Dr. Eric S. Fortune, PhD
  Department of Biological Sciences
  New Jersey Institute of Technology
  Newark, NJ 07102-1982 USA
  Tel: +1 443 312 9610, FAX: +1 973 596 5689
  e-mail: eric.fortune@njit.edu


Research program: electric fish
Research program: songbirds


Social Behavior

Perhaps the most amazing feature of weakly electric fishes are the 'massless' electrosensory behaviors that they exhibit. These include complex behaviors such as the jamming avoidance response and social signaling. Because these behaviors do not require movement, intracellular recordings from the CNS neurons that control these behaviors can be achieved in awake, behaving animals. These sorts of experiments have been at the core of our experimental analysis for many years now.

These social electrosensory behaviors also have broader consequences for the organism, potentially having profound impacts on locomotion control, electrosensory perception of moving objects, and the spatial distribution of conspecifics. Due to its pervasive role in behavioral control, and because these social signals are experimentally tractable, we use these signals as both experimental tools and experimental measures in almost every experiment we conduct.


Relevant works

Madhav M.S., Stamper, S.A., Fortune, E.S., and N.J. Cowan (2013) Closed-loop stabilization of the Jamming Avoidance Response reveals its locally unstable and globally nonlinear dynamics., J. Exp. Biol., 216:4272-4284, PMID:23997196.
Linear and non-linear analyses of the Jamming Avoidance Behavior in which a robotic control system closed the behavioral loop around this escape behavior in Eigenmannia virescens.
Stamper, S.A., Fortune, E.S., and M.J. Chacron (2013) Perception and coding of envelopes in weakly electric fishes. J. Exp. Biol., 216:2393-2402, PMID:23761464.
This is a review that covers the rapid progress that has been made in understanding how weakly electric fishes generate envelope signals through social interactions and movements, and how these envelope signals are encoded in CNS circuits.
Stamper S.A., Madhav M.S., Cowan N.J., and Fortune E.S. (2012) Beyond the Jamming Avoidance Response: weakly electric fish respond to the envelope of social electrosensory signals, J. Exp. Biol., 215:4196-4207, PMID:23136154.
Behavioral experiments show how Eigenmannia virescens regulate the frequencies of low-frequency envelopes in groups of three individuals by changing their electric organ discharge frequences.
McGilligray, P., Vonderschen, K., Fortune, E.S., and M.J. Chacron (2012) Parallel coding of first- and second-order stimulus attributes by midbrain electrosensory neurons. J. Neurosci., 32:5510-5524, PMID:22514313.
This work shows how different combinations of response properties at one level of brain processing, the ELL, are combined at the next level to extract different features of the stimulus.
Hitschfeld, É.M., Stamper, S.A., Vonderschen, K., Fortune, E.S., and M.J. Chacron (2009) Effects of restraint and immobilization on electrosensory behavior of weakly electric fish. ILAR J., 50:361-372, PMID:19949252.

Here we quantitatively assesed electrosensory behaviors in three experimental conditions - freely moving, restrained, and immobilized using paralytic drugs. We find no consistent differences in these three conditions. This suggests 1) that the fish are likely to not experience pain and distress under each of these experimental conditions and 2) that this category of experiments involving electrosensory behaviors when conducted in immobilized fishes match the natural behavior of the fish under normal conditions.
Ramcharitar, J.U., Tan, E.W., E.S. Fortune (2006) Global electrosensory oscillations enhance directional responses of midbrain neurons in Eigenmannia. J. Neurophys., PMID:16790600.

Characterizes the responses of midbrain neurons to moving objects in the presence and absence of post-Jamming-Avoidance-Response global stimuli. Remarkably, gamma band interference seems to enhance direction selectivity in these neurons. This phenomenon is strongly correlated with a measure of short-term synaptic depression in these neurons.
Ramcharitar, J.U., Tan, E.W., and E.S. Fortune (2005) Effects of global electrosensory signals on motion processing in the midbrain of Eigenmannia. J. Comp. Physiol. A, 191:865-872, PMID:16001182.

Characterizes the magnitudes of the responses of midbrain neurons to moving objects in the presence and absence of global electrosensory stimuli.
Fortune, E.S. and G.J. Rose (2001) Short-term synaptic plasticity as a temporal filter. Trends in Neurosciences, 24:381-385, PMID:11410267.

This Opinion article argues that synaptic plasticity in sensory systems of many vertebrate species, including mammals, should be considered a mechanism for dynamic temporal filtering. A sub-theme is that natural patterns of afferent activity are necessary to assess the functional roles of the interplay between synaptic depression and facilitation.
Rose, G.J. and E.S. Fortune (1999) Frequency-dependent PSP depression contributes to low-pass temporal filtering in Eigenmannia. J. Neurosci., 19:7629-7639, PMID:10460268.
Behavioral and neuropysiological data demonstrate that short-term depression can act to enhance low-pass temporal filtering.
Fortune, E.S. and G.J. Rose (1997) Passive and active membrane properties contribute to the temporal filtering properties of midbrain neurons, in vivo. J. Neurosci., 17:3815-3825, PMID:9133400.
Biophysical measurements of membrane properties were made in vivo to assess and quantify how passive and active electrical characteristics of neurons affect their functional properties. Because all neurons in all animals have such electrical properties, these data are widely applicable.
@ericfortunephd 11-Dec-2015