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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

Component spectral distribution organized by population group: (A) young healthy adult (YHA), (B) old healthy adult (OHA), (C) stroke-early, and (D) stroke-late. Colored plots in each panel representing the mean of a distinct component, the shaded area portraying the standard error of the mean. Color coding is as follow: pDMN (magenta), aDMN (cyan), vDMN (yellow), visual (black), and motor (white). Population spectral distribution appeared highly disrupted in the stroke-late population with non-unique distribution peak, and wider spectral distribution with lower overall amplitude.
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Figure 3: Component spectral distribution organized by population group: (A) young healthy adult (YHA), (B) old healthy adult (OHA), (C) stroke-early, and (D) stroke-late. Colored plots in each panel representing the mean of a distinct component, the shaded area portraying the standard error of the mean. Color coding is as follow: pDMN (magenta), aDMN (cyan), vDMN (yellow), visual (black), and motor (white). Population spectral distribution appeared highly disrupted in the stroke-late population with non-unique distribution peak, and wider spectral distribution with lower overall amplitude.

Mentions: Network spectral distributions from the group IC time-series for the YHA (Figure 3A) and OHA (Figure 3B) subjects and stroke patients in their early stage (Figure 3C) demonstrated a stable distribution of network oscillations with a distinctive peak. Qualitatively, the stroke-early population did not present drastic differences in frequency distribution of the LFOs in comparison to the OHA participants (Figure 3). However, variation of the distribution among and within the different components was larger in the stroke-early group in contrast to the YHA group (Figure 3). These findings were also observed in the older healthy adult group (OHA), and presented no significant difference in comparison to the OHA group. Quantitatively, assessment of the measure of slow-5 component fALFF demonstrated no difference of the frequency distribution in the stroke-early population group in comparison to the OHA group (pDMN: t = 0.270; aDMN: t = 0.264; vDMN: t = 0.971; visual: t = 0.152; sensorimotor: t = 0.633; all with p-value > 0.5, Figure 5). The amplitudes of the frequency distribution in our stroke-early patients did not differ from that observed in the older healthy individuals. In contrast, stroke patients in their later stage (Figure 3D) presented a difference in the spectral distribution of the network oscillations. They exhibited a lower amplitude and wider spectral distribution common to all five assessed network components with respect to the healthy old group, at various levels of significance, potentially reflecting disrupted network oscillations within an impaired system.


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)

Component spectral distribution organized by population group: (A) young healthy adult (YHA), (B) old healthy adult (OHA), (C) stroke-early, and (D) stroke-late. Colored plots in each panel representing the mean of a distinct component, the shaded area portraying the standard error of the mean. Color coding is as follow: pDMN (magenta), aDMN (cyan), vDMN (yellow), visual (black), and motor (white). Population spectral distribution appeared highly disrupted in the stroke-late population with non-unique distribution peak, and wider spectral distribution with lower overall amplitude.
© Copyright Policy
Related In: Results  -  Collection

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Figure 3: Component spectral distribution organized by population group: (A) young healthy adult (YHA), (B) old healthy adult (OHA), (C) stroke-early, and (D) stroke-late. Colored plots in each panel representing the mean of a distinct component, the shaded area portraying the standard error of the mean. Color coding is as follow: pDMN (magenta), aDMN (cyan), vDMN (yellow), visual (black), and motor (white). Population spectral distribution appeared highly disrupted in the stroke-late population with non-unique distribution peak, and wider spectral distribution with lower overall amplitude.
Mentions: Network spectral distributions from the group IC time-series for the YHA (Figure 3A) and OHA (Figure 3B) subjects and stroke patients in their early stage (Figure 3C) demonstrated a stable distribution of network oscillations with a distinctive peak. Qualitatively, the stroke-early population did not present drastic differences in frequency distribution of the LFOs in comparison to the OHA participants (Figure 3). However, variation of the distribution among and within the different components was larger in the stroke-early group in contrast to the YHA group (Figure 3). These findings were also observed in the older healthy adult group (OHA), and presented no significant difference in comparison to the OHA group. Quantitatively, assessment of the measure of slow-5 component fALFF demonstrated no difference of the frequency distribution in the stroke-early population group in comparison to the OHA group (pDMN: t = 0.270; aDMN: t = 0.264; vDMN: t = 0.971; visual: t = 0.152; sensorimotor: t = 0.633; all with p-value > 0.5, Figure 5). The amplitudes of the frequency distribution in our stroke-early patients did not differ from that observed in the older healthy individuals. In contrast, stroke patients in their later stage (Figure 3D) presented a difference in the spectral distribution of the network oscillations. They exhibited a lower amplitude and wider spectral distribution common to all five assessed network components with respect to the healthy old group, at various levels of significance, potentially reflecting disrupted network oscillations within an impaired system.

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