REVIEW A. Amedi Æ K. von Kriegstein Æ N. M. van Atteveldt M. S. Beauchamp Æ M. J. Naumer Functional imaging of human crossmodal identification and object recognition Received: 29 July 2004 / Accepted: 12 November 2004 / Published online: 19 July 2005 Ó Springer-Verlag 2005 Abstract The perception of objects is a cognitive func- tion of prime importance. In everyday life, object per- ception benefits from the coordinated interplay of vision, audition, and touch. The different sensory modalities provide both complementary and redundant information about objects, which may improve recog- nition speed and accuracy in many circumstances. We review crossmodal studies of object recognition in hu- mans that mainly employed functional magnetic reso- nance imaging (fMRI). These studies show that visual, tactile, and auditory information about objects can activate cortical association areas that were once be- lieved to be modality-specific. Processing converges ei- ther in multisensory zones or via direct crossmodal interaction of modality-specific cortices without relay through multisensory regions. We integrate these find- ings with existing theories about semantic processing and propose a general mechanism for crossmodal object recognition: The recruitment and location of multisen- sory convergence zones varies depending on the infor- mation content and the dominant modality. Keywords Object recognition Æ Crossmodal Æ Audio-visual Æ Visuo-tactile Æ Multisensory Æ Functional magnetic resonance imaging (fMRI) Introduction We experience our environment via several sensory modalities at the same time. For example, in an opera or a movie we perceive visual and sound information in parallel. The information provided by these diverse sensory systems is synthesized in our brains to create the coherent and unified percepts we are so familiar with. The multisensory nature of our perceptions has several behavioral advantages—for example, speeded response and improved recognition in noisy environments (e.g. Newell 2004). Until recently, the neural correlates of crossmodal integration and its development have been investigated mainly using (invasive) electrophysiology in a variety of animal species and brain structures (Stein and Meredith 1993; Wallace et al. 2004a). The advent of non-invasive functional neuroimaging techniques led to investigations of crossmodal processes important for human cognition, for example linguistic processing, person identification, and object categorization. In this paper, we mainly review fMRI investigations of human crossmodal object recognition. We define objects as ‘‘something material that may be perceived by the senses’’ (Merriam-Webster online dictionary). We use this definition in a broader sense by including not only concrete objects such as vehicles, tools, and per- sons, but also more abstract objects such as letters or A. Amedi, K. von Kriegstein, N. M. van Atteveldt, M. S. Beau- champ and M. J. Naumeri contributed equally to this work A. Amedi Laboratory for Magnetic Brain Stimulation, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA K. von Kriegstein Cognitive Neurology Unit, Johann-Wolfgang-Goethe University, Frankfurt/Main, Germany K. von Kriegstein Æ M. J. Naumer Brain Imaging Center (BIC), Frankfurt/Main, Germany N. M. van Atteveldt Department of Cognitive Neuroscience, Faculty of Psychology, University of Maastricht, Maastricht, The Netherlands M. S. Beauchamp Laboratory of Brain and Cognition, National Institute of Mental Health, Bethesda, MD, USA M. J. Naumer Department of Neurophysiology, Max Planck Institute for Brain Research, Frankfurt/Main, Germany M. J. Naumer (&) Institute of Medical Psychology, Frankfurt Medical School, Heinrich-Hoffmann-Strasse 10, 60528 Frankfurt/Main, Germany E-mail: m.j.naumer@med.uni-frankfurt.de Tel.: +49-69-63016581 Fax: +49-69-63017606 Exp Brain Res (2005) 166: 559–571 DOI 10.1007/s00221-005-2396-5