| المؤلفون: |
Peters-Founshtein G; The Computational Neuropsychiatry Lab, Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.; Department of Nuclear Medicine, Sheba Medical Center, Ramat-Gan, Israel., Gazit L; The Computational Neuropsychiatry Lab, Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.; Department of Neurology, Hadassah Hebrew University Medical School, Jerusalem, Israel., Naveh T; The Computational Neuropsychiatry Lab, Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.; Department of Neurology, Hadassah Hebrew University Medical School, Jerusalem, Israel., Domachevsky L; Department of Nuclear Medicine, Sheba Medical Center, Ramat-Gan, Israel.; Department of Nuclear Medicine, Assuta Medical Center, Tel-Aviv, Israel., Korczyn A; Department of Neurology, Tel-Aviv University, Tel-Aviv, Israel., Bernstine H; Department of Imaging, Tel-Aviv University, Tel-Aviv, Israel.; Department of Nuclear Medicine, Assuta Medical Center, Tel-Aviv, Israel.; Department of Nuclear Medicine, Rabin Medical Center, Petah Tikva, Israel., Groshar D; Department of Imaging, Tel-Aviv University, Tel-Aviv, Israel.; Department of Nuclear Medicine, Assuta Medical Center, Tel-Aviv, Israel., Marshall GA; Center for Alzheimer Research and Treatment, Department of Neurology, Brigham and Women's Hospital, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States., Arzy S; The Computational Neuropsychiatry Lab, Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.; Department of Neurology, Hadassah Hebrew University Medical School, Jerusalem, Israel. |
| مستخلص: |
Orientation is a fundamental cognitive faculty, allowing the behaving self to link his/her current state to their internal representations of the external world. Once exclusively linked to knowledge of the current place and present time, in recent years, the concept of orientation has evolved to include processing of social, temporal, and abstract relations. Concordantly with the growing focus on orientation, spatial disorientation has been increasingly recognized as a hallmark symptom of Alzheimer's disease (AD). However, few studies have sought to explore disorientation along the AD continuum beyond the spatial domain. 51 participants along the AD continuum performed an orientation task in the spatial, temporal and social domains. Under functional magnetic resonance imaging (fMRI), participants determined which of two familiar places/events/people is geographically/ chronologically/ socially closer to them, respectively. A series of analyses revealed disorientation along the AD- continuum to follow a three-way association between (1) orientation domain, (2) brain region, and (3) disease stage. Specifically, participants with MCI exhibited impaired spatio-temporal orientation and reduced task-evoked activity in temporoparietal regions, while participants with AD dementia exhibited impaired social orientation and reduced task-evoked activity in frontoparietal regions. Furthermore, these patterns of hypoactivation coincided with Default Mode Network (DMN) sub-networks, with spatio-temporal orientation activation overlapping DMN-C and social orientation with DMN-A. Finally, these patterns of disorientation- associated hypoactivations coincided with patterns of fluorodeoxyglucose (FDG) hypometabolism and cortical atrophy characteristic to AD-dementia. Taken together, our results suggest that AD may constitute a disorder of orientation, characterized by a biphasic process as (1) early spatio-temporal and (2) late social disorientation, concurrently manifesting in task-evoked and neurodegenerative changes in temporoparietal and parieto-frontal brain networks, respectively. We propose that a profile of disorientation across multiple domains offers a unique window into the progression of AD. |
