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This Journal Club article looks at a study by Tessitore et al.,(1) who investigated functional connectivity (FC) within the default-mode network (DMN) in cognitively unimpaired patients with Parkinson disease (PD). PD is the second most common neurodegenerative disorder after Alzheimer disease (AD) and is expected to become progressively more prevalent in our aging societies. Thus, its social and economic burden on societies is expected to be even greater in the future.(2) Cognitive impairment is one of the most disabling nonmotor symptoms of PD, further affecting functioning and quality of life, as well as increasing caregivers' burden and health-related costs.(3) When an individual is alert but not actively engaged in cognitive tasks, organized neural activity occurs in a set of brain regions called DMN (figure), which involves the posterior cingulate cortex (PCC), parts of the ventromedial prefrontal cortex, and the precuneus.(4) Interestingly, DMN abnormalities have been linked to cognitive profiles in several neurologic and psychiatric disorders, such as AD, autism, frontotemporal dementia, multiple sclerosis, and vegetative states(5); however, contradictory results have been reported in PD.(1) This study, for the first time, cogently demonstrates decreased FC within the DMN in cognitively unimpaired patients with PD.

Decision making is a crucial part of our life: we sense information from the environment and perform our motor response. However, "whether" and "when" decisions are embodied still needs to be fully elucidated. Neuroimaging data obtained by the disentanglement of perceptual decision from motor preparation revealed an increase in connectivity between inferior frontal cortex and sensory regions, and the important role played by intraparietal sulcus in motor decisions. The results obtained as well as the new research questions prompted by this work are carefully discussed herein. [ABSTRACT FROM AUTHOR]

The article focuses on the injury caused to brain due to cognitive tasks. It is stated that Angelo Mosso, Italian physiologist has carried an experiment in which he hypothesized that cerebral blood flow increases with the cognitive work. It is further stated that the techniques like magnetic resonance imaging and positron emission tomography helps in studying pathological and physiological condition and enables the quantification and imaging of neural system in resting and working states.