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. Author manuscript; available in PMC: 2014 Mar 14.
Published in final edited form as: J Comp Neurol. 2012 Oct 1;520(14):3256–3276. doi: 10.1002/cne.23096

Figure 6.

Figure 6

Correlating the patterns of striate–extrastriate and visual callosal connections. The callosal patterns were revealed in adult rats following multiple injections of HRP in the contralateral hemisphere, and the striate–extrastriate projections were revealed following single injections of BDA into striate cortex. Injection site is represented by the dot and the fine outline. Lateral is to the right, anterior is up. A–C: Rat enucleated at birth. Dark areas in A,C correspond to dense accumulations of retrogradely labeled callosal somas and anterogradely labeled callosal axons. Numbers in A indicate acallosal regions. Asterisk in A indicates interrupted callosal bridge. Arrows in A,C indicate an island of densely labeled callosal connections. Striate–extrastriate projections are represented in black in B, and as outlines in C. D–F: Rat enucleated at birth. Callosal pattern is represented in gray. Striate–extrastriate projections are represented in black in E and as outlines in F. Numbers in D represent acallosal islands. Asterisks in D mark interrupted callosal bridges. Arrow in D–F marks an island of densely labeled callosal connections. Arrowheads in D mark acallosal regions at the 17/18a border, while arrowheads in E mark anomalous striate projections into these 17/18a acallosal regions. A portion of the lateral border of area 18a is indicated by a black/white line in E. G: Callosal pattern revealed following multiple injections of HRP in adult rat enucleated at birth. Dark areas correspond to dense accumulations of retrogradely labeled somas and anterogradely labeled axons. H: Thresholded version of callosal pattern in G is shown in gray. Black areas in extrastriate cortex indicate anterograde transport of BDA from an injection of this tracer into striate cortex (thin outline). Arrowhead points to a small projection field within an area of reduced callosal connections at the 17/18a border. I: Callosal pattern in adult rat enucleated at P4. Lateral border of area 18a is indicated by black line in G–I. Scale bars = 1.0 mm.