Default mode network disruption secondary to a lesion in the anterior thalamus.
ABSTRACT To describe the neuroanatomical correlations of an isolated lesion in the anterior thalamus using functional imaging in a 40-year-old man with multiple sclerosis.
Case report with 10 cognitively normal controls.
Mayo Clinic, Rochester, Minnesota.
A 40-year-old man with a 2-week course of acute-onset amnesia, abulia, poor concentration, hypersomnolence, and reclusiveness.
Functional magnetic resonance imaging.
Magnetic resonance imaging demonstrated a large gadolinium-enhancing plaque in the left anterior thalamus and other demyelinating plaques in the subcortical and periventricular white matter, consistent with the diagnosis of multiple sclerosis. His symptoms persisted at the 7-month follow-up. The patient's resting state functional magnetic resonance image demonstrated an asymmetric disruption of the posterior cingulate portion of the default mode network ipsilateral to the left thalamic lesion.
A large multiple sclerosis plaque in the deep gray matter altered the resting state functional connectivity in a patient presenting with pure cognitive dysfunction. Such altered connectivity may underlie cognitive symptoms in neurologic disease. In addition, this case provides lesional evidence of default mode network circuitry involving the pathways of the circuit of Papez.
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ABSTRACT: Severe cognitive impairment involving multiple cognitive domains can occur early during the course of multiple sclerosis (MS). We investigated resting state functional connectivity changes in large-scale brain networks and related structural damage underlying cognitive dysfunction in patients with early MS. Patients with relapsing MS (3-5 years disease duration) were prospectively assigned to two groups based on a standardized neuropsychological evaluation: (1) cognitively impaired group (CI group, n = 15), with abnormal performances in at least 3 tests; (2) cognitively preserved group (CP group, n = 20) with normal performances in all tests. Patients and age-matched healthy controls underwent a multimodal 3T magnetic resonance imaging (MRI) including anatomical T1 and T2 images, diffusion imaging and resting state functional MRI. Structural MRI analysis revealed that CI patients had a higher white matter lesion load compared to CP and a more severe atrophy in gray matter regions highly connected to networks involved in cognition. Functional connectivity measured by integration was increased in CP patients versus controls in attentional networks (ATT), while integration was decreased in CI patients compared to CP both in the default mode network (DMN) and ATT. An anatomofunctional study within the DMN revealed that functional connectivity was mostly altered between the medial prefrontal cortex (MPFC) and the posterior cingulate cortex (PCC) in CI patients compared to CP and controls. In a multilinear regression model, functional correlation between MPFC and PCC was best predicted by PCC atrophy. Disconnection in the DMN and ATT networks may deprive the brain of compensatory mechanisms required to face widespread structural damage. Hum Brain Mapp, 2014. © 2014 Wiley Periodicals, Inc.Human Brain Mapping 03/2014; · 6.92 Impact Factor
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ABSTRACT: Background Functional imaging and lesion studies have associated willed behavior with anterior cingulate cortex (ACC). Abulia is a syndrome characterized by apathy and deficiency of motivated behavior. Abulia is most frequently associated with ACC damage, but also occurs following damage to subcortical nuclei (striatum, globus pallidus, thalamic nuclei). We present resting state functional connectivity MRI (fcMRI) data from an individual who suffered a stroke leading to abulia. We hypothesized that, although structural imaging revealed no damage to the patient’s ACC, fcMRI would uncover aberrant function in this region and in the relevant cortical networks. Methods Resting state correlations in the patient’s gray matter were compared to those of age-matched controls. Using a novel method to identify abnormal patterns of functional connectivity in single subjects, we identified areas and networks with aberrant connectivity. Results Networks associated with memory (default mode network) and executive function (cingulo-opercular network) were abnormal. The patient’s anterior cingulate was among the areas showing aberrant functional connectivity. In a rescan 3 years later, deficits remained stable and fcMRI findings were replicated. Conclusions These findings suggest that the aberrant functional connectivity mapping approach described may be useful for linking stroke symptoms to disrupted network connectivity.NeuroImage: Clinical. 01/2014; 6.
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ABSTRACT: Social anxiety disorder related alterations in basal ganglia regions, such as striatum and globus pallidus, though evident from metabolic imaging, remain to be explored using seed-based resting state functional connectivity MRI (fcMRI). Capitalizing on the enhanced sensitivity of a multichannel array coil, we collected high-resolution (2mm isotropic) data from medication naïve patients and healthy control participants. Subcortical resting state networks from structures including the striatum (caudate and putamen), globus pallidus, thalamus, amygdala and periaqueductal gray were compared between the two groups. When compared to controls, the caudate seed revealed significantly higher functional connectivity (hyper-connectivity) in the patient group in medial frontal, pre-frontal (anterior and dorso-lateral), orbito-frontal and anterior cingulate cortices, which are regions that are typically associated with emotional processing. In addition, with the putamen seed, the patient data exhibited increased connectivity in the fronto-parietal regions (Executive Control Network) and subgenual cingulate (Affective Network). The globus pallidus seed showed significant increases in connectivity in the patient group, primarily in the precuneus, which is part of the Default Mode Network. Significant hyper-connectivity in the precuneus, interior temporal and parahippocampal cortices was also observed with the thalamus seed in the patient population, when compared to controls. With amygdala as seed region, between group differences were primarily in supplementary motor area, inferior temporal gyrus, secondary visual cortex, angular gyrus and cingulate gyrus. Seed from periaqueductal gray resulted in hyper-connectivity in the patient group, when compared to controls, in dorsolateral prefrontal cortex, precuneus, middle temporal gyrus and inferior parietal lobule. In all the subcortical regions examined in this study, the control group did not have any significant enhancements in functional connectivity when compared to the patient group.Brain connectivity. 11/2013;