Figure 4. Recordings From the Dorsolateral Prefrontal Cortex (dlPFC) in Macaques During Working Memory: the Effects of Manipulating LTCC Activity on Delay Cell Firing in the dlPFC of Macaques.

The left subpanels show an example neuron’s delay-related firing under control and drug conditions with dark gray indicating the cue period and light gray indicating the delay period; the middle subpanels show the mean (SEM) delay-related firing for all delay cells under control vs drug conditions; the right subpanels show the mean (SEM) d’ measure of spatial tuning for all delay cells under control vs drug conditions. A, The LTCC channel agonist, (S)-(-)-Bay-K8644 (S-Bay; orange), was associated with reduced delay-related firing (R 2-way analysis of variance, F_1,13 = 20.06; P < .001) and decreased d’ (paired t test, t₁₃ = 4.16; P = .001). B, The LTCC antagonist diltiazem (dil) produced an inverted-U dose-response, with low doses of diltiazem (5-20nA, light blue) increasing delay-related firing and spatial tuning, while high doses (30-50nA, orange) were associated with reduced delay firing and spatial tuning (firing rate: R 2-way analysis of variance, F_2,26 = 26.90, P < .001; spatial tuning: R 1-way analysis of variance, F_1.786,32.15 = 13.86, P < .001).

^aP < .0001.

^bP < .01.

^cP < .005.