The purpose and function of sleep has been the topic of discussion for several centuries.  Though our understanding of the mechanisms underlying the propagation and maintenance of rest states has undergone significant improvement, much remains to be learned with regards to the effects of disrupted sleep on diseased states.  A deeper understanding of the neural circuitry and associated phenotypes would allow for the identification of sleep-related pathologies as well as the development of therapies for individuals with sleep disorders. To this end, the zebrafish ( danio rerio ) pose a great advantage.  In the adult animal, sleep is largely consolidated to dark phases.  Sleep may be disrupted via environmental, pharmacological or genetic manipulations.  Disrupted sleep rhythms in the adult animal are linked to changes in gene and protein expression, while behavioral measures of anxiety have produced mixed results. We propose that this variation is a result of the type of sleep disruption as well as the type of anxiety test employed.  This beckons the need for further study of the effects of environmental and pharmacological manipulations on the sleep rhythms of the animal.  Further, researchers must not rely solely on one test as a measure of stress or anxiety as it provides only a one-dimensional insight.

The zebrafish ( Danio rerio ) has been at the forefront of neurobiological research and is steadily gaining favor as a model for behavioral applications. The ease of handling, high yield of progeny, and efficient mode of drug delivery make this species a particularly useful model for behavior. Here, we append to the growing body of literature on zebrafish behavior by introducing a novel behavioral battery of tests aimed at identifying drug induced alterations in social and motoric behaviors. In a series of experiments, zebrafish were exposed to MK-801 (0, 2 μM, 20 μM), SFK 38393 (0, 10 μM, 100 μM), and ethanol (0, 0.5%, 1.0%) for one hour and overt locomotor behaviors were scored. Following a one-hour treatment exposure, circling behavior (a thigmotaxic display typical of dysregulated glutamate function) was scored from videotape at specific time points over a 37-minute session. In a separate experiment the zebrafish’s natural tendency to shoal (social display) was analyzed using a novel open-field paradigm that examined fish distribution over quadrants. Most notably, MK-801 (20 μM) significantly increased circling behavior compared to controls. However, shoaling displays were disrupted when zebrafish were exposed to both MK-801 and SKF 38393 (20 μM and 100 μM respectively). Our results, in part, complement existing knowledge about zebrafish behavior following acute drug exposure. Additionally, our novel approach to assessing shoaling behavior, reported here, introduces an alternative view of social/group behavior in the zebrafish that is sensitive to both NMDA and dopaminergic manipulation.