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Basal Forebrain Atrophy Contributes to Allocentric Navigation Impairment in Alzheimer's Disease Patients.

Kerbler GM, Nedelska Z, Fripp J, Laczó J, Vyhnalek M, Lisý J, Hamlin AS, Rose S, Hort J, Coulson EJ - Front Aging Neurosci (2015)

Bottom Line: When considering the entire sample, we found that basal forebrain volume correlated with spatial accuracy in allocentric (cued) and mixed allo/egocentric navigation tasks but not the egocentric (uncued) task, demonstrating an important role of the basal forebrain in mediating cue-based spatial navigation capacity.Regression analysis revealed that, although hippocampal volume reflected navigation performance across the entire sample, basal forebrain volume contributed to mixed allo/egocentric navigation performance in the AD group, whereas hippocampal volume did not.This suggests that atrophy of the basal forebrain contributes to aspects of navigation impairment in AD that are independent of hippocampal atrophy.

View Article: PubMed Central - PubMed

Affiliation: Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland , Brisbane, QLD , Australia.

ABSTRACT
The basal forebrain degenerates in Alzheimer's disease (AD) and this process is believed to contribute to the cognitive decline observed in AD patients. Impairment in spatial navigation is an early feature of the disease but whether basal forebrain dysfunction in AD is responsible for the impaired navigation skills of AD patients is not known. Our objective was to investigate the relationship between basal forebrain volume and performance in real space as well as computer-based navigation paradigms in an elderly cohort comprising cognitively normal controls, subjects with amnestic mild cognitive impairment and those with AD. We also tested whether basal forebrain volume could predict the participants' ability to perform allocentric- vs. egocentric-based navigation tasks. The basal forebrain volume was calculated from 1.5 T magnetic resonance imaging (MRI) scans, and navigation skills were assessed using the human analog of the Morris water maze employing allocentric, egocentric, and mixed allo/egocentric real space as well as computerized tests. When considering the entire sample, we found that basal forebrain volume correlated with spatial accuracy in allocentric (cued) and mixed allo/egocentric navigation tasks but not the egocentric (uncued) task, demonstrating an important role of the basal forebrain in mediating cue-based spatial navigation capacity. Regression analysis revealed that, although hippocampal volume reflected navigation performance across the entire sample, basal forebrain volume contributed to mixed allo/egocentric navigation performance in the AD group, whereas hippocampal volume did not. This suggests that atrophy of the basal forebrain contributes to aspects of navigation impairment in AD that are independent of hippocampal atrophy.

No MeSH data available.


Related in: MedlinePlus

Human analog of the MWM. (A) Schematic diagram of the real space version of the human MWM indicating the circular target zone on the floor, wall cues within the arena, and the lit pole used to indicate the position of the target. (B) Schematic of a computer screen view displaying the computerized task. The largest circle represents the arena, the smallest circle in the arena representing the goal position, the mid-sized circle on the edge of the arena representing the start position, and the lines on the edge of the arena representing the visual cues. The trajectory shows an individual subject’s hypothetical solution of getting from the start to the goal. (B,C) Schematic of the three subtasks: mixed allo/egocentric, egocentric (uncued), and allocentric (cued) displayed as for the computerized task or as an above view of the real space arena.
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Figure 1: Human analog of the MWM. (A) Schematic diagram of the real space version of the human MWM indicating the circular target zone on the floor, wall cues within the arena, and the lit pole used to indicate the position of the target. (B) Schematic of a computer screen view displaying the computerized task. The largest circle represents the arena, the smallest circle in the arena representing the goal position, the mid-sized circle on the edge of the arena representing the start position, and the lines on the edge of the arena representing the visual cues. The trajectory shows an individual subject’s hypothetical solution of getting from the start to the goal. (B,C) Schematic of the three subtasks: mixed allo/egocentric, egocentric (uncued), and allocentric (cued) displayed as for the computerized task or as an above view of the real space arena.

Mentions: Spatial navigation was tested using in-house developed real space and computerized versions of the hMWM (Figure 1) based in the Laboratory of Spatial Cognition, a joint workplace of the Department of Neurology, 2nd Faculty of Medicine, Charles University and the Institute of Physiology, Academy of Sciences of the Czech Republic. The hMWM was designed to examine the two basic types of navigation: (1) allocentric (cued) navigation, which is hippocampus-driven, self-position-independent, and uses salient distal cues to find the goal (Astur et al., 2002) and (2) egocentric (uncued) navigation, which is predominantly parietal cortex- and caudate nucleus-driven, and is self- and start-position-dependent (Weniger et al., 2009). The real space and computer-based versions of the task are described in detail elsewhere (Hort et al., 2007; Laczo et al., 2011).


Basal Forebrain Atrophy Contributes to Allocentric Navigation Impairment in Alzheimer's Disease Patients.

Kerbler GM, Nedelska Z, Fripp J, Laczó J, Vyhnalek M, Lisý J, Hamlin AS, Rose S, Hort J, Coulson EJ - Front Aging Neurosci (2015)

Human analog of the MWM. (A) Schematic diagram of the real space version of the human MWM indicating the circular target zone on the floor, wall cues within the arena, and the lit pole used to indicate the position of the target. (B) Schematic of a computer screen view displaying the computerized task. The largest circle represents the arena, the smallest circle in the arena representing the goal position, the mid-sized circle on the edge of the arena representing the start position, and the lines on the edge of the arena representing the visual cues. The trajectory shows an individual subject’s hypothetical solution of getting from the start to the goal. (B,C) Schematic of the three subtasks: mixed allo/egocentric, egocentric (uncued), and allocentric (cued) displayed as for the computerized task or as an above view of the real space arena.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585346&req=5

Figure 1: Human analog of the MWM. (A) Schematic diagram of the real space version of the human MWM indicating the circular target zone on the floor, wall cues within the arena, and the lit pole used to indicate the position of the target. (B) Schematic of a computer screen view displaying the computerized task. The largest circle represents the arena, the smallest circle in the arena representing the goal position, the mid-sized circle on the edge of the arena representing the start position, and the lines on the edge of the arena representing the visual cues. The trajectory shows an individual subject’s hypothetical solution of getting from the start to the goal. (B,C) Schematic of the three subtasks: mixed allo/egocentric, egocentric (uncued), and allocentric (cued) displayed as for the computerized task or as an above view of the real space arena.
Mentions: Spatial navigation was tested using in-house developed real space and computerized versions of the hMWM (Figure 1) based in the Laboratory of Spatial Cognition, a joint workplace of the Department of Neurology, 2nd Faculty of Medicine, Charles University and the Institute of Physiology, Academy of Sciences of the Czech Republic. The hMWM was designed to examine the two basic types of navigation: (1) allocentric (cued) navigation, which is hippocampus-driven, self-position-independent, and uses salient distal cues to find the goal (Astur et al., 2002) and (2) egocentric (uncued) navigation, which is predominantly parietal cortex- and caudate nucleus-driven, and is self- and start-position-dependent (Weniger et al., 2009). The real space and computer-based versions of the task are described in detail elsewhere (Hort et al., 2007; Laczo et al., 2011).

Bottom Line: When considering the entire sample, we found that basal forebrain volume correlated with spatial accuracy in allocentric (cued) and mixed allo/egocentric navigation tasks but not the egocentric (uncued) task, demonstrating an important role of the basal forebrain in mediating cue-based spatial navigation capacity.Regression analysis revealed that, although hippocampal volume reflected navigation performance across the entire sample, basal forebrain volume contributed to mixed allo/egocentric navigation performance in the AD group, whereas hippocampal volume did not.This suggests that atrophy of the basal forebrain contributes to aspects of navigation impairment in AD that are independent of hippocampal atrophy.

View Article: PubMed Central - PubMed

Affiliation: Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland , Brisbane, QLD , Australia.

ABSTRACT
The basal forebrain degenerates in Alzheimer's disease (AD) and this process is believed to contribute to the cognitive decline observed in AD patients. Impairment in spatial navigation is an early feature of the disease but whether basal forebrain dysfunction in AD is responsible for the impaired navigation skills of AD patients is not known. Our objective was to investigate the relationship between basal forebrain volume and performance in real space as well as computer-based navigation paradigms in an elderly cohort comprising cognitively normal controls, subjects with amnestic mild cognitive impairment and those with AD. We also tested whether basal forebrain volume could predict the participants' ability to perform allocentric- vs. egocentric-based navigation tasks. The basal forebrain volume was calculated from 1.5 T magnetic resonance imaging (MRI) scans, and navigation skills were assessed using the human analog of the Morris water maze employing allocentric, egocentric, and mixed allo/egocentric real space as well as computerized tests. When considering the entire sample, we found that basal forebrain volume correlated with spatial accuracy in allocentric (cued) and mixed allo/egocentric navigation tasks but not the egocentric (uncued) task, demonstrating an important role of the basal forebrain in mediating cue-based spatial navigation capacity. Regression analysis revealed that, although hippocampal volume reflected navigation performance across the entire sample, basal forebrain volume contributed to mixed allo/egocentric navigation performance in the AD group, whereas hippocampal volume did not. This suggests that atrophy of the basal forebrain contributes to aspects of navigation impairment in AD that are independent of hippocampal atrophy.

No MeSH data available.


Related in: MedlinePlus