Cerebral Cortex I and Vascular Territories Flashcards
Location of the primary visual cortex
Location of the primary auditory cortex
When we say language function is usually in the left hemisphere, what we really mean to say is. . .
. . . language function is usually in the dominant hemisphere
The “where” pathway
The connections between the occipital lobe and parietal lobe.
Visual information is processed here to determine where things are in space with respect to the body. Lesions here can cause neglect.
Neglect
Caused by damage to the territory linking the occipital and temporal lobes, more commonly in the non-dominant parietal lobe, causing non-dominant-sided neglect.
Examination findings in patients with neglect may include extinction to double simultaneous stimulation, anosognosia, and sometimes unilateral asomatognosia.
Angular gyrus
Located in the dominant hemisphere.
Lesions to this area cause Gerstmann’s syndrome: Left-right confusion, inability to count (acalculia), inability to name the fingers (finger agnosia), and inability to write (agraphia).
Broca’s and Wernicke’s areas
Located in the dominant hemisphere.
Apraxia
- Difficulty performing a complex learned motor action
- Caused by lesions within the parietal lobe, often on the dominant side
- Three types:
- Limb-kinetic apraxia: difficulty performing these movements
- Ideational apraxia: inability to conceive of the idea of how to accurately perform an action
- Ideomotor apraxia: inability to convert an idea about how to do something into a motor plan.
Ideomotor ataxia explanation
Affected patients may be able to explain the intended action but are unable to perform it normally, making errors in sequencing and/or timing of the component movements of complex learned actions.
Amnesia
- Caused by lesions within the middle temporal lobes and hippocampus
- May be retrograde or anterograde
Alexia
Caused by lesions to the inferior aspect of the domintant temporal lobe
Prosopagnosia
- Inability to recognize faces
- Caused by lesions to the inferior aspect of the non-domintant temporal lobe
Inferior frontal gyrus
Houses Broca’s area!
Superior temporal gyrus
Houses Wernicke’s area, among other things.
Wernicke’s area is close to the border with the parietal lobe.
Transcortical motor aphasia
This is essentially a Broca’s aphasia with preserved repetition
The aphasia hierarchy
Aphasias in which comprehension is impaired
Receptive aphasias
Transcortical sensory aphasia
Essentially Wernicke’s aphasia with preserved repetition
Global aphasia
Production, comprehension, and repetition are all impaired.