Neuroscience and Nervous System Function

Vocabulary flashcards covering brain structure, language processing, hemisphere lateralization, neurotransmission manipulation, and neuron electrophysiology.

Cerebral Cortex

The wrinkly outer layer of the brain responsible for higher-level functions including reasoning, planning, movement, emotion, visual, auditory, and sensory processing.

Geschwind-Wernicke theory of language

A model describing speech processing where sounds heard by the primary auditory cortex are sent to Wernicke's area for comprehension, formulated responses are sent to Broca's area for speech organization, and plans are sent to the motor cortex for execution.

Broca's aphasia

A form of language impairment where individuals have relatively good language comprehension but experience severe difficulty producing fluent speech, resulting in slow, effortful, short phrases missing grammatical words.

Wernicke's aphasia

A form of language impairment where individuals produce fluent, grammatical-sounding speech that lacks clear meaning, often using incorrect or invented words, alongside impaired language comprehension.

Contralateral control

The organizational arrangement of the central nervous system where the right cerebral hemisphere predominantly controls motor function and receives sensory input from the left side of the body, and vice versa.

Corpus Callosum

A large bundle of nerve fibers connecting the left and right cerebral hemispheres, facilitating interhemispheric communication and coordination.

Prosopagnosia

A neurological condition, also known as face blindness, characterized by an inability to recognize familiar faces while general vision and intelligence remain normal; linked to dysfunction in the fusiform face area and affecting roughly $2\text{--}3\%$ of the population.

Cambridge Face Memory Test

An assessment tool used to evaluate human facial recognition performance, where the population average is approximately $80\%$ correct and scores below $60\%$ suggest prosopagnosia.

Agonists

Chemical substances (such as heroin) that bind to and activate specific neural receptors, triggering a biological response similar to or stronger than endogenous neurotransmitters.

Antagonists

Chemical substances (such as Naloxone) that bind to receptor sites without activating them, blocking natural neurotransmitters or agonist drugs from binding or displacing them.

Buprenorphine

A medication used in opioid addiction treatment (Subutex) that acts as a partial opioid agonist and potent antagonist, helping manage withdrawal symptoms while reducing relapse risk.

Dopamine

A key neurotransmitter involved in regulating cognitive processes, voluntary movement, motivation, sleep, mood, attention, and reward processing.

Parkinson's Disease

A neurological movement disorder caused by a deficit of dopamine in specific brain regions, resulting in motor stiffness and cognitive impairment; treated with dopamine precursors or agonists like Levodopa and Ropinirole.

Schizophrenia

A psychiatric condition linked to excessive dopamine activity in brain pathways, characterized by delusions, hallucinations, and disorganized thinking; managed with dopamine antagonists like Thorazine.

Reuptake

The process by which released neurotransmitters are transported back from the synaptic cleft into the presynaptic terminal for recycling and clearance.

Reuptake Inhibitors

Drugs that block neurotransmitter transporter proteins, prolonging neurotransmitter presence in the synaptic cleft and increasing signaling at postsynaptic receptors.

Selective Serotonin Reuptake Inhibitor (S-SSRI)

A class of antidepressant medications (e.g., Prozac, Lexapro, Zoloft) that selectively block the reuptake transporter for serotonin, elevating synaptic serotonin concentration.

Cocaine

A compound derived from coca leaves that acts as a non-selective reuptake inhibitor of serotonin, norepinephrine, and dopamine, generating stimulant and local anesthetic effects.

Autonomic Nervous System

A major division of the peripheral nervous system regulating involuntary visceral functions, glands, and internal organs; subdivided into the sympathetic and parasympathetic divisions.

Sympathetic Division

The branch of the autonomic nervous system responsible for mobilizing the body's resources during stress or emergency ("fight or flight" response).

Parasympathetic Division

The branch of the autonomic nervous system that conserves energy and maintains baseline vegetative functions ("rest and digest" or "feed and breed").

Reflex Arc

A neural pathway mediating an automatic, involuntary reflex response (e.g., Patellar Reflex or Withdrawal Reflex) consisting of sensory input, spinal cord processing, and motor output.

Reticular Theory

An obsolete histological theory championed by Camillo Golgi claiming that the nervous system consists of a single continuous, interconnected mesh network of tissue.

Neuron Theory

The fundamental neurobiological principle advanced by Santiago Ramón y Cajal stating that the nervous system is composed of discrete, individual cellular units called neurons.

Synaptic Pruning

The developmental process in which underutilized synaptic connections are systematically eliminated, reducing total brain synapses from approximately $1$ quadrillion in early childhood to $500$ trillion in adulthood.

Dendrites

Branching neuronal projections that receive incoming chemical signals from presynaptic neurons and convey electrical changes toward the cell body.

Axon Hillock

The specialized region of a neuron connecting the soma to the axon that integrates incoming excitatory and inhibitory electrical potentials to trigger an action potential if the threshold ($-55\,mV$) is reached.

Myelin Sheath

An insulating fatty layer wrapped around axon segments that dramatically accelerates action potential conduction velocity via saltatory transmission.

Resting State

The baseline membrane potential of an inactive neuron, characterized by an internal electrical charge of $-70\,mV$ relative to the extracellular fluid.

Action Potential

A rapid, propagating wave of membrane depolarization that shifts the neuron's voltage to approximately $+40\,mV$ once the threshold potential ($-55\,mV$) is surpassed.

All-or-Nothing Principle

The neurophysiological rule stating that a neuron generates an action potential at full magnitude or not at all, without graded variations in firing intensity.

Frequency-Intensity Relation

The coding mechanism whereby stimulus intensity is represented in the nervous system by the rate or frequency of action potential firing rather than changes in individual spike amplitude.

Multiple Sclerosis (MS)

A chronic autoimmune disorder in which the immune system targets and destroys the myelin sheath of central nervous system axons, leading to impaired nerve impulse conduction.

Nerve Fiber Classification

The functional categorization of peripheral axon fibers based on myelination and conduction speed: C fibers (unmyelinated, slow pain at $2\,MPH$), A-delta fibers (thin myelin, fast pain at $25\,MPH$), A-beta fibers (medium myelin, touch at $120\,MPH$), and A-alpha fibers (thick myelin, proprioception at $225\,MPH$).