The long-term goal of our research is to understand how the visual system decides where to look. The activity of multiple neurons as well as local field potentials will be monitored simultaneously in monkeys performing visual search tasks designed to dissociate visual processing from saccade preparation. The frontal eye field will be studied because it is situated anatomically to sample the outcome of visual processing to orient attention and produce motor commands to orient gaze. Neural signals in frontal eye field will be analyzed to evaluate specific hypotheses about how visual information is processed for target selection and how saccade preparation relates to target selection (Aim 1) that will guide and constrain stochastic network models of the visual-to-motor transformation necessary to perform visual search (Aim 2). Neural signals in supplementary eye field will be analyzed to determine its contribution to target selection and error monitoring during visual search (Aim 3). The results of these experiments will be interpreted in the framework of a new Stage Theory of Attention and Decision which postulates that visually guided eye movements in complex environments are produced by a sequence of stages -- one stage that encodes and selects visual stimuli for attention followed by another stage that prepares to initiate saccades. This framework offers the opportunity to distinguish the respective contributions of these two, distinct stages to disorders of visual attention, orientation and mobility.
Clinical science has progressed by carving nature at its joints. The Stage Theory of Attention and Decision postulates that visually guided action in complex environments arises from the operation of one stage that encodes and selects visual stimuli for attention followed by another stage that prepares and initiates saccades. This framework offers the opportunity to distinguish the respective contributions of these two, distinct states to disorders of visual attention, orientation and mobility.
|Schall, Jeffrey D; Palmeri, Thomas J; Logan, Gordon D (2017) Models of inhibitory control. Philos Trans R Soc Lond B Biol Sci 372:|
|Nelson, Matthew J; Murthy, Aditya; Schall, Jeffrey D (2016) Neural control of visual search by frontal eye field: chronometry of neural events and race model processes. J Neurophysiol 115:1954-69|
|Logan, Gordon D; Yamaguchi, Motonori; Schall, Jeffrey D et al. (2015) Inhibitory control in mind and brain 2.0: blocked-input models of saccadic countermanding. Psychol Rev 122:115-47|
|Neggers, S F W; Zandbelt, B B; Schall, M S et al. (2015) Comparative diffusion tractography of corticostriatal motor pathways reveals differences between humans and macaques. J Neurophysiol 113:2164-72|
|Heitz, Richard P; Schall, Jeffrey D (2013) Neural chronometry and coherency across speed-accuracy demands reveal lack of homomorphism between computational and neural mechanisms of evidence accumulation. Philos Trans R Soc Lond B Biol Sci 368:20130071|
|Purcell, Braden A; Schall, Jeffrey D; Woodman, Geoffrey F (2013) On the origin of event-related potentials indexing covert attentional selection during visual search: timing of selection by macaque frontal eye field and event-related potentials during pop-out search. J Neurophysiol 109:557-69|
|Schall, Jeffrey D (2013) Macrocircuits: decision networks. Curr Opin Neurobiol 23:269-74|
|Reinhart, Robert M G; Heitz, Richard P; Purcell, Braden A et al. (2012) Homologous mechanisms of visuospatial working memory maintenance in macaque and human: properties and sources. J Neurosci 32:7711-22|
|Heitz, Richard P; Schall, Jeffrey D (2012) Neural mechanisms of speed-accuracy tradeoff. Neuron 76:616-28|
|Purcell, Braden A; Weigand, Pauline K; Schall, Jeffrey D (2012) Supplementary eye field during visual search: salience, cognitive control, and performance monitoring. J Neurosci 32:10273-85|
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