Neuroscience 2002 Abstract
| Presentation Number: | 159.12 |
|---|---|
| Abstract Title: | Modulation of V1 responses by an internal model of stimulus location. |
| Authors: |
Sharma, J.*1
; Dragoi, V.1
; Sur, M.1
1Dept Brain & Cognitive Sci, MIT, Cambridge, MA |
| Primary Theme and Topics |
Sensory Systems - Vision -- Striate visual cortex: Orientation, form and color |
| Secondary Theme and Topics | Cognition and Behavior<br />- Animal Cognition and Behavior<br />-- Attention |
| Session: |
159. Visual cortex: connectivity and organization Poster |
| Presentation Time: | Sunday, November 3, 2002 4:00 PM-5:00 PM |
| Location: | Hall A2-B3 F-64 |
| Keywords: | OCULOMOTOR, VISUAL CORTEX, MACAQUE, ORIENTATION |
Neurons in primary visual cortex (V1) are modulated by direction of gaze in monkeys trained to fixate at different locations in space (Sharma et al, SFN 1999). We have now examined the progressive dependence of responses on the sequential appearance of a fixation locus. Two monkeys were trained to fixate at one of three separate locations, while single unit recordings were made from V1 neurons in response to sinusoidal gratings presented in their receptive fields. In Condition 1, the spot appeared repeatedly at the same location for a number of trials. This resulted in progressively shorter latencies to achieve fixation as the trials progressed. No such systematic change in fixation latency was observed in Condition 2, where the fixation spot varied randomly from trial to trial. In a subset of neurons, there was a significant modulation in spike responses to gratings of the preferred orientation presented at a particular location in the sequential condition, compared to responses to gratings of the same orientation presented at the same location but in the random condition. Importantly, in the sequential condition, the magnitude of responses increased or decreased with each successive stimulus presentation, particularly in the early part of the sequence. The change in neuron responses paralleled the progressive shortening of fixation latencies in this condition. These data suggest that visuomotor behavior is guided by progressive acquisition of an internal model of stimulus location, and that cortical responses as early as V1 can be modulated by such internal constructs.
Supported by NIH grant EY07023 and McDonnell_Pew fellowship(VD).
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2002 Neuroscience Meeting Planner. Orlando, FL: Society for Neuroscience, 2002. Online.
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