Cortex Fxn and Lesions Flashcards
Motor Cortex
Frontal lobe
Lesion - UMN signs
Premotor cortex
Frontal lobe
Lesion - Slowed movements +/- UMN signs
Supplementary motor area
Frontal lobe
Lesion - Inability to do complex bimanual tasks +/- UMN signs
Frontal eye fields
Frontal lobe - premotor/prefrontal junction
Lesion - look to side of lesion
Seizure - look contra laterally
Frontal eye field function
Eye movements
Selective attention
Saccades to contralateral side
Prefrontal cortex regions
Dorsolateral prefrontal cortex
Medial prefrontal cortex
Orbito-Prefrontal cortex
Dorsolateral prefrontal cortex
Planning, organizing, working memory
Lesion - inability to plan, organize, poor working memory, PARATONIA, PERSEVERATION
Medial prefrontal cortex
Goal-directed behaviours - initiation and motivation
Lesion - apathy, akinetic mutism, incontinence
Orbito-Prefrontal cortex
Inhibition
Lesion - pseudo psychopathic
Broca’s Area
Frontal lobe on DOMINANT LEFT HEMI (for most)
Prosody on non-dominant right semi
Lesion - verbal motor deficit
Praxis
Apraxia usually caused by lesion to frontal or parietal lobe on dominant hemisphere
Right Visual cortex
Left homonymous hemianopsia
Left visual cortex
Right homonymous hemianopsia
Parieto-Occipital regions for higher visual processing
THE WHERE Dorsal-stream lesion = Balint's syndrome (1) Simultagnosia (2) Optic ataxia (3) Ocular apraxia
Optic ataxia
Can’t use visuospatial info to guide arm movements to objects (ie. poor eye hand coordination)
Ocular apraxia
Can’t control purposeful eye movements
Temporal-Occipital regions for higher visual processing
THE WHAT
Ventral stream lesion = Visual agnosia
Visual agnosia
Apperceptive
Associative
Both
Primary somatosensory cortex (post-central gyrus)
Parietal lobe
Receives sensory afferents from CONTRALATERAL peripheral receptors (via thalamus)
Lesion:
-Impaired discriminative touch and joint position sense
-Cortical sensory loss
(1) Astereognosia (in hand contralateral to lesion)
(2) Agraphesthesia
(3) 2 pt discrimination
(4) sensory inattention/extinction (can’t perceive sensory stimulus only if presented simultaneously on other side)
Non-dominant parietal lobe
Usually right side Used for complex visuospatial skills/attention CANADA: -Constructional apraxia -Neglect -Anosognosia -Dressing apraxia
Dominant parietal lobe
Langauge and praxis Lesion - language impairment, apraxia Angular gyrus lesion = Gerstmann Syndrome - Agraphia - Acalculia - Right/Left disorientation - Finger agnosia
Primary auditory cortex
Heschl’s Gyrus/Temporal lobe
Unilateral lesion - difficulty localizing sound
Bilateral lesion - cortical deafness
Wernicke’s Area
Surrounding Heschl’s Gyrus/Temporal lobe
Comprehension of sounds as words
Insular cortex
Primary gustatory cortex
