title: Point-process analysis of neural spiking activity of muscle spindles recorded from thin-film longitudinal intrafascicular electrodes.
abstract: Recordings from thin-film Longitudinal Intra-Fascicular Electrodes (tfLIFE) together with a wavelet-based de-noising and a correlation-based spike sorting algorithm, give access to firing patterns of muscle spindle afferents. In this study we use a point process probability structure to assess mechanical stimulus-response characteristics of muscle spindle spike trains. We assume that the stimulus intensity is primarily a linear combination of the spontaneous firing rate, the muscle extension, and the stretch velocity. By using the ability of the point process framework to provide an objective goodness of fit analysis, we were able to distinguish two classes of spike clusters with different statistical structure. We found that spike clusters with higher SNR have a temporal structure that can be fitted by an inverse Gaussian distribution while lower SNR clusters follow a Poisson-like distribution. The point process algorithm is further able to provide the instantaneous intensity function associated with the stimulus-response model with the best goodness of fit. This important result is a first step towards a point process decoding algorithm to estimate the muscle length and possibly provide closed loop Functional Electrical Stimulation (FES) systems with natural sensory feedback information.
authors.affiliation: Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital – Harvard Medical School, Boston, MA 02114, USA. flciti@neurostat.mit.edu
authors.forename: Luca
authors.initials: L
authors.lastname: Citi
authors.forename: Milan
authors.initials: M
authors.lastname: Djilas
authors.forename: Christine
authors.initials: C
authors.lastname: Azevedo-Coste
authors.forename: Ken
authors.initials: K
authors.lastname: Yoshida
authors.forename: Emery N
authors.initials: EN
authors.lastname: Brown
authors.forename: Riccardo
authors.initials: R
authors.lastname: Barbieri
mesh_terms: D000200:Action Potentials / Q000502:physiology*; D000465:Algorithms; D000818:Animals; D003198:Computer Simulation; D004566:Electrodes; D008959:Models, Neurological; D015233:Models, Statistical; D009470:Muscle Spindles / Q000502:physiology*; D011817:Rabbits