The effect of 5-HT receptor antagonist on reward-based decision-making.

When choosing the best action from several alternatives, we compare each value that depends on the balance between benefit and cost. Previous studies have shown that animals and humans with low brain serotonin (5-HT) level tend to choose smaller immediate reward. We used a decision-making schedule task to investigate whether 5-HT receptor is responsible for the decisions related to reward.

Reverse-filtering on extracellular action potential for waveform analysis.

For further understanding the role of serotonergic neurons, unit recordings using behaving primates are increasingly needed. A widely used criterion to identify serotonergic neuron relies on the duration of extracellular action potential (EAP). However, the duration is inaccurate due to the passband limitation needed to carry out the spike sorting.

Recency memory effects in Macaques during sequential delayed match-to-sample task with visual noise.

Visual object recognition requires both visual sensory information and memory, and its mechanisms are often studied using old-world monkeys. Wittig et al. (2014, 2016) reported that Rhesus monkeys and humans seem to adopt different strategies in a short-term visual memory task.

Neurons in the monkey orbitofrontal cortex mediate reward value computation and decision-making.

Choice reflects the values of available alternatives; more valuable options are chosen more often than less valuable ones. Here we studied whether neuronal responses in orbitofrontal cortex (OFC) reflect the value difference between options, and whether there is a causal link between OFC neuronal activity and choice. Using a decision-making task where two visual stimuli were presented sequentially, each signifying a value, we showed that when the second stimulus appears many neurons encode the value difference between alternatives.

Information Accumulation over Time in Monkey Inferior Temporal Cortex Neurons Explains Pattern Recognition Reaction Time under Visual Noise.

We recognize objects even when they are partially degraded by visual noise. We studied the relation between the amount of visual noise (5, 10, 15, 20, or 25%) degrading 8 black-and-white stimuli and stimulus identification in 2 monkeys performing a sequential delayed match-to-sample task. We measured the accuracy and speed with which matching stimuli were identified.