Abstract
The posterior cingulate cortex (PCC) is involved in higher order sensory and sensory-motor integration while the planum temporale/parietal operculum (PT/PO) junction takes part in auditory motion and vestibular processing. Both regions are activated during different types of visual stimulation. Here, we describe the response characteristics of the PCC and PT/PO to basic types of visual motion stimuli of different complexity (complex and simple coherent as well as incoherent motion). Functional magnetic resonance imaging (fMRI) was performed in 10 healthy subjects at 3 Tesla, whereby different moving dot stimuli (vertical, horizontal, rotational, radial, and random) were contrasted against a static dot pattern. All motion stimuli activated a distributed cortical network, including previously described motion-sensitive striate and extrastriate visual areas. Bilateral activations in the dorsal region of the PCC (dPCC) were evoked using coherent motion stimuli, irrespective of motion direction (vertical, horizontal, rotational, radial) with increasing activity and with higher complexity of the stimulus. In contrast, the PT/PO responded equally well to all of the different coherent motion types. Incoherent (random) motion yielded significantly less activation both in the dPCC and in the PT/PO area. These results suggest that the dPCC and the PT/PO take part in the processing of basic types of visual motion. However, in dPCC a possible effect of attentional modulation resulting in the higher activity evoked by the complex stimuli should also be considered. Further studies are warranted to incorporate these regions into the current model of the cortical motion processing network.
Highlights
The majority of physiological and neuroimaging studies investigating visual motion stimuli have focused on the initial stages of motion perception, with less regard to the later stages of processing motion information
The dPCC was activated by the different coherent visual motion stimuli ~VERTICAL, HORIZONTAL, ROTATION, and RADIAL! but no significant response to the incoherent motion stimulus ~RANDOM! was found
In agreement with previous neuroimaging reports, our study identified a widespread network of motion responsive areas in the human brain extending beyond the dorsal pathway, including distinct parietal and frontal areas engaged in the processing of different motion types ~Orban et al, 2003; Sunaert et al, 1999; Vanduffel et al, 2002!
Summary
The majority of physiological and neuroimaging studies investigating visual motion stimuli have focused on the initial stages of motion perception, with less regard to the later stages of processing motion information. The most intensively studied visual area related to motion perception is the human V5 ~Zeki et al, 1991; for a recent review see: Born & Bradley, 2005!. PCC seems to be involved in the later stages of visuospatial and motor information processing, it exemplifies the problem of an area that is poorly characterized using basic types of motion stimuli. As a by-product of recent publications, it has been found to be activated by various visual motion stimuli ~Braddick et al, 2001; Cornette et al, 1998a; Dieterich et al, 2003; Orban et al, 2003; Stebbins et al, 2004; Stiers et al, 2006; Sunaert et al, 1999! The dorsolateral part of PCC ~dPCC! is known to be involved in higher-order information processing during cognitive tasks and visuospatial orientation and integration processing ~for a review see: Vogt & Laureys, 2005; Vogt, 2005!
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
