The fusion of mental imagery and sensation in the temporal association cortex

• Published in: The Journal of neuroscience Vol. 34; no. 41; pp. 13684 - 13692
• Main Authors: Berger, Christopher C, Ehrsson, H Henrik
• Format: Journal Article
• Language: English
• Published: United States Society for Neuroscience 08.10.2014
• Subjects: Acoustic Stimulation; Adult; Auditory Cortex - physiology; Female; Humans; Illusions - physiology; Imagination - physiology; Male; Medicin och hälsovetenskap; Neural Pathways - cytology; Neural Pathways - physiology; Photic Stimulation; Sensation - physiology; Sound Localization - physiology; Temporal Lobe - physiology; Visual Perception - physiology; superior temporal sulcus; multisensory; auditory cortex; ventriloquism; mental imagery
• ISSN: 0270-6474; 1529-2401; 1529-2401
• DOI: 10.1523/JNEUROSCI.0943-14.2014

It is well understood that the brain integrates information that is provided to our different senses to generate a coherent multisensory percept of the world around us (Stein and Stanford, 2008), but how does the brain handle concurrent sensory information from our mind and the external world? Recent behavioral experiments have found that mental imagery--the internal representation of sensory stimuli in one's mind--can also lead to integrated multisensory perception (Berger and Ehrsson, 2013); however, the neural mechanisms of this process have not yet been explored. Here, using functional magnetic resonance imaging and an adapted version of a well known multisensory illusion (i.e., the ventriloquist illusion; Howard and Templeton, 1966), we investigated the neural basis of mental imagery-induced multisensory perception in humans. We found that simultaneous visual mental imagery and auditory stimulation led to an illusory translocation of auditory stimuli and was associated with increased activity in the left superior temporal sulcus (L. STS), a key site for the integration of real audiovisual stimuli (Beauchamp et al., 2004a, 2010; Driver and Noesselt, 2008; Ghazanfar et al., 2008; Dahl et al., 2009). This imagery-induced ventriloquist illusion was also associated with increased effective connectivity between the L. STS and the auditory cortex. These findings suggest an important role of the temporal association cortex in integrating imagined visual stimuli with real auditory stimuli, and further suggest that connectivity between the STS and auditory cortex plays a modulatory role in spatially localizing auditory stimuli in the presence of imagined visual stimuli.