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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

Significant correlations of anterior and posterior basal forebrain volumes (x-axis) to distance error (y-axis) in allocentric (A,B) and mixed allo/egocentric (C,D) real space tests. Both (A) Anterior (R = 0.32, p = 0.041) and (B) Posterior (R = 0.34, p = 0.028) basal forebrain volumes were significantly correlated to distance error in the allocentric real space test. Furthermore, distance error in the mixed allo/egocentric real space test was correlated to (C) Anterior basal forebrain volume (R = 0.38, p = 0.009), whereas distance error in the mixed allo/egocentric virtual space test was correlated to (D) Posterior basal forebrain volume (R = 0.31, p = 0.027). Data points are colored according to clinical diagnosis. A linear fit line with 95% confidence interval is shown.
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Figure 4: Significant correlations of anterior and posterior basal forebrain volumes (x-axis) to distance error (y-axis) in allocentric (A,B) and mixed allo/egocentric (C,D) real space tests. Both (A) Anterior (R = 0.32, p = 0.041) and (B) Posterior (R = 0.34, p = 0.028) basal forebrain volumes were significantly correlated to distance error in the allocentric real space test. Furthermore, distance error in the mixed allo/egocentric real space test was correlated to (C) Anterior basal forebrain volume (R = 0.38, p = 0.009), whereas distance error in the mixed allo/egocentric virtual space test was correlated to (D) Posterior basal forebrain volume (R = 0.31, p = 0.027). Data points are colored according to clinical diagnosis. A linear fit line with 95% confidence interval is shown.

Mentions: To investigate the relationship between allocentric, egocentric, as well as mixed allo/egocentric spatial navigation performance and the basal forebrain, we correlated navigation scores of both real space and computer-based versions of the navigation tasks with basal forebrain volumes of the elderly and cognitively impaired cohorts. In the whole cohort (Figure 4; Table 3), the distance error in the allocentric real space task was correlated to the anterior (Figure 4A; R = 0.32, p = 0.041), posterior (Figure 4B; R = 0.34, p = 0.028), and whole (R = 0.35, p = 0.022) basal forebrain volume. Furthermore, distance error in the mixed allo/egocentric real space test was significantly associated with anterior (Figure 4C; R = 0.38, p = 0.009) and whole (R = 0.34, p = 0.019) but not posterior basal forebrain volume. Associations between computer-based navigation test scores and basal forebrain volumes revealed that only the mixed allo/egocentric computer-based navigation task was significantly correlated to posterior (Figure 4D; R = 0.31, p = 0.027; Table 3) and whole basal forebrain (R = 0.29, p = 0.037) volumes. This was in spite of the performances of subjects in the real space and computer-based versions of navigation task being significantly correlated (allocentric, R = 0.78, p < 0.001; egocentric, R = 0.79, p < 0.001; allo/egocentric, R = 0.84, p < 0.001; delayed, R = 0.41, p = 0.006).


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)

Significant correlations of anterior and posterior basal forebrain volumes (x-axis) to distance error (y-axis) in allocentric (A,B) and mixed allo/egocentric (C,D) real space tests. Both (A) Anterior (R = 0.32, p = 0.041) and (B) Posterior (R = 0.34, p = 0.028) basal forebrain volumes were significantly correlated to distance error in the allocentric real space test. Furthermore, distance error in the mixed allo/egocentric real space test was correlated to (C) Anterior basal forebrain volume (R = 0.38, p = 0.009), whereas distance error in the mixed allo/egocentric virtual space test was correlated to (D) Posterior basal forebrain volume (R = 0.31, p = 0.027). Data points are colored according to clinical diagnosis. A linear fit line with 95% confidence interval is shown.
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Figure 4: Significant correlations of anterior and posterior basal forebrain volumes (x-axis) to distance error (y-axis) in allocentric (A,B) and mixed allo/egocentric (C,D) real space tests. Both (A) Anterior (R = 0.32, p = 0.041) and (B) Posterior (R = 0.34, p = 0.028) basal forebrain volumes were significantly correlated to distance error in the allocentric real space test. Furthermore, distance error in the mixed allo/egocentric real space test was correlated to (C) Anterior basal forebrain volume (R = 0.38, p = 0.009), whereas distance error in the mixed allo/egocentric virtual space test was correlated to (D) Posterior basal forebrain volume (R = 0.31, p = 0.027). Data points are colored according to clinical diagnosis. A linear fit line with 95% confidence interval is shown.
Mentions: To investigate the relationship between allocentric, egocentric, as well as mixed allo/egocentric spatial navigation performance and the basal forebrain, we correlated navigation scores of both real space and computer-based versions of the navigation tasks with basal forebrain volumes of the elderly and cognitively impaired cohorts. In the whole cohort (Figure 4; Table 3), the distance error in the allocentric real space task was correlated to the anterior (Figure 4A; R = 0.32, p = 0.041), posterior (Figure 4B; R = 0.34, p = 0.028), and whole (R = 0.35, p = 0.022) basal forebrain volume. Furthermore, distance error in the mixed allo/egocentric real space test was significantly associated with anterior (Figure 4C; R = 0.38, p = 0.009) and whole (R = 0.34, p = 0.019) but not posterior basal forebrain volume. Associations between computer-based navigation test scores and basal forebrain volumes revealed that only the mixed allo/egocentric computer-based navigation task was significantly correlated to posterior (Figure 4D; R = 0.31, p = 0.027; Table 3) and whole basal forebrain (R = 0.29, p = 0.037) volumes. This was in spite of the performances of subjects in the real space and computer-based versions of navigation task being significantly correlated (allocentric, R = 0.78, p < 0.001; egocentric, R = 0.79, p < 0.001; allo/egocentric, R = 0.84, p < 0.001; delayed, R = 0.41, p = 0.006).

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