Figure 7.

Mossy fibers originating in the LPN are necessary for the expression of trace, but not delay, conditioning. (A) Infusing muscimol into the LPN after the fourth block of dual delay/trace conditioning (break in abscissa) abolished trace (filled red circles) but not delay responses (filled green squares), while infusing ACSF had no affect (open squares indicate delay; open circles, trace; n = 8 for muscimol and 5 for ACSF). (B) Representative traces taken from an effective muscimol infusion session (same subjects as shown in D, top middle). (C) Representative traces taken from an ineffective muscimol infusion session (same subjects as in D, bottom right). (D) Histological verification of cannula placements revealed that effective infusion sites were located in the LPN, while ineffective sites were located near (<1mm), but outside of, the LPN.