Variables that were quantified: number of attempts, duration

of the last attempt, and duration of all attempts in a session. An “attempt” is defined as an event where the animal activates (by breaking the beam) the MS close to the gap (MS2 or MS3 in Fig. 2) and a “successful attempt” is an event where the animal actually crosses over the gap to reach the other platform. The duration of a successful attempt (“duration of last attempt”) is from activation of the MS close to the gap on one side until the activation Inhibitors,research,lifescience,medical of the corresponding sensor on the other platform. “Duration of all attempts” includes the duration of the last attempt but also the duration during which MS2 or MS3 was activated but without the animal eventually crossing (thus the duration from MS2-ON until MS2-OFF and MS3-ON until MS3-OFF). In essence, these parameters will quantify how often and for how long time the animal explores the gap. Analysis Inhibitors,research,lifescience,medical of whisker kinematics The movement of the whisker was tracked and quantified essentially as previously described (Voigts et al. 2008). The area of the gap between the two platforms was monitored by a high-resolution Inhibitors,research,lifescience,medical infrared video camera (Allied Vision Technologies, PIKE 032B) with sampling frequency at 314 Hz at 640 × 300 pixels with resolution of 9.7 pixels/mm. Tracking

of the mouse position and whisker was done off-line on the recorded video sequences as described in Voigts et al. (2008). The algorithm is fully automatized and unsupervised and is implemented in the following steps: The

first 50 frames, where there was no mouse Inhibitors,research,lifescience,medical detected, were used as an average for background subtraction and normalization of the brightness level. Next, the target platform and the animals nose were detected by simple averaging and thresholding in the x-direction. Whiskers were tracked initially as vector fields of polar representation of similarity index extracted by anisotropy functions (i.e., finding the direction of invariance due to blurring and shifting). In a later stage, these paths were integrated and Inhibitors,research,lifescience,medical spline interpolated to spatially contiguous representations of whiskers. Time series of whisking angle were extracted by selleck chemicals llc computing the angle of the whisker’s fifth pixel from the base across frames. The angle was calculated in reference to the Rebamipide mean position of the tracked pixel for every sequence. The periods (peak to peak) of this oscillatory signal represented whisking cycles. Whisking cycles were divided into pro- and retraction based on the position of set points (points with zero angular velocity). Whisking amplitude was defined as the angular excursion of the whisker between two set points, respectively, protraction and retraction amplitude. Analysis of frequencies was done by using windowed Fast Fourier Transform of the zero padded time series of whisking angles.