Electric Fish Module

brownghostSensory systems provide a wealth of information about the environment and the body to the animal. From this wealth of information, the brain extracts information that is relevant for making behavioural decisions, e.g. in the context of foraging or communication with conspecifics. In the electric fish cycle, we are going to investigate how neurons in the hindbrain and midbrain become more selective to behaviorally relevant sensory stimuli.

Weakly electric fish generate an electric field around their body (electric organ discharge: EOD) and sense perturbations of the self-generated field caused by the presence of nearby objects, such as prey, or by the EODs of conspecifics. Depending on the properties of the conspecific EOD a given fish may modulate its EOD in certain stereotyped fashion.

On the second day (i.e. after the demo) of the electric fish cycle, you will take a quantitative look at some of the animal’s electrical behaviors. Over the next few days, you will learn how to record extracellularly from pyramidal cells in the hindbrain as well as performing in vivo blind whole cell patch clamp recordings from midbrain neurons. You will be introduced to a range of analysis methods including information-theoretical methods. The file “ExperimentalSchedule2010_final.docx” in our Readings section contains more details on the stimuli and methodology used throughout the cycle.

Projects for the second weak may ask questions about the role of specific feedback pathways for sensory processing or about the role of specific ion channels for the response properties of central neurons. Other options include the processing of information on moving objects, which is crucial for prey detection and localization, linear versus nonlinear sensory processing, and electrosensory processing in species that have not been studied yet.

 

Electric Fish Module Faculty and Teaching Assistants

mauriceMaurice Chacron
McGill University

My long term research goal is to understand the basic mechanisms by which neurons process sensory information. While critical for diagnostic and treatment of sensory deficiencies, these mechanisms are poorly understood to this day. Since sensory processing strategies are shared amongst sensory systems, significant progress towards this goal can be achieved by studying the somewhat simpler sensory systems of lower vertebrates. These animals respond to simple natural stimuli with obvious behavioral relevance and share common brain architecture with higher vertebrates including humans. We use a combination of behavior, in vivo electrophysiology, and modeling to link cellular processes to sensory processing at the systems level as well as behavior in weakly electric fish. Research projects are on diverse topics such as: learning and memory, population coding of sensory input, feedback, and neuromodulators. Maurice was an NS&B student in 2004 and has been a faculty member since 2005.

 

fortune,E_imageEric Fortune
New Jersey Institute of Technology

Our research examines how neural systems control behavior. We use integrative studies that exploit the strong relations between behavioral adaptations, neural mechanisms, and the evolutionary and natural histories of the organism. The ultimate goal is to uncover fundamental neural mechanisms that are used in vertebrate species to generate a wide range of behaviors. Eric has been a faculty member since 2005.

 

 Michael MarkhamMichael Markham
University of Oklahoma

My research program investigates how animals balance the costs and benefits of their communication signals.  We tackle these questions in weakly electric fish that communicate and image their worlds with electric fields.  These electric organ discharges are a direct result of action potentials and their underlying ionic currents (of several microAmps!) in thousands of electrocytes in the electric organ. We want to understand the molecular, cellular, and ionic mechanisms that make such signals possible. What molecular and biophysical adaptations in electrocytes allow sustained action potential rates exceeding 500 Hz throughout the lifespan?  We also investigate how some species regulate the metabolic costs and predation risks associated with these signals by modulating the electrocyte action potentials and ionic currents on timescales ranging from seconds to months. At the organismal level we examine how the metabolic demands of electric signaling impact behavior and social interactions. Finally, from an evolutionary perspective, we are interested in the evolution of ionic mechanisms that enable and produce signal diversity across species.  Michael was an NS&B student in 2003, a TA in 2004, a Wednesday Night Speaker in 2015 and has been a faculty member since 2017.

Michael_Metzen smallMichael Metzen
McGill University

I am mainly interested in systems neuroscience, in particular how the brain processes natural sensory stimuli (i.e. communication stimuli, first- and second-order stimuli) that ultimately control specific observable behaviors. To understand the mechanisms by which neurons across successive stages of sensory processing mediate appropriate behaviors, I am combining different approaches such as electrophysiology, computer modeling, as well as behavioral assays using different species of weakly electric fish as an animal model system. Michael has been a TA since 2012.

yue-banYue Ban
University of Oklahoma

I am interested in the membrane physiology of energetically expensive excitable cells. I use the electric organ cells of the weakly electric fish Eigenmannia virescens as the model. The cells generate action potential at a constant frequency of 200-500 Hz and there is more than 10 uA Na+ current flowing into the cell during each action potential. The ATP required for action potential generation is two magnitudes larger than that needed for mammal’s cortical neuron. I investigated the mechanisms of these cells generating expensive action potentials by imaging the cell’s morphology using laser-scanning confocal microscopy, determining the molecular identities and expression pattern of ion channels in these cells, and studying the functional properties of these ion channels using two electrode voltage clamp after expressing them in Xenopus laevis oocytes. Yue has been a TA since 2017.

Chengjie huang(Gary) Huang
McGill University

I am primarily interested in systems neuroscience, in particular how the brain processes natural sensory stimuli. I work with wave-type weakly electric fish and my goal is to understand how they perceive and process second order stimuli (i.e. envelopes) in the electrosensory lateral line lobe. Electrosensory envelope signals are found naturally in movement and social communication between fish. Using a combination of extracellular electrophysiology and computer modeling, I hope to understand how several types of electrosensory neurons, receiving the same second-order stimulus information, are able to conduct parallel processing in the central nervous system. Gary has been a TA since 2014.

 

VH_02

Volker Hofmann
McGill University

Our perception of the world is inherently connected to our behavior: each behavioral (inter)action (with the environment) causes new and altered sensory input that is in turn integrated to behavior. This integration of sensory information is the main focus of my research interests.

Using weakly electric fish as a model system, I investigate the mechanisms by which the neuronal substrate encodes and processes sensory information of various behavioral contexts in the early stages of the electrosensory pathway. How the neuronal code is tailored to sensory signal processing but at the same time plastic and adaptive to altered stimulus statistics ensuring the robustness and adaptivity of behaviors observed in nature is what fascinates me the most about the central nervous system and neuronal coding. Volker joined the electric fish module in 2016.

 

rosalie-maltbyRosalie Maltby
University of Oklahoma

I am interested in the molecular mechanisms that drive the energetically challenging electrical signals of weakly electric fish, especially Eigenmannia virescens. I am particularly interested in how the genetic and cellular mechanisms affect the ionic currents and what role they play in maintaining a delicate energy balance in a cell where ionic currents can exceed 10 microamps. My primary focus is the IKIR­, produced by the KATP channel complex. Rosalie joined the electric fish module in 2017.