AIM This study was designed to test the ability of a portable computer driven, head mounted visual field testing system to perform automated perimetry on patients at their bedside and to compare these results with the "gold standard" for bedside examinations, confrontation visual fields. METHODS The Kasha visual field system is a portable automated perimeter which utilises a virtual reality h...

An intermediate image beta-ray spectrometer has been constructed utilizing the focusing properties of a Ushaped magnetic field distribution. The construction and performance of the instrument are discussed. A transmission of ten percent has been attained with a resolution of about six percent. A scintillation spectrometer is used in conjunction with the intermediate image spectrometer for the p...

In macaque ventral premotor cortex, we recorded the activity of neurons that responded to both visual and tactile stimuli. For these bimodal cells, the visual receptive field extended from the tactile receptive field into the adjacent space. Their tactile receptive fields were organized topographically, with the arms represented medially, the face represented in the middle, and the inside of th...

Neurons in the primary visual cortex of higher mammals are arranged in columns, and the neurons in each column respond best to light-dark borders of particular orientations. The basis of cortical cell orientation selectivity is not known. One possible mechanism would be for cortical cells to receive input from several lateral geniculate nucleus (LGN) neurons with receptive fields that are align...

The response properties of neurons to sensory stimuli have been used to identify their receptive fields and to functionally map sensory systems. In primary visual cortex, most neurons are selective to a particular orientation and spatial frequency of the visual stimulus. Using two-photon calcium imaging of neuronal populations from the primary visual cortex of mice, we have characterized the re...

Plasma turbulence in a linear device is explored for the first time with three-dimensional global two-fluid simulations, focusing on the plasma parameters of the Large Plasma Device. Three instabilities are present in the simulations: the Kelvin-Helmholtz instability, a sheath-driven instability, and a resistive drift wave instability. The Kelvin-Helmholtz mode is shown to dominate the transpor...

Visual performance for judging the length of a simultaneously presented pair of radial lines, reciprocally opposed by 180 degrees at a central fixation point, was assessed for 24 radial positions of test lines, for three viewing conditions (binocular, left and right monocular) and five different standard line sizes (1.43-7.13 degrees ). Generally, the results showed underestimation of the test ...

After coronary by-pass surgery, a 47 year old, right-handed man developed Gerstmann's syndrome, a visual-spatial perceptual deficit, and a gross impairment of movememt under visual guidance ("optic ataxia"). Visual fields and extraocular movements were intact; he had a left hemiparesis. The EMIscan showed three lesions: a left parietal-occipital lesion; a posterior callosal lesion, and a right ...