User:Eugene M. Izhikevich/Proposed/Gastropod neuroscience

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Dr. Paul S. Katz, Georgia State University, Atlanta, GA, USA

1 Overview
2 Organization of the nervous system
3 Important findings
4 Model Systems:
5 Areas of Research
6 Related Links

Overview

Gastropod molluscs are a very diverse group of animals that have served as important model systems in neuroscience since the early 1960s. They were attractive for neuroscience research because their nervous systems are relatively small (about 10,000 neurons in the CNS), many neurons are individually identifiable, and the behaviors produced by the nervous system are quite simple. Some of the identified neurons have giant somata (up to 1mm in diameter) making them the largest neuron cell bodies in the animal kingdom. For example, the R2 neuron in the Aplysia abdominal ganglion may have largest soma volume of any somatic cell of any organism. This allowed some of the earliest descriptions of biochemical composition, neurotransmitter actions, and neuronal functions.

Organization of the nervous system

Gastropod adults have a central nervous system that consists of ganglia or groups of neurons. These ganglia form a ring around the esophagus. There are species-differences in the exact number of ganglia and the names for each ganglion. The common ganglia include the cerebral, buccal, pedal, and pleural. In addition there are visceral, parietal, genital, tentacular, and abdominal ganglia in various species. It should be noted that the nervous system, like the body of gastropods, is not segmented.

Important findings

Notable research includes Nobel Prize winning work of Eric Kandel [1] on learning and memory using the gill and siphon withdrawal response of Aplysia. Learning and memory, decision making, locomotion, and feeding have all been studied in various Gastropod species.

Figure 1: Model Gastropod Neuroscience Species. From top: Helisoma trivolvis, Clione limacina, Hermissenda crassicornis, Tritonia diomedea, Lymnaea stagnalis, Pleurobranchaea californica, Aplysia californica