[1] Cerebrum and Diencephalon - Lesions

BA 4: Primary Motor Cortex (Precentral Gyrus)

Voluntary movement of SKELETAL muscles in the body (extremities, facial expressions)

BA 6: Motor Association Cortex

Plans (blueprint for BA 4), sequences, and executes voluntary movements.

BA 8: Frontal Eye Field

Controls voluntary rapid (particularly in horizontal gaze), and conjugate eye movements

BAs 9, 10, 11: Prefrontal Cortex

Controls personality, behavior, cognition, decision-making reasoning and judgement

BA 44: Broca’s Area

Speech production (supplies the muscle of speech)

BA 3, 1, 2: Primary Somatosensory Area

Receives touch, pressure, pain, temperature, vibration, proprioception, 2-point discrimination

BA 5: Somatosensory Association Cortex

Interprets somatosensory stimuli (size, texture, weight, and position of objects in 3D shapes by touch); stores memory and pattern recognition

BA 7: Posterior Parietal Association Cortex

Integrates all tactile, visual, and sensory input for spatial awareness and visuomotor coordination

BA 17: Primary Visual Cortex

Primary reception and processing of visual information

BA 18: Association Visual Cortex

Interprets and analyzes visual stimuli (color, size, movement, and distance)

BA 41: Primary Auditory Cortex

Conscious awareness of auditory stimuli; processes sound frequency

BA 42: Association Auditory Cortex

Interprets the sound in terms of pitch, volume, timbre, and location

BA 22: Wernicke’s Area

Responsible for comprehension and understanding of the written, auditory, and verbal speech

Primary Olfactory Cortex (Entorhinal Cortex)

Conscious perception of smell

Secondary Association Olfactory Cortex

Analyze, interpret, and recognize smell patterns

Primary Gustatory Cortex

Basic taste sensation; To remember the taste of a certain food

Orbito-Frontal (Secondary Gustatory) Cortex

Integration and recognition of taste, smell, texture, and visual; Reward value of taste experience

Vestibular Cortex

Conscious awareness of balance and spatial orientation

BA 4: Primary Motor Cortex (Precentral Gyrus)

Contralateral motor weakness/paralysis, loss of fine motor control, facial droop or gait abnormalities

BA 6: Motor Association Cortex

Difficulty initiating purposeful movements (apraxia) despite intact strength

BA 8: Frontal Eye Field

Eyes deviate toward side of lesion; impaired voluntary gaze to opposite side

BAs 9, 10, 11: Prefrontal Cortex

Personality changes, impaired judgment, poor decision-making, behavioral abnormalities (e.g., abulia)

BA 44: Broca’s Area

Expressive (Broca) aphasia (understands speech but cannot produce fluent speech)

BA 3, 1, 2: Primary Somatosensory Area

Contralateral sensory loss

BA 5: Somatosensory Association Cortex

Astereognosis, agraphesthesia, astatognosia, and abarognosia

BA 7: Posterior Parietal Association Cortex

Optic ataxia, visuospatial deficits

BA 17: Primary Visual Cortex

Contralateral homonymous hemianopia

BA 18: Association Visual Cortex

Visual and color agnosia; inability to recognize objects

BA 41: Primary Auditory Cortex

Partial bilateral hearing loss, difficulty localizing sound

BA 42: Association Auditory Cortex

Auditory agnosia

BA 22: Wernicke’s Area

Receptive (Wernicke) aphasia: fluent but nonsensical speech with poor comprehension

Primary Olfactory Cortex (Entorhinal Cortex)

Anosmia

Secondary Association Olfactory Cortex

Olfactory agnosia (inability to identify scent or odor)

Primary Gustatory Cortex

Ageusia or hypogeusia

Orbito-Frontal (Secondary Gustatory) Cortex

Impaired taste recognition/discrimination

Vestibular Cortex

Vertigo, imbalance, disorientation