We asked 12 right-brain-damaged patients (6 with left neglect signs and 6 without left neglect signs) to perform a straight ahead pointing task and a visual detection task with lateralized motor response, in order to investigate the relationship between the position of the egocentric reference and response time and accuracy in producing lateralized arm movements. Results showed that there was no correlation between the position of the egocentric reference and neglect signs, nor between the position of the egocentric reference and the latencies to direct a motor response toward either side of space. These findings were interpreted within the context of egocentric hypotheses of neglect. In particular, it was suggested that attentional or intentional neglect signs cannot be considered as a direct consequence of an ipsilesional deviation of the egocentric reference.
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http://dx.doi.org/10.1006/brcg.1998.1005 | DOI Listing |
Psychol Res
January 2025
Univ. Bordeaux, CNRS, INCIA - Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, UMR 5287, Bâtiment Bordeaux Biologie Santé (BBS), 2, rue du Dr Hoffmann Martinot, 33000, Bordeaux, France.
From an embodied perspective of cognition, number processing influences the spatial organization of motor responses showing faster left/right responses to small/large numbers. Recent evidence suggests that such spatial-numerical associations (SNAs) along the transverse and sagittal planes are mutually exclusive with respect to the spatial reference frames used by the participant. Specifically, in egocentric and allocentric frames, SNAs appear along the sagittal and transverse plane, respectively.
View Article and Find Full Text PDFNat Commun
January 2025
Department of Neurosurgery, Xinqiao Hospital, Army Medical University, Chongqing, China.
Successful navigation relies on reciprocal transformations between spatial representations in world-centered (allocentric) and self-centered (egocentric) frames of reference. The neural basis of allocentric spatial representations has been extensively investigated with grid, border, and head-direction cells in the medial entorhinal cortex (MEC) forming key components of a 'cognitive map'. Recently, egocentric spatial representations have also been identified in several brain regions, but evidence for the coexistence of neurons encoding spatial variables in each reference frame within MEC is so far lacking.
View Article and Find Full Text PDFCurr Biol
December 2024
Behavioral and Systems Neuroscience, Department of Psychology, Rutgers University, New Brunswick, NJ 08854, USA. Electronic address:
Determining the location of objects relative to ourselves is essential for interacting with the world. Neural activity in the retina is used to form a vision-independent model of the local spatial environment relative to the body. For example, when an animal navigates through a forest, it rapidly shifts its gaze to identify the position of important objects, such as a tree obstructing its path.
View Article and Find Full Text PDFNat Commun
September 2024
Center for Systems Neuroscience and Department of Psychological and Brain Sciences, Boston University, Boston, MA, USA.
Complex sensory information arrives in the brain from an animal's first-person ('egocentric') perspective. However, animals can efficiently navigate as if referencing map-like ('allocentric') representations. The postrhinal (POR) and retrosplenial (RSC) cortices are thought to mediate between sensory input and internal maps, combining egocentric representations of physical cues with allocentric head direction (HD) information.
View Article and Find Full Text PDFNavigating space and forming memories based on spatial experience are crucial for survival, including storing memories in an allocentric (map-like) framework and conversion into body-centered action. The hippocampus and parietal cortex (PC) comprise a network for coordinating these reference frames, though the mechanism remains unclear. We used a task requiring remembering previous spatial locations to make correct future action and observed that hippocampus can encode the allocentric place, while PC encodes upcoming actions and relays this to hippocampus.
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