PMID- 20608868 OWN - NLM STAT- MEDLINE DCOM- 20110627 LR - 20211020 IS - 1530-888X (Electronic) IS - 0899-7667 (Print) IS - 0899-7667 (Linking) VI - 22 IP - 10 DP - 2010 Oct TI - Discrete time rescaling theorem: determining goodness of fit for discrete time statistical models of neural spiking. PG - 2477-506 LID - 10.1162/NECO_a_00015 [doi] AB - One approach for understanding the encoding of information by spike trains is to fit statistical models and then test their goodness of fit. The time-rescaling theorem provides a goodness-of-fit test consistent with the point process nature of spike trains. The interspike intervals (ISIs) are rescaled (as a function of the model's spike probability) to be independent and exponentially distributed if the model is accurate. A Kolmogorov-Smirnov (KS) test between the rescaled ISIs and the exponential distribution is then used to check goodness of fit. This rescaling relies on assumptions of continuously defined time and instantaneous events. However, spikes have finite width, and statistical models of spike trains almost always discretize time into bins. Here we demonstrate that finite temporal resolution of discrete time models prevents their rescaled ISIs from being exponentially distributed. Poor goodness of fit may be erroneously indicated even if the model is exactly correct. We present two adaptations of the time-rescaling theorem to discrete time models. In the first we propose that instead of assuming the rescaled times to be exponential, the reference distribution be estimated through direct simulation by the fitted model. In the second, we prove a discrete time version of the time-rescaling theorem that analytically corrects for the effects of finite resolution. This allows us to define a rescaled time that is exponentially distributed, even at arbitrary temporal discretizations. We demonstrate the efficacy of both techniques by fitting generalized linear models to both simulated spike trains and spike trains recorded experimentally in monkey V1 cortex. Both techniques give nearly identical results, reducing the false-positive rate of the KS test and greatly increasing the reliability of model evaluation based on the time-rescaling theorem. FAU - Haslinger, Robert AU - Haslinger R AD - Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA. robhh@nmr.mgh.harvard.edu FAU - Pipa, Gordon AU - Pipa G FAU - Brown, Emery AU - Brown E LA - eng GR - K25 NS052422/NS/NINDS NIH HHS/United States GR - DP1 OD003646/OD/NIH HHS/United States GR - K25 NS052422-02/NS/NINDS NIH HHS/United States GR - MH59733-07/MH/NIMH NIH HHS/United States GR - R01 MH059733/MH/NIMH NIH HHS/United States GR - DP1 OD003646-01/OD/NIH HHS/United States PT - Journal Article PT - Research Support, N.I.H., Extramural PT - Research Support, Non-U.S. Gov't PL - United States TA - Neural Comput JT - Neural computation JID - 9426182 SB - IM MH - Action Potentials/*physiology MH - Algorithms MH - Animals MH - Computer Simulation/statistics & numerical data MH - Haplorhini MH - Humans MH - *Models, Neurological MH - *Models, Statistical MH - *Neural Networks, Computer MH - Poisson Distribution MH - Reaction Time/physiology MH - Reproducibility of Results MH - Time Factors PMC - PMC2932849 MID - NIHMS186123 EDAT- 2010/07/09 06:00 MHDA- 2011/06/28 06:00 PMCR- 2011/10/01 CRDT- 2010/07/09 06:00 PHST- 2010/07/09 06:00 [entrez] PHST- 2010/07/09 06:00 [pubmed] PHST- 2011/06/28 06:00 [medline] PHST- 2011/10/01 00:00 [pmc-release] AID - 10.1162/NECO_a_00015 [doi] PST - ppublish SO - Neural Comput. 2010 Oct;22(10):2477-506. doi: 10.1162/NECO_a_00015.