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Differing Patterns of Altered Slow-5 Oscillations in Healthy Aging and Ischemic Stroke.

La C, Mossahebi P, Nair VA, Young BM, Stamm J, Birn R, Meyerand ME, Prabhakaran V - Front Hum Neurosci (2016)

Bottom Line: The 'default-mode' network (DMN) has been investigated in the presence of various disorders, such as Alzheimer's disease and Autism spectrum disorders.More recently, this investigation has expanded to include patients with ischemic injury.The mechanisms underlying those differing modes of network disruption need to be further explored to better inform our understanding of brain function in healthy individuals and following injury.

View Article: PubMed Central - PubMed

Affiliation: Neuroscience Training Program, University of Wisconsin-MadisonMadison, WI, USA; Department of Radiology, University of Wisconsin-MadisonMadison, WI, USA.

ABSTRACT
The 'default-mode' network (DMN) has been investigated in the presence of various disorders, such as Alzheimer's disease and Autism spectrum disorders. More recently, this investigation has expanded to include patients with ischemic injury. Here, we characterized the effects of ischemic injury in terms of its spectral distribution of resting-state low-frequency oscillations and further investigated whether those specific disruptions were unique to the DMN, or rather more general, affecting the global cortical system. With 43 young healthy adults, 42 older healthy adults, 14 stroke patients in their early stage (<7 days after stroke onset), and 16 stroke patients in their later stage (between 1 to 6 months after stroke onset), this study showed that patterns of cortical system disruption may differ between healthy aging and following the event of an ischemic stroke. The stroke group in the later stage demonstrated a global reduction in the amplitude of the slow-5 oscillations (0.01-0.027 Hz) in the DMN as well as in the primary visual and sensorimotor networks, two 'task-positive' networks. In comparison to the young healthy group, the older healthy subjects presented a decrease in the amplitude of the slow-5 oscillations specific to the components of the DMN, while exhibiting an increase in oscillation power in the task-positive networks. These two processes of a decrease DMN and an increase in 'task-positive' slow-5 oscillations may potentially be related, with a deficit in DMN inhibition, leading to an elevation of oscillations in non-DMN systems. These findings also suggest that disruptions of the slow-5 oscillations in healthy aging may be more specific to the DMN while the disruptions of those oscillations following a stroke through remote (diaschisis) effects may be more widespread, highlighting a non-specificity of disruption on the DMN in stroke population. The mechanisms underlying those differing modes of network disruption need to be further explored to better inform our understanding of brain function in healthy individuals and following injury.

No MeSH data available.


Related in: MedlinePlus

Confidence Intervals for DMN and ‘visual–sensorimotor’ combined components single-factor ANOVA. With the combined components, clear reduction of slow-5 fALFF in the stroke-late (SUBA) population can be observed in comparison to the acute stroke group and healthy old individuals within the DMN. Reductions in the stroke-early (ACU) group were very similar to the healthy older adults (OHA), and did not reach statistical significance. In contrast, behavior of the ‘visual–sensorimotor’ component differed between the healthy aging effect and the effect observed in the stroke-late patient population. In this ‘task-positive’ composite component, the stroke-late population exhibited a trend toward significance in a reduction of slow-5 oscillations (negative in SUBA-Old contrast), while the old presented an increase in those slow-5 oscillations compared to the young (negative in YNG-OLD contrast). **p < 0.001, *p < 0.05, #p < 0.1.
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Figure 7: Confidence Intervals for DMN and ‘visual–sensorimotor’ combined components single-factor ANOVA. With the combined components, clear reduction of slow-5 fALFF in the stroke-late (SUBA) population can be observed in comparison to the acute stroke group and healthy old individuals within the DMN. Reductions in the stroke-early (ACU) group were very similar to the healthy older adults (OHA), and did not reach statistical significance. In contrast, behavior of the ‘visual–sensorimotor’ component differed between the healthy aging effect and the effect observed in the stroke-late patient population. In this ‘task-positive’ composite component, the stroke-late population exhibited a trend toward significance in a reduction of slow-5 oscillations (negative in SUBA-Old contrast), while the old presented an increase in those slow-5 oscillations compared to the young (negative in YNG-OLD contrast). **p < 0.001, *p < 0.05, #p < 0.1.

Mentions: With components combined, similarly to Calhoun et al. (2011), to form a combined-DMN component and a ‘visual–sensorimotor’ component representative of task-positive systems, single-factor ANOVA on the slow-5 component fALFF measure confirmed a difference in slow-5 disruption of cortical networks between aging and onset of an ischemic stroke. In the stroke-late group, DMN and non-DMN components showed a uniform decrease of slow-5 oscillations (Tukey HSD, stroke-late minus OHA: DMN: p = 0.021*, visual–sensorimotor: p = 0.205). In contrast, healthy older adults displayed a slight decreased in slow-5 oscillations, which appeared more specific to the DMN (Tukey HSD, YHA minus OHA: DMN: p = 0.135), as power of the slow-5 oscillations in non-DMN network increased (Tukey HSD, YHA minus OHA: visual–sensorimotor: p = 0.099; Figure 7). This increase in non-DMN fluctuation power and the decrease in DMN activity, both observed in the healthy older subjects, may be related.


Differing Patterns of Altered Slow-5 Oscillations in Healthy Aging and Ischemic Stroke.

La C, Mossahebi P, Nair VA, Young BM, Stamm J, Birn R, Meyerand ME, Prabhakaran V - Front Hum Neurosci (2016)

Confidence Intervals for DMN and ‘visual–sensorimotor’ combined components single-factor ANOVA. With the combined components, clear reduction of slow-5 fALFF in the stroke-late (SUBA) population can be observed in comparison to the acute stroke group and healthy old individuals within the DMN. Reductions in the stroke-early (ACU) group were very similar to the healthy older adults (OHA), and did not reach statistical significance. In contrast, behavior of the ‘visual–sensorimotor’ component differed between the healthy aging effect and the effect observed in the stroke-late patient population. In this ‘task-positive’ composite component, the stroke-late population exhibited a trend toward significance in a reduction of slow-5 oscillations (negative in SUBA-Old contrast), while the old presented an increase in those slow-5 oscillations compared to the young (negative in YNG-OLD contrast). **p < 0.001, *p < 0.05, #p < 0.1.
© Copyright Policy
Related In: Results  -  Collection

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Figure 7: Confidence Intervals for DMN and ‘visual–sensorimotor’ combined components single-factor ANOVA. With the combined components, clear reduction of slow-5 fALFF in the stroke-late (SUBA) population can be observed in comparison to the acute stroke group and healthy old individuals within the DMN. Reductions in the stroke-early (ACU) group were very similar to the healthy older adults (OHA), and did not reach statistical significance. In contrast, behavior of the ‘visual–sensorimotor’ component differed between the healthy aging effect and the effect observed in the stroke-late patient population. In this ‘task-positive’ composite component, the stroke-late population exhibited a trend toward significance in a reduction of slow-5 oscillations (negative in SUBA-Old contrast), while the old presented an increase in those slow-5 oscillations compared to the young (negative in YNG-OLD contrast). **p < 0.001, *p < 0.05, #p < 0.1.
Mentions: With components combined, similarly to Calhoun et al. (2011), to form a combined-DMN component and a ‘visual–sensorimotor’ component representative of task-positive systems, single-factor ANOVA on the slow-5 component fALFF measure confirmed a difference in slow-5 disruption of cortical networks between aging and onset of an ischemic stroke. In the stroke-late group, DMN and non-DMN components showed a uniform decrease of slow-5 oscillations (Tukey HSD, stroke-late minus OHA: DMN: p = 0.021*, visual–sensorimotor: p = 0.205). In contrast, healthy older adults displayed a slight decreased in slow-5 oscillations, which appeared more specific to the DMN (Tukey HSD, YHA minus OHA: DMN: p = 0.135), as power of the slow-5 oscillations in non-DMN network increased (Tukey HSD, YHA minus OHA: visual–sensorimotor: p = 0.099; Figure 7). This increase in non-DMN fluctuation power and the decrease in DMN activity, both observed in the healthy older subjects, may be related.

Bottom Line: The 'default-mode' network (DMN) has been investigated in the presence of various disorders, such as Alzheimer's disease and Autism spectrum disorders.More recently, this investigation has expanded to include patients with ischemic injury.The mechanisms underlying those differing modes of network disruption need to be further explored to better inform our understanding of brain function in healthy individuals and following injury.

View Article: PubMed Central - PubMed

Affiliation: Neuroscience Training Program, University of Wisconsin-MadisonMadison, WI, USA; Department of Radiology, University of Wisconsin-MadisonMadison, WI, USA.

ABSTRACT
The 'default-mode' network (DMN) has been investigated in the presence of various disorders, such as Alzheimer's disease and Autism spectrum disorders. More recently, this investigation has expanded to include patients with ischemic injury. Here, we characterized the effects of ischemic injury in terms of its spectral distribution of resting-state low-frequency oscillations and further investigated whether those specific disruptions were unique to the DMN, or rather more general, affecting the global cortical system. With 43 young healthy adults, 42 older healthy adults, 14 stroke patients in their early stage (<7 days after stroke onset), and 16 stroke patients in their later stage (between 1 to 6 months after stroke onset), this study showed that patterns of cortical system disruption may differ between healthy aging and following the event of an ischemic stroke. The stroke group in the later stage demonstrated a global reduction in the amplitude of the slow-5 oscillations (0.01-0.027 Hz) in the DMN as well as in the primary visual and sensorimotor networks, two 'task-positive' networks. In comparison to the young healthy group, the older healthy subjects presented a decrease in the amplitude of the slow-5 oscillations specific to the components of the DMN, while exhibiting an increase in oscillation power in the task-positive networks. These two processes of a decrease DMN and an increase in 'task-positive' slow-5 oscillations may potentially be related, with a deficit in DMN inhibition, leading to an elevation of oscillations in non-DMN systems. These findings also suggest that disruptions of the slow-5 oscillations in healthy aging may be more specific to the DMN while the disruptions of those oscillations following a stroke through remote (diaschisis) effects may be more widespread, highlighting a non-specificity of disruption on the DMN in stroke population. The mechanisms underlying those differing modes of network disruption need to be further explored to better inform our understanding of brain function in healthy individuals and following injury.

No MeSH data available.


Related in: MedlinePlus