For over a century, electrical microstimulation has been the most direct method for causally linking brain function with behavior. Despite this long history, it is still unclear how the activity of neural populations is affected by stimulation. For example, there is still no consensus on where activated cells lie or on the extent to which neural processes such as passing axons near the electrod...

Electrical stimulation of the visual system might serve as the foundation for a prosthetic device for the blind. We examined whether microstimulation of the dorsal lateral geniculate nucleus of the thalamus can generate localized visual percepts in alert monkeys. To assess electrically generated percepts, an eye-movement task was used with targets presented on a computer screen (optically) or t...

BACKGROUND Neuroanatomical studies investigating the connectivity of brain areas have heretofore employed procedures in which chemical or viral tracers are injected into an area of interest, and connected areas are subsequently identified using histological techniques. Such experiments require the sacrifice of the animals and do not allow for subsequent electrophysiological studies in the same ...

Sensory cortical prostheses have potential to aid people suffering from blindness, deafness and other sensory deficits. However, research to date has shown that sensation thresholds via epicortical stimulation are surprisingly large. These thresholds result in potentially deleterious electrical currents, as well as large activation volumes. Large activation volumes putatively limit the correspo...

We demonstrate that distinct mechanisms of top-down control regulate, respectively, the sensitivity and gain of sensory responses in the owl's optic tectum (OT). Electrical microstimulation in the forebrain gaze control area, the arcopallial gaze field (AGF), results in a space-specific regulation of sensory responses in the OT. AGF microstimulation increases the responsiveness of OT neurons re...

The pathogenesis of juxtafacet cysts is closely related to degenerative instability of the lumbar spine and degenerative changes in the ligamentum flavum and the facet joint. A 56-year-old man presented with severe right thigh pain and numbness for 1 month after a laminar fracture of the L4 spine. Magnetic resonance imaging revealed a heterogenous cystic mass surrounding the facet joint between...