Stephan A. Brandt

Learn More
Covertly directing visual attention toward a spatial location in the absence of visual stimulation enhances future visual processing at the attended position. The neuronal correlates of these attention shifts involve modulation of neuronal "baseline" activity in early visual areas, presumably through top-down control from higher-order attentional systems.(More)
Attention can be used to keep track of moving items, particularly when there are multiple targets of interest that cannot all be followed with eye movements. Functional magnetic resonance imaging (fMRI) was used to investigate cortical regions involved in attentive tracking. Cortical flattening techniques facilitated within-subject comparisons of activation(More)
In nine naïve subjects eye movements were recorded while subjects viewed and visualized four irregularly-checkered diagrams. Scanpaths, defined as repetitive sequences of fixations and saccades were found during visual imagery and viewing. Positions of fixations were distributed according to the spatial arrangement of subfeatures in the diagrams. For a(More)
According to a classical view of visual object recognition, targets are detected "pre-attentively" if they carry unique features, whereas attention has to be deployed serially to object locations for feature binding if the targets can be distinguished from distracters only in terms of their feature conjunctions. Consistent with this view, recent reports(More)
Attending a certain region in space enhances activity in visual areas retinotopically mapped to this region; stimuli presented in this region are preferentially processed. The zoom lens model of visual attention proposes that the attended region can be adjusted in size and predicts a tradeoff between its size and processing efficiency because of limited(More)
Searching for a target object in a cluttered visual scene requires active visual attention if the target differs from distractors not by elementary visual features but rather by a feature conjunction. We used functional magnetic resonance imaging (fMRI) in human subjects to investigate the functional neuroanatomy of attentional mechanisms employed during(More)
BACKGROUND Transcranial magnetic stimulation (TMS) is the only noninvasive method for presurgical stimulation mapping of cortical function. Recent technical advancements have significantly increased the focality and usability of the method. OBJECTIVE To compare the accuracy of a 3-dimensional magnetic resonance imaging-navigated TMS system (nTMS) with the(More)
Functional magnetic resonance imaging (fMRI) was used to examine the influence of non-painful electrical stimulus intensity on the BOLD response in human primary somatosensory cortex (SI). In ten healthy subjects, index and middle finger of the right hand were stimulated separately at two different stimulus intensities. The activated volume of single finger(More)
In this study, we aimed to characterize the effect of anodal and cathodal direct current stimulation (tDCS) on contrast sensitivity inside the central 10 degrees of the visual field in healthy subjects. Distinct eccentricities were investigated separately, since at the cortical level, more central regions of the visual field are represented closer to the(More)
In addition to performance gains accrued concurrently with a given training experience (within-session gains) robust, delayed (between-session) performance gains may slowly evolve in the absence of any additional practice in a variety of tasks. The latter is regarded as a behavioral manifestation of skill memory consolidation. It is not known, however, how(More)