Cortical reorganization during PASAT task in MS patients with preserved working memory functions

Forn, Cristina; Barrós‐Loscertales, Alfonso; Escudero, Javier; Belloch, Vicente; Campos, S.; Parcet, Maria Antònia; Ávila, César

doi:10.1016/j.neuroimage.2005.12.030

Cited by 90 publications

(100 citation statements)

References 37 publications

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“…3 A major finding of these studies is that, at least in early phases of MS when cognitive impairment is not yet detectable, patients activate additional brain areas to compensate for potential functional deficits. 2,6,7 This observation has been supported and expanded on by studies describing enhanced connectivity as a neuroplasticity mechanism that probably compensates for cognitive deficits at early stages of the disease. 3,5,8,9 Despite this possible convergence among different studies, interpreting brain activity patterns during cognitive task performance can present difficulties, particularly when trying to identify compensatory adaptations in neurological populations.…”

Section: Introductionmentioning

confidence: 78%

“…3,5,8,9 Despite this possible convergence among different studies, interpreting brain activity patterns during cognitive task performance can present difficulties, particularly when trying to identify compensatory adaptations in neurological populations. First, to conclude that there is functional reorganisation secondary to a possible deficit, [5][6][7] patients must execute the task with similar accuracy as the control group. Second, differences in brain activation patterns may arise from using different strategies to solve a task, especially if tasks involve complex cognitive operations, thus complicating interpretation of results.…”

Section: Introductionmentioning

confidence: 99%

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The link between resting-state functional connectivity and cognition in MS patients

et al. 2013

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Objective: The objective of this paper is to explore differences in resting-state functional connectivity between cognitively impaired and preserved multiple sclerosis (MS) patients. Methods: Sixty MS patients and 18 controls were assessed with the Brief Repeatable Battery of Neuropsychological Tests (BRB-N). A global Z score of the BRB-N was obtained and allowed us to classify MS patients as cognitively impaired and cognitively preserved ( n = 30 per group). Functional connectivity was assessed by independent component analysis of resting-state networks (RSNs) related to cognition: the default mode network, left and right frontoparietal and salience network. Between-group differences were evaluated and a regression analysis was performed to describe relationships among cognitive status, functional connectivity and radiological variables. Results: Compared to cognitively preserved patients and healthy controls, cognitively impaired patients showed a lesser degree of functional connectivity in all RSNs explored. Cognitively preserved patients presented less connectivity than the control group in the left frontoparietal network. Global Z scores were positively and negatively correlated with brain parenchymal fraction and lesion volume, respectively. Conclusion: Decreased cognitive performance is accompanied by reduced resting state functional connectivity and directly related to brain damage. These results support the use of connectivity as a powerful tool to monitor and predict cognitive impairment in MS patients.

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Section: Introductionmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

The link between resting-state functional connectivity and cognition in MS patients

et al. 2013

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“…The main findings of these studies was the induction of a change in brain activation, in frontal and temporal regions, as well as in cerebellum, through cognitive rehabilitation. This increase in brain activation was thought to help compensate for the cognitive deficits seen in these patients 27,28 since failure of such mechanisms as a result of disease damage progressively leads to cognitive deterioration. 29 cortex, prefrontal cortex and posterior cingulate cortex), which showed an increase (or stability) of activity over time in the treatment group but a decrease in the control group.…”

Section: Imagingmentioning

confidence: 99%

Cognitive rehabilitation in multiple sclerosis: A systematic review

Mitolo

Venneri

Wilkinson

et al. 2015

Journal of the Neurological Sciences

125

106

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“…For example, by selecting individuals diagnosed with MS who did not exhibit obvious cognitive deficits (Forn et al, 2006(Forn et al, , 2007, investigators have attempted to control the performance-activation confounds endemic to clinical imaging studies (see Price & Friston, 1999;Price & Friston, 2002). The investigators interpreted increased PFC activation during WM performance in this MS sample as "reflective of the existence of neural reorganizative processes" (Forn et al, 2007).…”

Section: Current Findings In Clinical Imaging Of Wmmentioning

confidence: 99%

Neuroimaging of working memory dysfunction and the dilemma with brain reorganization hypotheses

Hillary

2008

J Int Neuropsychol Soc

102

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There is a growing literature examining working memory deficits using functional imaging and there has been great convergence in the findings, to date, but interpretations have varied. Investigators consistently observed recruitment of neural resources in clinical samples, with some examiners attributing these findings to neural inefficiency and others attributing differences to neural compensation and0or brain reorganization. It is the goal of this paper to address the current interpretation of altered brain activation in clinical imaging studies of working memory dysfunction with specific emphasis on findings in prefrontal cortex (PFC). Throughout this review, the methods used to examine brain reorganization associated with working memory dysfunction are critiqued with the goal of understanding how study design has influenced data interpretation. It is proposed that much of what has been considered "aberrant" neural activity is not indicative of neural compensation, as it has been typically defined, and does not represent brain reorganization. Instead, recruitment of neural resources in PFC can be explained by a natural, and largely overlooked, role of cognitive control in accommodating neural dysfunction secondary to brain injury and disease. This paper provides predictions based on this proposition and a critique of the current methods available for testing these predictions. (JINS, 2008, 14, 526-534.) Keywords: Plasticity, Traumatic brain injury, MS, Working memory, Reorganization, Cognitive control, Prefrontal, Functional magnetic resonance imaging An Alternative to Brain Reorganization HypothesesFunctional imaging techniques afford the unique opportunity to examine the relationships between basic brain changes and the behavioral deficits associated with brain injury and disease. There is a growing functional imaging literature examining the effects of neurological insult on working memory (WM), or the ability to maintain and0or manipulate small amounts of information for brief periods of time. In the functional imaging literature examining WM dysfunction, there has been increasing reference to "neural compensation" and "brain reorganization" to describe the altered (and almost universally increased) neural activation observed when comparing clinical samples to healthy adults. Specifically, the term "compensation" has been used to describe either transient or permanent alterations in neural activity, which operates to facilitate performance. Therefore, in this paper, the term "compensation" will be used to indicate a positive relationship between task performance and brain activation. The term "brain reorganization" has typically been used to indicate that the neural networks associated with WM have been permanently altered because of neurological insult, so that insult induces a "rewiring" of WM networks. Therefore, the primary distinction between "compensation" and "brain reorganization" is that the former may be transient whereas the latter represents permanent changes in the neural networks ...

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Cortical reorganization during PASAT task in MS patients with preserved working memory functions

Cited by 90 publications

References 37 publications

The link between resting-state functional connectivity and cognition in MS patients

The link between resting-state functional connectivity and cognition in MS patients

Cognitive rehabilitation in multiple sclerosis: A systematic review

Neuroimaging of working memory dysfunction and the dilemma with brain reorganization hypotheses

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