Organization of synaptic inputs to paracerebral feeding command interneurons of Pleurobranchaea californica. II. Inhibitory inputs

Kovac, M. P.; Davis, William J.; Matera, Eugene M.; Croll, Roger P.

doi:10.1152/jn.1983.49.6.1539

Cited by 17 publications

(7 citation statements)

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“…We were surprised to find that inhibition of the feeding command cells by the swim neurons did not involve excitation of the I2 interneurons presynaptic to the I1s. The I2s were previously found to mediate phasic inhibition via the I1s to the PC P s and PSEs during cyclic generation of the feeding motor pattern (Kovac et al 1983b;London and Gillette 1984) and they are hyper-excited in food-avoidance conditioned animals responding to food stimuli to cause tonic inhibition of the command neurons, thereby suppressing feeding (London and Gillette 1986). Indeed, it was notable that the swim neurons caused potent inhibition of the I2 interneurons.…”

Section: Figmentioning

confidence: 98%

“…The PSEs were identified with similar criteria and by their ability to potently and polysynaptically excite the PC P s and their shared IPSPs with PC P s (Kovac et al 1983a). The I2s were identified by their polysynaptic inhibition of the PC P s and monosynaptic excitation of the metacerebral giant (MCG) neurons (Kovac et al 1983b;London and Gillette 1984). The I1 neurons were identified by their monosynaptic IPSPs in the PC P s (Kovac et al 1983b;London and Gillette 1984).…”

Section: Cell Identificationmentioning

confidence: 99%

“…The I2s were identified by their polysynaptic inhibition of the PC P s and monosynaptic excitation of the metacerebral giant (MCG) neurons (Kovac et al 1983b;London and Gillette 1984). The I1 neurons were identified by their monosynaptic IPSPs in the PC P s (Kovac et al 1983b;London and Gillette 1984). The elements of the swim CPG and other elements of the cerebropleural A cluster were identified as previously described for their electrophysiology and circuitry connections (Jing and Gillette 1999).…”

Section: Cell Identificationmentioning

confidence: 99%

“…Inhibition of the feeding command neurons by the swim neurons was mediated monosynaptically by the identified I1 interneurons. The I1 interneurons, monosynaptic inhibitors of the PC P s and PSEs (Kovac et al 1983b;London and Gillette 1984), were weakly excited by A1/A10 (n ϭ 3) and more strongly by A-ci1 (n ϭ 3). Discharge of A1/A10 caused moderate depolarization in I1s that occasionally induced spik-ing ( Fig.…”

Section: Figmentioning

confidence: 99%

“…6B). At least three I1-like cells inhibitory to the PC P s exist (Kovac et al 1983b) and their combined activity may provide most swim neuron-induced inhibition of feeding motor output. Synaptic connections were largely one-way from swim neurons to feeding neurons, consistent with the observation that swim neurons were not affected by feeding behavior in the whole animal nor by induced fictive feeding (cf.…”

Section: Figmentioning

confidence: 99%

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Escape Swim Network Interneurons Have Diverse Roles in Behavioral Switching and Putative Arousal inPleurobranchaea

Jing

Gillette

2000

Journal of Neurophysiology

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Escape swimming in the predatory sea slug Pleurobranchaea is a dominant behavior that overrides feeding, a behavioral switch caused by swim-induced inhibition of feeding command neurons. We have now found distinct roles for the different swim interneurons in acute suppression of feeding during the swim and in a longer-term stimulation of excitability in the feeding network. The identified pattern-generating swim neurons A1, A3, A10, and their follower interneuron A-ci1, suppress feeding motor output partly by excitation of the I1 feeding interneurons, which monosynaptically inhibit both the feeding command neurons, PC(P), PSE, and other major interneurons, the I2s. This mechanism exerts broad inhibition of the feeding network suitable to an escape response; broader than feeding suppression in learned and satiation-induced food avoidance and acting through a different presynaptic pathway. Four intrinsic neuromodulatory neurons of the swim network, the serotonergic As1-4, add little to direct suppression of feeding. Rather, they monosynaptically excite the serotonergic metacerebral giant (MCG) neurons of the feeding network, themselves intrinsic neuromodulators of feeding, as well as a cluster of adjacent serotonergic feeding neurons, with both fast and slow EPSPs. They also provide mild neuromodulatory excitation of the PC(P)/PSE feeding command neurons, and I1 and I2 feeding interneurons, which is masked by inhibition during the swim. As1-4 also excite the serotonergic pedal ganglion G neurons for creeping locomotion. These observations further delineate the nature of the putative serotonergic arousal system of gastropods and suggest a central coordinating role to As1-4.

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Section: Figmentioning

confidence: 98%