Both electro-physiological and psychophysical studies point to the existence of detectors specialised for the analysis of optic flow. However, it is unclear whether these detectors are tuned to specific 'cardinal directions' (such as radial and circular motion), or whether they respond equally to all directions of optic-flow motion, including intermediate spiral motions. Here summation and mask...

We studied the time of origin, development and location of glial elements in the developing optic nerve of Xenopus with light and electron microscopy. The first cells acting as a primitive glia are ependymal cells lying dorsal to the chiasmatic optic nerve (CON) at Nieuwkoop & Faber (1956) NF stage 39. Later (stage 47/48), immature astrocyte cell bodies migrate from the periphery of the middle ...

When illusory self-motion is induced in a stationary observer by optic flow, the perceived distance traveled is generally overestimated relative to the distance of a remembered target (Redlick, Harris, & Jenkin, 2001): subjects feel they have gone further than the simulated distance and indicate that they have arrived at a target's previously seen location too early. In this article we assess h...

Earlier studies of neurons in the anterior region of the superior temporal polysensory area (STPa) have demonstrated selectivity for visual motion using stimuli contaminated by nonmotion cues, including texture, luminance, and form. The present experiments investigated the motion selectivity of neurons in STPa in the absence of form cues using random dot optic flow displays. The responses of ne...

STUDY DESIGN A prospective audit. OBJECTIVE To establish the efficacy of lumbar medial branch neurotomy under optimum conditions. SUMMARY OF BACKGROUND DATA Previous reports of the efficacy of lumbar medial branch neurotomy have been confounded by poor patient selection, inaccurate surgical technique, and inadequate assessment of outcome. METHODS Fifteen patients with chronic low back pai...

Objective: To determine the safety and the efficacy of lumbar spine radiofrequency neurotomy performed in the presence of pedicle screws in patients with chronic low back pain. Methos: Retrospective practice audit. Review of charts of all patients who underwent lumbar radiofrequency neurotomy in the presence of pedicle screws. Patients were tested with a minimum of two controlled medial branch ...