title: Role of the lateral line mechanosensory system in directionality of goldfish auditory evoked escape response.
abstract: Goldfish (Carassius auratus) escape responses to sudden auditory stimuli are mediated by a pair of reticulospinal neurons, the Mauthner (M-) cells, which integrate mechanosensory inputs from the inner ear and the lateral line (LL) to initiate a fast directional response away from the aversive stimulus. This behavior is context dependent; when near an obstruction the fish may rather turn towards the sound to avoid hitting the object. Mechanisms underlying this directionality remain unknown. Here we investigate the contribution of the LL system to auditory evoked escapes and provide behavioral evidence that it transmits stimulus - and environmental-dependent information that determines the initial response direction of the escape. We quantified escape latency, probability and directionality following abrupt sound stimuli before and after removal of the entire LL with 0.03 mmol l(-1) cobalt chloride (CoCl(2)), 0.002% gentamicin or selective posterior LL nerve (pLLn) transection. CoCl(2) significantly increased escape onset latency without affecting probability and reduced open field directionality from 77% to chance, 52%. This effect on directionality was also observed with gentamicin. Transection of the pLLn had no effect on directionality, indicating the anterior LL nerve (aLLn) afferents are more likely to transmit directional information to the M-cell. When the fish were near a wall, the error rate was quadrupled by both CoCl(2) and pLLn transection. Visual elimination had no influence on directionality unless combined with LL elimination.
authors.affiliation: Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461,  USA.
authors.forename: Mana
authors.initials: M
authors.lastname: Mirjany
authors.forename: Thomas
authors.initials: T
authors.lastname: Preuss
authors.forename: Donald S
authors.initials: DS
authors.lastname: Faber
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena / Q000187:drug effects; D003035:Cobalt / Q000633:toxicity; D004924:Escape Reaction / Q000187:drug effects / Q000502:physiology; D005072:Evoked Potentials, Auditory / Q000187:drug effects / Q000502:physiology*; D006054:Goldfish / Q000502:physiology*; D053403:Lateral Line System / Q000187:drug effects / Q000502:physiology*; D040542:Mechanotransduction, Cellular / Q000187:drug effects / Q000502:physiology*; D008954:Models, Biological; D009949:Orientation / Q000187:drug effects / Q000502:physiology*; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D014785:Vision, Ocular / Q000187:drug effects / Q000502:physiology
chemical_list: D003035:Cobalt; C018021:cobaltous chloride