Central Nervous System - Brains and Spinal Cord

Comprehensive vocabulary flashcards covering CNS structures, cortical lobes, nerve fiber types, diencephalon, limbic system, brainstem regions, EEG patterns, brain imaging modalities, and spinal cord pathologies based on lecture notes.

Forebrain

Major division of the brain comprising the diencephalon (thalamus, hypothalamus, and epithalamus) and telencephalon (cerebrum).

Midbrain

Region of the brainstem (mesencephalon) that carries signals from the forebrain into the brainstem.

Hindbrain

Brain division (rhombencephalon) containing the cerebellum and brainstem, colloquially referred to as the 'Lizard Brain'.

Grey Matter

Central nervous system tissue composed of non-myelinated axons and nerve cell bodies, forming the cerebral cortex.

White Matter

Central nervous system tissue composed of myelinated axons.

Contralateral Function

Organizational feature of the cerebral cortex where each hemisphere controls and processes information for the opposite side of the body.

Cortical Lateralization

Division of labor between the cerebral hemispheres; about $90\%$ of humans exhibit left-side dominance associated with logical, analytic, and verbal tasks.

Commissural Fibers

Nerve fibers that connect corresponding regions across the two cerebral hemispheres, with the corpus callosum being the largest region.

Association Fibers

Nerve fibers that connect local regions within the same cerebral hemisphere.

Projection Fibers

Nerve fibers projecting vertically into the thalamus, brainstem, and spinal cord, consisting of ascending sensory neurons and descending motor neurons.

Pyramidal Cells

Primary output neurons in the cerebral cortex involved in motor processes that take in stimuli and send out signals.

Stellate Cells

Input and processing neurons (often interneurons) in the cerebral cortex that receive signals from neighboring neurons.

Gyri

Elevated ridges located on the surface of the brain.

Sulci

Shallow grooves on the surface of the cerebral cortex.

Fissures

Deep grooves on the brain surface, such as the longitudinal fissure separating hemispheres and the transverse fissure separating cerebrum and cerebellum.

Occipital Lobe

Cerebral lobe dedicated to visual processing.

Temporal Lobe

Cerebral lobe responsible for initial sound sensation reception and language development.

Parietal Lobe

Cerebral lobe located posterior to the central sulcus that handles somatosensory processing.

Frontal Lobe

Cerebral lobe responsible for voluntary motor activity, speaking ability, elaboration of thought, planning, personality, mood, and emotion.

Broca's Area

Cortical area present in one hemisphere (typically left) containing motor neurons that direct speech production and plan voluntary movements.

Wernicke's Area

Temporal lobe association area responsible for language comprehension and word interpretation; damage leads to aphasia.

Thalamus

Diencephalon structure functioning as a relay station and synaptic integrating center for sensory input, aiding in focus and crude sensory awareness.

Hypothalamus

Diencephalon structure directly regulating homeostatic internal stability, endocrine functions, body temperature, thirst, hunger, and sleep-wake cycles.

Basal Nuclei

Grey matter regions near the thalamus that inhibit unnecessary muscle tone, suppress excess movements, and coordinate posture and support.

Parkinson's Disease

Neurological disorder caused by inadequate dopamine in the basal nuclei, characterized by muscle rigidity, resting tremors, slow motor activity, and poor gait.

Amygdala

Limbic system structure responsible for processing emotional responses such as fear and anticipation and sending signals to the hypothalamus.

Hippocampus

Limbic system structure essential for memory encoding and formation.

Cingulate Gyrus

Limbic structure that bridges the neocortex to the limbic system, integrating senses and pain into emotional memory and social behavior.

Reticular Activating System (RAS)

Network of brainstem neurons that stimulates cortical alertness, directs attention toward specific stimuli, and filters repetitive information.

Cerebellum

Hindbrain structure responsible for subconscious motor coordination, balance, and planning voluntary muscle activity.

Pons

Hindbrain region coordinating arousal, sleep, REM dreaming, and connecting cerebrum/cerebellum movement signals to the spinal cord.

Medulla Oblongata

Brainstem region generating signals to control autonomous cardiovascular, respiratory, and digestive systems.

Functional MRI (fMRI)

Functional imaging technique that maps blood flow in the brain based on the magnetic properties of oxygenated versus deoxygenated blood.

PET Scan

Positron Emission Tomography scan using radiolabeled tracers to track radioactivity and map metabolic activity in the brain.

Alpha Waves

Regular, rhythmic low-amplitude EEG brain waves ($8\text{--}13\,\text{Hz}$) indicating an idling, awake but relaxed brain.

Beta Waves

Rhythmic EEG brain waves ($14\text{--}30\,\text{Hz}$) occurring during active mental alertness.

Delta Waves

High-amplitude EEG brain waves ($\le 4\,\text{Hz}$) typical of deep sleep, anesthesia, or brain damage in awake adults.

Theta Waves

EEG brain waves ($4\text{--}8\,\text{Hz}$) occurring during light sleep, deep meditation, REM sleep, or reduced awareness.

Absence Seizure

Brief epileptic seizure characterized by short-duration disorganized cortical discharges and absent facial expressions.

Tonic-clonic Seizure

Intense, longer-lasting epileptic seizure marked by severe disorganized cortical activity and muscle jerking.

Dorsal Horns

Regions of spinal grey matter composed primarily of interneurons that process incoming sensory input.

Ventral Horns

Regions of spinal grey matter housing motor neuron cell bodies that transmit motor commands to skeletal muscles.

Flaccid Paralysis

Condition caused by severe damage to ventral roots or ventral horn cells, preventing nerve impulses from reaching muscles and leading to muscle atrophy.

Spastic Paralysis

Condition caused by damage to upper motor neurons of the primary motor cortex, resulting in loss of voluntary control while spinal reflex activity remains intact.

Amyotrophic Lateral Sclerosis (ALS)

Progressive disorder involving destruction of ventral horn motor neurons, excess extracellular glutamate excitotoxicity, and loss of ability to speak, swallow, and breathe.