The role of Posterior Parietal Cortex in spatial representation of time: a TMS study.

The existence of a spatial representation of time, where temporal intervals are represented on a mental temporal line (MTL), oriented in ascending order from left to right, was demonstrated manipulating spatial attention (by means of Prismatic Adaptation - PA). In young healthy subjects, prisms adaptation inducing a rightward orientation of spatial-attention produced an overestimation of time intervals, whereas prisms adaptation inducing a leftward shift of spatial-attention produced an underestimation of time intervals (Frassinetti, Magnani, Oliveri, 2009). Here we investigate, by using TMS, the role of the Posterior Parietal Cortex (PPC) in spatial representation of time and in cerebral plasticity phenomena mediating prismatic adaptation effects on time processing. According with neuro-functional studies (Luautè et al., 2006, 2009) different results are expected in order of the side of PPC deactivated (right or left) and of the phase of PA procedure in which TMS is applied (before or after PA procedure).