Neuroscience, Behavior, Sensation, and Perception

Comprehensive vocabulary flashcards covering neural structure, action potential dynamics, synaptic transmission, neuroanatomy, brain imaging, genetics, and sensory psychophysics.

Neurons

Cells in the nervous system that communicate with one another to perform information-processing tasks; there are approximately $100\text{ billion}$ in the human brain.

Cell Body (Soma)

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

Dendrites

Specialized branch-like extensions of the neuron that receive information from other neurons and relay it to the cell body.

Axon

A long nerve fiber that transmits information from the cell body to other neurons, muscles, or glands.

Myelin Sheath

An insulating layer of fatty material composed of glial cells that covers the axon to facilitate and speed up electrical signal transmission.

Glial Cells

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

Demyelinating Diseases

Disorders such as multiple sclerosis in which the myelin sheath deteriorates, causing a significant slowing of signal transmission.

Synapse

The junction or region between the axon terminal of one neuron and the dendrites or cell body of another.

Sensory Neurons

Neurons with specialized dendritic endings that receive information from the external world (such as light, sound, touch, taste, and smell) and convey it to the brain via the spinal cord.

Motor Neurons

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

Interneurons

Neurons that connect sensory neurons, motor neurons, or other interneurons to process information.

Purkinje Cells

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

Pyramidal Cells

Cerebral cortex neurons characterized by a triangular cell body and a single long dendrite surrounded by multiple smaller dendrites.

Bipolar Cells

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

Mirror Neurons

Neurons situated in the frontal and parietal lobes that activate both when an animal performs a behavior and when it observes another animal performing that same behavior.

Resting Potential

The difference in electrical charge between the inside and outside of a neuron's cell membrane, characterized by a negative interior charge of approximately $-70\,\text{mV}$.

Action Potential

An all-or-nothing electrical signal conducted along the length of an axon to the synapse when stimulation reaches the excitation threshold, reaching a maximum value of $+40\,\text{mV}$.

Refractory Period

The time interval following an action potential during which a new action potential cannot be initiated due to ionic imbalance across the membrane.

Sodium-Potassium Pump

An active chemical pump in the cell membrane that reverses the ion imbalance after an action potential by moving sodium ($\text{Na}^+$) outside and potassium ($\text{K}^+$) inside the axon.

Nodes of Ranvier

The unmyelinated break points along the length of an axon between segments of myelin sheath.

Saltatory Conduction

The process by which electrical currents jump rapidly from node to node along a myelinated axon, speeding up signal transmission.

Terminal Buttons

Knoblike structures branching out from the end of an axon that contain vesicles filled with neurotransmitters.

Neurotransmitters

Chemical substances stored in vesicles that transmit information across the synaptic cleft to receptors on a receiving neuron's dendrites.

Receptors

Specialized proteins located on the postsynaptic cell membrane that bind neurotransmitters in a lock-and-key fashion to initiate or inhibit electrical signaling.

Autoreceptors

Receptor sites on the presynaptic terminal buttons that detect the concentration of released neurotransmitter and signal the neuron to cease release when in excess.

Reuptake

The reabsorption process by which excess neurotransmitters in the synaptic gap are taken back into the presynaptic terminal buttons.

Enzyme Deactivation

The clearance mechanism wherein specific enzymes present in the synapse chemically break down and destroy neurotransmitters.

Acetylcholine (ACh)

A neurotransmitter involved in voluntary motor control, attention, learning, and memory, the deterioration of which is linked to Alzheimer's disease.

Glutamate

The major excitatory neurotransmitter in the brain that enhances information transmission throughout neural pathways.

GABA (Gamma-Aminobutyric Acid)

The primary inhibitory neurotransmitter in the brain that calms neural activity.

Dopamine (DA)

A neurotransmitter that regulates motor behavior, motivation, pleasure, and emotional arousal; heavily implicated in Parkinson's disease, schizophrenia, and addiction.

Norepinephrine (NE)

A neurotransmitter that influences mood, vigilance, and heightened physiological arousal.

Serotonin (5-HT)

A neurotransmitter involved in regulating sleep and wakefulness, eating behaviors, mood, and aggression.

Endorphins

Endogenous chemicals that operate within pain pathways and emotion centers of the brain to dull pain and elevate mood.

Agonist and Antagonist

Agonists are substances that increase or mimic the action of a neurotransmitter, whereas antagonists are substances that block or inhibit neurotransmitter function.

L-Dopa

A biochemical precursor to dopamine developed to treat Parkinson's disease by crossing the blood-brain barrier and acting as a dopamine agonist.

Central Nervous System (CNS)

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

Peripheral Nervous System (PNS)

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

Nervous System Organization

The structural breakdown of the nervous system into central and peripheral branches, the peripheral further dividing into somatic and autonomic branches.

Somatic Nervous System

The branch of the peripheral nervous system that conveys information into and out of the CNS to control voluntary movements of skeletal muscles.

Autonomic Nervous System (ANS)

The involuntary division of the peripheral nervous system controlling the automatic actions of blood vessels, internal organs, and glands.

Sympathetic Nervous System

The subdivision of the autonomic nervous system that arouses and mobilizes the body for action in threatening situations (e.g., dilating pupils, accelerating heartbeat).

Parasympathetic Nervous System

The subdivision of the autonomic nervous system that calms the body and returns it to a resting, homeostatic state (e.g., constricting pupils, slowing heartbeat).

Spinal Reflexes

Simple, rapid neural pathways in the nervous system that generate muscle contractions directly through interneurons in the spinal cord without brain input.

Hindbrain

An area continuous with the spinal cord coordinating information coming in and out of the spine, controlling basic functions like respiration, alertness, and motor skills.

Medulla

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

Reticular Formation

A hindbrain structure extending up from the medulla that regulates sleep, wakefulness, and levels of physiological arousal.

Pons

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

Cerebellum

A large structure located at the base of the hindbrain responsible for fine motor skills, coordination, and balance.

Midbrain

A brain region located on top of the hindbrain containing the tectum and tegmentum, coordinating basic movement and environmental orientation.

Tectum

A midbrain structure that receives sensory stimuli from the eyes, ears, and skin to orient an organism toward environmental events.

Tegmentum

A midbrain structure involved in movement, physiological arousal, and motor pathways connecting to the forebrain.

Thalamus

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

Hypothalamus

A subcortical structure located below the thalamus that regulates body temperature, hunger, thirst, and sexual behavior.

Hippocampus

A limbic system structure critical for creating new factual and episodic memories and integrating them into the cerebral cortex for long-term storage.

Amygdala

A limbic system structure located at the tip of the hippocampus that plays a central role in emotional processes and emotional memory consolidation.

Basal Ganglia

A set of subcortical structures, including the striatum, that directs intentional movements and controls posture.

Pituitary Gland

The master gland of the endocrine system that secretes hormones directing the functions of numerous other glands throughout the body.

Gyri and Sulci

The distinct structural folds of the cerebral cortex, where gyri are the raised, smooth ridges and sulci are the indents or fissures.

Contralateral Control

The anatomical organization whereby each cerebral hemisphere receives sensory signals from and controls voluntary functions on the opposite side of the body.

Corpus Callosum

A thick band of nerve fibers connecting parallel areas of the cerebral cortex across both hemispheres, supporting interhemispheric communication.

Occipital Lobe

The cortical region located at the back of the brain responsible for processing incoming visual information and generating spatial feature maps.

Parietal Lobe

The cortical region that contains the somatosensory cortex, dedicated to processing tactile sensations such as touch, pressure, and temperature.

Temporal Lobe

The cortical region located on the lower side of each hemisphere responsible for hearing, language comprehension, and visual object recognition.

Frontal Lobe

The cortical region specialized for movement, abstract thinking, planning, executive control, memory, and judgment; contains the highest density of dopamine-sensitive neurons.

Brain Plasticity

The capacity of the brain to structurally and functionally reorganize itself in response to learning, training, experience, or sensory changes.

Phantom Limb Syndrome

A condition in which amputees continue to experience vivid sensations or pain in a missing limb due to cortical reorganization within the somatosensory cortex.

Split-Brain Procedure

A surgical intervention severing the corpus callosum to alleviate intractable epilepsy, isolating the two hemispheres and preventing interhemispheric transfer of information.

Wada Test

A clinical procedure using intracarotid sodium amobarbital injection to temporarily anesthetize one hemisphere at a time to establish lateralized language representation before neurosurgery.

Hemispatial Neglect

A neurological condition typically resulting from a right hemisphere stroke characterized by an inability to attend to or perceive stimuli on the contralateral (left) side.

Diffusion Tensor Imaging (DTI)

A specialized structural MRI technique that visualizes white matter pathways to map the connectivity of the human brain.

Transcranial Magnetic Stimulation (TMS)

A non-invasive method delivering magnetic pulses through the skull to briefly deactivate cortical neurons, providing a tool to establish causal relationships between brain areas and behaviour.

Ct scan

Locates tumors and brain density

Structural brain imaging

Info about basic structure that allows professionals to see

Functional brain imaging

Provides info about brain activity when people perform tasks

MRI

Magnetic pulses that reveal structure composition better than ct

EEG

Electrical activity in synapse

PET

Radioactive in blood stream that demands more blood flow for high radiation

FMRI

Oxygenated blood and gives images of level of activation

Gene

The basic biological unit of hereditary transmission, consisting of segments of DNA strands organized along chromosomes.

Epigenetics

The study of environmental influences that regulate gene expression or suppress gene activity without altering underlying DNA sequences.

DNA Methylation

An epigenetic modification involving the addition of methyl groups to DNA that turns off the expression of a specific gene.

Histone Modification

Chemical modifications applied to histone packaging proteins that determine whether DNA is unwound or tightly packed, turning genes on or off.

Heritability

A statistical measure varying between $0$ and $1.00$ estimating the proportion of trait variation across individuals attributable to genetic factors.

Sensation

The simple stimulation of a sense organ by physical energy from the environment.

Perception

The organization, identification, and interpretation of sensory inputs in the brain to construct a meaningful mental representation.

Transduction

The biological process whereby physical energy from the environment is converted into encoded neural signals dispatched to the central nervous system.

Synesthesia

A neurological condition wherein sensory stimulation of one pathway evokes an involuntary, perceptual experience in a completely different sensory modality.

Sensory Adaptation

The decline in neural responsiveness that occurs following prolonged, unchanging exposure to a sensory stimulus.

Psychophysics

Methods developed by Gustav Fechner that measure the strength of a physical stimulus and the observer's psychological sensitivity to it.

Absolute Threshold

The minimal intensity of physical stimulation required for an observer to just barely detect a stimulus $50\%$ of the time.

Just Noticeable Difference (JND)

The minimal change in physical intensity required to detect a difference between two sensory stimuli.

Weber's Law

The psychophysical principle stating that the just noticeable difference of a stimulus is a constant proportion of the initial stimulus intensity (e.g., $2\text{--}3\%$ for weight).

Signal Detection Matrix

A decision framework categorizing perceptual responses into hits, misses, false alarms, and correct rejections depending on the presence of a signal amidst background noise.

Visual Acuity

The ability of the visual system to distinguish fine details, commonly evaluated using a standard Snellen chart with a benchmark of $20/20$ vision.

Human Eye Anatomy

The anatomical arrangement of the eye comprising the cornea, pupil, iris, lens, vitreous humor, and retina.

Accommodation (Vision)

The optical process by which ciliary muscles change the shape and thickness of the lens to focus images of near and distant objects clearly onto the retina.

Cones

Retinal photoreceptors operating under daylight conditions that detect color and enable high-acuity fine detail perception.

Rods

Retinal photoreceptors that activate under low-light conditions to provide night and peripheral vision, incapable of discriminating color.