Papers by Michael Bendiksby
Journal of Vision, Mar 24, 2010
Abstract Distinct neural systems process motivation and attention. At the behavioral level, howev... more Abstract Distinct neural systems process motivation and attention. At the behavioral level, however, both attention and motivation influence the reaction times of monkeys orienting to visual targets. Similarly, both attention and motivation enhance neuronal responses to visual targets in several visual and oculomotor brain areas in monkeys. Since both attention and motivation are conditioned by fluid rewards in such studies, the extent to which modulations in neuronal activity reflect attention or motivation remains unclear. Distinguishing these ...
Journal of Vision, Mar 17, 2010
Abstract Both saccade reaction times and orienting choices are sensitive to the value of rewards ... more Abstract Both saccade reaction times and orienting choices are sensitive to the value of rewards associated with visual targets. Similarly, increasing the reward value of orienting to a visual target enhances neuronal responses in several visual-oculomotor brain areas. One question these observations raise is to what extent reward modulation of neuronal activity in such areas reflects nonspecific changes in motivation or arousal rather than the relative value of a particular target or eye movement. Here we show that increasing the size of ...
Journal of Vision, Aug 1, 2004
Abstract Distinct neural circuits process motivation and attention. Deficits in attention observe... more Abstract Distinct neural circuits process motivation and attention. Deficits in attention observed in neurological disorders such as ADD/ADHD are associated with disruptions in motivational signaling, suggesting functional interaction between these neural systems. To investigate the influence of motivation on attention, humans and rhesus monkeys were trained to perform a peripheral attention task at psychophysical threshold. Subjects were required to indicate the brief flicker of one of two peripheral cues by making a manual ( ...
Journal of Vision, Mar 16, 2010
Abstract Prior studies have demonstrated that neuronal activity in the lateral intraparietal area... more Abstract Prior studies have demonstrated that neuronal activity in the lateral intraparietal area (LIP) is correlated with the probability or magnitude of reward that can be expected upon execution of visually-guided saccades as well as by the deployment of visual attention. Reward-related modulations in neuronal activity may thus reflect differential deployment of attention to visual stimuli based on reward size or certainty. The goal of this study was to distinguish motivational from attentional representations in LIP. To accomplish this, rhesus ...
Neuropsychologia, Jan 1, 2006
Saccade reaction times decrease and the frequency of target choices increases with the size of re... more Saccade reaction times decrease and the frequency of target choices increases with the size of rewards delivered for orienting to a particular visual target. Similarly, increasing rewards for orienting to a visual target enhances neuronal responses in the macaque lateral intraparietal area (LIP), as well as other brain areas. These observations raise several questions. First, are reward-related modulations in neuronal activity in LIP, as well as other areas, spatially specific or more global in nature? Second, to what extent does reward modulation of neuronal activity in area LIP reflect changes in visual rather than motor processing? And third, to what degree are reward-related modulations in LIP activity independent of performance-related modulations thought to reflect changes in attention? Here we show that increasing the size of fluid rewards in blocks reduced saccade reaction times and improved performance in monkeys performing a peripherally-cued saccade task. LIP neurons responded to visual cues spatially segregated from the saccade target, and for many neurons visual responses were systematically modulated by expected reward size. Neuronal responses also were positively correlated with reaction times independent of reward size, consistent with re-orienting of attention to the saccade target. These observations suggest that motivation and attention independently contribute to the strength of sustained visual responses in LIP. Our data thus implicate LIP in the integration of the sensory, motor, and motivational variables that guide orienting.
Journal of Vision, Jan 1, 2004
Abstract Distinct neural circuits process motivation and attention. Deficits in attention observe... more Abstract Distinct neural circuits process motivation and attention. Deficits in attention observed in neurological disorders such as ADD/ADHD are associated with disruptions in motivational signaling, suggesting functional interaction between these neural systems. To investigate the influence of motivation on attention, humans and rhesus monkeys were trained to perform a peripheral attention task at psychophysical threshold. Subjects were required to indicate the brief flicker of one of two peripheral cues by making a manual ( ...
Journal of Vision, Jan 1, 2003
Abstract Prior studies have demonstrated that neuronal activity in the lateral intraparietal area... more Abstract Prior studies have demonstrated that neuronal activity in the lateral intraparietal area (LIP) is correlated with the probability or magnitude of reward that can be expected upon execution of visually-guided saccades as well as by the deployment of visual attention. Reward-related modulations in neuronal activity may thus reflect differential deployment of attention to visual stimuli based on reward size or certainty. The goal of this study was to distinguish motivational from attentional representations in LIP. To accomplish this, rhesus ...
Journal of Vision, Jan 1, 2006
Abstract Distinct neural systems process motivation and attention. At the behavioral level, howev... more Abstract Distinct neural systems process motivation and attention. At the behavioral level, however, both attention and motivation influence the reaction times of monkeys orienting to visual targets. Similarly, both attention and motivation enhance neuronal responses to visual targets in several visual and oculomotor brain areas in monkeys. Since both attention and motivation are conditioned by fluid rewards in such studies, the extent to which modulations in neuronal activity reflect attention or motivation remains unclear. Distinguishing these ...
Journal of Vision, Jan 1, 2005
Abstract Both saccade reaction times and orienting choices are sensitive to the value of rewards ... more Abstract Both saccade reaction times and orienting choices are sensitive to the value of rewards associated with visual targets. Similarly, increasing the reward value of orienting to a visual target enhances neuronal responses in several visual-oculomotor brain areas. One question these observations raise is to what extent reward modulation of neuronal activity in such areas reflects nonspecific changes in motivation or arousal rather than the relative value of a particular target or eye movement. Here we show that increasing the size of ...
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Papers by Michael Bendiksby