Assessing neural activity related to decision-making through flexible odds ratio curves and their derivatives
Article first published online: 24 MAR 2011
Copyright © 2011 John Wiley & Sons, Ltd.
Statistics in Medicine
Volume 30, Issue 14, pages 1695–1711, 30 June 2011
How to Cite
Roca-Pardiñas, J., Cadarso-Suárez, C., Pardo-Vazquez, J. L., Leboran, V., Molenberghs, G., Faes, C. and Acuña, C. (2011), Assessing neural activity related to decision-making through flexible odds ratio curves and their derivatives. Statist. Med., 30: 1695–1711. doi: 10.1002/sim.4220
- Issue published online: 2 JUN 2011
- Article first published online: 24 MAR 2011
- Manuscript Accepted: 4 JAN 2011
- Manuscript Received: 8 JUN 2009
- generalized additive models;
- kernel smoothing;
- neural activity
It is well established that neural activity is stochastically modulated over time. Therefore, direct comparisons across experimental conditions and determination of change points or maximum firing rates are not straightforward. This study sought to compare temporal firing probability curves that may vary across groups defined by different experimental conditions. Odds-ratio (OR) curves were used as a measure of comparison, and the main goal was to provide a global test to detect significant differences of such curves through the study of their derivatives. An algorithm is proposed that enables ORs based on generalized additive models, including factor-by-curve-type interactions to be flexibly estimated. Bootstrap methods were used to draw inferences from the derivatives curves, and binning techniques were applied to speed up computation in the estimation and testing processes. A simulation study was conducted to assess the validity of these bootstrap-based tests. This methodology was applied to study premotor ventral cortex neural activity associated with decision-making. The proposed statistical procedures proved very useful in revealing the neural activity correlates of decision-making in a visual discrimination task. Copyright © 2011 John Wiley & Sons, Ltd.