This paper presents analytical solutions for the forward displacement and velocity kinematics of the “321-HEXA”, a fully-parallel manipulator design with R-RR-RRR legs as in the “HEXA” design and with a “3-2-1” top platform. The forward position and velocity kinematics rely on simple geometric algorithms that find the position and velocity of the top of a tetrahedron from the knowledge of the t...

How stable is vertical eye-in-head position control in darkness when no visual targets are present? We evaluated this while varying both body-in-space orientation and eye-in-orbit position in six subjects who were free from oculomotor/vestibular disease. Vertical eye movements were monitored using a CCD-video tracking system, and results were confirmed on one subject with the magnetic search co...

The activity of 62 antidromically identified prepositus hypoglossi neurons was recorded in 10 alert cats during spontaneous, vestibular or visually induced eye movements. Neurons were antidromically activated from stimulating electrodes implanted in the ipsilateral medial longitudinal fasciculus (n = 24), the ipsilateral interstitial nucleus of Cajal (n = 6), the ipsilateral parabigeminal nucle...

The oculomotor system produces eye-position signals during fixations and head movements by integrating velocity-coded saccadic and vestibular inputs. A previous analysis of nucleus prepositus hypoglossi (nph) lesions in monkeys found that the integration time constant for maintaining fixations decreased, while that for the vestibulo-ocular reflex (VOR) did not. On this basis, it was concluded t...

OBJECTIVE Insufficient information exists about the ability of hemiparetic patients to adjust reach extent during early recovery from stroke. Further knowledge may suggest guidance for therapy intervention. The objective of this study was to investigate the ability of hemiparetic subjects to adjust reach extent within 6 months after stroke. DESIGN Repeated-measures design experiment with two ...