Neuroscience 2004 Abstract
| Presentation Number: | 983.4 |
|---|---|
| Abstract Title: | Interactions between noisy inputs and realistic current kinetics in an integrate-and-fire-or-burst model of thalamic relay neurons. |
| Authors: |
Fisher, T.*1
; Carden, W. B.1,2
; Salinas, E.1
; Alexander, G. M.1
; Daunais, J. B.2,3
; Friedman, D. P.2,3
; Grant, K. A.2,3
; Godwin, D. W.1,2
1Dept. of Neurobiology and Anat., Wake Forest Univ. Hlth. Sci., Winston-Salem, NC 2Ctr. for the Neurobehavioral Study of Alcohol, Wake Forest Univ. Hlth. Sci., Winston-Salem, NC 3Dept. of Physiology and Pharmacol., Wake Forest Univ. Hlth. Sci., Winston-Salem, NC |
| Primary Theme and Topics |
Sensory Systems - Vision -- Subcortical visual pathways |
| Secondary Theme and Topics | Synaptic Transmission and Excitability<br />- Ion Channels<br />-- Calcium Channels: Other |
| Session: |
983. Visual Thalamus Poster |
| Presentation Time: | Wednesday, October 27, 2004 4:00 PM-5:00 PM |
| Location: | San Diego Convention Center - Hall A-H, Board # BB16 |
| Keywords: | LGN , MACAQUE, SINUSOIDAL AND RANDOM NOISE STIMULI , ACTIVATION AND INACTIVATION KINETICS |
Using voltage clamp recordings of thalamic neurons in slices, we have measured the kinetics of the low-threshold Ca2+ current, IT in both monkey and ferret (Carden et al, SFN abstr, 2003). The kinetics of IT in the two species are similar but not identical, leading to differences in burst activity. Moreover, these differences may represent modulatory influences on IT that can affect biophysical channel properties. Using our in vitro data, we have constructed integrate-and-fire-or-burst (IFB) models of thalamic responses (Fisher et al, SFN abstr, 2003) that incorporate the key kinetic parameters of the native IT of the macaque for comparison to a similar model equipped with parameters derived from our recordings in ferret under the same conditions. Here we studied the response of the models when driven with sinusoidal current and, in separate experiments, with random stimuli composed of “colored” noise (i.e., correlation time τcor > 0). We found that burst activity varied across the two models. Isolated bursts were observed within a limited frequency range when the model based on ferret IT parameters was driven by sinusoidal current. In contrast, with the monkey parameters, bursts only tended to occur with trailing tonic spikes. The noisy inputs generated streams of bursts and tonic spikes, but in the monkey model, bursts were observed within a much narrower range of stimulation parameters — both more negative mean values and greater standard deviations were required to elicit a burst. Therefore, the subtle changes in IT kinetics measured across species may influence the frequency of thalamic bursts and their impact on downstream targets.
Supported by EY11695, AA013246, NRSA AA014063, NS044894-01, AA11997, and SFN
Sample Citation:
[Authors]. [Abstract Title]. Program No. XXX.XX. 2004 Neuroscience Meeting Planner. San Diego, CA: Society for Neuroscience, 2004. Online.
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