title: Analogue modulation of back-propagating action potentials enables dendritic hybrid signalling.
abstract: We report that back-propagating action potentials (bAPs) are not simply digital feedback signals in dendrites but also carry analogue information about the overall state of neurons. Analogue information about the somatic membrane potential within a physiological range (from -78 to -64 mV) is retained by bAPs of dentate gyrus granule cells as different repolarization speeds in proximal dendrites and as different peak amplitudes in distal regions. These location-dependent waveform changes are reflected by local calcium influx, leading to proximal enhancement and distal attenuation during somatic hyperpolarization. The functional link between these retention and readout mechanisms of the analogue content of bAPs critically depends on high-voltage-activated, inactivating calcium channels. The hybrid bAP and calcium mechanisms report the phase of physiological somatic voltage fluctuations and modulate long-term synaptic plasticity in distal dendrites. Thus, bAPs are hybrid signals that relay somatic analogue information, which is detected by the dendrites in a location-dependent manner.
authors.affiliation: Institute of Experimental Medicine, Hungarian Academy of Sciences, 43 Szigony Street, Budapest 1083, Hungary.
authors.forename: János
authors.initials: J
authors.lastname: Brunner
authors.affiliation: Institute of Experimental Medicine, Hungarian Academy of Sciences, 43 Szigony Street, Budapest 1083, Hungary.
authors.forename: János
authors.initials: J
authors.lastname: Szabadics
mesh_terms: D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000502:physiology; D015220:Calcium Channels / Q000502:physiology*; D003712:Dendrites / Q000502:physiology*; D018891:Dentate Gyrus / Q000502:physiology*; D005260:Female; D006624:Hippocampus / Q000502:physiology; D007700:Kinetics; D008297:Male; D008564:Membrane Potentials; D018613:Microscopy, Confocal; D009473:Neuronal Plasticity / Q000502:physiology; D009474:Neurons / Q000502:physiology; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D012984:Software; D013569:Synapses / Q000502:physiology
chemical_list: D015220:Calcium Channels; D002118:Calcium