Lecture 21: CNS II - Cerebral White Matter, Basal Nuclei, Diencephalon, Brain Stem, Cerebellum, and Limbic System

Vocabulary flashcards covering the structure and function of cerebral white matter, basal nuclei, the diencephalon, brain stem, cerebellum, and the limbic system.

Commissural fibers

A type of cerebral white matter fiber that allows the sharing of information between cerebral hemispheres.

Association fibers

A type of cerebral white matter fiber that connects different parts of the same hemisphere.

Projection fibers

Cerebral white matter fibers that run vertically to connect the cerebral cortex with lower brain or spinal cord centers.

Corpus callosum

The largest white matter tract in the brain that allows information to be shared between hemispheres.

Anterior commissure

A major white matter commissure connecting the two temporal lobes that shares sensory and emotional information.

Posterior commissure

A white matter commissure connecting parietal, temporal, and occipital regions that shares visual, memory, and motor information.

Short association fibers

Association fibers that connect adjacent gyri and link nearby areas of the brain.

Long association fibers

Association fibers bundled into tracts that connect different cortical lobes across more distant areas.

Ascending projection fibers

Projection fibers that carry sensory information upward to the cerebral cortex.

Descending projection fibers

Projection fibers that convey motor output from the cerebral cortex downward to lower areas.

Basal nuclei

Subcortical structures composed of the caudate nucleus, putamen, and globus pallidus that regulate movement intensity, start/stop actions, and slow or stereotypical movements.

Striatum

A component of the basal nuclei composed of the caudate nucleus and putamen.

Lentiform nucleus

A structure of the basal nuclei formed by the combination of the putamen and globus pallidus.

Diencephalon

A division of the brain enclosing the third ventricle, composed of the thalamus, hypothalamus, and epithalamus.

Thalamus

The 'gateway to the cerebral cortex' that sorts, edits, and relays sensory, motor, visceral, emotional, and memory inputs to and from the cerebral cortex.

Suprachiasmatic nucleus

A nucleus within the hypothalamus that acts as a biological clock to regulate sleep-wake cycles.

Pineal gland

An epithalamic structure responsible for assisting the hypothalamus in regulating sleep cycles by secreting melatonin.

Brain stem

A region consisting of the midbrain, pons, and medulla oblongata that controls automatic survival behaviors, contains pathways for fiber tracts, and houses 10 of 12 pairs of cranial nerves.

Corpora quadrigemina

Midbrain structures composed of the superior and inferior colliculi, involved in visual and auditory reflexes.

Superior colliculi

The upper pair of midbrain reflex centers within the corpora quadrigemina that coordinate visual reflexes.

Inferior colliculi

The lower pair of midbrain reflex centers within the corpora quadrigemina involved in auditory relay and reflex responses.

Substantia nigra

A pigmented midbrain nucleus containing dopamine-producing neurons that regulate movement via basal nuclei; its degeneration is linked to Parkinson's disease.

Pons

A brain stem region that works with the medulla oblongata to regulate breathing rhythm and facilitates motor coordination through projection fibers and transverse pontine projections to the cerebellum.

Medulla oblongata

The inferior part of the brain stem containing cardiovascular and respiratory centers, as well as reflex centers for swallowing, vomiting, coughing, sneezing, and hiccupping.

Nucleus cuneatus and nucleus gracilis

Nuclei located in the medulla oblongata that relay ascending somatosensory and proprioceptive information from the spinal cord.

Cerebellum

The second largest brain region, accounting for roughly $10\%$ of total brain mass, that subconsciously coordinates skeletal muscle activity for smooth, agile movements.

Anterior lobe of cerebellum

A cerebellar lobe that helps coordinate movements of the trunk and limbs, particularly focusing on posture and muscle control.

Posterior lobe of cerebellum

A cerebellar lobe that coordinates skilled voluntary movements and assists in movement planning.

Flocculonodular lobe

A cerebellar lobe that maintains balance, equilibrium, and posture using sensory input from the inner ear.

Superior cerebellar peduncles

Cerebellar fiber tracts that carry instructions upward to the motor cortex via the thalamus.

Middle cerebellar peduncles

Cerebellar fiber tracts providing one-way communication from the pons regarding voluntary motor activity.

Inferior cerebellar peduncles

Cerebellar fiber tracts that carry sensory input from proprioceptors and vestibular nuclei for balance.

Amygdala

A cerebral structure of the limbic system that controls emotions such as fear, anger, and aggression, and aids in the formation of emotional memories.

Cingulate gyrus

A cerebral structure of the limbic system that controls emotional expression through gestures and assists in resolving mental conflicts.

Hippocampus

A cerebral component of the limbic system that plays a critical role in memory formation.

Rhinencephalon

The 'smell brain' representing the anatomical origin of the limbic system, linking olfactory sensations directly to emotion and memory.