+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Contributions of principal neocortical neurons to magnetoencephalography and electroencephalography signals



Contributions of principal neocortical neurons to magnetoencephalography and electroencephalography signals



Journal of Physiology 575(Pt 3): 925-936



A realistically shaped three-dimensional single-neuron model was constructed for each of four principal cell types in the neocortex in order to infer their contributions to magnetoencephalography (MEG) and electroencephalography (EEG) signals. For each cell, the soma was stimulated and the resulting intracellular current was used to compute the current dipole Q for the whole cell or separately for the apical and basal dendrites. The magnitude of Q is proportional to the magnetic field and electrical potential far from the neuron. A train of spikes and depolarization shift in an intracellular burst discharge were seen as spikes and an envelope in Q for the layer V and layer II/III pyramidal cells. The stellate cells lacked the envelope. As expected, the pyramidal cells produced a stronger Q than the stellate cells. The spikes produced by the layer V pyramidal cells (n = 4) varied between -0.78 and 2.97 pA m with the majority of the cells showing a current toward the pia (defined as positive). The basal dendrites, however, produced considerable spike currents. The magnitude and direction of dipole moment are in agreement with the distribution of the dendrites. The spikes in Q for the layer V pyramidal cells were produced by the transient sodium conductance and potassium conductance of delayed rectifier type; the conductances distributed along the dendrites were capable of generating spike propagation, which was seen in Q as the tail of a triphasic wave lasting several milliseconds. The envelope was similar in magnitude (-0.41 to -0.90 pA m) across the four layer V pyramidal cells. The spike and envelope for the layer II/III pyramidal cell were 0.47 and -0.29 pA m, respectively; these values agreed well with empirical and theoretical estimates for guinea pig CA3 pyramidal cells. Spikes were stronger for the layer IV spiny stellate (0.27 pA m) than the layer III aspiny stellate cell (0.06 pA m) along their best orientations. The spikes may thus be stronger than has been previously thought. The Q for a population of stellate cells may be weaker than a linear sum of their individual Q values due to their variable dendritic geometry. The burst discharge by pyramidal cells may be detectable with MEG and EEG when 10 000-50 000 cells are synchronously active.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 011900737

Download citation: RISBibTeXText

PMID: 16613883

DOI: 10.1113/jphysiol.2006.105379


Related references

Neocortical propagation in temporal lobe spike foci on magnetoencephalography and electroencephalography. Annals of Neurology 25(4): 373-381, 1989

Contribution of ionic currents to magnetoencephalography (MEG) and electroencephalography (EEG) signals generated by guinea-pig CA3 slices. Journal of Physiology 553(Pt 3): 975-985, 2003

New developments in clinical neurophysiology: magnetoencephalography. Contributions of magnetoencephalography to the study of epilepsy. Revista de Neurologia 30(4): 364-370, 2000

Spike-induced calcium signals and afterhyperpolarizations in neocortical pyramidal neurons. Society for Neuroscience Abstracts 27(1): 1004, 2001

Cellular and network contributions to excitability of layer 5 neocortical pyramidal neurons in the rat. Plos one 2(11): E1209, 2007

Preferential loss of large neocortical neurons during HIV infection: A study of the size distribution of neocortical neurons in the human brain. Brain Research 828(1-2): 119-126, 1999

Membrane potential dynamics of neocortical projection neurons driving target-specific signals. Neuron 80(6): 1477-1490, 2013

Contributions of Kv7-mediated potassium current to sub- and suprathreshold responses of rat layer II/III neocortical pyramidal neurons. Journal of Neurophysiology 106(4): 1722-1733, 2011

Optogenetic drive of neocortical pyramidal neurons generates fMRI signals that are correlated with spiking activity. Brain Research 1511: 33-45, 2013

Comparison of electroencephalography and magnetoencephalography. Advances in Neurology 54: 33-37, 1990

On the forward solution of electroencephalography and magnetoencephalography. Clinical Physics and Physiological Measurement 12 Suppl A: 95-99, 1991

Magnetoencephalography is not a substitute for intracranial electroencephalography. Annals of Neurology 60(2): 270-270, 2006

Model evaluation using electroencephalography and magnetoencephalography. Acta Oto-Laryngologica. Supplementum 432: 5-10, 1986

The inverse problem in electroencephalography and magnetoencephalography. Advances in Neurology 54: 79-88, 1990