June 2004
Volume 4, Issue 8
Free
Vision Sciences Society Annual Meeting Abstract  |   August 2004
Preparatory gap and memory-delay fMRI activation in the human frontal eye field is higher for pointing as compared to saccade trials
Author Affiliations
  • Jason D. Connolly
    University of Western Ontario
  • Melvyn A. Goodale
    University of Western Ontario
  • Jon S. Cant
    University of Western Ontario
  • Douglas P. Munoz
    Queen's University, Canada
Journal of Vision August 2004, Vol.4, 112. doi:10.1167/4.8.112
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      Jason D. Connolly, Melvyn A. Goodale, Jon S. Cant, Douglas P. Munoz; Preparatory gap and memory-delay fMRI activation in the human frontal eye field is higher for pointing as compared to saccade trials. Journal of Vision 2004;4(8):112. doi: 10.1167/4.8.112.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

We have previously reported data showing that the frontal eye fields (FEF) but not the intraparietal sulcus (IPS) codes preparatory set in the human. In the present study, we further manipulated preparatory set by instructing subjects to move different effectors, either the eyes or the hand. Event-related fMRI was used to examine the activation during a preparatory gap period during which no visual stimulus was presented and no movements were made. The subjects (N = 8) simply anticipated the appearance of a flashed peripheral target. Each trial included the presentation of a green (saccade) or red (point) central instructional cue (3s). On pointing trials, subjects rotated the pointing index finger about the wrist while maintaining central fixation. The instructional cue was followed by a 0-s (no gap), 2-s (gap) or 4-s (gap) period of darkness, followed by the peripheral target (100 ms). A memory-delay condition was also run in which the target that was presented for 100 ms at the beginning of trial was then held in mind during a 0-s, 2-s, or 4-s delay period. Comparison of activation maps revealed substantial anatomical overlap in the locus of activation of the FEF, supplementary eye fields (SEF/SMA), and IPS areas across pointing and saccades trials. Surprisingly, both gap and memory-delay FEF activation was higher for pointing than saccades. There was, however, a ventral to dorsal gradient across these areas, with progressively more pointing activation in dorsal regions. In fact, ventral FEF showed less gap and memory-delay activity altogether and no differences across the two effector types. Consistent with our previous work, the SEF showed preparatory gap activity. In contrast to the FEF, SEF activity was higher on saccade as compared to pointing trials. The IPS did not exhibit gap activity but showed memory-delay activity. These data provide support for the idea that the frontal cortex plays a central role in preparing an organism for action.

Connolly, J. D., Goodale, M. A., Cant, J. S., Munoz, D. P.(2004). Preparatory gap and memory-delay fMRI activation in the human frontal eye field is higher for pointing as compared to saccade trials [Abstract]. Journal of Vision, 4( 8): 112, 112a, http://journalofvision.org/4/8/112/, doi:10.1167/4.8.112. [CrossRef]
Footnotes
 Supported by CIHR and CRC.
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