Higher Order cerebral Function Flashcards
Describe the organization of fibers traveling with visual information from the lateral
geniculate nucleus to the occipital lobe. How are they, and their destinations, organized?
superior striations (go to the parietal lobe) provide retinal input for inferior inferior striations (to temporal lobe) with retinal input from superior ; the more central the field, the more caudal and closer it is to the occipital pole
what is a key feature of the occipital pole blood supply as opposed to the rest of the visual cortex?
bilateral vascularization
what type of damage would result in central scotoma? Describe what this looks like.
blindness in acuity/focal point of one eye; damage to the fovea of that eye
what type of damage would result in monocular blindness?
damage to that eye’s optic nerve, one-eyes blindness
Describe bitemporal hemianopia. What might cause this?
damaged optic chiasm> commonly caused by pituitary tumors; blindness on the lateral visual fields
Describe homonymous hemianopia. What might cause this?
damage to the contralateral optic tract or thalamus; hemified blindness in each eye on the same side
Describe superior quadrantanopia . What might cause this?
damage to inferior striations (in the temporal lobe) in contralateral side> upper quadrant blindness in the opposite side of injury
Describe inferior quadrantanopia. What might cause this?
damage to superior striations (in the temporal lobe) in contralateral side> lower quadrant blindness on the opposite side of injury
Describe homonymous hemianopia with macular sparing. What might cause this?
damage to the contralateral primary visual cortex but due to bilateral vascularization of the occipital pole > blindness in the same side of both eyes
Where are the visual association cortices located?
parieto-occipital association cortex
occipitotemporal association cortex
what kind of info is relayed through the parieto-occipital association cortex?
motions and spatial relationships between objects, body, and visual stimuli (where)
what kind of info is relayed through the occipitotemporal association cortex?
form, colors, face, letters,etc (what)
What types of eye movements do supranuclear structures of extraocular muscles control?
horizontal and vertical eye movements saccades smooth pursuits vergence reflexes
Identify the supranuclear structures and connections involved horizontal eye movements.
medial and lat rectus (abducens and OCM via MLF)
abducens + paramedian pontine reticular formation
Identify the supranuclear structures and connections involved vertical eye movements.
muscles: superior and inf recti and obliques
nuclei: trochlear and OCM
supranuclear: pretectal areas, rostral midbrain and reticular formation
saccades
rapid, voluntary eye movements wherein our vision is temporarily suppressed
smooth pursuit
slow following of a visual target either voluntarily or involuntarily
vergence
maintaining fused fixation as targets move towards or away from the person-very slow for acuity
reflexive eye movements: Nystagmus
eyes one way to self correct
What cortical structures are involved in extraocular movements?
frontal eye fields (contra saccades), parietal-occipital-temporal cortex (ipsa smooth pursuit), basal ganglia (OCM loop)
define unimodal association cortices
unidirectional and modality-specific: Motor, somatosensory, Visual and Auditory
define heteromodal association cortices
bidirectional and higher-order mental functions found at frontal and parieto-occipitotemporal junctions
Explain what we know about handedness and how it relates to cortical asymmetry.
each hemisphere controls simple movements of contralat limbs, but highly skilled and complex movements are controlled by the dominant hemisphere
Explain what we know about language centers as they relate to cortical asymmetry.
language centers are predominantly on the left hemisphere (regardless of handedness) for 95% R and over 70% L (also bilateral in many lefthanders)
