occipital and temporal lobes Flashcards
(18 cards)
What is the primary visual pathway in the brain?
Retina → Lateral Geniculate Nucleus (LGN) → Primary Visual Cortex (V1).
How is visual information processing organized in the brain?
It is hierarchical and functionally differentiated, with complexity increasing from the retina to association cortices.
What does functional differentiation in visual processing mean?
Different regions and neuron types process different visual features (e.g., color, motion, form).
What role does the extrastriate cortex play in visual processing?
It processes global scene properties like pattern motion and color constancy.
What is color constancy, and where is it processed?
It is the perception of consistent object color despite changes in lighting, processed in V4.
What are the two major visual processing streams beyond V1?
The ventral stream (“what”) and the dorsal stream (“where/how”).
What is the function of the ventral stream?
Object recognition and analysis—“what” something is.
What is the function of the dorsal stream?
Spatial awareness and visually guided actions—“where” or “how”.
What deficits are associated with ventral stream damage?
Visual agnosia—impaired object recognition with intact motor abilities (e.g., patient DF).
What deficits are associated with dorsal stream damage?
Optic ataxia—difficulty using vision to guide actions despite otherwise normal vision.
What does the inferior temporal cortex do in vision?
It supports recognition by responding selectively to specific shapes and objects, invariant to size or orientation.
What type of memory is indicated by sustained neuron activity in the inferior temporal cortex?
Short-term visual memory.
What are ‘face cells’ and where are they located?
Neurons in the inferior temporal lobe that respond selectively to individual faces.
What is the role of the medial temporal lobe (MTL)?
It integrates multimodal sensory input and is crucial for forming declarative (episodic and semantic) memories.
What condition did patient H.M. have after MTL surgery?
Severe anterograde amnesia—unable to form new long-term memories.
What are “place cells” in the hippocampus?
Neurons that fire in response to specific spatial locations, aiding navigation and spatial memory.
What kind of information does the hippocampus encode?
Multimodal percepts including objects, locations, and experiences (episodic memory).
What are the overarching principles of visual processing in the brain?
Hierarchical organization and functional differentiation.
