|Budget Amount *help
¥3,400,000 (Direct Cost : ¥3,400,000)
Fiscal Year 2003 : ¥2,700,000 (Direct Cost : ¥2,700,000)
Fiscal Year 2002 : ¥700,000 (Direct Cost : ¥700,000)
For the purpose of elucidating spatial cognitive functions of the cingulate cortex, we have recorded single neuron activities from the cingulate cortical areas in two monkeys trained to perform oculomotor delayed response (ODR) and visually-guided saccade (VGS) tasks. About 15% (105/703) of the cingulate cortical neurons exhibited significant event-related changes in firing rate in the ODR task. As in the dorsolateral prefrontal cortex, cingulate neurons exhibited cue-, delay- and saccade-related responses (10%,10% and13%, respectively). Most of the task event-related neurons in the cingulate cortex exhibited spatial tuning : 83%,87%, and 81% of cue-, delay- and saccade-related neurons, respectively. The majority of these spatially tuned neurons had the visual, memory and response fields contralateral to the recording site, respectively. Regarding the temporal profile of the saccade-related neurons, about a half(46%) of them started the response before saccade-initiation. Four hundreds and forty-three neurons that were examined in the ODR task were also studied in the VGS task. Not all neurons were activated in both tasks ; 33 neurons had saccadic responses only during the ODR task, 24 only during the VGS task and 27 during both. The results thus suggested that the saccade-related activity in the context of the oculomotor tasks is contributive to some information of memory- or visual-guided saccade. The cingulate cortex has anatomical connections with the dorsolateral prefrontal (areas 9,46) and posterior parietal (area 7) cortices and the mediodorsal thalamic nucleus, and also in these cortical areas neurons with the same spatial coding were reported during ODR task performance. Therefore, cingulate neurons may participate in spatial coding, working memory and efference copy in neural network including brain structures mentioned above.