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In a multi-agent environment, where the outcomes of one's actions change dynamically because they are related to the behavior of other beings, it becomes difficult to make an optimal decision about how to act. Although game theory provides normative solutions for decision making in groups, how such decision-making strategies are altered by experience is(More)
The process of decision making in humans and other animals is adaptive and can be tuned through experience so as to optimize the outcomes of their choices in a dynamic environment. Previous studies have demonstrated that the anterior cingulate cortex plays an important role in updating the animal's behavioral strategies when the action outcome contingencies(More)
The striatum is thought to play a crucial role in value-based decision making. Although a large body of evidence suggests its involvement in action selection as well as action evaluation, underlying neural processes for these functions of the striatum are largely unknown. To obtain insights on this matter, we simultaneously recorded neuronal activity in the(More)
Reward from a particular action is seldom immediate, and the influence of such delayed outcome on choice decreases with delay. It has been postulated that when faced with immediate and delayed rewards, decision makers choose the option with maximum temporally discounted value. We examined the preference of monkeys for delayed reward in an intertemporal(More)
The brain processes information about sensory stimuli and motor intentions using a massive ensemble of neurons arrayed in parallel. Individual neurons receive convergent inputs from thousands of other neurons, leading to the possibility that patterns of spikes across the input neurons might be crucial components of the neural code. Recently, advances in(More)
Human behaviors can be more powerfully influenced by conditioned reinforcers, such as money, than by primary reinforcers. Moreover, people often change their behaviors to avoid monetary losses. However, the effect of removing conditioned reinforcers on choices has not been explored in animals, and the neural mechanisms mediating the behavioral effects of(More)
Previous studies have shown that non-human primates can generate highly stochastic choice behaviour, especially when this is required during a competitive interaction with another agent. To understand the neural mechanism of such dynamic choice behaviour, we propose a biologically plausible model of decision making endowed with synaptic plasticity that(More)
Newly experienced events are often remembered together with how rewarding the experiences are personally. Although the hippocampus is a candidate structure where subjective values are integrated with other elements of episodic memory, it is uncertain whether and how the hippocampus processes value-related information. We examined how activity of dorsal CA1(More)
We analyzed the variability of spike counts and the coding capacity of simultaneously recorded pairs of neurons in the macaque supplementary motor area (SMA). We analyzed the mean-variance functions for single neurons, as well as signal and noise correlations between pairs of neurons. All three statistics showed a strong dependence on the bin width chosen(More)
Response variability is often correlated across populations of neurons, and these noise correlations may play a role in information coding. In previous studies, this possibility has been examined from the encoding and decoding perspectives. Here we used d prime and related information measures to examine how studies of noise correlations from these two(More)