Neuroscience 2003 Abstract
| Presentation Number: | 767.3 |
|---|---|
| Abstract Title: | Subthreshold electrical stimulation of the superior colliculus (SC) modulates activity in the middle temporal visual area (MT). |
| Authors: |
Muller, J. R.*1
; Philiastides, M. G.2
; Newsome, W. T.1
1Howard Hughes Med. Inst.-NeuroBiol., Stanford Univ. Med. Ctr, Stanford, CA 2Electrical Engin., Stanford Univ. Med. Ctr, Stanford, CA |
| Primary Theme and Topics |
Sensory Systems - Vision -- Visual cortex: Attention and cognition |
| Session: |
767. Visual Cortex: Attentional Modulation & Decision Slide |
| Presentation Time: | Wednesday, November 12, 2003 8:30 AM-8:30 AM |
| Location: | Morial Convention Center - Room 262 |
| Keywords: | attention, visual cortex, awake monkey, microstimulation |
Attention is known to exert at least three effects on MT neurons (Treue & Maunsell, J Neurosci 1999). When two competing stimuli, one preferred and one non-preferred, are simultaneously presented within the receptive field (RF), attention to the preferred stimulus increases the response (effect 1), and attention to the nonpreferred stimulus decreases the response (effect 2A). In addition, attention to a remote stimulus outside the RF also decreases the response (effect 2B). Recent evidence suggests these attentional effects may be mediated via feedback projections to visual cortex from oculomotor structures, e.g. the SC (Gattass & Desimone, SFN 1992) and the frontal eye fields (Moore & Fallah, PNAS 2001; Moore & Armstrong, Nature 2003). To test this idea further, we examined the effects of subthreshold microstimulation of the SC on the visual responses of MT neurons. We stimulated the SC (50 msec trains, biphasic pulses, 333 Hz, current < eye-movement threshold) while recording MT activity from an awake, fixating monkey. The monkey passively viewed two stimuli simultaneously, one preferred and one nonpreferred. If microstimulation of the SC mimics the effects of attention on MT, we predicted that microstimulation would: (1) excite MT when the SC movement field (MF) enclosed the preferred stimulus, and both stimuli fell within the MT RF (attention effect 1 above), and (2) inhibit MT when the SC MF enclosed the null stimulus, whether the null stimulus fell within the MT RF (attention effect 2A above) or outside the MT RF (attention effect 2B above). In all cases the preferred stimulus fell within the MT RF. Both predictions were confirmed by the experimental data, consistent with the notion that SC plays a role in mediating the effects of visual attention.
Supported by HHMI and NEI (05603).
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2003 Neuroscience Meeting Planner. New Orleans, LA: Society for Neuroscience, 2003. Online.
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