Functional implications of age differences in motor system connectivity

Langan, Jeanne; Peltier, Scott; Bo, Jin; Fling, Brett W.; Welsh, Robert C.; Seidler, Rachael D.

doi:10.3389/fnsys.2010.00017

Cited by 105 publications

(147 citation statements)

References 90 publications

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“…For each participant, a laterality index (LI) of average Zscores was computed for the healthy hemisphere and epileptic sensorimotor ROIs as follows, using a method similar to that of Langan et al (2010):…”

Section: Laterality Indexmentioning

confidence: 99%

Frontal Lobe Epilepsy Alters Functional Connections Within the Brain's Motor Network: A Resting-State fMRI Study

et al. 2014

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Patients with frontal lobe epilepsy (FLE) often experience motor deficits, yet little is known of the impact of FLE on the activity of motor networks in the brain. Resting-state functional magnetic resonance imaging (rs-fMRI) has previously demonstrated an association between cognitive deficits in temporal lobe epilepsy patients and disruption of activity within pertinent brain networks. Hence, in the present study, rs-fMRI was used to determine whether FLE is associated with motor network disruption. Seven right-hemisphere FLE patients, six lefthemisphere FLE patients, and nine control subjects underwent rs-fMRI. Functional connectivity was computed between the sensorimotor cortex contralateral to the seizure focus and each voxel in the brain, and then compared voxel-by-voxel between patient groups and controls. A laterality index (LI) of connectivity between contralateral and ipsilateral sensorimotor cortices was calculated to investigate its association with epilepsy duration and seizure frequency. Positive laterality indices indicate reduced connectivity, and zero values indicate strong connectivity. Connectivity between the left and right sensorimotor cortices was significantly reduced in FLE patients compared with controls ( p < 0.05), and LI was positively correlated with the number of lifetime seizures (left FLE: r s = 0.89, right FLE: r s = 1.00). Patients with FLE exhibit decreased connectivity within the motor network, in correlation with the number of lifetime seizures, thus demonstrating a potential relationship between seizure activity and changes in motor network organization. These findings suggest that motor network disturbances may in part be responsible for the motor deficits observed in FLE patients.

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Section: Laterality Indexmentioning

confidence: 99%

Frontal Lobe Epilepsy Alters Functional Connections Within the Brain's Motor Network: A Resting-State fMRI Study

et al. 2014

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“…A number of studies have reported increased bilateral activation in older adults relative to younger adults during the performance of unilateral movements (e.g., Fujiyama et al 2012a;Hinder et al 2011;Riecker et al 2006;Ward and Frackowiak 2003). Although one view is that the recruitment of bilateral motor cortices in older adults is due to nonselective recruitment (e.g., Langan et al 2010), the present results suggest that the activation of the ipsilateral M1 plays a functional role, lending support to the HAROLD model (Cabeza et al 2002), which postulates that reduced asymmetry of motor cortical activation in the aging brain is beneficial for the maintenance of motor performance . It is conceivable that left M1 stimulation resulted in different effects on response time for the two groups because of age-related differences in interhemispheric connectivity, i.e., left M1 stimulation affected the right (responding) M1 differently in the two groups, resulting in different behavioral effects.…”

Section: Response Time Delay Induced By M1 Tmsmentioning

confidence: 99%

Functional role of left PMd and left M1 during preparation and execution of left hand movements in older adults

Fujiyama

Hinder

Summers

2013

Journal of Neurophysiology

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“…This has been particularly suggested for highly lateralized functions such as motor or language task performance. Here, lateralized intra-hemispheric network connectivity may support superior behavior, while increased inter-hemispheric functional connectivity (even within functional networks like the motor network) may have a negative impact on function [17,18]. For example, Langan et al [18] demonstrated degenerated anterior callosal fibers - which carry primarily inhibitory functions between the hemispheres - in older compared to young adults.…”

Section: Structural and Functional Brain Network In The Context Of Amentioning

confidence: 99%

“…Here, lateralized intra-hemispheric network connectivity may support superior behavior, while increased inter-hemispheric functional connectivity (even within functional networks like the motor network) may have a negative impact on function [17,18]. For example, Langan et al [18] demonstrated degenerated anterior callosal fibers - which carry primarily inhibitory functions between the hemispheres - in older compared to young adults. This degeneration was associated with prolonged reaction times in a motor task as well as increased functional connectivity between left and right motor areas [18].…”

Section: Structural and Functional Brain Network In The Context Of Amentioning

confidence: 99%

“…For example, Langan et al [18] demonstrated degenerated anterior callosal fibers - which carry primarily inhibitory functions between the hemispheres - in older compared to young adults. This degeneration was associated with prolonged reaction times in a motor task as well as increased functional connectivity between left and right motor areas [18]. This observation might be explained by a shift from a strong inhibitory communication between the hemispheres in the young brain that restricts functional communication towards lower inter-hemispheric inhibitory tone in the older brain [for a discussion, see [17]].…”

Section: Structural and Functional Brain Network In The Context Of Amentioning

confidence: 99%

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Healthy Aging by Staying Selectively Connected: A Mini-Review

Antonenko

Flöel

2013

Gerontology

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Cognitive neuroscience of the healthy aging human brain has thus far addressed age-related changes of local functional and structural properties of gray and white matter and their association with declining or preserved cognitive functions. In addition to these localized changes, recent neuroimaging research has attributed an important role to neural networks with a stronger focus on interacting rather than isolated brain regions. The analysis of functional connectivity encompasses task-dependent and -independent synchronous activity in the brain, and thus reflects the organization of the brain in distinct performance-relevant networks. Structural connectivity in white matter pathways, representing the integrity of anatomical connections, underlies the communication between the nodes of these functional networks. Both functional and structural connectivity within these networks have been demonstrated to change with aging, and to have different predictive values for cognitive abilities in older compared to young adults. Structural degeneration has been found in the entire cerebral white matter with greatest deterioration in frontal areas, affecting whole brain structural network efficiency. With regard to functional connectivity, both higher and lower functional coupling has been observed in the aging compared to the young brain. Here, high connectivity within the nodes of specific functional networks on the one hand, and low connectivity to regions outside this network on the other hand, were associated with preserved cognitive functions in aging in most cases. For example, in the language domain, connections between left-hemisphere language-related prefrontal, posterior temporal and parietal areas were described as beneficial, whereas connections between the left and right hemisphere were detrimental for language task performance. Of note, interactions between structural and functional network properties may change in the course of aging and differentially impact behavioral performance in older versus young adults. Finally, studies using noninvasive brain stimulation techniques like transcranial direct current stimulation (tDCS) to simultaneously modulate behavior and functional connectivity support the importance of ‘selective connectivity' of aging brain networks for preserved cognitive functions. These studies demonstrate that enhancing task performance by tDCS is paralleled by increased connectivity within functional networks. In this review, we outline the network perspective on healthy brain aging and discuss recent developments in this field.

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Functional implications of age differences in motor system connectivity

Cited by 105 publications

References 90 publications

Frontal Lobe Epilepsy Alters Functional Connections Within the Brain's Motor Network: A Resting-State fMRI Study

Frontal Lobe Epilepsy Alters Functional Connections Within the Brain's Motor Network: A Resting-State fMRI Study

Functional role of left PMd and left M1 during preparation and execution of left hand movements in older adults

Healthy Aging by Staying Selectively Connected: A Mini-Review

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