Two types of reorganization in multifunctional neural networks of Helix pomatia L.

The visceral functions of the snail Helix pomatia: Were shown to be regulated by overlapping and variable neural networks consisting of multifunctional neurons distributed in various parts of the CNS. The results showed that: 1. reorganization of the neural networks is accompanied by alterations in the firing mode of the neurons; 2. most identified neurons change their firing pattern from a tonic to a phasic type depending on the combination of signal molecules present or on the activation of their synaptic inputs; 3.the appearance of a slow membrane oscillation or burst firing was shown to make the neurons insensitive to input activation originating from visceral organs; 4. inputs from various visceral organs converge on a large number of neurons in the temporarily formed neural networks. In the vicinity of the multifunctional neurons a whole group of neurons can store various forms of transitory patterns; 5. both voltage (IK and ICa) and ligand (Ach and GABA) activated currents can be targets of signal molecules in altering the firing mode of the neurons. This will result in the reconfiguration of circuits; 6. because of to the large number of neurons involved in the regulation of visceral organs, the overlapping and reorganizing circuit can be interpreted more efficiently as a distributed network also including elements of dedicated regulatory circuits.