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A21 - Modulation of rhythmic activity by two distinct sensory receptor neurons
Central pattern generators (CPGs) are the neural circuits responsible for rhythmic behaviors.
A21 - Modulation of rhythmic activity by two distinct sensory receptor neurons
Mentor: Dawn Blitz, Ph.D.
Central pattern generators (CPGs) are the neural circuits responsible for rhythmic behaviors. Some activities may be spontaneously and perpetually active (e.g., breathing), while others are state dependent and must be initiated by extrinsic modulatory input (e.g., walking).
In the crab, the Stomatogastric Ganglion (STG) contains circuitry that underlies the continuous filtering rhythm (pyloric) and the state dependent chewing rhythm (gastric mill). This system is well defined and flexible.
GPR1 and GPR2 are two bilateral pairs of sensory receptor cells in the crab stomatogastric nervous system. They are both proprioceptors, meaning they respond to changes in muscle stretch, but they innervate different muscles in the stomach of the crab (GPR1: gm8b, GPR2: gm9a and cpv3a) (1, 2). They can be stimulated via the mgn and gpn (GPR1 and GPR2, respectively).
GPR neurons send axonal projections to the STG and the anterior ganglia as well (CoGs). Here, they excite MCN1 and CPN2, two modulatory projection neurons necessary and sufficient for gastric mill rhythm production (3, 4).
Furthermore, it has been observed that pyloric activity slows upon GPR stimulation, then increases in frequency and regularizes (5). It has not been determined if there is a difference between these these distinct receptor neurons on this rhythmic activity.