Role of parietal cortex in spatial imagery investigated by functional imaging and transient lesion studies
Final Report Abstract
Background: Mental imagery refers to the experience of a perception in the absence of a corresponding physical stimulus. Objects in visual imagery can be manipulated much like actual objects, which can help one to reason about the consequences of the corresponding physical manipulation. In this sense, we can not only generate a mental visual image, but also manipulate, transform or rotate this image in our mind. This aspect of mental imagination is often referred to as spatial imagery. Though often unconsciously, we commonly use spatial imagery in a large variety of our everyday-life activities such as object recognition, reasoning, language comprehension, or memory. Due to its exceptional importance the exact processes associated with imagery have long occupied cognitive psychologists. In particular, the neurobiological processes underlying mental imagery continue to be a matter of debate and controversy among neuroscientists, cognitive psychologists, philosophers, and biologists. Early insights were depending strongly on studying effects of lesions in humans. Modern brain imaging techniques, such as functional magnetic resonance imaging (fMRI), allow us to non-invasively identify which exact brain regions underlie the successful execution of spatial imagery. Aim: Understanding the specific role of parietal cortex in spatial imagery, and study the interconnection and communication within and among the different brain networks active during mental imagery tasks. Methodology: We conducted a series of interconnected studies employing a range of non-invasive neuroimaging (functional MRI, EEG, simultaneous fMRI – EEG) and interference (transcranial magnetic stimulation) methods. Healthy human volunteers were asked to execute several behaviorally-controlled imagery paradigms, while their neural network activity changes was recorded, using full brain fMRI and/or EEG, and subsequently analyzed using cutting-edge data-driven multivariate analysis tools. Results: When participants perform spatial imagery, we were able to functionally segregate an early from a late bilateral parietal activation network which was orchestrated by respective early versus late premotor, occipito-temporal, and late prefrontal cortex activity changes. We also investigated the nature and the direction of information flow within and between these networks, revealing that the information upcoming from sensory brain regions is first sent to the premotor cortex and then to the medial-dorsal parietal cortex, i.e., in a top-down manner from the motor to the perceptual pole of spatial imagery. In fact, the premotor cortex turned out to be the central relay-station, projecting to parietal cortex at two functionally distinct time-points with the late premotor-parietal activity network also sending neural input to bilateral prefrontal and occipito-temporal-cortex. When participants imagine realistic senses, parietal and frontal lobe work closely with remote visual areas in the occipital and temporal cortex to encode and retain an integrated visuo-spatial mental picture. Moreover, our combined evidence from fMRI and timefrequency EEG analysis shows that during scene imagery the activity of frontal areas precedes that of parietal cortex and suggests a correlation between observed fMRI activation patterns and induced power increase of neuronal oscillations in the theta and beta frequency bands. Conclusion: The neurobiological basis of mental imagery is characterised by complex neural network dynamics and functional segregation. We showed that brain regions which are conventionally modelled as functional units, e.g. areas within the parietal cortex; can be functionally segregated into distinct subdivisions with different functional contributions. While spatial imagery relies on dynamic interactions from premotor to parietal cortex, the imagination of realistic scenes activates information flow between fronto-parietal and remote occipital-temporal brain regions. Our results provide the empirical basis for a reconsideration of the mono-casuistic role of parietal cortex in (spatial) imagery, putting prefrontal, premotor and occipito-temporal regions, and the dynamic interplay between them, into a new focus of being critical mediating relay-stations and functional subdivions during imagery.
Publications
- (2006) FMRI mental chronometry reveals the spatiotemporal neuronal dynamics underlying the modality-specific construction and spatial analysis of visual mental images. Poster presented at the 12th Annual Meeting of the Organization of Human Brain Mapping, Florence, Italy
Sack, A.T. Staeren, N., Roebroeck, A., Goebel, R., Formisano, E.
- Timeresolved fMRI during imagery of complex scenes. (2006) Poster presented at HBM2006, 12th Annual Meeting of the Organization of Human Brain Mapping, Florence, Italy
Aline W. de Borst, Alexander T. Sack, Fabrizio Esposito, Rainer Goebel, Elia Formisano
- (2007) A spatio-temporal interaction on the apparent motion trace. Vision Res. 47(28):3424-33
Schwiedrzik CM, A. Alink, A. Kohler, W. Singer & L. Muckli
- (2007) Dissecting cognitive stages with time-resolved fMRI data: a comparison of fuzzy clustering and independent component analysis. Magnetic Resonance Imaging. 2007; 25(6):860-8
Smolders A, De Martino F, Staeren N, Scheunders P, Sijbers J, Goebel R, Formisano E.
- (2007) Imagined Motion: investigating effective connectivity between early visual areas, hMT/V5 and parietal cortex. Poster presented at HBM2007, 13th Annual Meeting of the Organization of Human Brain Mapping, Chicago (Ill.), USA
Kaas, A.L., E. Formisano, D. Linden,W. Singer and L. Muckli
- (2007) Separate cortical stages in amodal completion revealed by functional magnetic resonance adaptation. BMC Neurosci. 31;8:70
Weigelt S., W. Singer, & L. Muckli
- (2007) The cortical representation of objects rotating in depth. J Neurosci. 2007 Apr 4;27(14):3864-74
Weigelt S, Kourtzi Z, Kohler A, Singer W, Muckli L
- ICA in the analysis of complex cognitive tasks. Invited presentation at HBM2007, 13th Annual Meeting of the Organization of Human Brain Mapping, Chicago, US
Formisano E.
- (2008) A Comparison of Feature Selection Strategies for Classification of fMRI Activation Patterns. Oral presentation at the 14th Annual Meeting of the Organization for Human Brain Mapping. Melbourne, Australia
Valente, G., De Martino, F., Goebel R, Formisano, E.
- (2008) Deciding what to see: The role of intention and attention in the perception of apparent motion. Vision Res. 48(8):1096-106
Kohler A., L. Haddad, W. Singer & L. Muckli
- (2008) Functional magnetic resonance adaptation in visual neuroscience. Reviews in the Neurosciences 19 (4-5): 363-380
Weigelt S. L. Muckli & A. Kohler
- (2008) Imagery of a moving object affects activation patterns and directed influences of hMT/V5+, posterior parietal and early visual regions. Proceedings of the 14th annual meeting of the Organization for Human Brain Mapping, Melbourne, Australia, June 2008
Kaas AL, Formisano E, Linden D, Singer W, Muckli L
- (2008) Imagined motion: interactions between parietal cortex, human MT and early visual areas. Proceedings of the 6th forum of the Federation of European Neuroscience Societies (FENS), Geneva, Switzerland, June 2008
Kaas, A.L., Formisano, E., Linden, D., Singer, W., Muckli, L.
- (2008). Dynamic Premotor-To-Parietal interactions during Spatial Imagery. Journal of Neuroscience, 28(34), 8417-8429
Sack, A. T., Jacobs, C., De Martino, F., Staeren, N., Goebel, R., & Formisano, E.
- (2008). Optimizing functional accuracy of TMS in cognitive studies: a comparison of methods. Journal of Cognitive Neuroscience 21(2):207-21
Sack, A. T., Cohen Kadosh, R., Schuhmann, T., Moerel, M., Walsh, V., & Goebel, R.
- (2009) Predicting evoked and induced EEG responses during mental visual imagery using fMRI and multivariate regression. Proceedings of the 15th annual meeting of the Organization for Human Brain Mapping, Chicago, USA, June 2009
F. De Martino, A. de Borst, G. Valente, R. Goebel, E. Formisano
- (2009) Target Detection on the Apparent Motion Trace –A TMS Study. ECVP Meeting, Regensburg
Vetter P, L. Wilkie, Arjen Alink, Marie-Helene Grosbras & Lars Muckli
- (2009) The timing of feedback to early visual cortex in the perception of long-range apparent motion. Cerebral Cortex;19(7):1567-82
Wibral M., C. Bledowski, A. Kohler, W. Singer & L. Muckli
- Optimizing ICA in fMRI using information on spatial regularities of the sources. (2009) Magn Reson Imaging. 27(8):1110-9
Valente G, De Martino F, Filosa G, Balsi M, Formisano E.
- Spatial topography (fMRI) and spectro-temporal brain dynamics (EEG) during mental imagery of scenes (2009) Proceedings of the 15th annual meeting of the Organization for Human Brain Mapping, Chicago, USA, June 2009
A.W. de Borst, A.T. Sack, B.M. Jansma, F. Esposito, F. de Martino, G. Valente, F. di Salle, R. Goebel, E. Formisano
- Imagery of a moving object: the role of occipital cortex and human MT/V5+. Neuroimage. 2010 Jan 1;49(1):794-804
Kaas A, Weigelt S, Roebroeck A, Kohler A, Muckli L
