AP Psych Unit 1

Central Nervous System (CNS)

Consists of the brain and spinal cord; the body's major decision-making and information-processing center.

Peripheral Nervous System (PNS)

All nerves connecting the CNS to the rest of the body; carries information body → CNS and CNS → body.

Nerve

A bundle of axons that carries information through the peripheral nervous system.

Sensory Neuron (Afferent Neuron)

Carries incoming sensory information from receptors in the body → CNS.

Motor Neuron (Efferent Neuron)

Carries outgoing commands from the CNS → muscles and glands.

Interneuron

Neuron located mainly in the brain and spinal cord that processes information and communicates between sensory and motor neurons.

Sensory → Interneuron → Motor

The basic information pathway: sensory neurons bring information to the CNS, interneurons process it, and motor neurons carry commands out.

Somatic Nervous System

Division of the PNS that controls skeletal muscles and primarily enables voluntary movement.

Autonomic Nervous System (ANS)

Division of the PNS controlling involuntary functions of internal organs, glands, and smooth muscles; includes sympathetic and parasympathetic divisions.

Sympathetic Nervous System

Division of the autonomic nervous system that arouses the body and prepares it for action; "fight or flight."

Parasympathetic Nervous System

Division of the autonomic nervous system that calms the body, conserves energy, and returns the body toward its resting state; "rest and digest."

Reflex

Automatic response to sensory stimulation that can be rapidly coordinated through the spinal cord without waiting for conscious processing.

Reflex Arc

Sensory receptor → sensory neuron → spinal-cord interneuron → motor neuron → muscle.

Neuron Signal Direction

Dendrites → cell body → axon → terminal branches → synapse.

Dendrites

Branches extending from the cell body that receive and integrate incoming information and carry it toward the cell body.

Cell Body (Soma)

Neuron's life-support center; contains the nucleus.

Axon

Long extension from the cell body that carries neural impulses away from the cell body toward other neurons, muscles, or glands.

Myelin Sheath

Fatty tissue covering portions of some axons; speeds neural impulses.

Glial Cells (Glia)

Support cells that nourish and protect neurons, support neural communication, help form myelin, and participate in learning and thinking.

Resting Potential

Electrical charge difference across a neuron's membrane when it is not firing; the neuron is polarized.

Action Potential

Brief electrical charge that travels down an axon; neural communication within a neuron is electrical.

Depolarization

Change in the neuron's membrane charge when positively charged ions flow in, helping initiate the action potential.

Threshold

Minimum level of stimulation required to trigger an action potential.

All-or-None Response

Once threshold is reached, a neuron fires completely; stronger stimulation does not create a larger individual action potential.

How Does a Stronger Stimulus Affect Neural Firing?

It can cause more neurons to fire and/or increase firing frequency; it does not make an individual action potential larger.

Refractory Period

Brief period immediately after firing when the neuron must reset and temporarily cannot fire normally again.

Synapse

Junction where one neuron communicates with another; neurons generally do not physically touch.

Synaptic Gap (Synaptic Cleft)

Tiny space between the sending neuron's terminal and the receiving neuron across which neurotransmitters travel.

Neurotransmitter

Chemical messenger released by a neuron that crosses the synaptic gap and influences a receiving neuron.

Neurotransmission

Action potential reaches terminal → neurotransmitters released → cross synaptic gap → bind to receptors → influence receiving neuron.

Electrical vs. Chemical Neural Communication

Communication within a neuron is electrical; communication between neurons across a synapse is chemical.

Receptor Site

Location on a receiving neuron where a neurotransmitter binds and influences that cell.

Reuptake

Process in which neurotransmitters released into the synapse are reabsorbed by the sending neuron; drugs can alter this process.

Acetylcholine (ACh)

Neurotransmitter involved in muscle action, learning, and memory. Memory aid: ACh = Action of muscles.

Dopamine

Neurotransmitter involved in movement, learning, attention, emotion, and reward.

Serotonin

Neurotransmitter involved in mood, hunger, sleep, and arousal.

Norepinephrine

Neurotransmitter involved especially in alertness and arousal.

GABA

Major inhibitory neurotransmitter; reduces neural activity.

Glutamate

Major excitatory neurotransmitter; important for learning and memory.

Endorphins

Natural opiate-like neurotransmitters produced by the body; involved in pain reduction and pleasure.

Agonist

A substance that increases or mimics a neurotransmitter's action.

Antagonist

A substance that blocks a neurotransmitter's action.

Endocrine System

The body's slower chemical communication system; glands release hormones that travel through the bloodstream.

Hormones

Chemical messengers released by endocrine glands and carried through the bloodstream.

Nervous System vs. Endocrine System

Nervous: neurons, electrochemical, very fast, neural pathways, often brief effects. Endocrine: hormones, chemical, bloodstream, slower, often longer-lasting effects.

Pituitary Gland

Small endocrine gland associated with the brain; called the "master gland" because it influences other endocrine glands; controlled/influenced by the hypothalamus.

Hypothalamus → Pituitary → Endocrine Glands

The hypothalamus controls/influences the pituitary, which in turn influences other endocrine glands.

Adrenal Glands

Endocrine glands located on top of the kidneys; release stress-related hormones including epinephrine/adrenaline and norepinephrine.

Adrenal Gland Functions

Release stress hormones that can increase heart rate, blood pressure, and available energy.

Psychoactive Drug

Chemical substance that alters perception, mood, or consciousness by affecting neural activity.

Substance Use Disorder

Continued craving or use of a substance despite significant life disruption or physical risk.

Tolerance

With repeated use, the same drug dose produces a smaller effect, so more may be needed to achieve the previous effect.

Withdrawal

Unpleasant physical or psychological symptoms that may occur when a person who has developed dependence stops using a substance.

Addiction

Compulsive craving and use of a substance despite harmful consequences.

Three Major Psychoactive Drug Categories

Depressants decrease CNS activity; stimulants increase neural activity; hallucinogens distort perceptions.

Depressants

Drugs that reduce CNS/neural activity and slow bodily functions; examples include alcohol, barbiturates, and opioids.

Alcohol

Depressant that slows CNS activity and neural processing; can impair judgment, memory, and coordination and reduce inhibition.

Why Can Alcohol Make Someone Appear Excited if It Is a Depressant?

It can depress brain systems responsible for inhibition and self-control, causing louder or riskier behavior despite slowing CNS activity.

Barbiturates

Depressants that reduce CNS activity and anxiety but can impair memory and judgment; large amounts can dangerously suppress breathing.

Opioids

Depressants that slow neural activity and can produce pain relief and euphoria; interact with systems associated with natural endorphins.

Stimulants

Drugs that increase neural activity and speed bodily functions; can increase heart rate, blood pressure, energy, and alertness.

Caffeine

Stimulant that increases wakefulness, alertness, and arousal; withdrawal can include headaches, fatigue, and irritability.

Nicotine

Highly addictive stimulant that can increase alertness and arousal and reaches the brain rapidly.

Cocaine

Powerful stimulant that can produce euphoria, energy, confidence, and increased arousal; strongly affects reward pathways and may be followed by a crash.

Amphetamines

Stimulants that increase neural activity, energy, and alertness.

Methamphetamine

Powerful addictive stimulant that can produce intense stimulation, euphoria, energy, and increased arousal.

MDMA (Ecstasy)

Drug with stimulant and mild hallucinogenic effects; strongly affects serotonin systems.

Hallucinogens

Drugs that distort perceptions and may create sensory experiences without corresponding sensory input.

LSD

Powerful hallucinogen that alters sensations, perceptions, and experiences of reality.

THC

Marijuana's major psychoactive ingredient; can cause relaxation, altered perception/time, and impaired memory and coordination.

Marijuana

can alter perception, sense of time, memory, and coordination and may produce relaxation.

Lesion

Destruction of brain tissue; researchers examine resulting changes in abilities to infer the damaged area's function.

EEG (Electroencephalogram)

Uses electrodes on the scalp to measure electrical brain activity; useful for brain waves, sleep, and seizures.

MEG (Magnetoencephalography)

Measures magnetic fields produced by neural activity.

CT Scan

Uses X-rays to show brain structure and identify structural abnormalities.

PET Scan

Uses radioactive glucose to reveal brain activity; more active areas consume more energy/glucose.

MRI

Uses magnetic fields and radio waves to produce detailed images of brain structure/anatomy.

fMRI (Functional MRI)

Tracks blood-flow-related changes to show brain function/activity while also providing structural information.

MRI vs. fMRI

MRI primarily shows brain structure/anatomy; fMRI shows function/activity associated with blood-flow changes.

Hindbrain

Brain division associated with essential survival-related functions; includes the medulla, pons, and cerebellum.

Midbrain

Brain division involved in connecting brain regions and in movement and sensory functions.

Forebrain

Brain division associated with more complex processing and higher-level functions.

Brainstem

Lowest central region of the brain connecting the spinal cord with higher brain regions; controls many automatic survival functions.

Medulla

Located at the very bottom of the brainstem directly above the spinal cord; controls heartbeat and breathing.

Pons

Located above the medulla; coordinates movement and helps regulate sleep.

Reticular Formation

Neural network running through the brainstem toward the thalamus; filters incoming stimulation and regulates arousal and alertness; severe disruption can cause coma.

Thalamus

Located on top of the brainstem; major sensory relay station that routes sensory information toward appropriate cortical areas, except smell.

Which Sense Is the Major Exception to the Thalamus?

Smell; it does not follow the same initial thalamic relay pathway as the other major senses.

Cerebellum

Located behind the brainstem; coordinates balance, smooth voluntary movement, and procedural/nonverbal learning and memory.

Cerebellum vs. Hippocampus

Cerebellum: procedural/skill learning and coordination. Hippocampus: formation/processing of new explicit memories.

Limbic System

Located largely beneath the cerebral cortex in the forebrain; associated with emotion, motivation/drives, and memory.

Amygdala

Two small neural clusters deep in the limbic region; especially associated with fear, aggression, and emotional processing.

Hypothalamus

Located below the thalamus; regulates hunger, thirst, body maintenance, temperature/homeostasis, reward, emotion, and endocrine activity; controls the pituitary.

Hypothalamus Location

Located below the thalamus

Hippocampus

Located deep in the brain in the medial temporal/limbic region; processes and helps form new explicit memories of facts and events.

Explicit Memory

Consciously recalled memories of facts and events; formation of new explicit memories is strongly associated with the hippocampus.

Pituitary Gland Location

Small gland located beneath and connected with the hypothalamus.

Cerebral Cortex

Thin outer layer of the cerebral hemispheres; responsible for sophisticated information processing.

Four Lobes of the Cerebral Cortex

Frontal, parietal, occipital, and temporal lobes.

Frontal Lobe

Located behind the forehead; involved in planning, judgment, decision-making, speaking, voluntary movement, and higher cognition.