Pleural 9 Neuron
Pleural 9 is a neuron in Tritonia.
- The Pl 9 neuron type refers to one or two 70 micron cells located one or two cell layers below the dorsal surface of the pleural ganglion on each side of the brain.
- Pl 9 is situated close to the region where Pleural Nerve 1 enters the ganglion.
- Pl 9 is known to receive direct EPSPs from most or all of the ipsilateral S cells and conversely, it produces fast IPSPs onto the entire S cell population.
- Pl 9 can be identified in an isolated brain preparation by first impaling one or more S cells with a microelectrode and then probing the cells below with another microelectrode for a cell that receives monosynaptic EPSPs from the S cells and produces one-for-one fast IPSPs onto the S cells.
- Pleural 9 produces direct IPSPs onto the TR1, DRI and VSI-B interneurons.
- Pl 9 is known to play a role in mediating prepulse inhibition (PPI) in Tritonia. Intracellular stimulation of Pl 9 mimics the inhibitory effects of skin prepulses on the S cell activity. Pl 9 can block the swim motor program, partly due to the cell's ability to reduce the efficacy of the excitatory S cell synapse onto the interneurons that initiate the stereotypic Tritonia escape response.