Occipital Cortex Flashcards
Vision
Series of action potential (processing via electrical signals)
Retina–>Optic Nerve-> Optic chiasm–>Optic Tract–> Lateral geniculate body (LGB in thalamus)–> Optic radiation –> Primary Visual cortex (first point where visual info is processed)
Primary Visual Cortex
V1->V5 increases acuity of visual info ei light vs dark to finer details
Calcarine Sulcus
Divides the crude visual info from V1 into upper and lower halves in the Occipital Cortex
(Sulcus are cracks in the brain)
Lingual Gyrus
Visual cortical region of V2 and Ventral Posterior area
Gyrus are bumps in the brain folds
Fusiform Gyrus
V4 Complex processing near the temporal lobe (hearing and vision) aiding with processing
Human Cortex
6 layers of cells
V1 could have more than 6
V1
First cortical area involved in visual processing
Relays visual input from LGN to the extrastriate cortex for higher-order processing (ei shape motion and colour)
Laminar (dark then light repeat) organization (striated)
Heterogeneous with more than 1 distinct function with the function preserved in V2
Striated Cortex (V1 and V2)
Thin Stripe = color perception
Thick Stripes = form and motion
Blobs = metabolically active and sensitive to colour
Interblobs = sensitive to orientation
V4
Colour vision and facial recognition movement depth and position
Connections of the visual cortex
V1 inputs from LGN to upper levels
V2 further outputs to other levels
Other outer outputs include:
Parietal lobe -> Dorsal Stream
Superior Temporal Sulcus -> STS stream
Inferior Temporal Lobe -> Ventral Stream
Dorsal Stream
Parietal Lobe
Visual Guidance of Movement
“the where”
Ventral Stream
Temporal inferior
Object Perception
the What
Superior Temporal Sulcus
Combination of visuospatial function
Social Perception and Cognition
Language, voices, faces, biological motion, theory of mind
Occipital Lobe Function Movement
Blobs(V1) –> V4 (Colour)
Interblobs(V1) –> V5 (Motion)
V1+V2 –> V3 (Shape of objects in motion)
Damage to Occipital Lobe
Legions in specific areas of the Occipital lobe up the different hierarchy produce different visual deficits
Visual Function beyond Occipital Lobe
55% of the total cortex of the brain is visually related
present in temporal, parietal and frontal lobes