Reactions of central neurons to peripheral thermal stimuli in the snail Helix pomatia L

In Helix pomatia L. recordings have been made of 91 single neurons from the cerebral ganglia during peripheral thermal stimulation of the lip region. Temperatures ranged between 12 and 32 degrees C. Different reactions to thermal stimulation could be observed: hyperpolarisation (n=43), depolarisation (n=9), increasing frequency of action potentials (n=10), decreasing frequency of action potentials (n=3). A number of cells did not show any changes in neuronal activity (n=26). The assumption that distinct cell clusters are responsible for the processing of thermal stimuli had to be rejected since cells responding to peripheral thermal stimulation were found in all parts of the ganglia.