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Monkeys made saccades to one of two peripheral targets based on the brightness of a central stimulus. Task difficulty was manipulated by varying the ratio of stimulus black-and-white pixels. Correct response probability for two monkeys varied directly with difficulty. Deep layer SC neurons exhibited robust presaccadic activity the magnitude of which was(More)
Extracellular recordings were made simultaneously in the frontal eye field and superior colliculus in awake, behaving rhesus monkeys. Frontal eye field microstimulation was used to orthodromically activate the superior colliculus both to locate the depth of the strongest frontal eye field input to the superior colliculus and to identify superior colliculus(More)
We examined the activity of neurons in the deep layers of the superior colliculus of awake behaving rhesus monkeys during the performance of standard oculomotor tasks as well as during self-guided eye movements made while viewing natural images. The standard tasks were used to characterize the activity of neurons based on established criteria. The natural(More)
Generating sequences of multiple saccadic eye movements allows us to search our environment quickly and efficiently. Although the frontal eye field cortex (FEF) has been linked to target selection and making saccades, little is known about its role in the control and performance of the sequences of saccades made during self-guided visual search. We recorded(More)
While some decision-making processes often result in the generation of an observable action, for example eye or limb movements, others may prevent actions and occur without an overt behavioral response. To understand how these decisions are made, one must look directly at their neuronal substrates. We trained two monkeys on a go/no-go task which requires a(More)
The frontal eye field (FEF) plays a central role in saccade selection and execution. Using artificial stimuli, many studies have shown that the activity of neurons in the FEF is affected by both visually salient stimuli in a neuron's receptive field and upcoming saccades in a certain direction. However, the extent to which visual and motor information is(More)
Simultaneous recordings were collected from between two and four buildup neurons from the left and right superior colliculi in rhesus monkeys in a simple two-choice brightness discrimination task. The monkeys were required to move their eyes to one of two response targets to indicate their decision. Neurons were identified whose receptive fields were(More)
Brain-machine interfaces (BMIs) have the potential to improve the quality of life for individuals with disabilities. We engaged in the development of neural mind-reading techniques for cognitive BMIs to provide a readout of decision processes. We trained 2 monkeys on go/no-go tasks, and monitored the activity of groups of neurons in their mid-brain superior(More)
When we search for visual objects, the features of those objects bias our attention across the visual landscape (feature-based attention). The brain uses these top-down cues to select eye movement targets (spatial selection). The frontal eye field (FEF) is a prefrontal brain region implicated in selecting eye movements and is thought to reflect(More)
When a saccade is expected to result in a reward, both neural activity in oculomotor areas and the saccade itself (e.g., its vigor and latency) are altered (compared with when no reward is expected). As such, it is unclear whether the correlations of neural activity with reward indicate a representation of reward beyond a movement representation; the(More)