelinated axons.

Action potentials at axon terminals

Neurotransmitters released from synaptic vesicles into synaptic cleft.

Excitatory synapses

Membrane potential of postsynaptic neuron becomes positive, and if exceeds threshold, action potential initiated.

Inhibitory synapses

Neurotransmitters affect postsynaptic neuron by causing cell's membrane potential to become more negative.

Amino acid neurotransmitters

Gamma aminobutyric acid (GABA)→principal inhibitory neurotransmitter of CNS. Glycine→primarily inhibitory neurotransmitter found in CNS. Glutamate→primary excitatory neurotransmitter of CNS.

Acetylcholine

Neurotransmitter released by somatic motor neurons at neuromuscular junction. Involved in learning and memory, arousal, sleep-wake cycles.

Catecholamines

Neurotransmitters including dopamine, epinephrine, norepinephrine.

Dopamine

Involved in movement, reward, motivation, cognition, involved in schizophrenia, Parkinson's.

Epinephrine and norepinephrine

ANS ⇒ wakefulness, alertness, attention, memory, mood.

Monoaminergic neurotransmitters

Catecholamines and serotonin.

Serotonin

Sleep/wake regulation, mood, appetite.

Endorphins

Peptide hormones that act as neurotransmitters. Opioids produced by body to modulate pain and mood.

Excess neurotransmitters

Get broken down or reabsorbed back into presynaptic neuron through reuptake.

Agonists

Mimic or enhance effects of neurotransmitter.

Antagonists

Block or reduce effects of neurotransmitter.

Regions of the brain

Forebrain, midbrain, hindbrain.

Forebrain

(aka prosencephalon)→has cerebrum, brain's left and right hemisphere. Main forebrain structures→olfactory bulbs, basal ganglia, pineal gland.

Basal ganglia

Initiated voluntary movement.

Pineal gland

Releases melatonin, hormone that causes sleepiness when dark.

Limbic system

A complex set of structures that lies on both sides of the thalamus, right under the cerebrum.

Amygdala

Aggression and fear; stimulation to amygdala causes fear and aggression; damage to amygdala causes lack of fear.

Hypothalamus

Releases hormones and controls pituitary gland's hormone release; coordinates bodily processes like hunger, growth, fight or flight response.

Hippocampus

Learning and memory; formation of explicit memories; damage to hippocampus causes severe memory loss.

Thalamus

Sensation and perception; responsible for processing and relaying sensory information and received information from all senses except olfaction.

Midbrain

Area of brainstem that connects brain and spinal cord; contains superior and inferior colliculi.

Substantia nigra

One of the two areas in the midbrain with large numbers of dopaminergic neurons.

Ventral Tegmental Area (VTA)

Projects to different parts of forebrain; important for reward.

Hindbrain (rhombencephalon)

Made of cerebellum and lower part of brainstem: medulla, pons, reticular formation.

Medulla

Part of the brainstem closest to the medulla; controls critical functions like breathing and heart rate.

Pons

Above medulla; regulates sleeping, waking, dreaming.

Reticular formation

Series of neurons that spans entire brainstem leading to consciousness and wakefulness.

Cerebellum

Coordinates voluntary movements, posture, balance; integrates visual, vestibular, kinesthetic information for balance and posture.

Frontal lobe

Higher order processing; planning, decision, personality, judgement, voluntary movement.

Parietal lobe

Proprioception (awareness of body position in space) and somatosensation (perception of touch, pain, temperature).

Temporal lobe

Auditory cortex; processing auditory stimuli; learning and memory (hippocampus) and language (Wernicke's).

Occipital lobe

Back of cerebral cortex for visual processing; visual cortex processes input from eyes.

Cerebral cortex

Outermost portion of brain divided into frontal, temporal, parietal, occipital lobes.

Prefrontal cortex

Area of frontal lobe for decision making, personality, memory.

Motor cortex

Relays motor commands from motor cortex to skeletal muscle.

Somatosensory cortex

Processes somatosensory information in parietal lobe.

Hemispheric lateralization

Brain's right and left hemispheres specialized for processes.

Corpus callosum

Myelinated axonal projections connecting right and left hemispheres; severed corpus callosum leads to disrupted communication between hemispheres.

Spinal cord

Relays messages between PNS and brain; contains white matter (myelinated) and grey matter (cell bodies, dendrites).

Spinal reflex

Neural process of receiving and acting on sensory information in reflex arc.

Somatosensory receptors

Receptors in skin stimulated by something painful.