Neuroscience: Neurotransmission, Neuroanatomy, Cortical Specialization, and Sensory Systems

Comprehensive vocabulary flashcards covering synaptic transmission, neuroanatomy, cortical localization, split-brain experiments, and sensory transduction principles.

Vesicle

Small, membrane-bound sacs inside the axon terminal that store neurotransmitters before release.

Exocytosis

The cellular process by which vesicles fuse with the cell membrane to release neurotransmitters into the synaptic cleft.

Neurotransmitter

A chemical messenger released by neurons that travels across the synapse to signal neighboring cells.

Receptor

Specialized protein molecules on the postsynaptic membrane that bind to specific neurotransmitters.

Ion Channel

Protein pores in the cell membrane that open or close to allow specific ions to pass through, changing the cell's electrical charge.

Reuptake

The clearance mechanism where neurotransmitters are actively transported back into the presynaptic neuron to be recycled.

Enzymatic Degradation

The breakdown of neurotransmitters in the synaptic cleft by specific enzymes (such as acetylcholinesterase).

Diffusion (Synaptic)

The passive movement of neurotransmitters away from the synaptic cleft into the surrounding fluid.

Excitatory Postsynaptic Potential (EPSP)

A depolarizing change in the membrane potential that makes the postsynaptic neuron more likely to fire an action potential.

Inhibitory Postsynaptic Potential (IPSP)

A hyperpolarizing change in the membrane potential that makes the postsynaptic neuron less likely to fire an action potential.

Divergence

A neural communication pattern in which one neuron signals to many postsynaptic neurons.

Convergence

A neural communication pattern in which many presynaptic neurons send signals to a single postsynaptic neuron.

Vagusstoff

The chemical substance discovered in Otto Loewi's frog heart experiment that demonstrated chemical neurotransmission, later identified as acetylcholine (ACh).

Hormones

Chemical messengers released by endocrine glands directly into the bloodstream to travel long distances and slowly affect widespread, systemic target organs.

Acetylcholine (ACh)

A neurotransmitter responsible for muscle contraction, memory formation, and autonomic nervous system regulation.

Dopamine (DA)

A neurotransmitter primarily involved in reward, reinforcement, motivation, and motor control.

Serotonin (5-HT)

A neurotransmitter involved in mood regulation, sleep, appetite, and arousal.

Norepinephrine (NE)

A neurotransmitter that mediates the fight-or-flight response, alertness, and physiological arousal.

GABA

The primary inhibitory neurotransmitter in the brain that acts to reduce neural activity.

Glutamate

The primary excitatory neurotransmitter in the brain, critical for learning and memory.

Endorphins

Endogenous opioid neurotransmitters responsible for natural pain relief and reward signaling.

Myasthenia Gravis

An autoimmune disorder characterized by antibodies attacking and blocking acetylcholine receptors at the neuromuscular junction, resulting in severe muscle weakness and fatigue.

Nuclei

Clusters of neuron cell bodies located within the central nervous system.

Circuits (Neural)

Interconnected groups of neurons that execute specific information processing tasks.

Networks (Neural)

Large-scale systems of interconnected brain circuits collaborating to produce complex behaviors.

Central Nervous System (CNS)

The division of the nervous system comprising the brain, spinal cord, and retina.

Peripheral Nervous System (PNS)

All nervous tissue and nerves branching out from the central nervous system to the rest of the body.

Somatic Nervous System

The division of the peripheral nervous system that governs voluntary movements of skeletal muscles.

Afferent Nervous System

Sensory pathways that convey incoming neural signals toward the central nervous system.

Efferent Nervous System

Motor pathways that carry neural instructions away from the central nervous system to effectors (muscles and glands).

Autonomic Nervous System

The division of the peripheral nervous system controlling involuntary internal organ and physiological functions.

Sympathetic Nervous System

The autonomic division responsible for initiating the 'fight-or-flight' survival response.

Parasympathetic Nervous System

The autonomic division responsible for regulating 'rest-and-digest' bodily functions.

Dorsal

Anatomical direction referring toward the top of the brain or the back (posterior) of the spinal cord.

Ventral

Anatomical direction referring toward the bottom of the brain or the front (anterior) of the spinal cord.

Meninges

The three protective membrane layers (dura mater, arachnoid mater, and pia mater) enveloping the brain and spinal cord to guard against mechanical shock and infection.

Cerebrospinal Fluid (CSF)

Fluid buffering the central nervous system that provides mechanical shock absorption, buoyant support, nutrient transport, and waste removal.

Ventricular Enlargement

An anatomical sign where fluid-filled brain ventricles expand, commonly indicating brain atrophy or neurodegeneration.

Hindbrain

The evolutionarily oldest brain division that is shared most closely across animal species, responsible for vital autonomic survival functions; includes the cerebellum, pons, and medulla.

Midbrain

The middle brain division containing motor control structures and relay centers for sensory routing and visual/auditory reflex integration.

Forebrain

The highest, evolutionarily newest division of the brain—least similar to other animals—responsible for complex thought, reasoning, and higher processing; includes the cerebrum, thalamus, and hypothalamus.

Cerebellum

A hindbrain structure essential for balance, coordination, fine motor timing, and certain cognitive/language processes.

Reticular Formation

A neural network spanning the hindbrain and midbrain that regulates sleep, wakefulness, arousal, and attention.

Medulla

A hindbrain structure regulating essential life-support autonomic functions, including respiration, heart rate, and blood pressure.

Superior Colliculus

Midbrain structures dedicated to visual tracking and orienting responses.

Inferior Colliculus

Midbrain structures dedicated to auditory localization and tracking.

Substantia Nigra

A midbrain nucleus that synthesizes dopamine to facilitate smooth, coordinated movement; its degeneration is linked to Parkinson's disease.

Thalamus

The primary sensory relay hub in the forebrain that directs incoming sensory signals (excluding olfaction) to the cerebral cortex.

Hypothalamus

A forebrain structure that manages motivated drives (hunger, thirst, body temperature) and directs the endocrine system through the pituitary gland.

Hippocampus

A forebrain structure essential for the consolidation and formation of new declarative memories.

Amygdala

A limbic forebrain structure central to processing emotional responses, threat detection, fear, and anger.

Corpus Callosum

A dense band of transverse nerve fibers connecting the left and right cerebral hemispheres, enabling interhemispheric communication.

Frontal Lobe

The cerebral lobe responsible for voluntary motor execution, reasoning, planning, executive function, and impulse control.

Parietal Lobe

The cerebral lobe specialized for spatial processing and somatosensory perception (touch, pressure, pain, and temperature).

Temporal Lobe

The cerebral lobe dedicated to auditory perception, memory consolidation, and language comprehension.

Occipital Lobe

The posterior cerebral lobe dedicated to visual input processing and visual perception.

Coronal Plane

An anatomical section that divides the brain vertically into anterior (front) and posterior (back) sections.

Sagittal Plane

An anatomical section that divides the brain vertically into left and right hemispheres.

Horizontal Plane (Axial)

An anatomical section that cuts the brain horizontally into superior (top) and inferior (bottom) halves.

Contralaterality

The neurological principle where each cerebral hemisphere senses and controls the opposite side of the body.

Localism

The theory that specific psychological functions and cognitive behaviors are localized to dedicated, discrete brain regions.

Holism

The theory that the brain operates as an integrated whole to perform complex psychological operations, rather than via isolated compartments.

Motor Cortex

A specialized cortical region in the frontal lobe directly controlling voluntary skeletal movement.

Somatosensory Cortex

A cortical strip located in the parietal lobe responsible for processing bodily tactile sensations such as touch, temperature, and pain.

Broca's Area

A dedicated speech production and language generation area situated in the left frontal lobe.

Wernicke's Area

A dedicated language comprehension and semantic processing area located in the left temporal lobe.

Auditory Cortex

The cortical region in the temporal lobe responsible for processing primary sound features, frequencies, and pitch.

Topographical Organization

The structural mapping principle where adjacent peripheral sensory or motor locations map to adjacent cortical coordinates.

Cortical Homunculus

A distorted physical depiction ('little man') of the human body mapped along the motor and somatosensory cortices reflecting relative cortical representation.

Proportionality Rule

The neuroanatomical principle stating that cortical space is apportioned according to motor precision or sensory acuity, rather than physical body surface area.

Visible Light Spectrum

The segment of the electromagnetic spectrum detectable by human photoreceptors, spanning roughly $400\,\text{nm}$ to $700\,\text{nm}$.

Sensation

The passive physical detection of environmental energy by specialized sensory receptors.

Perception

The brain's higher-order active process of organizing, integrating, and consciously interpreting sensory signals.

Transduction

The biophysical process of converting physical external energy (such as light waves) into electrical neural impulses.

Rods

Retinal photoreceptors with high light sensitivity operating in scotopic (dim) lighting that do not mediate color vision.

Cones

Retinal photoreceptors operating optimally in photopic (bright) lighting that mediate high visual acuity and color perception.

Reflex Arc

An involuntary neural circuit pathway linking a receptor, sensory neuron, spinal interneuron, motor neuron, and effector muscle to execute an automatic somatic response.

Localisation of Function (Neocortex)

The structural assignment of dedicated cortical regions to distinct sensory, motor, and cognitive processes (including motor, somatosensory, visual, and language areas).

Cerebral Lobes and Functional Strips

The primary macro-anatomical divisions of the cerebral cortex—frontal, parietal, occipital, and temporal—including the precentral motor strip and postcentral sensory strip.