| Abstract No.: | B-D2159 |
| Country: | Canada |
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| Title: | DORSAL PREMOTOR ACTIVITY DURING INCREASINGLY COMPLEX VISUOMOTOR TASKS. |
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| Authors/Affiliations: | 1 Bogdan Neagu*; 1 Patricia Sayegh; 1 Lauren Sergio;
1 York University, Toronto, ON, Canada
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| Content: | Objectives: Examine the contribution of the dorsal premotor cortex (PMd) under increasingly dissociated conditions using multiunit cell recording in awake behaving primates.
Materials and methods: We examined eye- and movement-related single cell activity in primary motor (MI) and premotor (PM) cortex in a standard and non-standard situation (Figure 1). Monkeys (macaca mulatta) were trained to displace a cursor from a central to a cued peripheral target (cue period 2000±500 ms) under direct (“standard”) and dissociated (“non-standard”) visuomotor conditions, and to hold the cursor at the target (1000 ms) for a liquid reward.
In the direct condition, the animal moves its finger along a customized touch screen placed at waist height in a horizontal plane so that the cursor is under its finger.
In the dissociated condition, the cursor and targets are displayed on a monitor positioned in a frontal plane 40 cm in front of the animal. The animal must move along the horizontal touch screen to displace the vertically displayed cursor.
There are eight peripheral targets equally spaced every 45o on a circle 80 mm in radius. The start target is in the middle of the circle, aligned with the animal’s midline approximately level to the zyphoid process. The animals were extensively trained on the task with the spatial plane change. The addition of off-axis targets will assist us in assessing the directionality of cell tuning under the different task conditions. The animals were trained to fixate on the central target throughout the cue period, then move its eyes to the cued peripheral target and hold them there throughout the target hold period (note that in the rotation conditions this will lead to a dissociation of the eye and limb motion directions).
The cylinder was implanted just anterior to the central sulcus in the hemisphere opposite to the trained arm in order to record from rostral MI and PMd cortices (both rostral and caudal subdivisions).
Results: Dissociating the guiding visual information from the required motor output in a reaching task is associated with directionality, amplitude, and dynamic range changes in PMd. These data are in keeping with our human imaging research using this task.
Conclusions: These data suggest that this area is prominently involved in visuomotor transformations for increasingly complex reaches.
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