Action Potentials; Axons; Dendrites; Nervous System; Neurobiology; Neurons; Physiology; Excitatory Postsynaptic Potentials; Dendritic Spines; Inhibitory Postsynaptic Potentials
A central question in neurobiology is how the interaction between individual neurons produces behavior and behavioral modifications. This task depends critically on how exactly are signals integrated by individual nerve cells functioning as complex operational units. Regional electrical properties of branching neuronal processes which determine the input-output function of any neuron are extraordinarily complex, dynamic, and, in the general case, impossible to predict in the absence of detailed measurements. To obtain such a measurement one would, ideally, like to be able to monitor, at multiple sites, subthreshold events as they travel from the sites of origin (synaptic contacts) and summate at particular locations to influence action potential initiation (the spiking output of a neuron). We developed a technique to carry out this type of measurement at sub-micrometer and sub-millisecond resolution, using high-resolution multisite recording of membrane potential changes with intracellular voltage-sensitive dyes.
With this approach we now investigate: (a) The non-linear and spatially inhomogeneous interactions of dendritic membrane potential signals that represent the first step in the induction of activity-dependent long-term synaptic plasticity (LTP); (b) The input–output transform performed by mitral cells, the principal projection neurons of the olfactory bulb; (c) Electrical role of individual dendritic spines; (d) Action potential initiation and propagation in the axonal arbor of cerebellar Purkinje cells and cortical pyramidal neurons.
Specialized Terms: Physiology of axons, dendrites and dendritic spines; Input-output function of individual nerve cells; Voltage sensitive dyes; Optical recording methods
Extensive Research Description
- FHF-independent conduction of action potentials along the leak-resistant cerebellar granule cell axon. Nat Commun. 7:12895 (2016) PMID: 27666389
- Electrical behaviour of dendritic spines as revealed by voltage imaging. Popovic MA, Carnevale N, Rozsa B, Zecevic D. (2015) Nat Commun. 6:8436
- Imaging with organic indicators and high-speed charge-coupled device cameras in neurons: some applications where these classic techniques have advantages. Ross WN, Miyazaki K, Popovic MA, Zecevic D. (2015) Neurophotonics. 2:021005
- Combining Membrane Potential Imaging with Other Optical Techniques. Jaafari N, Vogt KE, Saggau P, Leslie LM, Zecevic D, Canepari M. (2015). Adv Exp Med Biol. 859:103-25
- Cortical dendritic spine heads are not electrically isolated by the spine neck from membrane potential signals in parent dendrites. Popovic M, Gao X, Carnevale N, Zecevic D. (2014). Cerebral Cortex, 24(2): 385-95.
- Voltage-sensitive dye recording from axons, dendrites and dendritic spines of individual neurons in brain slices Popovic M, Gao X, Zecevic D (2012). JoVE (69), e4261.
- Somatic membrane potential and Kv1 channels control spike repolarization in cortical axon collaterals and presynaptic boutons. Foust A.J., Y. Yu, M, Popovic, D. Zecevic, D.A. McCormick. (2011) J. Neurosci. 31:15490-8.
- Voltage-imaging from axons and collaterals of cortical pyramidal neurons in brain slices. Popovic M, Foust AJ, McCormick DA and Zecevic D (2011). J Physiol. 589:4167-87.
- Spike initiation and branch-point propagation fidelity elucidated in Purkinje neurons with voltage sensitive dye recording. Foust AJ, Popovic M, Zecevic D, McCormick DA (2010) J. Neurosci. 30: 6891-6902.
- Imaging Inhibitory Synaptic Potentials Using Voltage Sensitive Dyes. Marco Canepari, Silvia Willadt, Dejan Zecevic and Kaspar E Vogt (2010) Biophysical J. 98: 2032-2040.
- Rapid time-course of action potentials in spines and remote dendrites of mouse visual cortical neurons. Holthoff K, Zecevic D, Konnerth A (2010) J Physiol (jphysiol.2009.184960).