Miyazaki K.,Okinawa Institute of Science and Technology |
Miyazaki K.W.,Okinawa Institute of Science and Technology |
Doya K.,Okinawa Institute of Science and Technology |
Doya K.,Japan Advanced Telecommunications Research Institute International
Journal of Neuroscience | Year: 2011
The serotonergic system plays a key role in the control of impulsive behaviors. Forebrain serotonin depletion leads to premature actions and steepens discounting of delayed rewards. However, there has been no direct evidence for serotonin neuron activity in relation to actions for delayed rewards. Here we show that serotonin neurons increase their tonic firing while rats wait for food and water rewards and conditioned reinforcement tones. The rate of tonic firing during the delay period was significantly higher for rewards than for tones, for which rats could not wait as long. When the delay was extended, tonic firing persisted until reward or tone delivery. When rats gave up waiting because of extended delay or reward omission, serotonin neuron firing dropped preceding the exit from reward sites. Serotonin neurons did not show significant response when an expected reward was omitted, which was predicted by the theory that serotonin signals negative reward prediction errors. These results suggest that increased serotonin neuron firing facilitates a rat's waiting behavior in prospect of forthcoming rewards and that higher serotonin activation enables longer waiting. Copyright © 2011 the authors.
Ugurlu B.,Japan Advanced Telecommunications Research Institute International |
Kawamura A.,Yokohama National University
IEEE Transactions on Industrial Electronics | Year: 2014
When realizing jumping locomotion on legged robots, trajectories that are generated without assessing angular momentum information are found to be prone to backward hopping motions, due to the undesired body rotations developed during the support phase, prior to liftoff. In this letter, we succinctly discuss the underlying characteristics of such an undesired motion and propose a possible solution that is based on our previous work. In order to validate our claims, we conducted vertical jumping experiments on the actual bipedal robot MARI-3. As the result, the robot is able to exhibit dynamically balanced jumping motions without any backward hopping motion. © 1982-2012 IEEE.
Japan Advanced Telecommunications Research Institute International | Date: 2014-03-14
NEC Communication Systems Ltd., Kansai University and Japan Advanced Telecommunications Research Institute International | Date: 2015-09-15
A transmitter generates a header frame having a frame length indicating the beginning of data to be transmitted, data frames having frame lengths representing the data to be transmitted, and an end frame having a frame length indicating the end of the data to be transmitted. Then, for all of the header frame, data frames and end frame, the transmitter executes transmitting the kth frame when the wireless communication space is available, thereby transmitting the header frame, data frames and end frame, one after another, in accordance with the CSMA/CA scheme.
Japan Advanced Telecommunications Research Institute International | Date: 2014-04-24
Provided is a method of analyzing brain activities for realizing a biomarker for neurological/mental disorder, based on brain function imaging. From measured data of resting-state functional connectivity MRI of a healthy group and a patient group, correlation matrix (