Sustained potential shift responses and their relationship to the ecg response during arousal in the goldfish ( Carassius auratus)

Abstract

1. 1. Goldfish, when presented with a 10 sec light-on stimulus against a background of 2hr of sensory restriction, exhibited sustained potential shift (SPS) activity, of differing polarity, at each of four surface recording sites, on the medulla, cerebellum, optic tectum and telencephalon. 2. 2. Principle components analysis (PCA) indicated that SPS responses from each region comprised superimposed early and late waveforms. At the cerebellar, tectal and telencephalic surfaces, neuronal activity appeared to contribute strongly to the early (<2 sec) SPS waveform. 3. 3. While, in response to repeated stimulus presentations, habituation was apparent in the early SPS waveforms recorded from the medulla, cerebellum and telencephalon, an increase in negativity occurred in late SPS waveforms throughout the brain. 4. 4. The tectal SPS response was directly proportional to the telencephalic SPS response both in terms of average SPS amplitudes following the first presentation of the light-on stimulus and in terms of their increasing negativity in response to stimulus repetition. 5. 5. The increasing negativity of the telencephalic SPS was also associated with the habituation of the ECG response over repeated trials. 6. 6. Results are discussed with regard to a possible neuromodulatory role for glia.