Postganglionic Responses Upon Tactile Stimulation in Lymnaea Stagnalis (L)

Postganglionic responses upon tactile stimulation of the lip of Lymnaea stagnalis were recorded in the right internal pallial nerve. These responses appeared to consist of two types: smaller fibre activity and a few larger fibre impulses. The receptive field of the larger fibres included skin areas surrounding the lip. They habituated very quickly whereas dishabituation took several minutes. The possibility is discussed that the larger fibres belong to the "giant fibre" type and command withdrawal reactions.