The effects of response-independent mirror presentation schedules on the swimming behaviour of Betta splendens were studied in two experiments. In experiment 1, four fish received alternating baseline (no mirror) and fixed-time (FT) 2-min or variable-time (VT) 2-min mirror presentation conditions. Two fish consistently showed increased rates of mirror-side lap-swimming (MSLS; a back-and-forth swimming pattern) and decreased distance from the mirror during the inter-stimulus intervals (ISIs) of FT and VT sessions, and during baseline sessions that followed FT and VT phases. Data from one fish indicated that a VT schedule might increase both proximity to the mirror and MSLS rates that have decreased on FT. Therefore, in experiment 2 three fish from experiment 1 received alternating FT and VT conditions. Proximity to the mirror and MSLS rates increased during VT phases relative to FT phases in two fish, though effects were small and did not occur across all alternations. Additional findings were that MSLS during ISIs tended to increase within FT phases, that MSLS generally occurred either at a steady rate within ISIs or showed a scalloped effect, that mirror presentations produced approach to the mirror side that persisted during ISIs and subsequent baseline phases, and that mirror-side distance during the mirror presentations was less than during the ISIs. Although the findings were not consistent across all fish, they were replicated a number of times within at least two of the fish. The findings are discussed in terms of adventitious operant conditioning, respondent conditioning, and the behaviour systems approach. The results of this study increase the generality of response-independent schedule effects on locomotive behaviour. / May 2009

The effects of response-independent mirror presentation schedules on the swimming behaviour of Betta splendens were studied in two experiments. In experiment 1, four fish received alternating baseline (no mirror) and fixed-time (FT) 2-min or variable-time (VT) 2-min mirror presentation conditions. Two fish consistently showed increased rates of mirror-side lap-swimming (MSLS; a back-and-forth swimming pattern) and decreased distance from the mirror during the inter-stimulus intervals (ISIs) of FT and VT sessions, and during baseline sessions that followed FT and VT phases. Data from one fish indicated that a VT schedule might increase both proximity to the mirror and MSLS rates that have decreased on FT. Therefore, in experiment 2 three fish from experiment 1 received alternating FT and VT conditions. Proximity to the mirror and MSLS rates increased during VT phases relative to FT phases in two fish, though effects were small and did not occur across all alternations. Additional findings were that MSLS during ISIs tended to increase within FT phases, that MSLS generally occurred either at a steady rate within ISIs or showed a scalloped effect, that mirror presentations produced approach to the mirror side that persisted during ISIs and subsequent baseline phases, and that mirror-side distance during the mirror presentations was less than during the ISIs. Although the findings were not consistent across all fish, they were replicated a number of times within at least two of the fish. The findings are discussed in terms of adventitious operant conditioning, respondent conditioning, and the behaviour systems approach. The results of this study increase the generality of response-independent schedule effects on locomotive behaviour.

The effects of response-independent mirror presentation schedules on the swimming behaviour of Betta splendens were studied in two experiments. In experiment 1, four fish received alternating baseline (no mirror) and fixed-time (FT) 2-min or variable-time (VT) 2-min mirror presentation conditions. Two fish consistently showed increased rates of mirror-side lap-swimming (MSLS; a back-and-forth swimming pattern) and decreased distance from the mirror during the inter-stimulus intervals (ISIs) of FT and VT sessions, and during baseline sessions that followed FT and VT phases. Data from one fish indicated that a VT schedule might increase both proximity to the mirror and MSLS rates that have decreased on FT. Therefore, in experiment 2 three fish from experiment 1 received alternating FT and VT conditions. Proximity to the mirror and MSLS rates increased during VT phases relative to FT phases in two fish, though effects were small and did not occur across all alternations. Additional findings were that MSLS during ISIs tended to increase within FT phases, that MSLS generally occurred either at a steady rate within ISIs or showed a scalloped effect, that mirror presentations produced approach to the mirror side that persisted during ISIs and subsequent baseline phases, and that mirror-side distance during the mirror presentations was less than during the ISIs. Although the findings were not consistent across all fish, they were replicated a number of times within at least two of the fish. The findings are discussed in terms of adventitious operant conditioning, respondent conditioning, and the behaviour systems approach. The results of this study increase the generality of response-independent schedule effects on locomotive behaviour.

Falk's pivotal 1961 study showed that rats would drink excessive amounts of water when exposed to a time based schedule of reinforcement. Since then, schedule-induced drinking or polydipsia, has been demonstrated with several species and with a variety of different behaviors. Rats, the most commonly used animal, have been shown to drink excessive amounts of water under a variety of different time based schedules of reinforcement; exclusively during a free operant procedure. The current study shows that water drinking can be induced during a discrete trial procedure, and instead of using a time-based schedule of reinforcement, this study used a variable-ratio schedule of reinforcement. The results showed that excessive water drinking was induced under these conditions with a canine.

Primary polydipsia, excessive drinking without known medical cause, continues to occur with a significant prevalence in psychiatric populations. While the etiology of polydipsia remains unknown, the fact that it is significantly associated with a diagnosis of schizophrenia has led some to postulate that the two may share common neurological pathophysiologies. Animal models of schizophrenia-like symptoms have focused on modeling the core behavioral and neurochemical features of the illness, like cognitive deficits and enhanced dopamine transmission. Here, we used three well-established models, including repeated amphetamine treatment, subchronic MK-801 (an N-methyl-D-aspartate [NMDA]-receptor antagonist), and post-weaning social isolation. We also examined a “double-hit” model, combining NMDA-receptor antagonism and social isolation. We paired these models to test the hypothesis that drinking will be enhanced in a paradigm of excessive drinking in the rat. In rodents, non-physiologic drinking can be induced by intermittent presentation of food (e.g., one sugar-pellet a minute) in the presence of a drinking spout to a hungry animal, termed schedule-induced polydipsia (SIP). Animals pretreated with pharmacological or non-pharmacological models of schizophrenia-like symptoms showed significantly increased SIP, The “double hit” model did not further increase drinking above that of either social isolation or MK-801 treatment alone. A moderate amount of spontaneous polydipsia in the homecage of MK-801-treated rats was also observed and resulted in one death secondary to excessive drinking, a phenomenon also found in inpatients with schizophrenia. Following repeated treatment with AMPH, there was some evidence that over time, animals learned to drink increased amounts independently of the scheduled food presentation. This evidence suggests that the excessive drinking behavior observed in polydipsia associated with schizophrenia may have a learned component. In summary, animal models of schizophrenia-like symptoms augmented SIP behavior, showing that polydipsia associated with schizophrenia may be modeled in rodents. As each model has been shown to modify dopamine transmission to some degree, the evidence suggests augmented SIP may reflect changes in dopamine transmission and dopamine may be the common link between polydipsia and schizophrenia. Further research is necessary to fully elucidate the mechanisms underlying SIP, polydipsia and schizophrenia. / Thesis (Ph.D, Neuroscience Studies) -- Queen's University, 2012-10-31 17:43:18.34