Human neuropsychiatric conditions associated with abnormally exaggerated or misdirected fear (anxiety disorders and phobias) still represent a large unmet medical need because the biological mechanisms underlying these diseases are not well understood. Animal models have been proposed to facilitate this research. Here I review the literature with a focus on zebrafish, an upcoming laboratory organism in behavioral brain research. I argue that abnormal human fear responses are likely the result of the malfunction of neurobiological mechanisms (brain areas, circuits and/or molecular mechanisms) that originally evolved to support avoidance of predators or other harm in nature. I also argue that the understanding of the normal as well as pathological functioning of such mechanisms may be best achieved if one utilizes naturalistic experimental approaches. In case of laboratory model organisms, this may entail presenting stimuli associated with predators and measuring species-specific antipredatory responses. Although zebrafish is a relatively new subject of such inquiry, I review the recently rapidly increasing number of zebrafish studies in this area, and conclude that zebrafish is a promising research tool for the analysis of the neurobiology and genetics of vertebrate fear responses.
Copyright 2009 Elsevier B.V. All rights reserved.