Email this pagePrincipal Investigator
Research Projects
Visually guided behaviors require processing, remembering, interpreting, and linking visual information to the appropriate motor action. Thus, the successful execution of visual tasks are likely to depend on the activity of neurons processing visual information as well as on the neurons capable of integrating this information with the demands of behavioral task. In our lab we are studying cortical circuitry underlying the ability to discriminate and remember visual motion. Current projects in the lab are aimed at identifying and characterizing the components of this circuitry by recording from neurons in motion processing area MT and from neurons in prefrontal and parietal cortical areas likely to play an executive and integrative functions leading to perceptual decisions.
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Representation of Visual Motion in the Prefrontal Cortex
This project is focused on characterizing the way neurons in prefrontal cortex represent visual motion used in tasks requiring discriminating and remembering this information. We are recording from the region in prefrontal cortex that is reciprocally interconnected with neurons in motion processing area MT while the monkeys discriminate and remember either speed or direction of visual motion. This work has revealed that the representation of behaviorally relevant stimulus motion resembles that observed in motion processing cortical area MT, suggesting that these responses represent bottom-up signals. More info...
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Memory-Related Signals In the Prefrontal Cortex and in area MT
In this project we are examining whether during the memory delay PFC neurons carry information about the remembered sample. Our results show that individual neurons do not show sustained activity reflecting remembered direction or speed (see transient significant differences between preferred and non-preferred activity in A and B). While individual neurons do not appear to carry consistent stimulus related signals, this information appears at different times in different neurons suggesting the distributed nature of these signals. More info...
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Contribution of top-down projections from the PFC to motion processing in area MT
Neurons in the prearcuate region of prefrontal cortex (PFC) receive inputs from the motion-processing area MT and during motion discrimination exhibit direction selectivity (DS) suggestive of their MT origins. This region also sends direct top-down projections to MT and the nature of activity in both areas recorded during the same motion task indicates strong functional links between them. More info...
Recent Publications
- (2009). Flexibility of sensory representations in prefrontal cortex depends on cell type. Neuron. In press.
- (2006 Nov 09). Directional signals in the prefrontal cortex and in area MT during a working memory for visual motion task. J Neurosci. 26, 11726-42.
- (2005 Nov 18). Area MT neurons respond to visual motion distant from their receptive fields. J Neurophysiol. 94, 4156-67.
