COGNITIVE NEUROSCIENCE Motor foundations of higher cognition: similarities and differences in processing regular and violated perceptual sequences of different specificity Andreja Bubic, 1,3 D. Yves von Cramon 1,2 and Ricarda I. Schubotz 1,2 1 Department of Cognitive Neurology, Functional Anatomy of the Frontal Lobes, Max Planck Institute for Human Cognitive and Brain Sciences, Stephanstrasse 1a, 04103 Leipzig, Germany 2 Max Planck Institute for Neurological Research, Cologne, Germany 3 University of Leipzig, Leipzig, Germany Keywords: categorization, deviant detection, prediction, premotor cortex, sequencing Abstract Processing perceptual sequences relies on the motor system, which is able to simulate the dynamics of the environment by developing internal representations of external events and using them to predict the incoming stimuli. Although it has previously been demonstrated that such models may incorporate predictions based on exact stimulus properties and single stimulus dimensions, it is not known whether they can also support abstract predictions pertaining to the level of stimulus categories. This issue was investigated within the present event-related functional magnetic resonance imaging study, which compared the processing of perceptual sequences of different specificity, namely those in which the sequential structure was based on the order of presentation of individual stimuli (token), and those in which such structure was defined by stimulus categories (type). The results obtained indicate a comparable engagement of the basic premotor–parietal network in processing both specific and categorical perceptual sequences. However, type sequences additionally elicited activations within the lateral prefrontal, occipital and posterior temporal regions that supported categorization in this task context. Introducing sequential deviants into token sequences activated parietotemporal and ventrolateral frontal cortices, whereas a less pronounced overall response, dominated by lateral prefrontal activation, was elicited by violations introduced into type sequences. Overall, the findings obtained suggest that, although forward models in perception may be able to incorporate expectations of lower specificity when compared to the motor domain, such processing is crucially dependent on additional contributions from lateral prefrontal as well as inferior occipital and temporal cortices that support categorization occurring in such a dynamic context. Introduction It has long been accepted that fast and accurate execution of movements is supported by different classes of internal models, among which the crucial role of simulating the executed actions and their outcomes is attributed to the so-called forward models (Wolpert & Miall, 1996; Wolpert & Kawato, 1998). Extending this view, in recent years it has been proposed that forward models can also be used for modeling the structure of the external environment and predicting incoming perceptual events (Wolpert & Kawato, 1998; Grush, 2004). Support for this proposal comes from studies showing that prediction of purely perceptual events relies on different parts of the motor system, primarily the premotor cortex and its parietal projection areas (Schubotz & von Cramon, 2003), regardless of whether participants predict an upcoming stimulus with regard to all of its properties (Schubotz & von Cramon, 2002a,b) or to only one of its features, for example form or color (Schubotz & von Cramon, 2001; Schubotz et al., 2003). On the basis of previous findings, it is not possible to say whether a higher class of abstraction, namely a categorical one based on an arbitrary rule-based conjunction of stimulus features, would be represented in a similar fashion. Naturally, similarity in this case would not imply equivalence, as categorizing exemplars would always require an additional processing step when compared to recognizing events whose identity is defined by immediately available physical features. However, it is possible to suggest that processing dynamic events of higher abstraction may still be somewhat comparable to processing those of higher specificity, given that our judgements and reactions to external events often presuppose automatic abstraction and categorization processes, for example when moving away from cars driving towards us, regardless of their exact features. Motivated by such a suggestion, the present event-related functional magnetic resonance imaging (fMRI) study investigated and mutually compared the processing of perceptual sequences. In addition, the process of detecting sequential (associative) deviants embedded within the two classes of perceptual sequences was explored. Both classes of Correspondence: Dr A. Bubic, as above. E-mail: bubic@cbs.mpg.de Received 17 March 2009, revised 6 October 2009, accepted 16 October 2009 European Journal of Neuroscience, Vol. 30, pp. 2407–2414, 2009 doi:10.1111/j.1460-9568.2009.07030.x ª The Authors (2009). Journal Compilation ª Federation of European Neuroscience Societies and Blackwell Publishing Ltd European Journal of Neuroscience