Chapter 13: Neurophysiology for Fishes: Electrophysiology and Neuronal Labeling Techniques
Allen F. Mensinger and Karen P. Maruska
Mensinger, A. F., and K. P. Maruska. 2022. Neurophysiology for fishes: electrophysiology and neuronal labeling techniques. Pages 449–498 in S. Midway, C. Hasler, and P. Chakrabarty, editors. Methods for fish biology, 2nd edition. American Fisheries Society, Bethesda, Maryland.
The nervous system in vertebrates is remarkably conserved at the cellular level, making fishes excellent model organisms for studying fundamental neural processes. The neuron’s (nerve cell) role is to carry electrical impulses to convey information to secondary neurons, sensory cells, muscles and/or other target organs. The electrical currents are produced by differential ion cascades between the inside and outside of the cell and allow the investigator to “eavesdrop” on this cellular communication network to understand how fishes detect, integrate, and respond to stimuli. This chapter will summarize the current neurophysiological and neuroanatomical methods used to explore the physiology and structure of the nervous system while focusing on the techniques involved in whole animal preparations.
The nervous system consists of individual neurons, which possess electrically excitable membranes that function to transmit information, and glial cells, which had been thought historically to predominantly provide support and insulation in the form of a myelin sheath but are now known to function in bidirectional communication with neurons in contexts such as development, plasticity, and repair (Lindsey et al. 2018). The central nervous system (CNS) consists of the brain and spinal cord, whereas, the peripheral nervous system comprises the nerves and ganglia outside the CNS. Information is sent from the periphery to the CNS via afferent neurons, while efferent neurons carry impulses from the CNS to the periphery.