In primates, visual information passes from the primary visual area (V1) to the second visual area (V2) before distribution to higher cortical areas. An accurate description of the projections linking V 1 and V2 is crucial for understanding how the brain deciphers visual images. Prior studies have shown that V2 is partitioned into three compartments, known as pale, thin, and thick stripes, defined by their content of a metabolic enzyme called cytochrome oxidase (CO). Our principal goal is to describe the anatomical projections from V1 to each V2 stripe compartment.
In Specific Aim #1 we will make injections of a retrograde tracer into single CO stripes in V2 of normal macaques. The resulting pattern of labeled cells in V1 will be correlated with the V2 stripe that received the injection. Our preliminary data indicate that, contrary to a previous report, layer 4B and interblobs both project to thick stripes and pale stripes.
In Specific Aim #2 we will make paired injections of two different tracers into adjacent thick stripes and pale stripes to determine if different subpopulations of cells in layer 4B and interblobs project to these V2 compartments.
In Specific Aim #3 we will make injections of [3H]proline into V1 to correlate patches of efferent projections with CO staining patterns in V2. In Specific Ai/s #4 we will examine the V1->V2 projections in animals raised with early monocular deprivation. These experiments will advance our knowledge of the mechanisms underlying amblyopia, an important cause of visual loss that affects 2% of the American population. We hypothesize that a selective loss of V1->V2 projections emanating from the ocular dominance columns serving the deprived eye contributes to the loss of vision in amblyopia.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32EY013676-02
Application #
6525092
Study Section
Visual Sciences B Study Section (VISB)
Program Officer
Oberdorfer, Michael
Project Start
2002-08-01
Project End
Budget Start
2002-08-01
Budget End
2003-07-31
Support Year
2
Fiscal Year
2002
Total Cost
$46,192
Indirect Cost
Name
University of California San Francisco
Department
Ophthalmology
Type
Schools of Medicine
DUNS #
073133571
City
San Francisco
State
CA
Country
United States
Zip Code
94143
Sincich, Lawrence C; Jocson, Cristina M; Horton, Jonathan C (2012) Neuronal projections from V1 to V2 in amblyopia. J Neurosci 32:2648-56
Economides, John R; Sincich, Lawrence C; Adams, Daniel L et al. (2011) Orientation tuning of cytochrome oxidase patches in macaque primary visual cortex. Nat Neurosci 14:1574-80
Sincich, Lawrence C; Jocson, Cristina M; Horton, Jonathan C (2010) V1 interpatch projections to v2 thick stripes and pale stripes. J Neurosci 30:6963-74
Sincich, Lawrence C; Jocson, Cristina M; Horton, Jonathan C (2007) Neurons in V1 patch columns project to V2 thin stripes. Cereb Cortex 17:935-41
Sincich, Lawrence C; Horton, Jonathan C (2005) Input to V2 thin stripes arises from V1 cytochrome oxidase patches. J Neurosci 25:10087-93
Sincich, Lawrence C; Horton, Jonathan C (2003) Independent projection streams from macaque striate cortex to the second visual area and middle temporal area. J Neurosci 23:5684-92
Sincich, Lawrence C; Adams, Daniel L; Horton, Jonathan C (2003) Complete flatmounting of the macaque cerebral cortex. Vis Neurosci 20:663-86
Sincich, Lawrence C; Horton, Jonathan C (2002) Divided by cytochrome oxidase: a map of the projections from V1 to V2 in macaques. Science 295:1734-7
Sincich, Lawrence C; Horton, Jonathan C (2002) Pale cytochrome oxidase stripes in V2 receive the richest projection from macaque striate cortex. J Comp Neurol 447:18-33
Sincich, Lawrence C; Horton, Jonathan C (2002) An albino-like decussation error in the optic chiasm revealed by anomalous ocular dominance columns. Vis Neurosci 19:541-5