Week 1: Key CNS structures and anatomy

Vocabulary flashcards summarising key neuroanatomical structures, pathways, and clinical concepts from the lecture notes.

Frontal Lobe

Anterior brain lobe responsible for social behaviour, cognition, and posteriorly for voluntary motor functions.

Includes primary motor cortex (voluntary motor), Pre-motor cortex (motor planning/praxis), supplimentary motor cortex (postural control), prefrontal Cortex (executive functioning, working memory, social interaction), prefrontal cortex motor association area (movement planning), and Broca's area (left language production).

Parietal Lobe

Cortex involved in sensory detection, perception, interpretation, attention, and arithmetic.

Contains primary somatosensory cortex (recieves tactile and proprioceptive info), association area (interpretation of sensory info) and Wernicke’s area

Temporal Lobe

Lobe that processes hearing and language; houses limbic structures for memory and emotion.

Contains primary auditory cortex (recieves auditory info), Associative cortex (interprets info) and Wernicke’s area (speech and language comprehension)

Occipital Lobe

Responsible for visual processing

Contains Primary visual cortex (recieves visual info, distinguishes intensity of light, shape, size and location), association cortex (interprets this info)

Insula

Deep cortical region involved in taste, visceral sensation, autonomic & homeostatic functions, and emotional processing.

Left Hemisphere

(right side)

Controls right-side motor/sensory functions; specialised for concrete processing and language expression/interpretation.

Right Hemisphere

Controls left-side motor/sensory functions; excels at perceptual, spatial and abstract processing, music, tone of language.

Corpus Callosum

Large commissural fibre bundle enabling communication between cerebral hemispheres.

Pyramidal Tracts

Motor pathways originating in cerebral cortex goinf to spinal cord/ brainstem for voluntary control of face and body (corticospinal & corticobulbar).

Extrapyramidal Tracts

Brainstem-origin tracts—> spinal cord+beyond mediating involuntary control of tone, balance, posture (e.g., vestibulospinal, reticulospinal, rubrospinal). (Motor)

Corticospinal Tract

Key decending motor tract

Pyramidal pathway from primary motor cortex

Lateral tracts (most) decussate at pyramids and innervate LMNs controlling UL and LL skeletal muscles and fine motor in hands

Anterior tracts remain ipsilateral as they pass through medulla, decussating at spinal cord level innervating LMNs that control neck, shoulder and trunk skeletal muscles

Both innervate contralaterally (opposite side)

Corticobulbar (Corticobrainstem) Tract

Originates in primary motor cortex, innervates LMN controlling face, pharynx, larynx, sternocleidomastois and trapezius muscles

Mostly bilateral except lower facial (creates contralateral facial droop) & hypoglossal branches (tongue deviation).

Non-key decending motor tracts

Vestibulospinal Tract: Brainstem tract from vestibular nuclei to ipsilateral extensor LMNs; maintains upright posture.

Rubrospinal tract: Midbrain red-nucleus tract crossing in midbrain to limb flexor LMNs; modulates tone and basic hand skills.

Reticulospinal tracts:Pontine (medial) and medullary (lateral) pathways adjusting extensor tone for posture and locomotion.

Tectospinal tract: Brainstem tract orienting head and neck to visual/auditory stimuli.

Internal Capsule

Transmits info between between cortex and thalamus, basal ganglia, brainstem/spinal cord; small lesions produce widespread contralateral deficits.

Corona radiata: Fan-shaped cortical white-matter fibres that converge to form the internal capsule lower down

Upper Motor Neuron (UMN) Lesion

Damage to cortex or brainstem pathways causing contralateral paresis/paralysis, hypertonia (^ tone/ ^resistance to passive movement)/spasticity, hyperreflexia, primitive reflex return, abnormal synergies.

Lower Motor Neuron (LMN) Lesion

Injury to peripheral LMNs(e.g. polio) causing paralysis, flaciddity, atrophy, fasciculations (small, localised involuntary twitch).

Primary Motor Cortex (Precentral Gyrus)

Frontal lobe

Cortical area executing voluntary movement.

Premotor Cortex

Frontal lobe

Region planning and sequencing movements (motor praxis).

Supplementary Motor Area

Frontal lobe

Medial frontal region aiding bimanual coordination and postural setup.

Broca’s Area

Frontal lobe

Left frontal region organising language production (spoken & written).

Prefrontal Cortex

Frontal lobe area for executive functions, working memory, judgement, social behaviour modulation.

Primary Somatosensory Cortex

Pariatal lobe

Postcentral gyrus receiving tactile and proprioceptive input.

Somatosensory Association Cortex

Parietal areas interpreting tactile, visuospatial, auditory sensory information.

Wernicke’s Area

Parieto-temporal cortex responsible for comprehension of spoken and written language.

Primary Auditory Cortex

Superior temporal gyrus region receiving auditory signals.

Associative Auditory Cortex

Temporal lobe area interpreting sound patterns and meaning.

Primary Visual Cortex

Occipital cortex receiving raw visual data (light intensity, shape, size, location).

Visual Association Cortex

Occipital regions interpreting visual information into recognisable objects and scenes.

Thalamus

Relay centre routing sensory & motor information to cortex; involved in emotion, memory, arousal, attention.

Basal Ganglia

Subcortical nuclei (not elaborated) regulating movement initiation, tone, and procedural learning.

Dorsal Column (Medial Lemniscus/ Posterior columns)

Sensory

Ascending pathway crossing in medulla conveying discriminatiory touch, vibration, pressure, kinesthesia and vibration to primary somatosensory cortex.

(overachiever)

Lateral Spinothalamic Tract

Ascending tract crossing in spinal cord carrying pain and temperature sensations to primary somatosensory cortex.

Anterior Spinothalamic Tract

Ascending tract crossing in spinal cord conveying crude touch to primary somatosensory cortex.

("Ant tells crude jokes").

Lateral corticospinal tracts

Originates in primary motor cortex, decussating in medullary pyramind and ending in the spinal cord vental horn (LMNs for UL and LL), Executes movement, fine motor control, skeletal muscles of ULs and LLs

Medial corticospinal tracts (anterior or ventral corticospinal tracts)

Originates in primary motor cortex, decussating at spinal cord and ending in the spinal cord vental horn (LMNs for postural control), Executes postural control (muscles of neck, shoulders, trunk)

Corticobrainstem

Originates in primary motor cortex, decussating in bilateral tract and ending in the brainstem (LMN cranial nerves w a motor function), Executes movement: facial, neck, swallowing and shoulder muscles

Vestibulospinal tracts (lateral and medial)

Originates in medulla (vestibular nuclei), decussating ipsilaterally and ending in the spinal cord (LMN for extensor muscles), Maintains upright posture

Rubrospinal tracts

Originates in midbrain (red nucleus), decussating in the midbrain and ending in the spinal cord (LMN flexor muscles in limbs), Maintains muscle tone, enables basic hand skills (with corticospinal)

Pontine (medial) retriculospinal tracts

Originates in Pontine reticular formation, decussating ipsilaterally and ending in the spinal cord (LMN to extensor muscles), Controls posture and locomotion

Medullary (lateral) reticulospinal tracts

Originates in medullary reticular formation, decussating ipsilaterally and ending in the spinal cord (LMN to extensor muscles), Controls posture and locomotion