PSYC MODULE 5 - Neuroscience Core Concepts: Brain, Neurons, Sleep, and Drugs

Neuron

The primary cell of the nervous system that transmits information via electrochemical signals.

Glial Cells

Helper cells that provide structural and functional support to neurons.

Dendrites

Extensions of the neuron's cell body that receive incoming chemical messages from other cells.

Axon Hillock

The region of the neuron that generates an action potential if the electrical signal crosses the activation threshold.

Axon

The long extension of a neuron that transmits electrical impulses away from the cell body over long distances.

Nodes of Ranvier

Gaps in the myelin sheath along an axon that facilitate the rapid transmission of electrical signals.

Myelin

A fatty substance that wraps around axons to speed up electrical signal transmission.

Oligodendrocytes

Glial cells responsible for producing myelin within the Central Nervous System.

Schwann Cells

Glial cells responsible for producing myelin within the Peripheral Nervous System.

Astrocytes

Glial cells that maintain extracellular ion balances, deliver nutrients, and form the brain's immune shield.

Microglia

Glial cells that act as immune defense by eliminating metabolic cellular debris and infectious agents.

Neuroplasticity

The ability of neurons and glia to change, adapt, or remap their functions in response to experiences or injury.

Resting Membrane Potential

The stable electrical charge of a neuron when it is not firing, exactly −70 mV.

Sodium-Potassium Pump

A mechanism that maintains resting voltage by pumping 3 Na+ ions out of the cell and 2 K+ ions in.

Threshold of Excitation

The voltage level (−55 mV) that must be breached to trigger an action potential.

Depolarization

The rapid rise in membrane potential during an action potential, peaking at roughly +40 mV due to an influx of sodium ions.

Repolarization

The phase where potassium channels open and K+ ions exit the cell, returning the neuron to a negative state.

Hyperpolarization

A momentary drop in membrane potential past normal resting values, making the neuron temporarily less likely to fire.

All-or-Nothing Rule

The principle that an action potential always fires at full strength; signal intensity is coded by the frequency of the impulses, not their size.

Graded Potentials

Localized, temporary electrical changes in a neuron that fade quickly and do not propagate down the axon.

Central Nervous System

The division of the nervous system consisting entirely of the brain and spinal cord.

Autonomic Nervous System

The division of the Peripheral Nervous System that controls unconscious internal processes.

Prefrontal Cortex

The region of the frontal lobe responsible for executive function, impulse control, and decision-making.

Broca’s Area

A region in the left hemisphere of the frontal lobe essential for fluent language production.

Parietal Lobe

The brain region responsible for processing contralateral somatosensory inputs, spatial mapping, and math calculations.

Temporal Lobe

The brain region responsible for auditory processing, explicit memory routing, and language comprehension.

Occipital Lobe

The brain region dedicated to processing visual attributes using specialized feature detectors.

Thalamus

The sensory relay node that routes all incoming sensory data to the cortex, with the exception of smell.

Hypothalamus

The master node regulating the autonomic and endocrine systems, driving hunger, body temperature, and stress responses.

Hippocampus

The critical brain structure responsible for cataloging, processing, and consolidating new explicit memories.

Amygdala

The structure that evaluates emotional intensity, valence, and threat levels of incoming sensory data.

Medulla

The brainstem region regulating mandatory life functions like breathing, heart rate, and swallowing.

Cerebellum

The structure responsible for motor timing, balance, rhythm, and sensory-motor error correction.

Basal Ganglia

The primary operational switch for voluntary movement control, balancing excitatory and inhibitory motor pathways.

Substantia Nigra

A dopamine-secreting structure that modulates the basal ganglia; its degeneration causes Parkinson's disease.

Suprachiasmatic Nucleus

The brain structure located in the hypothalamus that sets the body's internal 24-hour circadian clock.

Corpus Callosum

The thick bundle of white matter axons connecting the left and right hemispheres.

Visual Neglect

An attentional deficit caused by lesions to the right inferior parietal lobe, leading to a lack of awareness of the left side of space.

Anterograde Amnesia

The inability to form new explicit, declarative memories after brain damage.

Homunculus

A sensorimotor topography map illustrating the relative density of neural innervation across the body.

Attention

The neurobiological process of selecting and prioritizing specific information from internal and external environments.

Passive Attention

Bottom-up, involuntary attention driven automatically by highly noticeable environmental stimuli.

Active Attention

Top-down, goal-directed attention driven voluntarily by an individual's internal instructions or expertise.

Inattentional Blindness

The psychological phenomenon of failing to see a perfectly visible, unexpected stimulus because attention is engaged in a demanding task.

Cocktail Party Effect

The ability to selectively isolate and focus on a single voice in a crowded room while still processing unattended auditory streams.

Theory of Mind

The cognitive ability to attribute mental states to oneself and others, typically emerging around 3 years of age.

Electroencephalogram

A tool that measures cortical electrical activity, offering high temporal resolution.

Beta Waves

Irregular, alert brain waves associated with active wakefulness or REM sleep.

Alpha Waves

Highly regular, synchronized brain waves associated with relaxed wakefulness.

Delta Waves

High-amplitude, slow brain waves characteristic of Slow-Wave Sleep, vital for physical restoration.