Trimodal processing of complex stimuli in inferior parietal cortex is modality-independent

Cortex, vol. 139, pp. 198–210

Abstract

In humans, multisensory mechanisms facilitate object processing through integration of sensory signals that match in their temporal and spatial occurrence as well as their meaning. The generalizability of such integration processes across different sensory modalities is, however, to date not well understood. As such, it remains unknown whether there are cerebral areas that process object-related signals independently of the specific senses from which they arise, and whether these areas show different response profiles depending on the number of sensory channels that carry information. To address these questions, we presented participants with dynamic stimuli that simultaneously emitted object-related sensory information via one, two, or three channels (sight, sound, smell) in the MR scanner. By comparing neural activation patterns between various integration processes differing in type and number of stimulated senses, we showed that the left inferior frontal gyrus and areas within the left inferior parietal cortex were engaged independently of the number and type of sensory input streams. Activation in these areas was enhanced during bimodal stimulation, compared to the sum of unimodal activations, and increased even further during trimodal stimulation. Taken together, our findings demonstrate that activation of the inferior parietal cortex during processing and integration of meaningful multisensory stimuli is both modality-independent and modulated by the number of available sensory modalities. This suggests that the processing demand placed on the parietal cortex increases with the number of sensory input streams carrying meaningful information, likely due to the increasing complexity of such stimuli.

Authors 5

1. Danja K. Porada corresponding

   Karolinska Institutet

   Affiliation as printed

   Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden. Electronic address: danja.porada@ki.se

   Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden

2. Christina Regenbogen Aachen Department of Psychiatry, Psychotherapy and Psychosomatics Medical School JARA-Institute Brain Structure Function Relationship

   RWTH Aachen University · Jülich Aachen Research Alliance · Karolinska Institutet

   Affiliation as printed

   Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Department of Psychiatry, Psychotherapy and Psychosomatics, Medical School, RWTH Aachen University, Aachen, Germany; JARA Institute Brain Structure Function Relationship, RWTH Aachen University, Aachen, Germany

   Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden

   Department of Psychiatry, Psychotherapy and Psychosomatics, Medical School, RWTH Aachen University, Aachen, Germany

   JARA Institute Brain Structure Function Relationship, RWTH Aachen University, Aachen, Germany

3. Jessica Freiherr

   Friedrich-Alexander-Universität Erlangen-Nürnberg

   Affiliation as printed

   Department of Psychiatry and Psychotherapy, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany

4. Janina Seubert

   Karolinska Institutet

   Affiliation as printed

   Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden

5. Johan N. Lundström corresponding

   Stockholm University · University of Pennsylvania · Karolinska Institutet · Monell Chemical Senses Center

   Affiliation as printed

   Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden; Monell Chemical Senses Center, Philadelphia, USA; Department of Psychology, University of Pennsylvania, Philadelphia, USA; Stockholm University Brain Imaging Centre, Stockholm University, Stockholm, Sweden. Electronic address: johan.lundstrom@ki.se

   Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden

   Department of Psychology, University of Pennsylvania, Philadelphia, USA

   Monell Chemical Senses Center, Philadelphia, USA

   Stockholm University Brain Imaging Centre, Stockholm University, Stockholm, Sweden