Neuroscience 2001 Abstract
| Presentation Number: | 306.23 |
|---|---|
| Abstract Title: | Premotor interneuronal output of leech heartbeat pattern generator. |
| Authors: |
Morris, L. G.*1
; Calabrese, R. L.1
1Dept Biol, Emory Univ, Atlanta, GA |
| Primary Theme and Topics |
Motor Systems - Pattern Generation |
| Secondary Theme and Topics | Motor Systems<br />- Invertebrate Motor and Sensory Systems |
| Session: |
306. Pattern generation: circuitry and behavior Poster |
| Presentation Time: | Monday, November 12, 2001 10:00 AM-11:00 AM |
| Location: | Exhibit Hall SS-65 |
| Keywords: | phase relationships, central pattern generator, medicinal leech, motor pattern |
Wenning et al. (SFN Abstr 164.4, 2000) described the phase relations of the motor neurons driving constrictions of the two hearts in leech. One heart is driven to constrict synchronously along its length, while the other is driven to constrict in a peristaltic fashion. The hearts alternate between these two coordination modes every 20-40 cycles. The activity of the motor neurons is sculpted by the activity of four identified and one unidentified pair(s) of heart (HN) interneurons. To understand how the heartbeat network generates these patterns in the motor neurons, we need to describe fully the output of all the premotor heart interneurons. We used chains of ganglia, from the head-brain to ganglion 7, which contain the entire heartbeat network. The HN cells were recorded extracellularly with suction electrodes applied to the soma. The HN(4) cell was used as a reference cell, and mainly ipsilateral heart interneurons were recorded. We found that during both the synchronous and the peristaltic modes, the phase relationship between the ipsilateral HN(4) and HN(3) cells was ~0%. In the synchronous mode, the ipsilateral HN(6) and HN(7) cells lag behind the reference HN(4 )cell by ~4% and ~5% of the cycle respectively. Thus the ipsilateral HN(6) and HN(7) cells are in phase with one another and relatively in phase with the reference HN(4) cell. The HN(6) and HN(7) cells in peristaltic mode lead the ipsilateral HN(4) cell by ~13% and ~6%, respectively. We plan to further characterize these interneuronal phase relationships and correlate interneuronal output with the described motor neuron behavior.
Supported by NIH NS24702 and 1K12GM00680
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2001 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2001. Online.
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