Complex learned motor sequences can be composed of a combination of a small number of elementary actions. To investigate how the brain represents such sequences, we devised an oculomotor sequence task in which the monkey had to choose the target solely by the sequential context, not by the current stimulus combination. We found that many neurons in the supplementary eye field (SEF) became active with a specific target direction (D neuron) or a specific target/distractor combination (C neuron). Furthermore, such activity was often selective for one among several sequences that included the combination (S neuron). These results suggest that the SEF contributes to the generation of saccades in many learned sequences.
Bibliographical noteFunding Information:
We thank Johan Lauwereyns, Katsumi Watanabe, Hiro Nakahara, and Hideaki Itoh for their helpful comments; Makoto Kato for designing the computer programs; and Masashi Koizumi for technical support. This work was supported by Grant-in-Aid for Scientific Research on Priority Areas (C) of the Ministry of Education, Culture, Sports, Science and Technology (MEXT); CREST (Core Research for Evolutional Science and Technology) of Japan Science and Technology Corporation (JST); and JSPS (Japan Society for the Promotion of Science) Research for the Future program.