This Article Full Text Full Text (PDF) All Versions of this Article: biophysj.107.111179v1 94/3/784    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Pettersen, K. H. Articles by Einevoll, G. T. PubMed PubMed Citation Articles by Pettersen, K. H. Articles by Einevoll, G. T.

Amplitude Variability and Extracellular Low-Pass Filtering of Neuronal Spikes

Klas H. Pettersen ^* and Gaute T. Einevoll ^* 

^* Department of Mathematical Sciences and Technology, and Center for Integrative Genetics, Norwegian University of Life Sciences, Ås, Norway

Correspondence: Address reprint requests to Gaute T. Einevoll, Tel.: 47-64965433; E-mail: gaute.einevoll{at}umb.no.

The influence of neural morphology and passive electrical parameters on the width and amplitude of extracellular spikes is investigated by combined analytical and numerical investigations of idealized and anatomically reconstructed pyramidal and stellate neuron models. The main results are: 1), All models yield a low-pass filtering effect, that is, a spike-width increase with increasing distance from soma. 2), A neuron's extracellular spike amplitude is seen to be approximately proportional to the sum of the dendritic cross-sectional areas of all dendritic branches connected to the soma. Thus, neurons with many, thick dendrites connected to soma will produce large amplitude spikes, and therefore have the largest radius of visibility. 3), The spike shape and amplitude are found to be dependent on the membrane capacitance and axial resistivity, but not on the membrane resistivity. 4), The spike-amplitude decay with distance r is found to depend on dendritic morphology, and is decaying as 1/rⁿ with 1 n 2 close to soma and n 2 far away.