The Journal of Neurophysiology Vol. 83 No. 1 January 2000, pp. 588-610
Copyright ©2000 by the American Physiological Society
Fourier Analysis of Sinusoidally Driven Thalamocortical Relay
Neurons and a Minimal Integrate-and-Fire-or-Burst Model
Gregory D.
Smith,1,4
Charles L.
Cox,3
S. Murray
Sherman,3 and
John
Rinzel1,2,4
1Center for Neural Science and
2Courant Institute of Mathematical Sciences, New
York University, New York, New York 10003;
3Department of Neurobiology, State University of
New York, Stony Brook, New York 11794; and
4Mathematical Research Branch, National
Institute of Diabetes and Digestive and Kidney Diseases, National
Institutes of Health, Bethesda, Maryland 20814
Smith, Gregory D.,
Charles L. Cox,
S. Murray Sherman, and
John Rinzel.
Fourier Analysis of Sinusoidally Driven Thalamocortical Relay
Neurons and a Minimal Integrate-and-Fire-or-Burst Model. J. Neurophysiol. 83: 588-610, 2000. We performed
intracellular recordings of relay neurons from the lateral geniculate
nucleus of a cat thalamic slice preparation. We measured responses
during both tonic and burst firing modes to sinusoidal current
injection and performed Fourier analysis on these responses. For
comparison, we constructed a minimal "integrate-and-fire-or-burst" (IFB) neuron model that reproduces salient features of the relay cell
responses. The IFB model is constrained to quantitatively fit our
Fourier analysis of experimental relay neuron responses, including: the
temporal tuning of the response in both tonic and burst modes,
including a finding of low-pass and sometimes broadband behavior of
tonic firing and band-pass characteristics during bursting, and the
generally greater linearity of tonic compared with burst responses at
low frequencies. In tonic mode, both experimental and theoretical
responses display a frequency-dependent transition from massively
superharmonic spiking to phase-locked superharmonic spiking near 3 Hz,
followed by phase-locked subharmonic spiking at higher frequencies.
Subharmonic and superharmonic burst responses also were observed
experimentally. Characterizing the response properties of the
"tuned" IFB model leads to insights regarding the observed stimulus
dependence of burst versus tonic response mode in relay neurons.
Furthermore the simplicity of the IFB model makes it a candidate for
large scale network simulations of thalamic functioning.
