FIGURE 3.

Effect of muscimol injection in the PMd on the performance of internally generated sequential movements. (A) Sequence 5-3-1 of the repeating task. (B) Lateral view of a Cebus brain. Dashed lines indicate the M1–PMd border and the pre-PMd–PMd border. PS, principal sulcus; ArS, arcuate sulcus; CS, central sulcus; IPS, intra parietal sulcus; LS, lateral sulcus; pre-PMd, pre-dorsal premotor cortex; PMd, dorsal premotor cortex; M1, primary motor cortex; R, rostral; L, lateral. (C) Intracortical stimulation map of a Cebus monkey. Letters indicate the movements evoked at each site. S, shoulder; E, elbow; W, wrist; D, digit; F, face. Injections were done at sites in which intracortical stimulation evoked shoulder or elbow movements (i.e., arm representation) in the PMd. (D) Reaching end points of movements from target 5 to target 3 before and after muscimol injection in the PMd. Left: pre-injection; right: post-injection. Top: random task; bottom: repeating task. The monkey was performing sequence 5-3-1 during the repeating task. E_A: accuracy errors, a reach performed in the correct direction (e.g., to the left), but to an end point outside of the correct target. Gray dots: correct response; black dots: error response. The percentages of trials ending in each target are given below the targets. *p < 0.05. (E) Error rates of the random task (left) and the repeating task (Right) in the injection session in (D). After muscimol injection, the number of errors increased dramatically in the repeating task, but not in the random task (modified from Ohbayashi et al., 2016. Copyright 2016 Society for Neuroscience).