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Updated: Mar 26, 2026
Intracortical Inhibition Within the Primary Motor Cortex Can Be Modulated by Changing the Focus of Attention
Published on: September 11, 2017
The ventral tegmental area modulates intracortical microstimulation (ICMS)-evoked M1 activity in a time-dependent
Nobuo Kunori1, Riichi Kajiwara2, Ichiro Takashima3
1Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba 305-8568, Japan; Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8577, Japan; RIKEN Brain Science Institute, 2-1 Hirosawa, Wako 351-0198, Japan.
Abstract:
Intracortical microstimulation (ICMS)-evoked neural activity combined with ventral tegmental area (VTA) stimulation was studied in rat primary motor cortex (M1). We used voltage-sensitive dye (VSD) imaging to analyze the spatiotemporal dynamics of M1 activity following VTA-M1 paired stimulation. VTA stimulation was preceded by M1 ICMS at inter-stimulus intervals (ISIs) of 15-350ms. VSD imaging showed an excitatory-inhibitory sequence of neural activity after composing VTA stimulus- and ICMS-induced M1 neural activity. To evaluate the net ICMS M1 response, the optical response to unpaired VTA stimulation was subtracted from the VTA-M1 paired response. This revealed that the net ICMS-evoked M1 neural activity was inhibited when the ISI was 30-50ms, but highly facilitated when the ISI was 100-350ms. These results suggest that VTA modulates M1 excitability in the order of tens to hundreds of milliseconds and might directly affect the motor command generation process in the M1.
