Competing Neural Centers in a Pteropod Mollusc1

• Main Authors: Tigran P. Norekian, Richard, A. Satterlie
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Clione limacina
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.512.4595; http://icb.oxfordjournals.org/content/41/4/993.full.pdf

SYNOPSIS. Initiation of a particular behavior requires not only activation of the neural center directly involved in its control but also inhibition of the neural net-works controlling competing behaviors. In the pteropod mollusc, Clione limacina, many identified serotonergic neurons activate or modulate different elements of the swimming system resulting in the initiation or acceleration of the swimming behavior. Cerebral serotonergic neurons are described here, which produce excit-atory inputs to the swimming system as well as inhibitory inputs to the neural centers that control competing behaviors. Whole-body withdrawal behavior is in-compatible with swimming activity in Clione. The main characteristic of whole-body withdrawal is complete inhibition of swimming. Cerebral serotonergic neu-rons were found to produce a prominent inhibition of the pleural neurons that control whole-body withdrawal behavior. By inhibiting pleural withdrawal cells, serotonergic neurons eliminate its inhibitory influence on the swimming system and thus favor increased swimming speed. Serotonergic neurons also produce a prominent inhibition of the Pleural White Cell, which is presumably involved in reproductive or egg-laying behavior. Thus the serotonergic system directly acti-vates swimming system and, at the same time, alters a variety of other neural systems preventing simultaneous initiation of incompatible behaviors.