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


 
Publications in peer-reviewed Journals


Rouse, M.L., Stevenson, T.J., Fortune, E.S., and G.F. Ball (2015) Reproductive state modulates testosterone-induced singing in adult female European starlings (Sturnus vulgaris). Horm. Behav., 72:78-87, PMID:25989596.
Testosterone-treated female starlings change their singing behavior in relation to reproductive state.
Cowan, N.J., Ankarali, M.M., Dyhr, J.P., Madhav, M.S., Roth, E., Sefati, S., Stamper, S.A., Fortune, E.S., and T.L. Daniel (2014) Feedback control as a framework for understanding tradeoffs in biology. Integr. Comp. Biol., 54:223-237, PMID:24893678.
A review of the application of control theoretic approaches to the study of animal behavior.
Sefati, S., Neveln I.D., Roth E., Mitchell T.R., Snyder J.B., Maciver M.A., Fortune E.S., and N.J. Cowan (2013) Mutually opposing forces during locomotion can eliminate the tradeoff between maneuverability and stability. PNAS, 110:19798-18803, PMID:24191034.
Eigenmannia virescens escapes the tradeoff between manueverability and stability by generating forces that directly oppose each other and do not contribute to the translation of the fish.
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 emeregent envelope signals in groups of three individuals by changing their electric organ discharge frequency.
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.
Stamper, S.A., Roth, E., Cowan, N.J., and E.S. Fortune (2012) Active sensing via movement shapes spatiotemporal patterns of sensory feedback. J. Exp. Biol., 215:1567-1574, PMID:22496294.
Eigenmannia and other species of weakly electric fishes will swim to maintain their position within a moving refuge. We compared the performance of fish in refuge tracking when the fish were in the light and dark. We found that when there were no visual cues, the fish made oscillatory movements that, although dramatically increasing the distance that the fish swam, resulted in the same tracking performance as when the animals were given visual cues.
Fortune, E.S., Rodriguez, C., Li, D., Ball, G.F., and M.J. Coleman (2011) Neural mechanisms for the coordination of duet singing in wrens. Science., 334:666-669, PMID:22052048.
This manuscript describes the basic singing patterns used by female and male plain-tailed wrens to produce remarkable duets. We then captured birds, anesthetized them with urethane, and recorded from neurons in the telencephalic song control area known as HVC. We expected that neurons in the female would respond best to the female parts of duets, and male neurons would respond to the male parts. What we found was surprising - neurons in both females and males repsonded best to the duet, and neurons preferred the female parts in both sexes.
Roth, E., Zhuang, K., Stamper, S.A., Fortune, E.S., and N.J. Cowan (2011) Stimulus predictability mediates a switch in locomotor smooth pursuit performance for Eigenmannia virescens. PMID:21389203.

Eigenmannia virescens improve their tracking performance depending on the predictability of a refuge trajectory. This nonlinear switch results in reduced tracking error to simpler sinusoidal stimuli despite an often dramatic reduction in motor effort.
Khosravi-Hashemi, N., Fortune, E.S., and M.J. Chacron (2011) Coding movement direction by burst firing in electrosensory neurons. PMID:21775723.

Direction selective responses are carried primarily by bursts of action potentials. As a result, if all of the spikes are used to measure direction selective responses, the level of directionality can be significantly less than that coded by the bursts alone. In this paper we include a model that uses an interaction between the receptive field organization and T-type Calcium channels to generate selective burst activity. We also include a model that selectively extracts burst activity in downstream decoders.
Chacron, M.J. and E.S. Fortune (2010) Subthreshold membrane conductances enhance directional selectivity in vertebrate sensory neurons. J. Neurophysiol., 4(2):e32, PMID:20445028.

Reichardt motion detectors require two features for direction selectivity: different delays of information from different spatial locations on the sensor array and a non-linear integrator of this information. This manuscript shows that the non-linear integrator for direction selectivity in midbrain electrosensory neurons is mediated by a T-type calcium channel.
Stamper, S.A., Carrera-G, E., Tan, E.W., Fugere, V., Krahe, R., and E.S. Fortune (2010) Species differences in group size and electrosensory interference in weakly electric fishes: Implications for electrosensory processing. Behav Brain Res., PMID:19874855.

We describe the electrosensory structure of multi-species flocks of Gymnotiform fishes along the Napo River in eastern Ecuador. We find that Apteronotus form groups of conspecifics, whereas Sternopygus are most commonly found alone. Interestingly, groups of 3 or more Apteronotus appear to not produce low-frequency 'envelopes' in the combined electric field. We believe that such envelopes might impair electrosensory function, and thus the fish may employ some currently unknown behavior to avoid the potentially detrimental envelopes.
Chacron, M.J., Toporikova, N., and E.S. Fortune (2009) Differences in the time course of short-term depression across receptive fields are correlated with directional selectivity in electrosensory neurons., J. Neurophysiol., 102:3270-3279, PMID:19793877.

Reichardt motion detectors require two features for direction selectivity: different delays of information from different spatial locations on the sensor array and a non-linear integrator of this information. This manuscript shows that the differences in the delays from different locations on the receptor array are mediated in midbrain electrosensory neurons is mediated by differences in the time course of short-term synaptic depression.
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.
Fortune, E.S. and M.J. Chacron (2009) From molecules to behavior: organismal-level regulation of ion channel trafficking. PLoS Biol., 7:e1000211, PMID:19787034.

This is a short "Primer" article in PLoS Biology for a very cool paper by our colleagues.
Carver, S., Roth, E., Cowan, N.J. and E.S. Fortune (2008) Synaptic plasticity can produce and enhance direction selectivity. PLoS Comput. Biol., 4(2):e32, PMID:18282087.

A model that demonstrates how two time constants associated with short-term synaptic depression - a fast time constant on the order of milliseconds to seconds and a slower time constant on the order of seconds to tens of seconds - contribute to the generation and enhancement of direction selectivity. The model captures the major features observed in a population of direction-selective midbrain neurons in the electrosensory midbrain of Eigenmannia virescens.
Cowan, N.J. and E.S. Fortune (2007) The critical role of locomotion mechanics in decoding sensory systems. J. Neurosci, 27:1123-1128, PMID:17267567.

Simple measurements - the position of the fish - were made during an image-stabilization task where fish swim back and forth to maintain position within a moving refuge. Using basic laws of swimming mechanics, we built a model for sensory computations necessary for the control of the motor system during the task. The model matched neurophysiological properties of the electrosensory system in these fish. These physiological properties, particularly high-pass filtering of sensory signals, are found in a wide array of sensory systems and may reflect a common role in motor control.
Fortune, E.S. (2006) The decoding of electrosensory systems. Curr. Opin. Neurobiol., PMID:16837187.

This review of how behavior is used to unlock neural mechanisms in weakly electric fishes was written to be accessible for a broad neuroscience audience. Towards this end, examples from the visual system are used to illustrate some of the interesting features of electrosensory stimuli.
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.
Fortune, E.S., Rose, G.J., and M. Kawasaki (2006) Encoding and processing biologically relevant temporal information in electrosensory systems. J. Comp. Physiol. A, 192:625-635, PMID:16450118.

A broad review of electrosensory encoding of temporal information (from microseconds to seconds) for the control of jamming avoidance response behaviors.
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.
Tan, E.W., Nizar, J.M., Carrera-G, E., and E.S. Fortune (2005) Electrosensory interference in naturally occurring aggregates of a species of weakly electric fish, Eigenmannia virescens. Behav. Brain Res., 164:83-92, PMID:16099058.

Characterizes the electric fields that are most commonly experienced by Eigenmannia both in the upper Amazon of Ecuador and in laboratory settings. Eigenmannia are preferentially found in groups and experience ongoing high-frequency (> 20 Hz) global oscillations.
Fortune, E.S. and G.J. Rose (2003) Voltage-gated Na+ channels enhance the temporal filtering properties of electrosensory neurons in the torus. J. Neurophys., 90:924-929, PMID:12750421.

Demonstrates the existance of two types of all-or-none PSPs in toral electrosensory neurons in Eigenmannia virescens. The first type, constant duration or "CD" PSPs can be 1) elicited by current injection alone and 2) are eliminated by application of sodium-channel blockers QX-222 and QX-314. CD PSPs appear to enhance responses to social communication signals. The second type, variable duration or "VD" PSPs are not elicited by current injection alone and are not blocked by QX drugs. These PSPs apparently require both synaptic input and depolarization for activation. VD PSPs enhance responses to signals that can elicit the jamming avoidance response, and may be mediated by NMDARs.
Fortune, E.S. and G.J. Rose (2002) Roles for short-term synaptic plasticity in behavior. J Physiol Paris, 96:539-545, PMID:14692501.

A review of data obtained in midbrain electrosensory neurons of Eigenmannia that suggest plasticity has at least two roles in sensory processing; enhancing low-pass temporal filtering and generating phase shifts used in processing moving sensory images.
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.
Fortune, E.S., and G.J. Rose (2000) Short-term synaptic plasticity contributes to the temporal filtering of electrosensory information, J. Neurosci., 20:7122-7130, PMID:10995860.
Intracellular recordings from midbrain neurons in awake, behaving animals demonstrate the dynamics and functional roles of short-term synaptic plasticity. Short-term depression enhances low-pass temporal filtering and allows responses to sensory transients, and short-term facilitation maintains responses to low-frequency information in the presence of depressing, high frequency information.
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.
Rose, G.J. and E.S. Fortune (1999) Mechanisms for generating temporal filters in the electrosensory system. J. Exp. Biol., 202:1281-1289, PMID:10210668.
A review article summarizing the constellation of mechanisms that midbrain neurons employ to generate low-, band- , and high-pass temporal filtering properties.
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.
Fortune, E.S. and G.J. Rose (1997) Temporal filtering properties of ampullary electrosensory neurons in the torus semicircularis of Eigenmannia: evolutionary and computational implications. Brain, Behav., and Evol., 49:312-323, PMID:9167857.
A comparison of the properties of the phylogenetically ancient ampullary system with the evolutionarily novel tuberous (p-type) system. The two systems share many anatomical and physiological features, which is consistent with the hypothesis that the tuberous system is an elaboration or duplication of the ampullary system.
Rose, G.J. and E.S. Fortune (1996) New techniques for making whole-cell recordings from CNS neurons in vivo. Neurosci. Res. 26:89-94, PMID:8895897.
A technical note describing details of how to make intracellular recordings from neurons in vivo using low-resistance patch-type pipettes.
Fortune, E.S. and D. Margoliash (1995) Parallel pathways and convergence onto HVc and adjacent neostriatum of adult male zebra finches (Taeniopygia guttata). J. Comp. Neurol. 360(3): 413-441, PMID:8543649.
This paper has two major parts: a descriptive definition of HVc based on Nissl stained material and the connectivity of HVc and adjacent areas based on injection of tracers. There are three major conclusions: 1. HVc is composed of 3 cytoarchitectonically distinct regions. One of these regions has indistinct borders from adjacent neostriatum. 2. HVc receives direct input from a small number of neurons in field L. 3. Areas adjacent to HVc receive and send parallel projections to those of HVc.
Margoliash, D., E.S. Fortune, M. Sutter, C-H. Yu, D. Hardin, and A.Dave (1994) Distributed representation in the song system of oscines: evolutionary implications and functional consequences. Brain Behav. Evol. 44:247-264, PMID:7842284.
A review of thinking about song learning and production. It considers HVc as a form of central pattern generator.
Fortune, E.S. and D. Margoliash (1992) Cytoarchitectonic organization and morphology of cells of the field L complex in adult male zebra finches (Taeniopygia guttata). J. Comp. Neurol., 325:388-404, PMID:1447407.
A detailed description of the anatomy of "field L" of the Nidopallium.
Margoliash, D. and E.. Fortune (1992) Temporal and harmonic combination-sensitive neurons in the zebra finch's HVc. J. Neurosci., 12:4309-4326, PMID:1432096.
The most complex, both in the temporal and spectral domains, selectivities for acoustic signals in any animal system are described in this paper. These complex selectivities are produced by the song-learning process.
@ericfortunephd 11-Dec-2015