Role of the Mauthner Cell in Sensorimotor Integration by the Brain Stem Escape Network

Abstract

The Mauthner neurons have become synonymous with the C start evasive response of fishes. C starts are a two-part movement pattern. First, the fish bends its body so that it has a C-like profile (stage 1) when viewed from above. Second, the fish rapidly accelerates away from its starting position (stage 2). Until recently, it has not been possible to determine the contribution of Mauthner cell activity to the expression of this behavior. In this paper we focus on three of our recent papers that address this issue. Our work combines high-speed digital image analysis of the C start with chronic Mauthner cell and electromyographic recordings, lesions of the Mauthner cells, and stimulation of single Mauthner axons in swimming fishes. This work shows that the firing of the Mauthner cell results in a short-latency body contraction that orients the initial stage of the C start away from the direction of the threatening stimulus. The direction of the escape trajectory, however, is more finely tuned to stimulus angle than can be explained by the firing of just the Mauthner cell and its postsynaptic followers. Precise control of trajectory must, therefore, require participation of other neurons. These neurons together with the Mauthner cell form a system that we term the brain stem escape network. We have identified candidate neurons of this network which can now be studied at the single-cell level. Because of both its accessibility for neurophysiological study and its neuroanatomical simplicity, we assert that the brain stem escape network is a useful preparation for understanding fundamental processes of sensorimotor integration in the brain stem.

Sensorimotor Gating in Larval Zebrafish

“…In zebrafish, fast responses initiated with a C-bend (C-start responses) require just three bilateral pairs of reticulospinal neurons including the Mauthner cells (Liu and Fetcho, 1999). These cells receive multimodal sensory input (Zottoli et al, 1995) and have been previously suggested as a model for sensorimotor integration in the brainstem without the complication of corticospinal influences found in mammals (Eaton et al, 1991).…”

Visual Prey Capture in Larval Zebrafish Is Controlled by Identified Reticulospinal Neurons Downstream of the Tectum

“…Few attempts have been made to link identifiable premotor systems to certain behaviors. Best known are the Mauthner neuron (or M cell) and its segmental homologs MiD2 and MiD3, which play a critical role in fast-start escapes (Zottoli et al, 1987;Faber et al, 1989;Eaton et al, 1991;Svoboda and Fetcho, 1996;O'Malley et al, 1996;Liu and Fetcho, 1999;Eaton et al, 2001;Zottoli et al, 1987). However, even the apparently simple startle circuit is complex: stimuli eliciting escapes activate many other RS neurons in addition to these three pairs (Gahtan et al, 2002), and even triple ablations do not eliminate startle responses altogether (Liu and Fetcho, 1999).…”

Wind generated by an attacking bat: anemometric measurements and detection by the praying mantis cercal system

“…Although some escape responses occur in this amount of time, i.e. crayfish tailflip <20·ms (Krasne and Wine, 1984) and fish Mauthner-mediated C-start 14·ms (Eaton et al, 1991), many responses have latencies of 40·ms or more, i.e. cricket terrestrial response 87·ms (Tauber and Camhi, 1995), locust jump up to 1100·ms (Heitler, 1974), insect flight responses 40-240·ms, depending on insect and response type (Nolen and Hoy, 1986;.…”