Flashcards in L18 - Visual Cortex 2 (TV) Deck (7)
List 3 neuroanatomical tracing techniques
1) Radioactive amino acids-Inject into one eye and determine labeling in cortex of ocular DOMINANCE columns
2) 2-Deoxyglucose (2DG)-ONLY TAKEN UP BY ACTIVE CELLS - Injecting glucose analogue (C14 is radioactive - allows us to identify cells that are active) taken up after visual stimulation BUT only by the cells in which the ORIENTATION it was showed in
*Layer 4C is labelled because the cells are not orientation selective - infragranular layers 5 and 6 have orientation columns
3) Cytochrome oxidase levels - Mitochondrial enzyme (High basal metabolic rate - layer 4 and blobs). Cells that are more active have more cytochrome oxidase. This can be shown using radioactive proline injections.
Which layer is not orientation selective?
Cytochrome oxidase staining in macaque V1 shows? V2 shows?
V1 - Blobs
V2 - Stripes (thick and thin stripes)
Cells more active seem to be more clustered compared to the rest
Where does cytochrome oxidase blobs coincide with in regards to ocular dominance columns?
The centre of the columns
*You rarely find them at the border of two columns
How may one attempt to see the relationship between ocular dominance and orientation columns?(addresses 3rd dot point of learning objectives)
Inject radioactive amino acids (ocular dominance columns) then inject 2-deoxyglucose (orientation columns)
Where do all orientation domains seem to converge?
At the pinwheel centre