Restoring vision in the blind by direct cortical stimulation has been a dream since the discovery of electricity in the 18th century. In the centuries since these optimistic beginnings, researchers have made important progress in several aspects of the problem, although in many ways the ultimate goal still seems as distant as ever. In this paper I will review the current state of the art of hum...

Research has consistently revealed enhanced neural activation corresponding to attended cues coupled with suppression to unattended cues. This attention effect depends both on the spatial features of stimuli and internal task goals. However, a large majority of research supporting this effect involves circumscribed tasks that possess few ecologically relevant characteristics. By comparison, nat...

Stroke survivors often lose the ability to move their joints independently, which results in abnormal movement patterns when attempting to perform an isolated motion. For instance, many stroke subjects exhibit unwanted secondary knee extension movement when performing hip adduction. This study aimed at characterizing whether the neural substrates mediating abnormal activation patterns after str...

PURPOSE Results in several studies have suggested that the visual evoked potential (VEP) amplitude can vary with stimulus duration. The purpose of this study was to determine whether acuity estimates obtained by extrapolation of the sweep VEP are altered by this adaptation effect. METHODS Sweep VEP data were obtained from 16 healthy observers under binocular viewing conditions. Data were acqu...

Transcranial magnetic stimulation (TMS) has emerged as an important technique in cognitive neuroscience, permitting causal inferences about the contribution of a given brain area to behavior. Despite widespread use, exactly how TMS influences neural activity throughout an interconnected network, and how such influences ultimately change behavior, remain unclear. The oculomotor system of nonhuma...

In this paper, a novel independent brain-computer interface (BCI) system based on covert non-spatial visual selective attention of two superimposed illusory surfaces is described. Perception of two superimposed surfaces was induced by two sets of dots with different colors rotating in opposite directions. The surfaces flickered at different frequencies and elicited distinguishable steady-state ...

This study measured the development of contrast-sweep VEP thresholds to a range of chromatic and luminance stimuli. Subjects were 14-32 week-old infants (n=21) and three adults. Stimuli were 1 c/d sine gratings reversed at 5.6 Hz. Chromaticity was varied from the L-M axis to an achromatic axis. VEP thresholds when plotted in L- and M-cone contrasts showed that: (1) VEP thresholds did not consis...

Background noise is often discussed in terms of mental costs. In this study the effect of background noise on brain activity as reflected by the direct coupled (DC) potential was investigated by a within design in ten participants. During two successive blocks of 7 min each, participants performed 156 trials of a visual display terminal (VDT)-based visual-spatial attention task without noise an...

Transformational apparent motion (TAM) arises when a shape that is abruptly flashed on and off next to a static shape of similar color or texture appears as a protrusion that extends and retracts smoothly from the static object. Here we report that the strength of the TAM percept can be predicted from the waveform of visual evoked potentials (VEPs) measured while observers rated their percepts....

The visual evoked potential is commonly used to estimate visual acuity in infants. The stimulus used is temporally modulated in order to drive the cortical response. Here it is proposed that distortion products generated by a front-end nonlinearity may contaminate the acuity estimate. Specifically, the nonlinearity might convert temporal modulation of a high spatial frequency grating into appar...