Grover- Central Visual Function Flashcards
Retinal ganglion cells release ____ and excite their neuronal targets
Glutamate
Part of hypothalamus involved w/ light entrainment of the internal circadian clock
Suprachiasmatic nucleus
Area RGC’s synapse for stimulation of the pupillary light reflex
Pretectal area
Involved in reflexie orienting movement of head and eyes
Superior colliculus
Magnocellular (m-type) rgc’s are best suited for the detection of ?
Motion
P type (parvocellular) RGC’s are best suited for ?
Detection of fine detail and colour
Non-M Non-P RGC’s detect
Color
LGN neurons release __ _as their nuerotransmitter and ____ the cells they synapse
Glutamate
Excite
Axons of LGN neurons terminate in layer IVC of the primary visual cortex, synapsing onto _______
Stellate neurons
The stellate neurons in layer IVC of the primary visual cortex, release ____ and excite ____
Glutamte.
Pyramidal neurons in other layers of cortex
Layer II/III pyramidal neurons ( of primary visual cortex ) project to ?
Other cortical areas
Layer V/ VI pyramidal neurons project to ?
This is talking about layers of the primary visual cortex
Subcortical areas
Ocular dominance columns or stripes?
The LGN axons from layers IVCalpha and IVCbeta are organized to relay information specifically from either left or right eye to the cortical neurons in one column.
Defined histologically by a high concentration of cytochrome oxidase
Blobs
Layer IVCalpha cells are _____ selective
Orientation.
They respond best to stimuli presented in a specific orientation that is aligned with their “on” zone
P-IB layer III neurons are relatively _ ____ to wavelength
Insensitive
The high degree of orientation selectivity w/in the P-Ib channel allows for detection of ?
Form
Shape
Blob channel neurons are the principle wavelength sensitive neurons of primary visual cortex and therefore have the primary function in the ____-
Detection of colour
A small cube of cortex.
Contains a compete set of orientation columns, representing all possible 360 degrees.
Input from both eyes (complete set of ocular dominance columns)
All three info processing channels
Hypercolumn
Neurons in area MT (which receives projections from area IV) are specialized for analysis of ______
Motion.
(Directionally selective
Large receptive field
Directional tuning
Organized in direction of motion columns )
Lesions here are rare, but when they occur are associated w/ impaired perception of motion
Dorsal stream (including areas MT/MST)
The ______ is formed by cortico-cortical projections from primary visual cortex. It is involved in the analysis of form and color
Area V4
A rare condition caused by a lesion in area V4 of the ventral stream. There is partial or complete loss of colour vision despite normally functioning cones in the retina.
Pt’s describe the world as drab, existing only in shades of gray.
Achromatopsia
Inferior temporal (IT) area, fed by V4. Contains major face recognition and a deficit here will cause prosopagnosia
Fusiform gyrus
In children w/ strabismus (5% of kids), one eye’s input is suppressed to avoid dipolopia. If untreated, what will occur?
Permanent low acuity in the suppressed eye and poor depth perception.
The critical period for vision in children?
Period when LGN axon terminals arborize the layer IV of the primary visual cortex.
Correction of vision in children should be done _____ for the most effective recovery of normal visual function.
The first critical period.
Visual cues for far-field depth perception
Size
Interposition (if one object is in front of the other)
Linear perspecitve (parallel lines converge)
Light and shadow
Motion parallax
