Conducting processes in simulated chronic in°ammatory demyelinating polyneuropathy at 20  C–42  C D. I. Stephanova * , ‡ , M. Daskalova * and M. Mladenov † * Institute of Biophysics and Biomedical Engineering Bulgarian Academy of Sciences, Acad. G. Bontchev Str., Bl. 21, So¯a 1113, Bulgaria † Institute of Biology, Faculty of Natural Science and Mathematics Arhimedova 6, PO Box 162 " Sv. Kiril i Metodij " University Skopje, Republic of Macedonia ‡ dsteph@bio.bas.bg [Received 29 November 2014; Accepted 3 December 2014; Published ] Decreased conducting processes leading usually to conduction block and increased weakness of limbs during cold (cold paresis) or warmth (heat paresis) have been reported in patients with chronic in°ammatory demyelinating polyneuropathy (CIDP). To explore the mechanisms of these symptoms, the e®ects of temperature (from 20  C to 42  C) on nodal action potentials and their current kinetics in previously simulated case of 70% CIDP are investigated, using our temperature dependent multi-layered model of the myelinated human motor nerve ¯ber. The results show that potential amplitudes have a bi¯d form at 20  C. As in the normal case, for the CIDP case, the nodal action potentials are determined mainly by the nodal sodium currents ðI Na Þ for the temperature range of 20–39  C, as the contribution of nodal fast and slow po- tassium currents (I Kf and I Ks ) to the total ionic current (I i ) is negligible. Also, the contribution of I Kf and I Ks to the membrane repolarization is enhanced at temperatures higher than 39  C. However, in the temperature range of 20–42  C, all potential parameters in the CIDP case, except for the conduction block during hyperthermia ( 40  C) which is again at 45  C, worsen: (i) conduction velocities and potential amplitudes are decreased; (ii) afterpotentials and threshold stimulus currents for the potential generation are increased; (iii) the current kinetics of action potentials is slowed and (iv) the conduction block during hypothermia ( 25  C) is at temperatures lower than 20  C. These potential parameters are more altered during hyper- thermia and are most altered during hypothermia. The present results suggest that the con- ducting processes in patients with CIDP are in higher risk during hypothermia than hyperthermia. Keywords: Temperature; hypothermia; hyperthermia; CIDP; action potentials; current kinetics; computational neuroscience. 1. Introduction The e®ect of temperature on neurological disorders is complicated and has not been fully explored, neither in patients, nor in physiological researches. A well-known e®ect is the worsening of conducting processes after warming in patients with various January 9, 2015 9:16:53am WSPC/179-JIN 1550006 ISSN: 0219-6352 2nd Reading Journal of Integrative Neuroscience, Vol. 14, No. 1 (2015) 1–12 ° c Imperial College Press DOI: 10.1142/S0219635215500065 1