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51 Cards in this Set

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This recieves input from the retinal ganglion cells and processes information from the contralateral visual hemifield?
Lateral Geniculate Body
A point of light in the contralateral visual field is represented in the LGB in (all or some) of the 6 layers in (horizontal or vertical ) register?
All; Vertical
True or False A retinotopic map is established in each layer of the LGB?
True(
Is there any convergence in the projection from the retina to the LGB?
No (each retinal ganglion cell makes a one-one connection with a single neuron in the LGB)
Layers 1,4,6 of the R LGB receive information from the (left temporal, left nasal, right temporal, right nasal)?
Left Nasal
How is incoming information to the LGB segregated?
By eye (ipsilateral or contralateral) and by cell type (M-Cell and P-cell)
Uncrossed fibers going to the LGB from the ipsilateral eye terminate onto which layers?
2,3,5
Information from the M-Cells terminates onto which layers of the LGB?
1 and 2
This pathway responds to visual signals by actional potential bursts as opposed to sustained increase in action potential frequency (magnocellular or parvocellular)?
Magnocellular
This pathway is color sensitive (magnocellular, parvocellular)?
Parvocellular
Visual acuity in this pathway is poor (magnocellular or parvocellular)?
Magnocellular
What kind of receptive fields do retinal ganglion cells have ?
circular , concentric
Is the receptive field of each LGB neuron identical to that of the single retinal ganglion cell that provides its input?
Yes (remember no convergenceā€¦.1:1)
Where do the fibers from all 6 layers of the LGB project to?
Primary visual cortex
What is the location of the primary visual cortex?
Upper and lower banks of the calcarine sulcus
What layer of the primary visual cortex do axons of the LGB neurons terminate on?
Layer 4
Is there convergence of input from the LGB to neurons in layer 4 of the primary visual cortex?
Yes
What is the function of LGB to V1 projection?
Maintains segregation of both location of eye (ipsilateral vs contralateral) and M,P pathways (different sub-layers)
What is an Ocular Dominance Columns?
An ODC is a vertical column that spans all six cortical layers and processes information predominantly from one eye
How are ODCs arranged?
left eye columns alternate with right eye columns
A pair of adjacent left-right ODCs processes information from the (same, different) point in the (ipsilateral, contralateral) visual field?
Same, contralateral
Information from the upper part of the R visual field is processed by a pair of ODCs located where?
L lower bank of the calcarine sulcus
ODC is absent for these two representations?
Blind spot of retina; Monocular temporal crescent of the contralateral visual field
Neurons in layer 4 of V1 have (monocular or binocular) responses?
Monocular (an ODC recives info from one eye)
Where do layer 4 neurons of the primary visual cortex project to?
Layers 2 and 3 above; Layers 5 and 6 below
Which layers of the primary visual cortex are the initial regions for processing binocular features of vision?
2,3,5,6
Most of the input from neurons of the primary visual cortex found in layers 2,3,5,6 are come from (one eye, both eyes)?
One eye (ocularly dominant still)
These are smaller vertical slabs within an ODC in which all cells respond to stimuli with a preferred orientation?
Orientation Columns
These are pillar-like collections of cells in layers 2,3,5,6 of V1 that respond to the color of the stimulus and are insensitive to stimulus orientation?
Blobs
Input to neurons within blobs is exclusive for which pathway (M, or P)?
P-pathway
What are blobs assumed to be involved in (light sensitivity, color information, contrast)?
Color information
Which layers of the LGB terminate primarily on blobs?
6-Mar
What does a hypercolumn have?
ODC for both eyes; 180 degree orientation columns for both eyes; Several Blobs
Neurons of layer 4 of the primary visual cortex respond to (spots of light, bars/slits of light)?
Bars and slits of light (because of convergence of several LGB)
What are the various characteristics of the receptive fields located within Layer 4 of the primary visual cortex?
On in center flanked by OFF; OFF in center flanked by ON; ON/OFF and vice versa; Orientation Specific
Neurons in layers 2,3,5,6 of the primary visual cortex respond to a light bar under what conditions?
Anywhere within the receptive field but ONLY with a required specific orientation
Layers 2,3,5,6 do not have On/OFF specificity (true or false)?
True(
What pathway does the M-path take after layer 4 of the primary visual cortex?
layer 4 > dorsal pathway > visual association cortex > Area V5 > Superior Parietal Cortex (SPC)
What pathway does the P-path take after layer 4 of the primary visual cortex?
Layer 4 > Ventral pathway > visual association cortex > area V4 > inferior temporal cortex (ITC)
The function of this pathway (M or P) is motion detection, spatial and depth analysis, and visual attention?
M pathway ("where" is it)
The function of this pathway (M or P) is recognition of objects and faces, visual perception, memory, and color processing?
P pathway
lesions of the visual association areas cause defecits known as ?
Visual Agnosias
Is there a loss of visual acuity in visual agnosia?
No
What are the two factorsat work for perception of an object/person?
Conscious visual perception; Linking to previous image (association)
A patient looks at a picture of several small objects but only sees one of the figures, he most likely has (Prospopagnosia, achromatopsia, akinetopsia, simultanagnosia)
Simultanagnosia
Where are lesions in patients with simultanagnosia?
bilaterally in the superior parietal cortex
A patient comes in complaining that the world appears to not be moving, he has difficulty pouring water into a cup, he most likely has (Prospopagnosia, achromatopsia, akinetopsia, simultanagnosia)?
Akinetopsia
A patient comes in but does not recognize you, he looks at your awesome leather boots and then says, hello doctor, he most likely has (Prospopagnosia, achromatopsia, akinetopsia, simultanagnosia)?
Prosopagnosia
Where would you find lesions in people with prospagnosia?
Bilateral inferior temporooccipital cortex (ventral P pathway)
A patient states that everything in his right visual field appears to be black and white, his depth perception and spatial resolution are maintained, he most likely has (Prospopagnosia, achromatopsia, akinetopsia, simultanagnosia)?
Achromatopsia (cortical color blindness)
Which of these (Prospopagnosia, achromatopsia, akinetopsia, simultanagnosia) are lesions of the M pathway ?
Simultanagnosia and Akinetopsia