This thesis entitled "Tactile discrimination and whisking behaviour in the rat" is submitted to the University of Manchester by David Merry for the consideration of the award of the degree of Doctor of Philosophy on the 23h of October, 2013 Spatial navigation and discriminatory tasks have long been a focus of scientific interest for research into to the underlying processes of memory formation for rats. These tasks are usually focused on the visual sensory domain alone, and those that do involve tactile sensory tasks usually involve either passive sensory stimulus or the rat is restrained. However rats are primarily crepuscular and, thus, rely upon other sensory modalities such as somatosensation via activation of their facial whiskers. While using these facial whiskers rats orientate their head and use varying whisking strategies, thus the information in which passive sensory stimulus or a restrained rat is not optimized and the picture incomplete. In this project the role of whisker modulation in discrimination and whisking behaviour is explored in the rat during three major discriminatory tasks in which the polarizing cue is tactile, as well as behavioural electrophysiological data from awake rats from electrodes implanted in the ventral medial nucleus of the rat while the rats undertake active whisking tasks is presented. My results showed that rats could be trained simultaneously in a texture discrimination task (x 2 (1, N = 527)=7.53, p 0.05). This degree of acuity was less then expected. The Ventral posteromedial nucleus (VPM) of the thalamus is the second step of the main whisker pathway in the rat, and conveys whisker responsive information to the primary sensory cortex. We implanted rats (N=2) with microwire arrays in the VPM. Our results show that MUA activity within the VPM is sensitive to the velocity of the whisking made by the rat both duringcontact and non-contact events and that there is a significant variety of strategiesexhibited by the rat during active whisking.
|Date of Award
|31 Dec 2013
- The University of Manchester
|John Gigg (Supervisor) & Rasmus Petersen (Supervisor)