Figure 3. Blockade of Gap Junctions Eliminates All Types of GC Spike Correlations.

(A) Application of 18β-GA (25 µM) effectively blocks the Neurobiotin tracer coupling of GCs. Micrographs show elimination of tracer coupling of an ON G₆ cell, which shows coupling to ACs under control conditions, and an OFF G₃ cell, which shows coupling to GC and AC neighbors under control conditions. Scale bar = 100 µm. (B) The blockade of gap junctions with 18β-GA does not significantly alter the full-field light responses of ON (bottom) and OFF (top) GCs. Presentation of the light stimulus (I = 3000 R*/rod/sec) is indicated by the grey bar. (C,D, and E) Blockade of gap junctions effectively eliminated all spike correlations reflected in narrow, medium, and broad CCFs.