Visual System: Retina, Pathways, and Visual Cortex Functions

What is the function of the retina?

The retina is a light-sensitive layer at the back of the eye that converts light into neural signals.

What are the main components of the visual pathways?

The main components are the retino-geniculate-striate pathway and the tectopulvinar pathway.

What is the optic chiasm?

The optic chiasm is the point of crossover for half of the visual projections from the eyes.

What is the blind spot?

The blind spot is where the optic nerve passes through the optic disc, and there are no cells to detect light.

What is hemianopia?

Hemianopia is the loss of vision in half of the visual field.

What is scotoma?

Scotoma is the loss of vision in one point of the visual field.

What is quadrantanopia?

Quadrantanopia is the loss of vision in a quarter of the visual field.

What is the ventral stream responsible for?

The ventral stream is the 'what' pathway, responsible for recognizing objects and their names and functions.

What is the dorsal stream responsible for?

The dorsal stream is the 'where/how' pathway, responsible for locating objects and how to interact with them.

What is prosopagnosia?

Prosopagnosia is the inability to recognize familiar faces despite having normal vision.

What is agnosia?

Agnosia is the inability to recognize objects despite having normal sensory abilities.

What is apperceptive visual agnosia?

Apperceptive visual agnosia is the impairment in forming a coherent visual perception of objects.

What is associative visual agnosia?

Associative visual agnosia is the impairment in linking visual perception to visual meaning.

What is blindsight?

Blindsight is the ability to respond to visual stimuli without conscious awareness of seeing them.

What is akinetopsia?

Akinetopsia is the inability to perceive motion, even though static objects are seen normally.

What is the role of the fusiform face area (FFA)?

The FFA responds to faces more than objects and is crucial for face recognition.

What is the parahippocampal place area (PPA)?

The PPA responds to places, such as pictures of houses and landmarks.

What happens when the inferotemporal (IT) cortex is lesioned?

Lesioning the IT cortex leads to agnosias, which is the inability to recognize objects.

What is pareidolia?

Pareidolia is the perception of patterns, like faces or objects, in ambiguous stimuli.

What is the primary visual cortex (V1) responsible for?

The primary visual cortex (V1) is responsible for processing basic features like edges and orientation.

What is the secondary visual cortex (V2/V3) responsible for?

The secondary visual cortex (V2/V3) is responsible for processing form, depth, and binocular vision.

What is the middle temporal region (MT; V5) responsible for?

The middle temporal region (MT; V5) is responsible for processing motion.

What is the significance of double dissociation in visual processing?

Double dissociation shows that face and object processing are distinct in the brain.

What is the take-home message regarding visual processing?

Vision begins in the retina, passes through the LGN, and splits into ventral and dorsal pathways for processing what and where stimuli are.