RT Journal Article SR Electronic T1 Nonuniform expression of habituation in the activity of distinct classes of neurons in the Aplysia abdominal ganglion JF The Journal of Neuroscience JO J. Neurosci. FD Society for Neuroscience SP 4072 OP 4081 DO 10.1523/JNEUROSCI.13-09-04072.1993 VO 13 IS 9 A1 CX Falk A1 JY Wu A1 LB Cohen A1 AC Tang YR 1993 UL http://www.jneurosci.org/content/13/9/4072.abstract AB Global observations of neuronal response in the Aplysia abdominal ganglion were made during habituation of the gill withdrawal reflex using voltage-sensitive dye recording. This technique makes it possible to measure the spike activity of 30–50% of the 1000 neurons present in the ganglion. Our experiments address the issue of how habituation is expressed in the activity of the population of neurons responding to siphon stimulation. Several classes of neurons exhibited characteristically distinct responses to the stimuli and to habituation training. One class of neurons (group I) responded to the onset and offset of the sensory stimulus although they are probably not primary sensory neurons. They habituate only partially when the behavioral reflex has already habituated completely. Two other classes (groups II and III) both have sustained responses to the touch, but habituate differently. Members of group III habituate completely while those in group II habituate only partially. Another class of neurons are inhibited by the stimulus (group IV). They become less inhibited after habituation. The response of both group I and group IV are new classes of response that have not been previously reported.