BACKGROUND: Cognitive deficits are common in early multiple sclerosis (MS), however, spatial navigation changes and their associations with brain pathology remain poorly understood. OBJECTIVE: To characterize the profile of spatial navigation changes in two main navigational strategies, egocentric (self-centred) and allocentric (world-centred), and their associations with demyelinating and neurodegenerative changes in early MS. METHODS: Participants with early MS after the first clinical event (n = 51) and age-, gender- and education-matched controls (n = 42) underwent spatial navigation testing in a real-space human analogue of the Morris water maze task, comprehensive neuropsychological assessment, and MRI brain scan with voxel-based morphometry and volumetric analyses. RESULTS: The early MS group had lower performance in the egocentric (p = 0.010), allocentric (p = 0.004) and allocentric-delayed (p = 0.038) navigation tasks controlling for age, gender and education. Based on the applied criteria, lower spatial navigation performance was present in 26-29 and 33-41% of the participants with early MS in the egocentric and the allocentric task, respectively. Larger lesion load volume in cortical, subcortical and cerebellar regions (ß ≥ 0.29; p ≤ 0.032) unlike brain atrophy was associated with less accurate allocentric navigation performance. CONCLUSION: Lower spatial navigation performance is present in up to 41% of the participants with early MS. Demyelinating lesions in early MS may disrupt neural network forming the basis of allocentric navigation.

• Keywords
• Allocentric, Cognition, Egocentric, Lesion load, MRI, Neuropsychology, Volumetry, Voxel-based morphometry,
• MeSH
• Cognition MeSH
• Cognitive Dysfunction * MeSH
• Humans MeSH
• Neuropsychological Tests MeSH
• Spatial Navigation * MeSH
• Multiple Sclerosis * diagnostic imaging   MeSH
• Space Perception MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

The dissociation between egocentric and allocentric reference frames is well established. Spatial coding relative to oneself has been associated with a brain network distinct from spatial coding using a cognitive map independently of the actual position. These differences were, however, revealed by a variety of tasks from both static conditions, using a series of images, and dynamic conditions, using movements through space. We aimed to clarify how these paradigms correspond to each other concerning the neural correlates of the use of egocentric and allocentric reference frames. We review here studies of allocentric and egocentric judgments used in static two- and three-dimensional tasks and compare their results with the findings from spatial navigation studies. We argue that neural correlates of allocentric coding in static conditions but using complex three-dimensional scenes and involving spatial memory of participants resemble those in spatial navigation studies, while allocentric representations in two-dimensional tasks are connected with other perceptual and attentional processes. In contrast, the brain networks associated with the egocentric reference frame in static two-dimensional and three-dimensional tasks and spatial navigation tasks are, with some limitations, more similar. Our review demonstrates the heterogeneity of experimental designs focused on spatial reference frames. At the same time, it indicates similarities in brain activation during reference frame use despite this heterogeneity.

• MeSH
• Humans MeSH
• Brain Mapping methods   MeSH
• Judgment physiology   MeSH
• Neuropsychological Tests MeSH
• Attention physiology   MeSH
• Spatial Memory physiology   MeSH
• Photic Stimulation methods   MeSH
• Space Perception physiology   MeSH
• Visual Perception physiology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

Lacunar cerebral infarction (LI) is one of risk factors of vascular dementia and correlates with progression of cognitive impairment including the executive functions. However, little is known on spatial navigation impairment and its underlying microstructural alteration of white matter in patients with LI and with or without mild cognitive impairment (MCI). Our aim was to investigate whether the spatial navigation impairment correlated with the white matter integrity in LI patients with MCI (LI-MCI). Thirty patients with LI were included in the study and were divided into LI-MCI (n=17) and non MCI (LI-Non MCI) groups (n=13) according neuropsychological tests.The microstructural integrity of white matter was assessed by calculating a fractional anisotropy (FA) and mean diffusivity (MD) from diffusion tensor imaging (DTI) scans. The spatial navigation accuracy, separately evaluated as egocentric and allocentric, was assessed by a computerized human analogue of the Morris Water Maze tests Amunet. LI-MCI performed worse than the CN and LI-NonMCI groups on egocentric and delayed spatial navigation subtests. LI-MCI patients have spatial navigation deficits. The microstructural abnormalities in diffuse brain regions, including hippocampus, uncinate fasciculus and other brain regions may contribute to the spatial navigation impairment in LI-MCI patients at follow-up.

• Keywords
• Gerotarget, diffusion tensor imaging, lacunar infarction, mild cognitive impairment, spatial navigation,
• MeSH
• Anisotropy MeSH
• White Matter diagnostic imaging   physiopathology   MeSH
• Diffusion Magnetic Resonance Imaging * MeSH
• Cognition * MeSH
• Cognitive Dysfunction diagnostic imaging   physiopathology   psychology   MeSH
• Stroke, Lacunar diagnostic imaging   physiopathology   psychology   MeSH
• Middle Aged MeSH
• Humans MeSH
• Neuropsychological Tests MeSH
• Spatial Behavior * MeSH
• Aged MeSH
• Case-Control Studies MeSH
• Space Perception * MeSH
• Diffusion Tensor Imaging * MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH