Jerald D. Kralik

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A paradigm is described for recording the activity of single cortical neurons from awake, behaving macaque monkeys. Its unique features include high-density microwire arrays and multichannel instrumentation. Three adult rhesus monkeys received microwire array implants, totaling 96-704 microwires per subject, in up to five cortical areas, sometimes(More)
A great deal of research on the prefrontal cortex (PF), especially in nonhuman primates, has focused on the theory that it functions predominantly in the maintenance of short-term memories, and neurophysiologists have often interpreted PF's delay-period activity in the context of this theory. Neuroimaging results, however, suggest that PF's function extends(More)
To explore the relationship between problem solving and inhibitory control, the authors present 4 experiments on cotton-top tamarins (Saguinus oedipus) using a reverse-reward contingency task. In Experiment 1, 1 group of tamarins was given a choice between a small and a large quantity of food. Whichever quantity the tamarins reached for first, they received(More)
To reinvestigate whether macaque monkeys could learn the reversed-contingency task, we trained six rhesus monkeys on the problem. On each trial, the monkeys chose between one and four pieces of the same food item. If a monkey selected four pieces of food, it received one instead; choice of one piece of food led to the receipt of four. All of the monkeys(More)
Previously we have shown that the kinematic parameters of reaching movements can be extracted from the activity of cortical ensembles. Here we used cortical ensemble activity to predict electromyographic (EMG) signals of four arm muscles in New World monkeys. The overall shape of the EMG envelope was predicted, as well as trial-to-trial variations in the(More)
When presented with a choice between 1 and 3 pieces of food in a type of reversed contingency task, 4 cotton-top tamarins (Saguinus oedipus) consistently chose the 3 pieces of food and received nothing, even though the choice of 1 piece would have yielded 3. However, in a task in which the tamarins received the 1 piece of food when they chose it, all(More)
Self-recognition has been explored in nonlinguistic organisms by recording whether individuals touch a dye-marked area on visually inaccessible parts of their face while looking in a mirror or inspect parts of their body while using the mirror's reflection. Only chimpanzees, gorillas, orangutans, and humans over the age of approximately 2 years consistently(More)
When food is launched down a vertically positioned S-shaped opaque tube, cotton-top tamarins (Saguinus oedipus) search for the food in the position directly beneath the release point, even though over several trials it never appears in this position (B. M. Hood et al., 1999). Experiment 1 showed that when the trajectory of the food shifts from the vertical(More)
Decision making is one of the principal cognitive processes underlying goal-directed behaviour and thus there is justifiably strong interest in modeling it. However, many of these models have yet to be tested outside of the laboratory. At the same time, field work would benefit from the use of experimental methods developed in the laboratory to determine(More)
In motor and sensory areas of cortex, neuronal activity often depends on the location of a movement target or a sensory stimulus, with each neuron tuned to a single part of space called a preferred direction (when motor) or a receptive field (when sensory). As we previously reported, some neurons in the monkey prefrontal cortex are tuned to two parts of(More)