Unit 1

Unit 1

Biological Bases of Behavior

1.1

Interaction of Heredity and Environment

Nature (heredity/genes)

Passed down biological traits that influence physical characteristics, temperance, personality, intelligence, and mental health risks.

Nurture (environment)

Experiences and surroundings that shape the environment, including parenting styles, education quality, culture and social norms, and life events.

Natural selection

Traits that offer an advantage for survival and reproduction (which are more likely to be passed down).

Evolutionary psychology

An approach to psychology that uses evolutionary principles to explain why certain behaviors/mental processes were a form of adaptation for survival and reproduction.

Eugenics

A discredited movement that uses genetics to try and control or “improve” the human population.

Social darwinism

A misuse of evolutionary concepts that justify and claim that social inequalities (like being poor) reflect the “survival of the fittest”.

_____ compare different subjects to examine the impact of “nature” (genes) and “nurture” (environment) on a specific trait.

Twin studies

Similar to twin studies, this kind of research examines traits or disorders between relatives.

Family studies

Adoption studies

Tests genetic and economic influence with biological and adoptive parents to separate genes vs. environment.

1.2

Overview of the Nervous System

Nervous system

The body’s communication and control network that coordinates sensation, thought, and action (divided into the CNS and PNS).

Central Nervous System (CNS)

Brain and spinal cord. Controls the processing of incoming sensory info and deciding how the body will respond by sending commands (for movement/behavior).

Peripheral Nervous System (PNS)

All the nerves in the body. Delivers messages from the body and the brain (and vice versa), collects sensory info, and carries out motor instructions. Made up of SNS and ANS.

Somatic Nervous System (SNS)

Voluntary/intentional movement that includes processing sensory info and moving skeletal muscles.

Automatic Nervous System (ANS)

Automatic/involuntary functions like breathing, heart rate, digestion, pupil dilation, and body temperature control. Has two opposing subsystem (sympathetic/parasympathetic NS).

Sympathetic Nervous System

Activates in stressful/emergency situations, boosting heart rate, dilating pupils, and slow digestion. Prepares your body for action (fight-or-flight).

Parasympathetic Nervous System

Helps bring the body back to a normal state after stress, slowing your heart rate and stimulating digestion. Restores calm (rest-and-digest).

1.3

The Neuron and Neural Firing

Neurons

A neural cell that sends electrical/chemical signals (allowing them to spread/receive info). Form complex pathways.

Glial cells

Neural cells that support neurons by structuring the nervous system, create insulation (myelin sheath), and helping with communication and waste clean up. Don’t send signals.

Reflex arc

A fast, automatic pathway that goes through the spinal cord to produce a response quickly.

Name the order of neurons in the reflex arc.

sensory neuron, interneuron, motor neuron

Sensory neuron

Neuron that detects incoming stimuli and carries information to the spinal cord or brain.

Interneuron

Neuron found in spinal cord/brain that processes incoming signals and relays commands.

Motor neuron

Neuron that carries info from the brain/spinal cord to muscles/glands.

Resting potential

The neuron is ready and not firing, with a stable slightly negative charge.

Threshold

The minimum level of stimulation needed to trigger a neuron to fire.

Action potential

A brief electrical impulse that travels down an axon when a neuron fires, either fires fully or doesn’t fire at all.

Depolarization

The influx of positive ions that reduces the neuron’s negative charge and starts the action potential. Flood in, flipping the charge.

Refractory period

The brief reset time after an action potential when a neuron cannot fire again.

Reuptake

The process of neurotransmitters being reabsorbed into the sending neuron after signaling.

Dopamine

A neurotransmitter involved in reward, motivation, and motor control.

Too much = Schizophrenia

Too little = Parkinson’s

Serotonin

A neurotransmitter that helps regulate mood, sleep, and appetite.

Too little = Depression

Norepinephrine

A neurotransmitter that increases alertness and arousal, especially during stress.

GABA

The main inhibitory neurotransmitter that reduces neural activity.

Too much = Anxiety, seizures

Glutamate

The most common excitatory neurotransmitter, important for learning and memory.

Too much = Migraines, seizures

Acetylcholine (ACh)

Neurotransmitter that controls muscle movement, important for learning and memory.

Linked to Alzheimer’s.

Endorphins

Neurotransmitters that act as natural painkillers, also producing feelings of pleasure.

Substance P

A neurotransmitter that carries pain signals from the body to the brain using the spinal cord.

Hormones are much _____ than neurotransmitters.

slower

Adrenaline (epinephrine)

Hormone that prompts fight-or-flight response

Leptin

A hormone that signals satiety and helps you feel full.

Ghrelin

A hormone that increases hunger.

Melatonin

A hormone that helps regulate the sleep–wake cycle.

Oxytocin

A hormone linked with bonding, trust, love, and human connection.

Why do psychoactive drugs mess with the brain?

Drugs interfere with normal neurotransmitter activity, affective behavior.

Agonists

Drugs that mimic neurotransmitters and activate their receptors.

Antagonists

Drugs that block neurotransmitters from binding to receptors.

Reuptake inhibitors

Drugs that prevent neurotransmitters from being reabsorbed, leaving more available in the synapse.

Psychoactive drugs affect neural activity differently, and are usually reduced to the categories of:

Stimulants, depressants, hallucinogens, and opioids.

Stimulants

Drugs that increase central nervous system activity and arousal. Raise heart rate, alertness, energy, and euphoria.

Examples of stimulants

Caffeine, nicotine, cocaine, amphetamines.

Depressants

Drugs that slow brain activity and body functions. Increase relaxation, slow processing, reduce coordination and memory.

Examples of depressants

Alcohol, benzodiazepines.

Hallucinogens

Drugs that distort perception and can trigger sensory experiences without external input. Create sensory distortions, hallucinations, and alter ways of thinking/memory.

Examples of hallucinogens

Marijuana (THC), LSD, psilocybin.

Opioids

Drugs that block pain, cause euphoria and have a high addiction risk.

Examples of opioids.

Heroin, morphine, OxyContin.

Tolerance

Needing more of a drug over time to get the same effect.

Addiction

Compulsively seeking out a drug despite harm.

Withdrawal

Physical (anxiety, cravings) and psychological (sweating, nausea) symptoms that occur when a person stops using a drug.

The brainstem contains the…

Medulla, pons, and midbrain.

Medulla

A brainstem structure that regulates vital autonomic functions such as heart rate, breathing, and blood pressure.

Pons

Brainstem structure that controls your body’s level of alertness after waking up, and relays/regulates pain signals.

Midbrain

Associated with vision, hearing, motor control, sleep/wake, arousal, and temperature regulation.

Reticular Activating System (RAS)

Controls your wakefulness/alertness, attention, and filters incoming sensory information (helping focus). Damage can cause sleep disorders or even comas.

Cerebellum

Coordinates precise/smooth movement, helping motor learning, and involving attention and language processing.

Cerebral cortex

The outer layer of your brain — highly folded and complex. Handles complex thoughts, perception, and voluntary movement.

Left hemisphere

Language and logic.

Right hemisphere

Spatial awareness, emotion, and holistic processing.

Frontal lobe

The front part of the cortex involved in decision-making, reasoning, impulse control, and voluntary movement.

Prefrontal cortex

Executive functions (planning, self-control).

1.4

The Brain

Motor cortex

Triggers voluntary movement.

Broca’s Area

A region in the left frontal lobe that controls speech production.

Parietal lobe

The cortical area that processes body sensations like touch and helps with spatial awareness.

Somatosensory cortex

Maps sensory input from the body.

Temporal lobe

A cortical region important for hearing, language comprehension, and aspects of memory and emotion.

Wenicke’s Area

A region in the left temporal lobe that supports language comprehension.

Limbic system

A network beneath the cortex involved in emotion, motivation, learning, and memory.

The temporal lobe contains part of the limbic system, containing the ______ and ______.

hippocampus, amygdala

Occipital lobe

The primary visual processing center of the cortex.

What are the components of the limbic system?

Thalamus, hypothalamus, hippocampus, amygdala, pituitary gland

Thalamus

The brain’s sensory relay station that routes incoming information to the appropriate cortical areas.

Hypothalamus

A small but crucial structure that regulates hunger, thirst, body temperature, and links the nervous and endocrine systems.

Hippocampus

Forms new long-term (explicit) memories.

Amygdala

Processes emotions, especially fear/aggression.

Pituitary gland

Releases hormones (regulated by hypothalamus).

Split-brain surgery

A procedure that cuts the corpus callosum to reduce severe epilepsy, isolating communication between hemispheres.

Hemispheric specialization

The idea that each hemisphere tends to be more involved in certain functions (e.g., left for language).

Contralateral organization

The cross-wiring of the nervous system where each hemisphere controls and receives input from the opposite side of the body/visual field.

Plasticity

Your brain’s ability to change and adapt over time — especially useful after injury or during learning.

Name a method of studying the brain that uses the brain’s electrical activity.

EEG (electroencephalogram)

Name a method of studying the brain that tracks blood flow in the brain.

fMRI (functional MRI)

Name a method of studying the brain that focuses on examining the effects of brain damage.

Lesioning

1.5

Sleep

Consciousness

Your awareness of your thoughts, feelings, and surroundings.

Circadian rhythms

Your internal 24-hour body clock plays a major role in regulating energy, mood, and mental clarity.