Contributions of Ih to feature selectivity in layer II stellate cells of the entorhinal cortex |
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Authors: | Julie S. Haas Alan D. Dorval II John A. White |
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Affiliation: | (1) Department of Biomedical Engineering, Center for BioDynamics, Center for Memory and Brain, Boston University, Boston, MA 02215, USA;(2) Present address: Institute for Nonlinear Science, MC0402, University of California, San Diego, La Jolla, CA 92093-0402, USA;(3) Present address: Department of Biomedical Engineering, Duke University, 136 Hudson Hall, Box 90281, Durham, NC 27708-0281, USA |
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Abstract: | Stellate cells (SCs) of the entorhinal cortex generate prominent subthreshold oscillations that are believed to be important contributors to the hippocampal theta rhythm. The slow inward rectifier I h is expressed prominently in SCs and has been suggested to be a dominant factor in their integrative properties. We studied the input-output relationships in stellate cells (SCs) of the entorhinal cortex, both in control conditions and in the presence of the I h antagonist ZD7288. Our results show that I h is responsible for SCs’ subthreshold resonance, and contributes to enhanced spiking reliability to theta-rich stimuli. However, SCs still exhibit other traits of rhythmicity, such as subthreshold oscillations, under I h blockade. To clarify the effects of I h on SC spiking, we used a generalized form of principal component analysis to show that SCs select particular features with relevant temporal signatures from stimuli. The spike-selected mix of those features varies with the frequency content of the stimulus, emphasizing the inherent nonlinearity of SC responses. A number of controls confirmed that this selectivity represents a stimulus-induced change in the cellular input-output relationship rather than an artifact of the analysis technique. Sensitivity to slow features remained statistically significant in ZD7288. However, with I h blocked, slow stimulus features were less predictive of spikes and spikes conveyed less information about the stimulus over long time scales. Together, these results suggest that I h is an important contributor to the input-output relationships expressed by SCs, but that other factors in SCs also contribute to subthreshold oscillations and nonlinear selectivity to slow features. Action Editor: Xiao-Jing Wang |
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Keywords: | Inward rectifier Reliability Information theory Spike-triggered covariance Principal component analysis Single-neuron computation |
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