Daniel M. Corcos

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The mesial premotor cortex (pre-supplementary motor area and supplementary motor area proper), lateral premotor cortex (dorsal premotor cortex and ventral premotor cortex), and primary sensorimotor cortex (primary motor cortex and primary somatosensory cortex) have been identified as key cortical areas for sensorimotor function. However, the(More)
1. Normal human subjects made discrete flexions of the elbow over a fixed distance in the horizontal plane from a stationary initial position to a visually defined target. We measured joint angle, acceleration, and electromyograms (EMGs) from two agonist and two antagonist muscles. 2. Changes in movement speed were elicited either by explicit instruction to(More)
BACKGROUND In the midbrain of patients with Parkinson disease (PD), there is a selective loss of dopaminergic neurons in the ventrolateral and caudal substantia nigra (SN). In a mouse model of PD, investigators have administered 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and found that measures derived using diffusion tensor imaging (DTI) were(More)
We examined the patterns of joint kinematics and torques in two kinds of sagittal plane reaching movements. One consisted of movements from a fixed initial position with the arm partially outstretched, to different targets, equidistant from the initial position and located according to the hours of a clock. The other series added movements from different(More)
1. Normal human subjects made discrete elbow flexions in the horizontal plane under different task conditions of initial or final position, inertial loading, or instruction about speed. We measured joint angle, acceleration, and electromyographic signals (EMGs) from two agonist and two antagonist muscles. 2. For many of the experimental tasks, the latency(More)
Previous neuroimaging studies have found hyperactivation in the cerebellum and motor cortex and hypoactivation in the basal ganglia in patients with Parkinson's disease (PD) but the relationship between the two has not been established. This study examined whether cerebellar and motor cortex hyperactivation is a compensatory mechanism for hypoactivation in(More)
Despite an intricate understanding of the neural mechanisms underlying visual and motor systems, it is not completely understood in which brain regions humans transfer visual information into motor commands. Furthermore, in the absence of visual information, the retrieval process for motor memory information remains unclear. We report an investigation where(More)
Studies of electromyographic (EMG) patterns during movements in Parkinson's disease (PD) have often yielded contradictory results, making it impossible to derive a set of rules to explain how muscles are activated to perform different movement tasks. We sought to clarify the changes in modulation of EMG parameters associated with control of movement(More)
1. Four subjects performed fast flexions of the elbow or shoulder over three different distances. Elbow flexions were performed both in a horizontal, single-degree-of-freedom manipulandum and in a sagittal plane with the limb unconstrained. Shoulder flexions were only performed in the sagittal plane by the unconstrained limb. We simultaneously recorded(More)
1. Normal human subjects made discrete elbow flexions and extensions in the horizontal plane from a stationary initial position to visually defined targets at different distances with a constant inertial load or made flexions to a visually defined target with different inertial loads. We measured joint angle, acceleration, and electromyograms (EMGs) from(More)