Novel peripheral motor neurons in the posterior tentacles of the snail responsible for local tentacle movements.

Three flexor muscles of the posterior tentacles of the snail Helix pomatia have recently been described. Here, we identify their local motor neurons by following the retrograde transport of neurobiotin injected into these muscles. The mostly unipolar motor neurons (15-35 µm) are confined to the tentacle digits and send motor axons to the M2 and M3 muscles.

Neuronal background of positioning of the posterior tentacles in the snail Helix pomatia.

The location of cerebral neurons innervating the three recently described flexor muscles involved in the orientation of the posterior tentacles was investigated by applying parallel retrograde Co- and Ni-lysine tracing via the olfactory and the peritentacular nerves. Their innervation patterns in the flexor muscles were studied by applying anterograde neurobiotin tracings via these nerves. The labeled neurons are clustered in eight groups in the cerebral ganglion.

Novel triplet of flexor muscles in the posterior tentacles of the snail, Helix pomatia.

The anatomy of three novel flexor muscles in the posterior tentacles of Helix pomatia is described. The muscles originate from the ventral side of the sensory pad and are anchored at different sites in the base of the tentacle stem. The muscles span the tentacle and always take the length of the stem which depends on the rate of tentacle protrusion indicating that the muscles are both contractile and extremely stretchable.

Lateralized memory storage and crossed inhibition during odor processing by Limax.

After odor conditioning intact Limax maximus and injecting LY into their haemocoel, labeled groups of neurons are found in either the right or left procerebral lobe but never in both procerebral lobes. This suggests that a competitive interaction occurs between right and left odor processing pathways of which the procerebral lobe is a part. We use the nerve discharge in the external peritentacular nerve evoked by applying a puff of conditioned odor to the nose to document crossed inhibition between left and right odor processing pathways.

Olfactory oscillations augment odor discrimination not odor identification by Limax CNS.

There is great interest in the function of synchronous oscillations in olfactory centers, as documented in a wide variety of species. In Limax procerebral (PC) lobe, local field potential oscillations are ongoing and altered by odor stimulation. Recordings from external peritentacular nerves (ePTNs) reveal a neural correlate of tentacle positioning, a response signifying recognition of a conditioned odor.