Neuroanatomy, Functional Systems, and Brain Imaging

Comprehensive vocabulary flashcards covering anatomical divisions of the brain, meningeal layers, brainstem structures, limbic and basal ganglia pathways, cortical functional organization, lateralization, language systems, and neuroimaging modalities.

Meninges

The three protective layers that cover and enclose the brain and spinal cord.

Dura Mater

The outermost, tough, protective covering layer of the meninges.

Arachnoid Membrane

The middle layer of the meninges, situated directly beneath the dura mater.

Subarachnoid Space

The region immediately below the arachnoid membrane that is filled with cerebrospinal fluid and many large blood vessels.

Pia Mater

The innermost layer of the meninges that rests directly against the surface of the brain.

Cerebrospinal Fluid (CSF)

Fluid filling the subarachnoid space, the spinal cord's central canal, and the cerebral ventricles; it cushions the brain against mechanical shock during head movement, provides buoyancy, and acts as a reservoir of hormones and nutrition.

Choroid Plexus

Cells located along the walls of the four ventricles of the brain that produce cerebrospinal fluid (CSF).

Brainstem

The brain region formed by the medulla, pons, midbrain, and certain portions of the forebrain.

Medulla Oblongata

A brainstem structure containing many cranial nerve cell bodies that controls vital autonomic reflexes such as breathing, heart rate, vomiting, coughing, salivation, and sneezing.

Contralateral Control

The structural arrangement where the right hemisphere receives sensory input from and controls the left side of the body, and the left hemisphere controls the right side.

Decussation of the Pyramids

The anatomical crossover point located at the medulla where the majority of motor and sensory nerve fibers cross to the opposite side of the body.

Reticular Formation

A complex network of approximately 100 tiny nuclei originating in the medulla and projecting diffusely to many brain areas; it participates in arousal, muscle tone maintenance, and cardiac, respiratory, and circulatory functions.

Reticular Activating System

A component of the reticular formation responsible for arousal by sending a continuous stream of impulses to keep the rest of the brain alert.

Cerebellum

A hindbrain structure containing 80 percent of the brain's neurons that guides motor activity, coordinates voluntary movement, smooths motor execution, and maintains balance and muscle tone without initiating movement.

Pons

The principal connective bridge between the cerebellum and the rest of the brain; contains centers for vestibular functions, certain eye movements, and the regulation of REM sleep.

Superior Olive

A pontine structure where auditory signals from both ears converge, enabling the brain to calculate which ear received a sound first.

Locus Coeruleus

A pontine nucleus that discharges bursts of impulses in response to meaningful, emotionally arousing events.

Tectum

The dorsal region of the midbrain comprising two pairs of surface swellings: the superior and inferior colliculi.

Inferior Colliculi

The posterior paired swellings of the midbrain tectum involved in auditory processing and orienting responses toward or away from auditory stimuli.

Superior Colliculi

The anterior paired swellings of the midbrain tectum involved in visual processing and orienting responses toward or away from visual stimuli.

Tegmentum

The ventral midbrain region containing the termination of the reticular formation, the periaqueductal gray, the substantia nigra, and the red nucleus.

Periaqueductal Gray

A tegmental structure rich in opiate receptors that plays an essential role in analgesic pain reduction.

Substantia Nigra

A tegmental structure that serves as one of the brain's primary dopamine-producing centers.

Red Nucleus

A tegmental structure that participates in motor control, arm movements, and muscle tone regulation.

Sensory Relay Nuclei

Thalamic nuclei that receive, process, and transmit all sensory signals (except olfactory information) to the cortex while actively filtering, dampening, prioritizing, or blocking signals before conscious perception.

Hypothalamus

A forebrain structure comprising multiple distinct nuclei that regulates homeostatic motivated behaviors (hunger, thirst, sleep, sex) and controls the endocrine system via the pituitary gland.

Mammillary Bodies

Paired structures situated on the underside of the hypothalamus that participate in spatial memory processing.

Nucleus Basalis

A basal forebrain structure receiving inputs from the hypothalamus and basal ganglia that releases acetylcholine to widespread cortical regions to regulate wakefulness, attention, and arousal.

Limbic System

A interconnected circuit of subcortical structures encasing the thalamus and hypothalamus involved in motivated behaviors, emotional experience, and memory.

Hippocampus

A limbic structure critical for consolidating and routing new spatial and long-term memories prior to permanent storage, though memories themselves are not stored within it.

Amygdala

A limbic structure critical for processing emotional memories, responding to aversive stimuli, and associating previously neutral events with fear, reward, punishment, or disgust.

Cingulate Cortex

Also called the cingulate gyrus; a limbic cortical region that integrates cognitive control, emotion, error detection, conflict monitoring, intentional motor planning, and the affective-motivational unpleasantness of pain.

Fornix

A major tract linking the hippocampus to the hypothalamus that acts as an information conduit essential for transitioning short-term memory to long-term storage and integrating emotional reactions.

Septum

A limbic structure central to the reward pathway that produces pleasure when electrically stimulated and acts as an inhibitory brake on negative emotions such as rage, fear, and aggression.

Basal Ganglia

A subcortical motor system separate from the limbic system that facilitates voluntary movement initiation and cessation, maintains preparatory posture, and controls motor switching.

Striatum

A subcortical structure composed of the caudate and putamen that receives input from the cortex and forms major pathways with the substantia nigra.

Direct Pathway

A basal ganglia motor loop where cortical stimulation acting on D1 dopamine receptors causes the striatum to inhibit the globus pallidus internal segment, disinhibiting the thalamus and enabling movement initiation.

Indirect Pathway

A basal ganglia motor loop where cortical stimulation via D2 dopamine receptors causes the striatum to inhibit the globus pallidus external segment, leading the subthalamic nucleus to excite the internal segment, suppressing thalamic excitation and unwanted movement.

Nucleus Accumbens

The primary pleasure, motivation, and reward center of the brain, packed with dopamine receptors and activated by natural rewards to signal value anticipation and reinforce behaviors.

Cholinergic System

A neurotransmitter network utilizing acetylcholine (ACh) that regulates attention, learning, memory formation, and muscular movement.

Serotonergic System

A neurotransmitter network utilizing serotonin to modulate appetite, sleep-wake cycles, emotional states, and mood stability.

Noradrenergic System

A neurotransmitter network utilizing norepinephrine (noradrenaline) that governs alertness, arousal, vigilance, and acute stress responses.

Nigrostriatal Pathway

A dopaminergic tract originating in the substantia nigra and innervating the striatum; it selects, initiates, and terminates motor behavior, and its degeneration underlies Parkinson's disease.

Mesolimbic Pathway

A dopaminergic circuit originating in the ventral tegmental area (VTA) and projecting to limbic structures and the nucleus accumbens to mediate reward and positive reinforcement.

Mesocortical Pathway

A dopaminergic circuit originating in the ventral tegmental area (VTA) and projecting widely to the frontal, motor, and premotor cortices to support executive functions.

White Matter

Subcortical nervous tissue located beneath the cerebral cortex consisting predominantly of myelinated axons linking various brain regions.

Fissures

The large, deep grooves or furrows found across the surface of the cerebral cortex.

Sulci

The relatively small furrows or shallow indentations found throughout the cerebral cortex.

Gyri

The raised folds or outward convoluted ridges situated between cortical sulci and fissures.

Cerebral Commissures

Nerve fiber tracts that span across the longitudinal fissure to structurally and functionally connect both cerebral hemispheres.

Corpus Callosum

The largest cerebral commissure bridging the longitudinal fissure to allow communication between the right and left cerebral hemispheres.

Neocortex

The phylogenetically recent six-layered grey matter structure that constitutes roughly 90 percent of the human cerebral cortex.

Pyramidal Neurons

Large multipolar neurons found across neocortical layers characterized by pyramid-shaped cell bodies, long axons, and a single dominant apical dendrite.

Stellate Neurons

Small, star-shaped local interneurons within the neocortex that possess either very short axons or no axon at all.

Columnar Organization

The vertical arrangement of cortical neurons wherein information flows and is processed primarily in perpendicular functional columns across layers.

Primary Visual Cortex

The primary sensory area in the occipital lobe responsible for processing visual input, encircled by secondary visual processing areas.

Cortical Blindness

A visual deficit resulting from damage to the primary visual cortex in which an individual has intact eyes but lacks all conscious visual perception and dream imagery.

Primary Somatosensory Cortex

A four-layered strip situated at the front of the parietal lobe that topographically maps tactile sensations from the body, dedicating specific layers to light touch, deep pressure, or a combination.

Astereognosis

The inability to identify or recognize objects through touch alone, occurring following somatosensory cortex impairment.

Primary Motor Cortex

The precentral cortical strip located at the posterior boundary of the frontal lobe that controls voluntary movements, allocating disproportionately large representations to body parts capable of fine motor coordination.

Premotor Cortex

The region positioned directly anterior to the primary motor cortex that coordinates and plans voluntary movements.

Supplementary Motor Cortex

A frontal motor region critical for sequencing, organizing, and executing rapid successions of movements, as well as inhibiting inappropriate actions.

Primary Auditory Cortex

The primary sensory region located in the temporal lobe responsible for registering and interpreting acoustic frequencies, speech, and sound signals.

Insula

Often termed the fifth lobe of the brain; it houses the primary gustatory cortex, mediates disgust processing, and activates during empathetic responses to another person's pain.

Association Areas

Cortical regions that integrate information across multiple sensory and cognitive modalities, linking current input with stored memories and internal somatic states.

Dorsolateral Prefrontal Cortex

A prefrontal subregion primarily involved in working memory operations and high-level executive functioning.

Orbitofrontal Cortex

A prefrontal subregion situated above the orbits that is centrally involved in processing emotional cues and value assessment.

Ventromedial Prefrontal Cortex

A prefrontal subregion critical for decision-making, judgment, and error detection.

Posterior Parietal Cortex

A parietal association area that monitors bodily coordinates in space and activates during the planning stages of motor movement.

Alexia

The neurological loss of the ability to read written text, often resulting from parietal lobe damage.

Agraphia

The neurological loss of the ability to communicate via writing, typically caused by parietal lesions.

Apraxia

A motor planning deficit in which a person is unable to translate conceptual ideas or mental representations into purposeful, skilled motor actions.

Hemispatial Neglect

A perceptual syndrome caused by unilateral brain damage wherein the patient ignores, fails to attend to, or behaves unaware of stimuli on the contralateral side of space or their body.

Prosopagnosia

A specific visual agnosia characterized by the inability to recognize familiar human faces, resulting from damage to the fusiform face area (FFA).

Agnosia

A modality-specific failure to recognize objects or sounds despite intact elementary sensory pathways and unimpaired sensory receptors.

Broca's Area

A language center located within the inferior frontal gyrus of the left frontal lobe that orchestrates motor patterns required for speech output and word formation.

Broca's Aphasia

An expressive language disorder characterized by slow, nonfluent, and labored speech output with preserved comprehension.

Wernicke's Area

A posterior language region located in the left temporal lobe adjacent to the auditory cortex that decodes and comprehends spoken and written language.

Wernicke's Aphasia

A receptive language disorder characterized by fluent, effortless speech containing nonsensical or empty phrases alongside profound comprehension deficits.

Dual-Stream Model

The modern framework of language processing demonstrating that linguistic tasks recruit distributed cortical networks (motor, premotor, temporal, parietal) alongside subcortical structures (basal ganglia, cerebellum).

Neuroplasticity

Also called brain plasticity; the central nervous system's capacity to structurally and functionally reorganize based on activity, learning, and differential use.

Neurogenesis

The generation and integration of new functional neurons, specifically observed within the hippocampus and the olfactory bulb.

Lateralization

The functional specialization of the brain wherein specific cognitive or physiological operations are selectively localized to one cerebral hemisphere.

Split-Brain Procedure

A surgical commissurotomy in which the corpus callosum is transected to prevent the interhemispheric spread of epileptic seizures.

The Interpreter

A left-hemisphere mechanism that constructs causal narratives, explains actions and environmental events, and shapes personal memory and worldview.

Lesioning

An experimental technique in animals where specific neural tissues are targeted and destroyed to observe resulting behavioral and physiological deficits.

Electroencephalogram (EEG)

A neurodiagnostic recording tool that uses scalp electrodes to amplify the summed electrical rhythms of neurons, providing high temporal data on consciousness states despite low spatial precision.

Structural Imaging

Diagnostic imaging methods (such as CT and structural MRI) designed to visualize the static anatomical morphology, dimensions, and lesions of the brain.

Functional Imaging

Dynamic imaging methods (such as PET and fMRI) designed to track and map localized metabolic rate, glucose uptake, or hemodynamic shifts during task engagement.

Computed Tomography (CT Scan)

A structural neuroimaging modality that rotates X-ray beams across various angles to reconstruct sectional density profiles of brain tissue.

Magnetic Resonance Imaging (MRI)

A structural imaging modality that applies magnetic pulses to align and perturb tissue molecules, reading out emitted radiofrequency signals to construct high-resolution soft tissue images.

Positron Emission Tomography (PET Scan)

A functional imaging method using injected radiolabeled tracers (such as radioactive glucose or oxygen) that accumulate in metabolically active brain regions.

Functional Magnetic Resonance Imaging (fMRI)

A noninvasive functional imaging technique that measures blood oxygen level-dependent (BOLD) hemodynamic signals to map active cortical regions with superior temporal resolution relative to PET.