Biology subjects

Salinas, E.

Publications and source records attributed to Salinas, E..

4 recordsLinked to original sources

bioRxiv2018

Urgency reveals an attentional vortex during antisaccade performance

In the antisaccade task, which is considered a sensitive assay of cognitive function, a salient visual cue appears and the participant must look away from it. This requires sensory, motor-planning, and cognitive neural mechanisms. But what are the unique contributions of these mechanisms to performance, and when exactly are they engaged? By introducing an urgency requirement into the antisaccade task, we track the evolution of the choice process with millisecond resolution and find a singular, nonlinear dependence on cue exposure: when viewed briefly ([~]100-140 ms), the cue captures attention so powerfully that looking at it (erroneously) is virtually inevitable, but as the cue viewing time increases, the probability of success quickly rises and saturates. The psychophysical and modeling results reveal concerted interactions between reflexive and voluntary cognitive mechanisms that (1) unfold extremely rapidly, (2) are qualitatively consistent across participants, and (3) are nevertheless quantitatively distinctive of each individuals perceptual capacities

neuroscience↗

bioRxiv2018

Pardon the interruption: saccadic inhibition enables the rapid deployment of alternate oculomotor plans

Diverse psychophysical and neurophysiological results show that oculomotor networks are continuously active, such that plans for making the next eye movement are always ongoing. So, when new visual information arrives unexpectedly, how are those plans affected? At what point can the new information start guiding an eye movement, and how? Here, based on modeling and simulation results, we make two observations that are relevant to these questions. First, we note that many experiments, including those investigating the phenomenon known as \"saccadic inhibition,\" are consistent with the idea that sudden-onset stimuli briefly interrupt the gradual rise in neural activity associated with the preparation of an impending saccade. And second, we show that this stimulus-driven interruption is functionally adaptive, but only if perception is fast. In that case, putting on hold an ongoing saccade plan toward location A allows the oculomotor system to initiate a concurrent, alternative plan toward location B (where a stimulus just appeared), deliberate (briefly) on the priority of each target, and determine which plan should continue. Based on physiological data, we estimate that the actual advantage of this strategy, relative to one in which any plan once initiated must be completed, is of several tens of milliseconds.

neuroscience↗

bioRxiv2017

Motor selection dynamics in FEF explain the reaction time variance of saccades to single targets

In studies of voluntary movement, a most elemental quantity is the reaction time (RT) between the onset of a visual stimulus and a saccade toward it. However, this RT demonstrates extremely high variability, which in spite of extensive research remains unexplained. It is well established that, when a visual target appears, oculomotor activity gradually builds up until a critical level is reached, at which point a saccade is triggered. Here, we further characterize the dynamics of this rise-to-threshold process based on computational work and single-neuron recordings from the frontal eye field (FEF) of behaving monkeys. We find that the baseline activity, build-up rate, and threshold level show strong, nonlinear co-dependencies that explain the distinct RT distributions observed experimentally. The results indicate that intrinsic randomness contributes little to saccade variance, which results mainly from an intricate, fundamentally deterministic mechanism of motor conflict resolution that has subtle yet highly characteristic manifestations.

neuroscience↗

bioRxiv2017

FireCloud, a scalable cloud-based platform for collaborative genome analysis: Strategies for reducing and controlling costs

FireCloud, one of three NCI Cloud Pilots, is a collaborative genome analysis platform built on a cloud computing infrastructure. FireCloud aims to solve the many challenges presented by the increasingly large data sets and computing requirements employed in cancer research. However, cost uncertainty associated with cloud computings pay-as-you-go model is proving to be a barrier to adoption of cloud computing. In this paper we present guidelines for optimizing workflows to minimize cost and reduce latency. Our guidelines include: (i) dynamic disk sizing to efficiently utilize virtual disks; (ii) tuned provisioning of virtual machines (VMs) using a performance monitoring tool; (iii) taking advantage of steep price discounts of preemptible VMs; and (iv) utilizing the optimal parallelization of a tasks workload.

bioinformatics↗