Unit 1: Biological Bases of Behavior

Association Areas

Parts of the brain that integrate different types of information from the senses and link it with stored memories; involved in higher mental functions.

Frontal Lobes

Areas of the brain involved in complex processes like reasoning, planning, and emotion.

Prefrontal Cortex

The part of the frontal lobes directly behind the forehead, involved in decision-making and self-control.

Parietal Lobes

Areas of the brain that process sensory information such as touch, temperature, and pain.

Somatosensory Cortex

A part of the parietal lobes that processes sensory input (touch + movement sensations).

Corpus Callosum

A large band of neural fibers that connects the left and right cerebral hemispheres and allows communication between them.

Brainstem

The central trunk of the brain continuing downward to form the spinal cord.

Medulla

The base of the brainstem that controls vital life-sustaining functions like heartbeat and breathing.

Reticular Activating System

A network of neurons in the brainstem that plays a role in waking and responsiveness.

Limbic System

Associated with emotions and drives; amygdala, hippocampus, thalamus, hypothalamus, and pituitary gland.

Reward Center

Brain regions that regulate the experience of pleasure, particularly related to survival and reward (primarily in limbic system).

Thalamus

A structure deep within the brain that relays sensory signals to the cerebral cortex.

Hypothalamus

Directs maintenance functions, governs the endocrine system, and is linked to emotion and reward.

Pituitary Gland

A gland at the base of the brain that controls growth and development (regulates hormone production; "master gland").

Nervous System

The network of nerve cells and fibers that transmits nerve impulses between parts of the body (speedy).

Autonomic Nervous System

The part of the nervous system responsible for control of the bodily functions not consciously directed, like breathing and the heartbeat.

Glial Cells

Cells in the nervous system that support, nourish, and protect neurons.

Motor (efferent) Neurons

Neurons that carry outgoing information from the brain and spinal cord to the muscles and glands.

Neural Transmission

The process by which neurons communicate with each other by sending electrical or chemical signals.

Threshold

The level of stimulation required to trigger a neural impulse.

Action Potential

A neural impulse; a brief electrical charge that travels down an axon.

Depolarization

A change in a cell's membrane potential to more positive; increases excitability.

Resting Potential

The stable state of the neuron when not firing a neural impulse.

Multiple Sclerosis (MS)

A disease in which the immune system breaks down the myelin sheath.

Myasthenia Gravis

A chronic autoimmune disease that affects the neuromuscular junction and produces serious weakness of voluntary muscles.

Excitatory Neurotransmitters

Chemical messengers increasing the likelihood of neuron firing an action potential.

Dopamine

A neurotransmitter influencing mood, reward, motivation, and movement.

Hormones

Chemical messengers manufactured by endocrine glands that travel through the bloodstream and affect other tissues.

Norepinephrine

A hormone and neurotransmitter involved in arousal and fight-or-flight response.

Split Brain Research

Studies on patients with severed corpus callosum to understand brain hemisphere functions.

Contralateral Hemispheric Organization

Arrangement where each hemishpere of the brain controls the opposite side of the body.

Broca's Area

Left frontal lobe area directing muscle movements involved in speech.

Opioids

A class of drugs including heroin and prescription pain relievers.

Heroin

An opioid drug made from morphine, derived from opium poppy plants.

Transduction

Conversion of stimulus energies into neural impulses in sensation.

Perception

Organization and interpretation of sensory information for object recognition (top-down processing).

Absolute Threshold

Minimum stimulus energy to detect a stimulus 50% of the time.

Weber's Law

Principle that stimuli must differ by a constant proportion for detection.

Synesthesia

A condition in which stimulation of one sense also evokes another.

Accommodation

Process of lens shape change to focus images on the retina.

Photoreceptors

Rods and cones in the retina converting light into neural signals.

Trichromatic Theory

Theory of three colour receptors in the retina for colour perception (red, green, blue); can produce perception of any colour when stimulated in combination.

Hyperpolarization

Change in membrane potential to more negative; decreases excitability

Hue

The dimension of colour that is determined by the wavelength of light (blue, green, etc.)

Sensory Interaction

Principle that one sense can influence another; smell of food influencing its taste

Inner ear

Cochlea, semicircular canals, vestibular sacs

Cochlea

A coiled, bony, fluid-filled tube in the inner ear through which sound waves trigger nerve impulses.

Wernicke's area

Located in the left temporal lobe; involved in language comprehension.

Fovea

The central focal point in the retina, where the eye's cones cluster.

Gate-control theory

The theory that the spinal cord contains a neurological "gate" that blocks pain signals or allows them to pass on to the brain. The "gate" is opened by the activity of pain signals traveling up small nerve fibers and is closed by activity in larger fibers or by information coming from the brain.

Activation-synthesis theory

Theory proposing that dreams are the result of random neural activity in the brainstem during REM sleep.

Synapse

Junction between the axon top of the sending neuron and the dendrite of the cell body of the receiving neuron (tiny gap at this junction is called the synaptic gap/cleft).

REM sleep behavior disorder

A sleep disorder in which normal REM paralysis does not occur; instead, twitching, talking, or even kicking or punching may occur, often acting out one's dream.

Agonist

A molecule that increases a neurotransmitter's action; mimics effects of neurotransmitters.

Narcolepsy

A sleep disorder characterized by uncontrollable sleep attacks; may lapse directly in REM sleep at inopportune times.

Subliminal

Below one's absolute threshold for conscious awareness.

Basilar membrane

Structure in the cochlea that transforms sound waves into electrical signals.

Ossicles

Malleus, incus, stapes (hammer, anvil, stirrup).

Wavelength

Distance from the peak of one wave to the peak of the next.

Place Theory

Links the pitch we hear with the place where the cochlea's membrane is stimulated (high pitches).

Pheromones

Chemical substances released by animals + humans that trigger social or behavioural responses in others of the same species.

Psychoactive drug

A chemical substance that alters the brain, causing changes in perceptions and moods.

Antagonist

A molecule that inhibits/blocks a neurotransmitter's action.

Conduction hearing loss

Less common form of hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea.

Feature detectors

Nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement.

Ganglion cells

Neurons in the retina that receive visual info from bipolar cells and transmits it to the brain via the optic nerve.

Hypnagogic sensations

Bizarre experiences, such as jerking or a feeling of falling or floating weightlessly, while transitioning to sleep (can also include sounds).

Kinesthesis

Our movement sense; system for sensing the position + movement of individual body parts.

Proprioceptors

Sensory receptors, located in the muscles and joints, that provide information about body position and movement (kinesthetic sense).

Nociceptors

Pain receptors.

Hindbrain

Directs essential survival functions; medulla, pons, cerebellum.

Priming

The activation, often unconsciously, of certain associations, thus predisposing one's perception, memory, or response.

Blindsight

A condition in which a person can respond to a visual stimulus without consciously experiencing it.

Afterimages

Visual stimulations that persist after a stimulus is removed; occurs due to a temporary overstimulation of cone cells in the retina.

Lesion

Tissue destruction.

Middle ear

The chamber between the eardrum and cochlea containing three tiny bones (hammer, anvil, and stirrup) that concentrate the vibrations of the eardrum on the cochlea's oval window.

Pitch

A tone's experienced highness or lowness; depends on frequency.

Nerves

Bundled axons that form neural "cables" connecting the central nervous system with muscles, glands, and sensory organs.

Evolutionary Perspective

A way of looking at human behavior that emphasizes the role of natural selection and survival of the fittest in shaping our actions.

Executive Functioning

Higher-level cognitive processes including thinking, planning, and problem-solving.

Motor Cortex

The part of the brain that controls voluntary movements.

Occipital Lobes

The part of the brain that processes visual information.

Temporal Lobes

Areas of the brain involved in processing auditory information and encoding memory.

Cerebellum

A part of the brain at the back of the skull that coordinates and regulates muscular activity ("little brain").

Hippocampus

A part of the limbic system involved in learning and memory.

Amygdala

A structure in the limbic system involved in emotion, particularly fear and aggression.

Central Nervous System

The part of the nervous system consisting of the brain and spinal cord.

Peripheral Nervous System

All the nerves that lie outside the brain and spinal cord.

Sympathetic Nervous System

The part of the autonomic nervous system that prepares the body for rapid action in emergencies (arouses).

Parasympathetic Nervous System

The part of the autonomic nervous system that calms the body and conserves energy.

Somatic Nervous System

The part of the peripheral nervous system associated with voluntary control of body movements via skeletal muscles.

Neurons

The basic working units of the brain, specialized cells that transmit information to other nerve cells, muscle, or gland cells.

Sensory (afferent) Neurons

Neurons that carry incoming information from the sensory receptors to the brain and spinal cord.

Interneurons

Neurons within the brain and spinal cord that communicate internally and process info between the sensory inputs and motor outputs.

Reflex Arc

A neural pathway that controls a reflex action. allowing for rapid responses to sensory stimuli without conscious thought (interneurons).

All-or-Nothing Principle

The rule that neurons are either firing at full strength or not firing.

Refractory Period

A brief resting pause that occurs after a neuron has fired; subsequent action potentials can't occur until the axon returns to its resting state.

Reuptake

A neurotransmitter's reabsorption by the sending neuron.

Glutamate

An excitatory neurotransmitter strengthening synaptic connections between neurons.

Inhibitory Neurotransmitters

Chemical messengers decreasing the likelihood of neuron firing an action potential.