CONICET | Buscador de Institutos y Recursos Humanos

The Mauthner-cell (M-cell) system of teleost fish has a long history as an experimental modelfor addressing a wide range of neurobiological questions. Principles derived from studies on thissystem have contributed significantly to our understanding at multiple levels, from mechanisms ofsynaptic transmission and synaptic plasticity to the concepts of a decision neuron that initiates keyaspects of the startle behavior. Here we will review recent work that focuses on the neurophysiologicaland neuropharmacological basis for modifications in the M-cell circuit. After summarizing the mainexcitatory and inhibitory inputs to the M-cell, we review experiments showing startle responsemodulation by temperature, social status, and sensory filtering. Although very different in nature,actions of these three sources of modulation converge in the M-cell network. Mechanisms ofmodulation include altering the excitability of the M-cell itself as well as changes in excitatory andinhibitor drive, highlighting the role of balanced excitation and inhibition for escape decisions. One ofthe most extensively studied forms of startle plasticity in vertebrates is prepulse inhibition (PPI), asensorimotor gating phenomenon, which is impaired in several information processing disorders.Finally, we review recent work in the M-cell system which focuses on the cellular mechanisms of PPIand its modulation by serotonin and dopamine.