Although perception of time is fundamental to human and animal behavior, there is no consensus in the scientific community with respect to the neural mechanisms that enable us to actually perceive and process time. This proposal seeks to answer three fundamental questions addressing the nature and localization of the underlying neuronal mechanisms enabling humans to use temporal information and keep track of time. The specific aims are: (i) To determine whether neural mechanisms of temporal processing are specific to a sensory modality or shared between different modalities. (ii) To determine whether information about elapsed duration of an event is encoded in neural activity (iii) To investigate the potential causal role of different brain regions in time perception. Additionally, throughout the project I will take advantage of individual differences in ability to judge time to investigate whether such individual differences have specific neuroanatomical correlates. To achieve these goals I will apply temporal paradigms using stimuli from different modalities and examine temporal processing using behavioral experiments, functional MRI (fMRI) measurements of brain activity, transcranial magnetic stimulation (TMS) to disrupt cortical function, and voxel-based morphometry (VBM) to correlate focal anatomical differences with behavioral differences, so as to provide converging evidence from multiple methodologies.