Neuroscience, Biological Rhythms, Eating, and Memory

Vocabulary flashcards covering core concepts from neuroanatomy, membrane dynamics, biological rhythms, eating behaviors, and memory principles.

Action Potential Dynamics

Diagram showing membrane potential changes over time, including resting membrane potential ($-70\,mV$), threshold of excitation, depolarization, peak at $+40\,mV$, refractory period, and return to resting level.

Sleep Stage Progression

Hypnogram illustrating the progression through sleep stages (1, 2, 3, 4, and REM) across an 8-hour period, showing recurring REM periods about every 90 minutes.

Blood Glucose and Insulin Feedback Loop

Feedback cycle showing how eating increases blood glucose and insulin release to facilitate storage, leading to declining blood glucose and insulin levels, followed by glucagon release to convert stored supplies back to glucose before hunger returns.

Operant Conditioning Matrix

A framework categorizing behavioral outcomes into Positive Reinforcement (+R), Negative Reinforcement (-R), Positive Punishment (+P), and Negative Punishment (-P) based on whether a stimulus is added (+) or removed (-) and whether behavior increases or decreases.

Dendrites

Neuronal structures that receive chemical signals from other cells and alter their electrical potential at that spot.

Afferent Axon

An axon that brings sensory information into a target structure.

Efferent Axon

An axon that carries motor information away from a structure toward muscles or organs.

Interneurons

Also called intrinsic neurons, these are neurons whose dendrites and axons are completely contained within a single neural structure.

Schwann Cell

A type of glial cell in the peripheral nervous system (PNS) that provides myelin to individual axons and recovers well after damage.

Oligodendrocyte

A glial cell in the central nervous system (CNS) that extends processes to wrap myelin around multiple axons, but recovers poorly from damage.

Microglia

Glial cells that act like amoebas, moving to damaged areas to remove waste material and harmful microorganisms.

Astrocytes

Glial cells that synchronize axon activity by wrapping around presynaptic terminals, taking up released chemicals, and wrapping around blood vessels to form the blood-brain barrier.

Blood-Brain Barrier

A protective mechanism surrounding the brain that blocks most chemicals from entering while permitting fat-soluble molecules and actively transported nutrients like glucose and amino acids.

Bell-Magendie Law

The principle stating that dorsal roots of the spinal cord carry incoming sensory (afferent) information while ventral roots carry outgoing motor (efferent) information.

Substantia Nigra

A pair of black nuclei in the midbrain critical for Parkinson's disease where dopamine is synthesized to trigger motor activity.

Thalamus

A major diencephalic processing hub containing around 30 groups of cell bodies that processes all sensory and motor information going to and from the cortex.

Hypothalamus

A forebrain regulatory structure that manages autonomic nervous system functions, hunger, sleep cycles, reproduction, and flight-or-fight responses.

Resting Membrane Potential

The stable electrical potential of a non-signaling neuron, typically measured at $-70\,mV$.

Sodium-Potassium Pump

A protein mechanism that uses significant energy to actively transport sodium out of the cell and pump leaking potassium back inside.

Absolute Refractory Period

The phase following an action potential where voltage-gated sodium channels are closed and inactive, preventing another action potential regardless of stimulus strength.

Relative Refractory Period

The phase following the absolute refractory period during which sodium channels reset and an action potential can be generated, but requires a stronger-than-normal stimulus.

Saltatory Conduction

The process by which action potentials rapidly travel down a myelinated axon by jumping from node of Ranvier to node of Ranvier.

Ionotropic Receptors

Transmembrane receptors that act directly as ligand-gated ion channels, opening quickly and producing brief postsynaptic effects.

Metabotropic Receptors

Receptors that initiate a G-protein second messenger system upon ligand binding, producing slower and longer-lasting cellular effects.

Reuptake

The presynaptic mechanism by which released neurotransmitters are transported back into the cytoplasm for reuse or breakdown.

Acetylcholine (ACh)

The primary neurotransmitter secreted by efferent CNS cells, active at the neuromuscular junction, parasympathetic ganglia, and brain regions involved in attention and dreaming.

Suprachiasmatic Nucleus (SCN)

The brain's master biological clock located in the hypothalamus that regulates circadian rhythms and controls melatonin secretion from the pineal gland.

Zeitgebers

External environmental stimuli, such as light, sound, or social cues, that entrain and reset endogenous biological rhythms.

Osmotic Thirst

Thirst resulting from eating salty foods, caused by an increased concentration of solutes in extracellular fluid drawing water out of cells.

Hypovolemic Thirst

Thirst triggered by a loss of overall fluid volume from bleeding or sweating, mediated by vasopressin and angiotensin II to restore blood pressure.

Conditioned Taste Aversion

A form of rapid one-trial learning where an organism avoids a specific taste after it is associated with illness.

Leptin

A peptide hormone produced by fat cells that signals long-term energy availability to the brain to modulate hunger.

Equipotentiality

Karl Lashley's principle stating that all parts of the cerebral cortex contribute equally to complex functions like learning.

Mass Action

The principle proposed by Karl Lashley stating that the cortex functions as a whole rather than as isolated independent units.

Anterograde Amnesia

The inability to form new long-term memories following brain damage.

Retrograde Amnesia

The loss of memory for events that occurred prior to brain injury or trauma.

Long-Term Potentiation (LTP)

A long-lasting increase in synaptic responsiveness following high-frequency stimulation, serving as a neural foundation for learning and memory.

Korsakoff's Syndrome

A neurological condition marked by permanent anterograde amnesia and confabulation caused by thiamine (vitamin B1) deficiency, typically seen in chronic alcoholism.