During recent decades numerous yoga-based practices (YBP) have emerged in the West, with their aims ranging from fitness gains to therapeutic benefits and spiritual development. Yoga is also beginning to spark growing interest within the scientific community, and yoga-based interventions have been associated with measureable changes in physiological parameters, perceived emotional states, and cognitive functioning. YBP typically involve a combination of postures or movement sequences, conscious regulation of the breath, and various techniques to improve attentional focus. However, so far little if any research has attempted to deconstruct the role of these different component parts in order to better understand their respective contribution to the effects of YBP. A clear operational definition of yoga-based therapeutic interventions for scientific purposes, as well as a comprehensive theoretical framework from which testable hypotheses can be formulated, is therefore needed. Here we propose such a framework, and outline the bottom-up neurophysiological and top-down neurocognitive mechanisms hypothesized to be at play in YBP.

Objective: To investigate the neural basis for the behavioral symptoms of frontotemporal lobar degeneration (FTLD) that cause the greatest caregiver distress. Background: FTLD is a progressive neurodegenerative disease associated with behavioral disturbances. Group studies have related these behaviors to volume loss on MRI. Methods: Forty caregivers of patients with the clinical diagnosis of FTLD completed the Neuropsychiatric Inventory. Twelve neuropsychiatric symptoms and the associated caregiver distress were assessed. Optimized voxel-based morphometry identified significant atrophy in subgroups of FTLD patients with isolated behavioral symptoms corresponding to the most distressing behaviors, and we correlated cortical atrophy directly with these distressing behavioral disorders in an unbiased group analysis. Results: The greatest stressors for caregivers were apathy and disinhibition (p < 0.005 for both contrasts). Partially distinct areas of cortical atrophy were associated with these behaviors in both individual patients with these symptoms and group-wide analyses, including the dorsal anterior cingulate cortex and dorsolateral prefrontal cortex in apathetic patients, and the medial orbital frontal cortex in disinhibited patients. Conclusions: Caregiver stress in families of FTLD patients is due in large part to apathy and disinhibition. The anatomic distribution of cortical loss corresponding to these distressing social behaviors includes partially distinct areas within the frontal lobe.

Objective: To test the hypothesis that different neurocognitive networks underlie verbal fluency deficits in frontotemporal lobar degeneration (FTLD).Methods: Letter ("FAS") and semantic ("animal") fluency tests were administered to patients with a behavioral/dysexecutive disorder (bvFTLD; n ϭ 71), semantic dementia (SemD; n ϭ 21), and progressive nonfluent aphasia (PNFA; n ϭ 26). Tests measuring working memory, naming/lexical retrieval, and semantic knowledge were also obtained. MRI voxel-based morphometry (VBM) studies were obtained on a subset of these patients (bvFTLD, n ϭ 51; PNFA, n ϭ 11; SemD, n ϭ 10). Results:Patients with SemD were disproportionately impaired on the semantic fluency measure.Reduced output on this test was correlated with impaired performance on naming/lexical retrieval tests. VBM analyses related reduced letter and semantic fluency to anterior and inferior left temporal lobe atrophy. Patients with bvFTLD were equally impaired on both fluency tests. Poor performance on both fluency tests was correlated with low scores on working memory and naming/ lexical retrieval measures. In this group, MRI-VBM analyses related letter fluency to bilateral frontal atrophy and semantic fluency to left frontal/temporal atrophy. Patients with PNFA were also equally impaired on fluency tests. Reduced semantic fluency output was correlated with reduced performance on naming/lexical retrieval tests. MRI-VBM analyses related semantic fluency to the right frontal lobe and letter fluency to left temporal atrophy. Frontotemporal lobar degeneration (FTLD) is a progressive neurodegenerative illness associated with frontal and temporal lobe atrophy. Conclusions:1 Clinical subgroups of patients with FTLD include a decline in behavior, comportment, and executive functioning (bvFTLD) 2,3 ; semantic dementia (SemD) 4 associated with fluent progressive aphasia, impaired word comprehension, and poor object knowledge; and progressive nonfluent aphasia (PNFA) 5 associated with effortful speech and impaired grammatic comprehension. Imaging studies have shown that these patients have different distributions of cortical atrophy. 6Recent research has demonstrated that these FTLD subgroups can present with impaired executive control as seen by reduced performance on tests of letter ("FAS") and semantic ("animals" 7,8 ) fluency. Because autopsy-confirmed patients with FTLD produce differing patterns of impairment on letter as compared with semantic fluency tests, these tests may help differentiate between Alzheimer disease (AD) and FTLD and between FTLD subtypes. [9][10][11][12] Functional neuroimaging studies of healthy adults associate these tasks with partially distinct activation patterns.

The present study examined the organization of complex familiar activities, known as "scripts" (e.g., "going fishing"). We assessed whether events in a script are processed in a linear-sequential manner or clustered-hierarchical manner, and we evaluated the neural basis for this processing capacity. Converging evidence was obtained from functional neuroimaging in healthy young adults and from behavioral and structural magnetic resonance imaging (MRI) data in patients with focal neurodegenerative disease. In both studies, participants judged the order of consecutive event pairs taken from a script. Event pairs either were clustered together within a script or were from different clusters within the script. Controls judged events more accurately and quickly if taken from the same cluster within a script compared with different clusters, even though all event pairs were consecutive, consistent with the hierarchical organization of a script. Functional magnetic resonance imaging associated this with bilateral inferior frontal activation. Patients with progressive nonfluent aphasia or behavior-variant frontotemporal dementia did not distinguish between event pairs from the same cluster or from different clusters within a script. Structural MRI associated this deficit with significant frontal cortical atrophy. Our findings suggest that frontal cortex contributes to clustering events during script comprehension, underlining the role of frontal cortex in the hierarchical organization of a script.

Objective To investigate the cognitive and neural correlates of discourse impairment in corticobasal syndrome (CBS). Background Difficulty communicating is a frequent clinical manifestation in patients with CBS. However, the mechanisms underlying this disabling problem are not well understood. Methods Twenty patients with CBS and 8 healthy seniors narrated a picture story. Narratives were analyzed for maintenance of the narrative theme, identification of the overall point of the story (global connectedness), and connectedness between consecutive events (local connectedness). Discourse measures were correlated with performance on cognitive tasks and with cortical atrophy as determined by magnetic resonance imaging voxel-based morphometry. Results Patients with CBS referred to the narrative theme significantly less frequently than controls. Global connectedness was intact in only 6 of 20 CBS patients (30%), but preserved in all controls. Local connectedness was significantly diminished in patients relative to controls. Discourse performance in CBS was related to tasks requiring higher-order integration of visual material, but not to basic visuospatial/visuoperceptual, language, or memory function. Discourse impairment was directly related to atrophy in the right parietal lobe and bilateral dorsolateral prefrontal cortex. Conclusions Our findings suggest that impaired information integration in CBS, related to parieto-frontal disease, interferes with patients’ ability to narrate a coherent story.