The shadow-induced withdrawal response, dermal photoreceptors, and their input to the higher-order interneuron RPeD11 in the pond snailLymnaea stagnalis

Abstract

SUMMARYThe shadow-induced withdrawal response in Lymnaea stagnalis is mediated by dermal photoreceptors located on the foot, mantle cavity, and skin around the pneumostome area. Here, we determined whether we could obtain a neural correlate of the withdrawal response elicited by a shadow in a higher-order central neuron that mediates withdrawal behavior. We measured the electrophysiological properties of the higher-order interneuron Right Pedal Dorsal 11 (RPeD11), which has a major role in Lymnaea withdrawal behavior. In semi-intact preparations comprising the circumesophageal ganglia, the mantle cavity and the pneumostome, but not the foot and eyes, a light-on stimulus elicited a small short-lasting hyperpolarization and a light-off stimulus elicited a depolarization of RPeD11. We also determined that dermal photoreceptors make a monosynaptic contact with RPeD11. The dermal photoreceptor afferents course to the circumesophageal ganglia via the anal and genital nerves to the visceral ganglion, and/or via the right internal and external parietal nerves to the parietal ganglion. Finally, in addition to responding to photic stimuli, RPeD11 responds to both mechanical and chemical stimuli delivered to the pneumostome.

Behavioral Responses of the SnailLymnaea acuminatatowards Photo and Chemo Attractants: A New Step in Control Program of Fasciolosis

“…Both food-finding and consummatory movements are modulated in response to different foods, in response to change in internal state, or as a result of previous learning as suggested by Sunada et al [28]. The tentacles and lip nervous contain the axon primary chemosensory neurons which sense food in environments [29].…”

Juveniles ofLymnaeasmart snails do not perseverate and have the capacity to form LTM

“…Both McComb et al (2005) and Sunada et al (2010b) thought that juvenile Lymnaea perseverated because the memory for the task was occluded as a result of a lack of specific inhibitory circuits. This appears to be a recurring theme in the literature across species.…”

“…It is unclear how this occurs. It is known that exposure to CE in juvenile Dutch snails counteracts the increased excitability of RPeD1 and forces the network into a more 'adult-like' configuration, thereby allowing operant conditioning to result in LTM formation (Sunada et al, 2010b;Forest et al, 2016). CE's effects in snails are blocked by DNA methylation blockers (Lukowiak et al, 2014) and the longlasting effects (at least 4 weeks) of training juvenile snails in CE are also dependent on DNA methylation (Forest et al, 2016).…”

Light avoidance by non-ocular photosensing system in the terrestrial slugLimax valentianus

“…As we recently found that five mRNA species belonging to the opsin family genes exist in L. valentianus (Matsuo et al, 2019), the expression of these mRNAs in the brain, the ST (including the eyes), the PS and the dorsal surface of the body (body wall, BW) was examined. We chose the PS because its light detection capability has been suggested in the pond snail Lymnaea stagnalis (Sunada et al, 2010). We detected all five mRNA species in the ST and three mRNA species in the brain (Opn5A, retinochrome and xenopsin; Fig.…”