Annals of neurology
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Lacunar strokes are a leading cause of cognitive impairment and vascular dementia. However, adequate characterization of cognitive impairment is lacking. The aim of this study was to estimate the prevalence and characterize the neuropsychological impairment in lacunar stroke patients. ⋯ In this large, well-characterized cohort of lacunar stroke patients, MCI was present in nearly half, including many with minimal or no physical disabilities. Cognitive dysfunction in lacunar stroke patients may commonly be overlooked in clinical practice but may be as important as motor and sensory sequelae.
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Annals of neurology · Sep 2012
Subthalamic discharges as a causal determinant of parkinsonian motor deficits.
We have reported that intrinsic membrane properties, especially T-type Ca2+ channels, play a key role in the genesis of burst discharges in the subthalamic nucleus (STN) and parkinsonian locomotor symptoms. Whether deep brain stimulation (DBS) exerts its clinical benefits on Parkinson disease (PD) with changes in T currents or other conductances, however, remains elusive. ⋯ The increased tendency of STN burst discharges may by itself serve as a direct cause of parkinsonian locomotor deficits, even in the absence of deranged dopaminergic innervation. Effective DBS therapy in PD very likely relies on adequate depolarization, and consequent modification of the relevant ionic currents and discharge patterns, of STN neurons.
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Annals of neurology · Sep 2012
A role for the default mode network in the bases of disorders of consciousness.
Functional connectivity in the default mode network (DMN) is known to be reduced in patients with disorders of consciousness, to a different extent depending on their clinical severity. Nevertheless, the integrity of the structural architecture supporting this network and its relation with the exhibited functional disconnections are very poorly understood. We investigated the structural connectivity and white matter integrity of the DMN in patients with disorders of consciousness of varying clinical severity. ⋯ These results provide a possible neural substrate for the functional disconnection previously described in these patients, and reinforce the importance of the DMN in the genesis of awareness and the neural bases of its disorders.