Leonard Maler, Ph.D.

Professor
Faculty of Medicine
451 Smyth Road, Ottawa, ON K1H 8M5
Office: 2233
Phone: (613) 562-5800 (8189)
FAX: (613) 562-5434
Email: lmaler@aix1.uottawa.ca

Feedback Regulation of Sensory Processing in a Neural Network Underlying Communication and Electrolocation.

All sensory systems of vertebrates have extensive feedback input, but its function is still obscure. Dr. Maler's research has focused on feedback input in the electrosensory system, which is especially amenable to detailed analysis at both the circuit and cellular levels. Morphological, electrophysiological, and computational techniques are used to investigate how the patterns of connectivity, the properties of neuronal ion channels and the behaviour of modifiable synapses act in concert to allow feedback input to modulate the spatio-temporal filtering of sensory systems.

A second project of this group is to examine the cellular properties of a neuronal group which controls aggressive and reproductive communication in electric fish. Immunohistochemical and electrophysiological techniques are used to study the interactions of transmitters (peptides and amino acids) and intrinsic voltage-sensitive ion channels in determining the quality of the communicatory output. A major goal of these investigations is to identify the cellular basis of the seasonal variations in aggressive/reproductive communication.

You may click on the inlined gifs to see the entire confocal laser microscope images. For a lay-level description of electric fish research see "the barking fish page".

Current Lab Members

Publications

Lewis, J.E. and Maler, L. (2001) Neuronal population codes and the perception of object distance in weakly electric fish. J. Neurosci. 21:2842-2850.

Doiron, B., Longtin, A., Turner, R.W. and Maler, L. (2001) Model of gamma frequent burst discharge generated by conditional backpropagation. J. Neurophysiol. 86: 1523-1545.

Chacron, M.J., Longtin, A. and Maler, L. (2001) Negative interspike interval correlations increase the neuronal capacity for encoding time dependent stimuli. J. Neurosci. 21:5328-5343.

Chacron, M.J., Longtin, A. and Maler, L. (2001) Modeling bursting and non-bursting electroreceptors in weakly electric fish with implications for weak signal detection. Neurocomputing 38:129-139.

Berman, N., Dunn, R. and Maler, L. (2002) Function of NMDA receptors and persistent sodium channels in a feedback pathway of the electrosensory system. J. Neurophysiol. 86: 1612-1621.

Doiron, B., Laing, C., Longtin, A. and Maler, L. (2002) Ghostbursting: a novel neuronal burst mechanism. J. Computational. Neurosci. 12 : 5-25.

Oswald, A.M., Lewis, J. and Maler, L. (2002) Dynamically interacting processes underlie synaptic plasticity in a feedback pathway. J. Neurophysiol. 87: 2450-2463.

Lewis, J. and Maler, L. (2002) Blurring of the senses: common cues for distance perception in diverse sensory systems. Neurosci. 114:19-22.

Bastian, J., Chacron, M.J. and Maler, L. (2002) Receptive field organization determines pyramidal cell stimulus encoding capability and spatial stimulus selectivity. J. Neurosci. 22: 4577-90.

Lewis, J.E. and Maler, L. (2002) Dynamics of electrosensory feedback: short-term plasticity and inhibition in a parallel fiber pathway. J. Neurophysiol. 88:1605-1706.

Laing, C., Doiron, B., Longtin, A. and Maler, L. (2002) Ghostbursting: the effects of dendrites on spike patterns. Neurocomputing 44-46:127-132.

Turner, R.W., Lemon, N., Doiron, B., Rashid, A.J., Morales, E., Longtin, A., Maler, L. and Dunn, R. (2002) Oscillatory burst discharge generated through conditional backpropagation of dendritic spikes. J. Physiol. ( Paris) 96:517-530.

Doiron, B., Chacron, M., Maler, L., Longtin, A. and Bastian, J. (2003) Inhibitory feedback required for network oscillatory responses to communication but not prey stimuli. Nature 421: 539-543.

Chacron, M., Doiron, B., Maler, L., Longtin, A. and Bastian, J. (2003) Non-classical receptive field mediated switch in a sensory neuron’s frequency tuning. Nature 423:77-81.

Laing, C.R., Doiron, B., Longtin, A., Noonan, L., Turner, R.W. and Maler, L. (2003) Type I burst excitability. J. Computational Neuroscience 14(3):329-342.

Chacron, M.J., Longtin, A. and Maler, L. (2003) The effects of spontaneous activity, background noise and the stimulus ensemble on information transfer in neurons. Computation in Neural Systems 14(4):803-824.

Lewis, J. and Maler, L. (2004) Synaptic dynamics on different time-scales in a parallel fiber feedback pathway of the weakly electric fish. J. of Neurophysiol. 91:1064-1070.

Bastian, J. Chacron, M. and Maler, L. (2004) Plastic and Non-Plastic Pyramidal Cells Perform Unique Roles in a Network Capable of Adaptive Redundancy Reduction. Neuron 41:767-779.

Oswald, A.-M., Chacron, M.J., Doiron, B., Bastian, J. and Maler, L. (2004) Parallel Processing of Sensory Input by Bursts and Isolated Spikes. J. Neurosci. 24:4351-4362.

Doiron, B., Lindner, B., Longtin, A., Maler, L. and Bastian, J. (2004) Delay induced network oscillations to spatially correlated stochastic stimuli. Physical Review Letters 93(4):048101-1.

Chacron, M.J., Longtin, A. and Maler, L. (2004) To burst or not to burst. J. Comp. Neurosci. 17:127-136.

Benda, J. Longtin, A. and Maler, L. (2005) Spike frequency adaptation separates transient communication signals from background oscillations. J. Neurosci. 25(9):2312-2321.

Chacron, M.J., Maler, L. and Bastian, J. (2005) Electroreceptor neuron dynamics shape information transmission. Nature Neurosci. 8:673-678.

Chacron, M.J., Maler, L. and Bastain, J. (2005) Feedback and feedforward control of frequency tuning to naturalistic stimuli. J. Neurosci. 25:5521-5532.

Chacron, M.J., Longtin, A. and Maler, L. (2005) Delayed excitatory and inhibitory feedback shape neural information transmission. Physical Letters E 72:051917.

Mehaffey, W.H., Doiron, B., Maler, L. and Turner, R.W. (2005) Deterministic gain control with active dendrites. J. Neurosci. 25:9968-9977.

Qingwei Deng, Asim J. Rashid,, Fernando R. Fernandez, Ray W. Turner, Leonard Maler, and Robert J. Dunn (2005) A C-terminal domain directs Kv3.3 channels to dendrites. J. Neurosci. 25 (50):11531-11541.

Bendan, J., Longtin, A. and Maler, L. (2006) A synchronization-desynchronization code for natural communication signals. Neuron 52:347-358.

Middleton, J.W., Longtin, A., Benda, J. and Maler, L. (2006) The cellular basis for parallel neural transmission of a high frequency stimulus and its low frequency envelope. PNAS 103(39):14596-14601.

Maler, L. (2006) Gamma oscillations, synaptic depression and the enhancement of spatio-temporal processing. J. Neurophysiol. 96:2173-2174.

A.-M. Oswald, B. Doiron, and L. Maler. (2007) Interval Coding I: Burst Interspike Intervals as Indicators of Stimulus Intensity. J. Neurophysiol. 97(4):2731-2743.

B. Doiron, A.-M. M. Oswald, L. Maler. (2007) Interval Coding II: Scale Codes and Dendritic Control. J. Neurophysiol. 97:2744-2757.

J. Middleton, E. Harvey-Girard, L. Maler, and A. Longtin. (2007) Envelope Gating and Noise Shaping in Populations of Noisy Neurons. Physical Review E 75:021918.

Daniel Gussin, Jan Benda, and Leonard Maler. (2007) Limits of Linear Rate Coding of Dynamic Stimuli by Electroreceptor Afferents. J. Neurophysiol. 97:2917-2929.