- Email: [email protected]
Relation of pedunculopontine tegmental nucleus neurons in monkeys to reward prediction and behavior
S114
Abstracts
study whether the DRN activity is involved in delay-based cost–benefit decisionmaking, we recorded single-neuronal activity in the DRN while a monkey performed a delayed-reward visually-guided saccade task. In the task, reward value (0.01 ml vs. 0.5 ml) was indicated by the location of saccade target (right vs. left), and after saccade, a reward was delivered with a 1600 ms delay. We found that about half (23/45) of DRN neurons exhibited sustained activity during the delay period ‘after’ saccade and before reward delivery, with either large- or small-reward preference. The same neurons often showed significantly less reward modulation if the delay (1600 ms) was introduced ‘before’ saccade in a memory-guided saccade task. These results suggest that the coding of the size of delayed reward is dependent on the task context such as the sequence in a task. doi:10.1016/j.neures.2009.09.525
P1-j04 Reward-dependent modulation of neuronal activity in the primate ventral striatum Ryuichi Matsuzaki 1 , Kazuko Nakao 1 , Kae Nakamura 1,2 1
Department Physiol, Kansai Med. University, Osaka, Japan; Japan
2
PRESTO, JST,
The ventral striatum (VS), including the nucleus accumbens, is a key element of the brain’s reward circuitry. To study the specific role of the VS in reward-seeking behavior, we recorded single-neuron activity in the VS while a monkey performed saccade tasks in which the target position (left or right) indicated the size of an upcoming reward (0.01 ml vs. 0.5 ml). We found that majority of task-related VS neurons (n = 174/188) exhibited long-lasting (often >1 s), tonic modulation in activity after reward delivery. Neurons showing stronger activity for small- than large-rewards were more prevalent than neurons showing stronger activity for large rewards. Some small-reward preferring neurons also exhibited enhanced activity after performance errors such as fixation break. The findings are in strong contrast to the dorsal striatum which showed increase in activity before the onset of saccade target, usually with stronger activity when the contralateral position is associated with reward. These results suggest that the VS is involved in evaluation of outcomes, either appetitive or aversive. doi:10.1016/j.neures.2009.09.526
P1-j05 Dopamine neurons encode multi-step future rewards and their errors Kazuki Enomoto, Naoyuki Matsumoto, Minoru Kimura Kyoto Prefectural University of Medicine, Kyoto, Japan To examine whether and how dopamine (DA) neurons represent expected total reward and its error, we recorded activity of 73 DA neurons in monkeys using two kinds of classical conditioning. Each trial started with depressing an illuminated button (start cue), then one of four kinds of CS (20, 50, 80 and 100% of reward probabilities) was presented in random order (RCC) or sequentially (SCC) as a separate block of trials. Under RCC condition, DA neurons responded to a start cue, CSs and reinforcer beeps. In agreement with previous reports, CS and beep responses were proportional to the probabilities of reward and its prediction errors in a single trial, respectively. On the other hand, under SCC condition in which animals can estimate future rewards as well as current reward cued by CS, no CS response occurred. Instead, responses to start cue preceding CS became slightly greater compared to those under RCC. These results suggest that start cue responses may reflect reward values of not only current but also multiple future trials.
turing of external events for the purpose of scheduled and timely initiation of future action. doi:10.1016/j.neures.2009.09.528
P1-j07 Involvement of lateral prefrontal cortex (LPFC) in a conceptbased action planning Tomoko Yamagata, Yoshihisa Nakayama, Jun Tanji, Eiji Hoshi Brain Sci. Inst., Tamagawa University, Tokyo, Japan We trained two monkeys to receive a visual instruction to formulate an action concept, i.e., whether to select the right or left of targets to reach, in the absence of actual targets. Subsequently, two targets appeared on a screen at different locations as a choice cue. The animals then determined a correct target based on the previous instruction and prepared a reaching movement. The task allowed us to differentiate activity reflecting the action concept from the motor plan. By recording neuronal activity of their LPFC, we obtained three major findings. (1) Neuronal activity in LPFC initially reflected the action concept. (2) The motor plan developed with a short latency after the onset of the choice cue. (3) During the motor preparation period, both the action concept and motor plan were reflected. These results emphasize the involvement of the LPFC in representing an action plan at a conceptual level, even at a behavioral stage of motor preparation. doi:10.1016/j.neures.2009.09.529
P1-j08 Relation of pedunculopontine tegmental nucleus neurons in monkeys to reward prediction and behavior Ken-Ichi Okada 1 , Yasushi Kobayashi 1,2 1 Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Japan; 2 ATR Computational Neuroscience Laboratories, Kyoto, Japan
The pedunculopontine tegmental nucleus (PPTN) is involved in reward processing and conditioned behavioral control. We recorded neuronal activity of PPTN from monkeys while they performed a reward value-conditioned visually guided saccade task, and examined the relation of the neuronal activity with the conditioned stimulus, behavior and reward. Many of the neurons exhibited sustained response between onset and offset of the task (i.e. onset of the fixation target (FT; reward–cue) and reward delivery (RD)), with the level of activity correlated with the value of predicted reward and some of the neuronal activity began before the FT onset depending on the monkey’s preparatory state. To examine shutdown timing of the activity, we reversed the order between saccade target off and RD. The monkeys kept fixation to the target even after RD, and some of the neuronal activity sustained until the target off. These results suggest that PPTN neurons carry reward prediction and behavioral control signal. doi:10.1016/j.neures.2009.09.530
P1-j09 Dynamics of magnetoencephalographic activity during performance of a visuo-spatial working memory task Chihiro Minami 1 , Jun Matsubayashi 1 , Takahiro Kinai 1 , Takashi Matsuhashi 3 , Tatsuya Mima 3 , Hidenao Nagamine 2 , Masao Fukuyama 3 , Akira Mitani 1 1 Lab. of Neurorehabilitation, HHS, Grad. Sch. of Med., Kyoto University, Kyoto, Japan; 2 System Neurosci., Sapporo Med. University, Sapporo, Japan; 3 HBRC, Grad. Sch. of Med., Kyoto University, Kyoto, Japan
doi:10.1016/j.neures.2009.09.527
P1-j06 Neuronal activity in the macaque prefrontal cortex reflecting the numerosity of multimodal sensory signals Yosuke Saga, Michiyo Iba, Tanji Jun, Eiji Hoshi Brain Science Institute, Tamagawa University, Tokyo, Japan To examine the involvement of the lateral prefrontal cortex (lPFC) in temporal structuring of sensory events for appropriate initiation of actions, we trained two monkeys to perform a behavioral task. The task began when the animals pressed a key and gazed at a fixation point, after which a series of sensory signals of 1-s duration was delivered repeatedly with an interval of 0.7–2.4 s. The animals were required to respond to the fourth of the appearance of signals of a visual, auditory, or vibrotactile modality, and release a key within 1 s. A signal of a single modality was repeated in a trial, which was altered after a block of 5 trials. The animals had to keep track of the numerosity of the sensory signals because either a premature or belated response was not rewarded. We found a subset of lPFC neurons whose delay-period activity reflected the numerosity of the cues, irrespective of the sensory modality. This finding indicates that the lPFC is involved in temporal struc-
The cortical activity was recorded using magnetoencephalography from normal humans performing a modified Sternberg task to elucidate brain activity during a visuo–spatial working memory task. Memory cues (2–4 dots) were sequentially presented on the screen (each dot was presented for 0.3 s with 1 s intervals). Following a 3 s delay period (retention interval), a probe cue was presented. Subjects were instructed to remember the locations of the memory cues and to judge whether the location of the probe cue was the same as any of the locations of the memory cues. During the retention interval, alpha band (8–13 Hz) brain activity was suppressed over the medial parieto-occipital cortex and the suppression increased with memory load. The load dependence suggests that the suppression reflects the brain activity responsible for visuo-spatial working memory. doi:10.1016/j.neures.2009.09.531
Abstracts
study whether the DRN activity is involved in delay-based cost–benefit decisionmaking, we recorded single-neuronal activity in the DRN while a monkey performed a delayed-reward visually-guided saccade task. In the task, reward value (0.01 ml vs. 0.5 ml) was indicated by the location of saccade target (right vs. left), and after saccade, a reward was delivered with a 1600 ms delay. We found that about half (23/45) of DRN neurons exhibited sustained activity during the delay period ‘after’ saccade and before reward delivery, with either large- or small-reward preference. The same neurons often showed significantly less reward modulation if the delay (1600 ms) was introduced ‘before’ saccade in a memory-guided saccade task. These results suggest that the coding of the size of delayed reward is dependent on the task context such as the sequence in a task. doi:10.1016/j.neures.2009.09.525
P1-j04 Reward-dependent modulation of neuronal activity in the primate ventral striatum Ryuichi Matsuzaki 1 , Kazuko Nakao 1 , Kae Nakamura 1,2 1
Department Physiol, Kansai Med. University, Osaka, Japan; Japan
2
PRESTO, JST,
The ventral striatum (VS), including the nucleus accumbens, is a key element of the brain’s reward circuitry. To study the specific role of the VS in reward-seeking behavior, we recorded single-neuron activity in the VS while a monkey performed saccade tasks in which the target position (left or right) indicated the size of an upcoming reward (0.01 ml vs. 0.5 ml). We found that majority of task-related VS neurons (n = 174/188) exhibited long-lasting (often >1 s), tonic modulation in activity after reward delivery. Neurons showing stronger activity for small- than large-rewards were more prevalent than neurons showing stronger activity for large rewards. Some small-reward preferring neurons also exhibited enhanced activity after performance errors such as fixation break. The findings are in strong contrast to the dorsal striatum which showed increase in activity before the onset of saccade target, usually with stronger activity when the contralateral position is associated with reward. These results suggest that the VS is involved in evaluation of outcomes, either appetitive or aversive. doi:10.1016/j.neures.2009.09.526
P1-j05 Dopamine neurons encode multi-step future rewards and their errors Kazuki Enomoto, Naoyuki Matsumoto, Minoru Kimura Kyoto Prefectural University of Medicine, Kyoto, Japan To examine whether and how dopamine (DA) neurons represent expected total reward and its error, we recorded activity of 73 DA neurons in monkeys using two kinds of classical conditioning. Each trial started with depressing an illuminated button (start cue), then one of four kinds of CS (20, 50, 80 and 100% of reward probabilities) was presented in random order (RCC) or sequentially (SCC) as a separate block of trials. Under RCC condition, DA neurons responded to a start cue, CSs and reinforcer beeps. In agreement with previous reports, CS and beep responses were proportional to the probabilities of reward and its prediction errors in a single trial, respectively. On the other hand, under SCC condition in which animals can estimate future rewards as well as current reward cued by CS, no CS response occurred. Instead, responses to start cue preceding CS became slightly greater compared to those under RCC. These results suggest that start cue responses may reflect reward values of not only current but also multiple future trials.
turing of external events for the purpose of scheduled and timely initiation of future action. doi:10.1016/j.neures.2009.09.528
P1-j07 Involvement of lateral prefrontal cortex (LPFC) in a conceptbased action planning Tomoko Yamagata, Yoshihisa Nakayama, Jun Tanji, Eiji Hoshi Brain Sci. Inst., Tamagawa University, Tokyo, Japan We trained two monkeys to receive a visual instruction to formulate an action concept, i.e., whether to select the right or left of targets to reach, in the absence of actual targets. Subsequently, two targets appeared on a screen at different locations as a choice cue. The animals then determined a correct target based on the previous instruction and prepared a reaching movement. The task allowed us to differentiate activity reflecting the action concept from the motor plan. By recording neuronal activity of their LPFC, we obtained three major findings. (1) Neuronal activity in LPFC initially reflected the action concept. (2) The motor plan developed with a short latency after the onset of the choice cue. (3) During the motor preparation period, both the action concept and motor plan were reflected. These results emphasize the involvement of the LPFC in representing an action plan at a conceptual level, even at a behavioral stage of motor preparation. doi:10.1016/j.neures.2009.09.529
P1-j08 Relation of pedunculopontine tegmental nucleus neurons in monkeys to reward prediction and behavior Ken-Ichi Okada 1 , Yasushi Kobayashi 1,2 1 Graduate School of Frontier Biosciences, Osaka University, Toyonaka, Japan; 2 ATR Computational Neuroscience Laboratories, Kyoto, Japan
The pedunculopontine tegmental nucleus (PPTN) is involved in reward processing and conditioned behavioral control. We recorded neuronal activity of PPTN from monkeys while they performed a reward value-conditioned visually guided saccade task, and examined the relation of the neuronal activity with the conditioned stimulus, behavior and reward. Many of the neurons exhibited sustained response between onset and offset of the task (i.e. onset of the fixation target (FT; reward–cue) and reward delivery (RD)), with the level of activity correlated with the value of predicted reward and some of the neuronal activity began before the FT onset depending on the monkey’s preparatory state. To examine shutdown timing of the activity, we reversed the order between saccade target off and RD. The monkeys kept fixation to the target even after RD, and some of the neuronal activity sustained until the target off. These results suggest that PPTN neurons carry reward prediction and behavioral control signal. doi:10.1016/j.neures.2009.09.530
P1-j09 Dynamics of magnetoencephalographic activity during performance of a visuo-spatial working memory task Chihiro Minami 1 , Jun Matsubayashi 1 , Takahiro Kinai 1 , Takashi Matsuhashi 3 , Tatsuya Mima 3 , Hidenao Nagamine 2 , Masao Fukuyama 3 , Akira Mitani 1 1 Lab. of Neurorehabilitation, HHS, Grad. Sch. of Med., Kyoto University, Kyoto, Japan; 2 System Neurosci., Sapporo Med. University, Sapporo, Japan; 3 HBRC, Grad. Sch. of Med., Kyoto University, Kyoto, Japan
doi:10.1016/j.neures.2009.09.527
P1-j06 Neuronal activity in the macaque prefrontal cortex reflecting the numerosity of multimodal sensory signals Yosuke Saga, Michiyo Iba, Tanji Jun, Eiji Hoshi Brain Science Institute, Tamagawa University, Tokyo, Japan To examine the involvement of the lateral prefrontal cortex (lPFC) in temporal structuring of sensory events for appropriate initiation of actions, we trained two monkeys to perform a behavioral task. The task began when the animals pressed a key and gazed at a fixation point, after which a series of sensory signals of 1-s duration was delivered repeatedly with an interval of 0.7–2.4 s. The animals were required to respond to the fourth of the appearance of signals of a visual, auditory, or vibrotactile modality, and release a key within 1 s. A signal of a single modality was repeated in a trial, which was altered after a block of 5 trials. The animals had to keep track of the numerosity of the sensory signals because either a premature or belated response was not rewarded. We found a subset of lPFC neurons whose delay-period activity reflected the numerosity of the cues, irrespective of the sensory modality. This finding indicates that the lPFC is involved in temporal struc-
The cortical activity was recorded using magnetoencephalography from normal humans performing a modified Sternberg task to elucidate brain activity during a visuo–spatial working memory task. Memory cues (2–4 dots) were sequentially presented on the screen (each dot was presented for 0.3 s with 1 s intervals). Following a 3 s delay period (retention interval), a probe cue was presented. Subjects were instructed to remember the locations of the memory cues and to judge whether the location of the probe cue was the same as any of the locations of the memory cues. During the retention interval, alpha band (8–13 Hz) brain activity was suppressed over the medial parieto-occipital cortex and the suppression increased with memory load. The load dependence suggests that the suppression reflects the brain activity responsible for visuo-spatial working memory. doi:10.1016/j.neures.2009.09.531