Neuroscience, Behaviour, Sensation, and Perception

Comprehensive vocabulary flashcards covering neural communication, brain structures, nervous system divisions, genetics, and sensory-perceptual mechanisms based on Chapters 3 and 4 lecture notes.

Neurons

Cells in the nervous system that communicate with one another to perform information-processing tasks.

Cell body (soma)

The largest part of the neuron that coordinates information-processing tasks and keeps the cell alive.

Dendrites

Branch-like specialized structures of a neuron that receive information from other neurons and relay it to the cell body.

Axon

The part of a neuron that carries information to other neurons, muscles, or glands.

Myelin sheath

An insulating layer of fatty material covering the axon, composed of glial cells, that speeds the transmission of electrical signals.

Glial cells

Support cells found in the nervous system that digest dead neurons, provide physical and nutritional support, and form myelin.

Synapse

The small gap between one neuron's axon and another neuron's dendrites or cell body, where signals are passed between neurons.

Sensory neurons

Neurons that receive information from the external world and convey this information to the brain through the spinal cord.

Motor neurons

Neurons that carry signals from the spinal cord to the muscles to produce movement.

Interneurons

Neurons that connect sensory neurons, motor neurons, or other interneurons to process information within the brain and spinal cord.

Purkinje cells

A type of interneuron that carries information from the cerebrum to the rest of the brain and spinal cord.

Pyramidal cells

Neurons found in the cerebral cortex that feature a triangular cell body and a single long dendrite among many smaller dendrites.

Bipolar cells

A type of sensory neuron found in the retina of the eye that has a single axon and a single dendrite.

Resting potential

The difference in electrical charge between the inside and outside of a neuron's cell membrane at rest, typically $-70\,\text{mV}$.

Action potential

An all-or-none electrical signal conducted along the length of a neuron's axon to the synapse, reaching approximately $+40\,\text{mV}$.

Refractory period

The time period following an action potential during which a new action potential cannot be initiated in that recently activated area.

Nodes of Ranvier

Small gaps between the sections of myelin along an axon where the action potential is regenerated.

Saltatory conduction

The rapid transmission of an electrical signal down a myelinated axon, where the signal appears to jump from node to node.

Terminal buttons

Knoblike structures that branch out at the end of an axon and are filled with vesicles containing neurotransmitters.

Vesicles

Tiny sacs located within terminal buttons that store neurotransmitters.

Neurotransmitters

Chemical messengers that transmit information across the synapse to a receiving neuron's dendrites.

Receptors

Parts of the cell membrane on a receiving neuron that receive neurotransmitters and either initiate or prevent a new electrical signal.

Reuptake

The process by which released neurotransmitters are reabsorbed by the presynaptic neuron's terminal buttons or nearby glial cells.

Enzyme deactivation

The breakdown of excess neurotransmitters in the synapse by specific enzymes.

Autoreceptors

Receptor sites on the presynaptic neuron that detect how much neurotransmitter has been released and signal the neuron to stop releasing more.

Acetylcholine (ACh)

A neurotransmitter involved in voluntary muscle movement, attention, learning, sleep, dreaming, and memory; its deterioration is linked to Alzheimer's disease.

Glutamate

The major excitatory neurotransmitter in the brain that increases the likelihood of a neuron firing; excess can lead to overactivity and seizures.

GABA (gamma-aminobutyric acid)

The major inhibitory neurotransmitter in the brain that decreases the likelihood of a neuron firing; too little can contribute to seizures.

Dopamine (DA)

A neurotransmitter that regulates motor behaviour, motivation, pleasure, and emotional arousal; linked to schizophrenia at high levels and Parkinson's disease at low levels.

Norepinephrine (NE)

A neurotransmitter involved in states of mood, arousal, vigilance, and alertness; low levels are implicated in mood disorders such as depression.

Serotonin (5-HT)

A neurotransmitter regulating sleep, wakefulness, eating, and aggressive behaviour; low levels are associated with mood disorders like depression.

Endorphins

Naturally produced chemicals that act within pain pathways and emotion centres of the brain to reduce pain and improve mood.

Agonists

Drugs that increase the action or effectiveness of a neurotransmitter.

Antagonists

Drugs that block or decrease the action of a neurotransmitter.

Central Nervous System (CNS)

The primary division of the nervous system composed of the brain and the spinal cord.

Peripheral Nervous System (PNS)

The division of the nervous system that connects the central nervous system to the body's organs and muscles.

Somatic nervous system

A set of nerves within the PNS that conveys information between voluntary skeletal muscles and the central nervous system.

Autonomic nervous system (ANS)

A set of nerves within the PNS that carries involuntary and automatic commands controlling blood vessels, body organs, and glands.

Sympathetic nervous system

A division of the autonomic nervous system that prepares the body for action in challenging, threatening, or stressful situations.

Parasympathetic nervous system

A division of the autonomic nervous system that helps the body return to a normal resting state.

Spinal reflexes

Simple pathways in the nervous system that rapidly generate muscle contractions without initial instruction from the brain.

Reflex arc

The neural pathway responsible for generating a reflex action.

Medulla

An extension of the spinal cord into the skull that coordinates heart rate, circulation, and respiration.

Reticular formation

A small cluster of neurons extending upward from the medulla that regulates sleep, wakefulness, and levels of arousal.

Cerebellum

A large hindbrain structure that controls fine motor skills and smooths or coordinates movements.

Pons

A hindbrain structure that relays information from the cerebellum to the rest of the brain.

Tectum

A midbrain structure that orients an organism in the environment by coordinating movement toward sensory stimuli from the eyes, ears, and skin.

Tegmentum

A midbrain structure involved in movement and arousal.

Thalamus

A subcortical forebrain structure that receives, filters, and relays sensory information (from all major senses except smell) to the cerebral cortex.

Hypothalamus

A subcortical structure that regulates basic body needs, including body temperature, hunger, thirst, and sexual behaviour.

Hippocampus

A subcortical forebrain structure critical for creating new memories and integrating them into long-term storage.

Amygdala

A subcortical structure located at the tip of the hippocampus that plays a central role in processing emotional information, particularly fear.

Basal ganglia

A set of subcortical structures that directs intentional movements, posture, and reward processing.

Endocrine system

A network of glands that release hormones into the bloodstream to regulate functions such as metabolism, growth, and sexual development.

Cerebral cortex

The outermost layer of the brain, divided into two hemispheres, responsible for the most complex aspects of perception, emotion, movement, and thought.

Corpus callosum

The largest commissure connecting large areas of the cerebral cortex across both hemispheres to support bilateral communication.

Occipital lobe

The cortical lobe located at the back of the cerebral cortex that processes visual information.

Parietal lobe

The cortical lobe located in front of the occipital lobe that processes information about touch and houses the somatosensory cortex.

Temporal lobe

The cortical lobe located on the lower side of each hemisphere responsible for hearing, language processing, and visual association.

Frontal lobe

The cortical lobe located behind the forehead that specializes in movement, abstract thinking, planning, memory, and executive judgment.

Brain plasticity

The brain's ability to adapt, change, and reassign functions based on experience or altered sensory input.

Mirror neurons

Neurons in the frontal and parietal lobes that activate both when performing an action and when observing another individual perform that same action.

Gene

The major unit of hereditary transmission, organized into strands of DNA within chromosomes.

Epigenetics

The study of environmental influences that determine whether or not genes are expressed without altering the basic DNA sequence.

Heritability

A statistical measure scaled from 0.00 to 1.00 indicating the proportion of variability in behavioural traits accounted for by genetic differences.

Sensation

The simple stimulation of a sense organ as parts of the body interact with the physical world.

Perception

The organization, identification, and interpretation of sensory signals in the brain to form a mental representation.

Transduction

The process by which physical signals from the environment are converted into neural signals sent to the central nervous system.

Psychophysics

Methods that systematically measure the strength of a physical stimulus and an observer's sensitivity to that stimulus.

Absolute threshold

The minimal intensity of a stimulus needed for an observer to barely detect it 50% of the time.

Just Noticeable Difference (JND)

The smallest change in a stimulus that can just barely be detected, which is a constant percentage of the original stimulus according to Weber's law.

Signal Detection Theory

A framework stating that the detection of a stimulus depends both on an observer's sensitivity to the signal amid noise and their decision criterion.

Sensory adaptation

The decline in sensitivity to prolonged, unchanging stimulation as the perceptual system adapts.

Accommodation

The process by which the eye's lens changes shape (flattening for far objects and rounding for near objects) to maintain clear focus on the retina.

Retina

The light-sensitive tissue lining the back of the eyeball containing rods and cones for phototransduction.

Cones

Photoreceptor cells in the retina that detect colour and fine details under normal daylight conditions.

Rods

Photoreceptor cells in the retina that become active only in low-light conditions for night vision and perceive shades of grey.

Fovea

The central region of the retina containing a high density of cones and no rods, responsible for sharpest visual acuity.

Ventral stream

The visual pathway traveling from the occipital lobe to the temporal lobe ('what' pathway) that identifies an object's shape and identity.

Dorsal stream

The visual pathway traveling from the occipital lobe to the parietal lobe ('where/how' pathway) that identifies an object's location and guides actions.

Binding problem

The question of how the brain links individual features (such as color, shape, and location) processed in different areas into a single unified object.

Perceptual constancy

The perceptual principle that an object's perceived properties remain the same even when its sensory image on the retina changes.

Inattentional blindness

A failure to perceive objects that are not the focus of attention.

Change blindness

A failure to notice changes to the visual details of a scene when attention is focused elsewhere.

Cochlea

A fluid-filled, spiral-shaped inner-ear structure that transduces sound vibrations into neural impulses.

Basilar membrane

A structure inside the cochlea that undulates in response to sound vibrations, causing hair cells to bend.

Hair cells

Specialized auditory receptor cells in the inner ear that transduce mechanical basilar membrane movement into neural impulses.

Conductive hearing loss

Hearing loss resulting from physical damage to the outer or middle ear (such as the eardrum or ossicles) that prevents vibrations from reaching the cochlea.

Sensorineural hearing loss

Hearing loss caused by damage to the cochlea's hair cells or the auditory nerve.

Haptic perception

The active exploration of the environment through touching and grasping objects with the hands.

A-delta fibres

Fast-conducting sensory nerve fibres that transmit initial, sharp pain from sudden injury.

C-fibres

Slower-conducting sensory nerve fibres that transmit dull, aching, and longer-lasting pain after an injury.

Gate-control theory

A theory of pain perception stating that interneurons in the spinal cord can block pain signals from reaching the brain via competing sensory signals or top-down brain control.

Referred pain

The sensation of feeling internal pain somewhere on the surface of the body due to convergent sensory pathways in the spinal cord.

Proprioception

The sensory sense of where body parts are positioned in space, mediated by receptors in muscles, tendons, and joints.

Vestibular system

The three fluid-filled semicircular canals and adjacent structures in the inner ear that maintain balance and detect head motion.

Olfactory epithelium

A mucous membrane located at the top of the nasal cavity that contains millions of olfactory receptor neurons.

Olfactory bulb

A brain structure located beneath the frontal lobes that receives neural input from olfactory receptor neurons and sends it to emotion and memory centres.

Pheromones

Biochemical odorants emitted by other members of a species that can influence behaviour or physiology.

Taste buds

The organs of taste transduction housed inside tongue papillae, containing receptor cells that react with tastants.