Research Report Putamen neurons process both sensory and motor information during a complex task Ana F. Vicente a , Maria A. Bermudez a, ⁎ , Maria del Carmen Romero a , Rogelio Perez b , Francisco Gonzalez a, c a CIMUS (Department of Physiology), University of Santiago de Compostela, Av. Barcelona s/n, E-15706 Santiago de Compostela, Spain b Department of Ophthalmology, Hospital da Barbanza, Ribeira, E-15993 A Coruña, Spain c Department of Ophthalmology, University Hospital, Santiago de Compostela, E-15706, Spain ARTICLE INFO ABSTRACT Article history: Accepted 18 May 2012 Available online 25 May 2012 The putamen has classically been considered to be primarily a motor structure. It is involved in a broad range of roles and its neurons have been postulated to function as pattern classifiers of behaviourally significant events. However, its specific role in motor and sensory processing is still unclear. For the purpose of better categorizing putamen neurons, we trained two rhesus monkeys to perform multisensory operant tasks by using complex stimuli such as short videoclips. Trials involved image or soundtrack or both. Some stimuli required a motor response associated to reward, whereas others did not require response and produced no reward. We found that neurons in the putamen showed pure visual responses, action-related activity, and reward responses. Insofar as action- related activity, preparation of movement, movement execution, and withholding of movement involved three different putamen neuron populations. Moreover, our data suggest an involvement of putamen neurons in processing primary rewards and visual events in a complex task, which may contribute to reinforcement learning through stimulus–reward association. © 2012 Elsevier B.V. All rights reserved. Keywords: Putamen Motor activity Reward Visual Withholding of movement 1. Introduction Several studies have shown that the putamen together with the caudate is the major input structures of the basal ganglia. The putamen receives connections from cortical areas, the thalamus, and the midbrain. In turn, it sends connections to other components of the basal ganglia such as globus pallidus and substantia nigra (DeLong, 2000; Galvan et al., 2006; Utter and Basso, 2008). Traditionally, neurons from the putamen nucleus have been related to the execution of movement (Jaeger et al., 1995; Tolkunov et al., 1998; Ueda and Kimura, 2003). However, considerable evidence also suggests its role in learning processes as shown by reward delivery activation (Cromwell et al., 2005; Graybiel, 1995; Lau and Glimcher, 2007) or activation by stimuli that anticipate the reward onset (Blazquez et al., 2002; Kimura et al., 2003; Ravel et al., 2003). Finally, recent studies suggest an involvement of the putamen in the processing of visual information (Romero et al., 2008). Motor-related activity in the putamen has conventionally been studied by using operant tasks in which animals need to learn associations between certain stimuli and a particular BRAIN RESEARCH 1466 (2012) 70 – 81 ⁎ Corresponding author at: CIMUS (Department of Physiology), University of Santiago de Compostela, Avda. Barcelona s/n, Santiago de Compostela 15706, Spain. Fax: +34 981574145. E-mail address: maria.bermudez@usc.es (M.A. Bermudez). 0006-8993/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.brainres.2012.05.037 Available online at www.sciencedirect.com www.elsevier.com/locate/brainres