Role of calcium electrogenesis in apical dendrites: generation of intrinsic oscillations by an axial current.
Dendrites are covered with conductances whose function is still mysterious. Using intracellular recording and calcium imaging, we describe an electrogenic band of calcium channels in distal apical dendrites of layer 5 pyramidal neurons (Yuste et al., 1994). We now explore the functional consequences of this distal electrogenic area with multicompartmental numerical simulations. A calcium imaging and electrophysiological database from a single neuron, recorded under blocked sodium and potassium conductances, is replicated by simulations having increased dendritic calcium current. In these models a significant axial current flows from the apical dendrite into the somatic region, activating low-threshold calcium channels and generating oscillations similar to those seen in the electrophysiological data. We propose that the distal electrogenic area in apical dendrites serves to inject current into the soma and produce intrinsic oscillatory dynamics.
Elaagouby
A
A
Division of Biology, California Institute of Technology, Pasadena 91125, USA.
Yuste
R
R
D000818:Animals; D002021:Buffers; D002118:Calcium / Q000502:physiology*; D015220:Calcium Channels / Q000502:physiology; D020746:Calcium Channels, L-Type; D020747:Calcium Channels, T-Type; D003712:Dendrites / Q000737:chemistry / Q000502:physiology*; D004594:Electrophysiology; D005456:Fluorescent Dyes; D016257:Fura-2; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008959:Models, Neurological; D009924:Organ Culture Techniques; D010507:Periodicity; D015221:Potassium Channels / Q000502:physiology; D017966:Pyramidal Cells / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000502:physiology; D013003:Somatosensory Cortex / Q000166:cytology / Q000502:physiology; D019789:Tetraethylammonium / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
D002021:Buffers; D015220:Calcium Channels; D020746:Calcium Channels, L-Type; D020747:Calcium Channels, T-Type; D005456:Fluorescent Dyes; D015221:Potassium Channels; D013779:Tetrodotoxin; D019789:Tetraethylammonium; D002118:Calcium; D016257:Fura-2