Team teaching 2 (vision) Flashcards
How does visual processing work?
The receptor cells to detect light are called photoreceptors – either in the form of rods or cones. These photoreceptors release neurotransmitter molecules that control the activity of the bipolar cells. The bipolar cells connect with ganglion cells. The axons of the ganglion cells form the optic nerve, which carries information from the eyes to the brain.
What are the parvocellular ganglion cells?
They receive information from small cells that project to the ventral layers. It is the fine details.
What are the magnocellular cells?
They detect movements and work with bigger things. Detects the light at night because it has high contrast sensitivity.
How is the dorsal pathway?
Starts at retina: magnocellular –> LGN layers 1 and 2 –> V1 –> parietal lobe.
How is the ventral pathway?
Starts at retina: parvocellular –> LGN layers 3-6 –> V1 –> temporal lobe.
How are the visual fields represented spatially on the retinas and projected to the cortex?
Some or all of the axons of each optic nerve cross to the opposite cerebral hemisphere. The optic nerves cross the midline at the optic chiasm.
The organization of the primary visual cortex
The primary visual cortex has separate representations for at least four dimensions of the visual stimuli:
* Location in the visual field, with larger, finer mapping of the central visual field than of the periphery
* Ocular dominance
* Orientation
* Color
Where are the rods and cones located?
At the back of the retina.
What is a simple cell?
The simple cell is a neuron in the visual cortex that responds best to a line or an edge with a particular orientation at a SPECIFIC location in the visual field.
Who do the bipolar cels have contacts with?
The amacrine, ganglion and receptor cells.
If most axons of the retinal ganglion cells were cut, which structure would lose light information?
Primary visual cortex, superior colliculus, and lateral geniculate.
Elderly drivers may be impaired in their ability to take in information regarding movement. Based on what you know, you might surmise that elderly drivers may have lost some function in?
Their magnocellular system.
The inferior temporal cortex plays a role in the recognition of?
Patterns and objects.
What does optical images help with?
Without them, light-sensitive cells would be able to detect only the presence or absence of light, not any forms.
Cililary muscles?
Focus is adjusted by this.
