André B Valdez

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OBJECTIVE Clinicians often use depth-electrode recordings to localize human epileptogenic foci. To advance the diagnostic value of these recordings, we applied logistic regression models to single-neuron recordings from depth-electrode microwires to predict seizure onset zones (SOZs). APPROACH We collected data from 17 epilepsy patients at the Barrow(More)
The present study used 1/f noise to examine how spatial, physical, and timing constraints affect planning and control processes in aiming. Participants moved objects of different masses to different distances at preferred speed (Experiment 1) and as quickly as possible (Experiment 2). Power spectral density, standardized dispersion, rescaled range, and an(More)
The present study tested for 1/f noise to examine how timing and target constraints affect cognitive processes in aiming. Participants pointed to targets of varied height and width at preferred speed (Experiment 1) and as quickly as possible (Experiment 2). Results show greater intensity of 1/f noise, or long-range correlation in variability, at preferred(More)
The authors tested for 1/f noise in motor imagery (MI). Participants pointed and imagined pointing to a single target (Experiment 1), to targets of varied size (Experiment 2), and switched between pointing and grasping (Experiment 3). Experiment 1 showed comparable patterns of serial correlation in actual and imagined movement. Experiment 2 suggested(More)
In four experiments, a multidimensional signal detection analysis was used to determine the influence of length, diameter, and mass on haptically perceived heaviness with and without vision. This analysis allowed us to test for sensory and perceptual interactions between mass and size. As in previous research, sensory interactions were apparent in all four(More)
It remains unclear how single neurons in the human brain represent whole-object visual stimuli. While recordings in both human and nonhuman primates have shown distributed representations of objects (many neurons encoding multiple objects), recordings of single neurons in the human medial temporal lobe, taken as subjects' discriminated objects during(More)
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