Search results for "Space Perception"
showing 10 items of 136 documents
1 Hz repetitive transcranial magnetic stimulation of the unaffected hemisphere ameliorates contralesional visuospatial neglect in humans
2002
The aim of the study was to investigate whether low-frequency repetitive transcranial magnetic stimulation (rTMS) over the unaffected hemisphere can ameliorate visuospatial neglect. We treated three right brain damaged patients with left neglect. 900 pulses (1 Hz frequency) were given over left posterior parietal cortex every other day for 2 weeks. Patients performed a computerized task requiring length judgement of prebisected lines, tachistoscopically presented for 150 ms. With respect to rTMS the task was given 15 days before, at the beginning, at the end and 15 days after. At these times patients performed also line bisection and clock drawing tasks. rTMS induced a significant improveme…
Far Space Remapping by Tool Use: A rTMS Study Over the Right Posterior Parietal Cortex
2015
Abstract Background In previous studies, rTMS has been successfully employed to interfere with the right posterior parietal cortex (rPPC) inducing neglect-like behavior in healthy subjects. Several studies have shown that the use of tools can modulate the boundaries between near and far space: indeed when far space is reached by the stick, far space can be remapped as near. Objective The aim of the present study was to investigate whether once that rTMS on the rPPC has selectively induced neglect-like bias in the near space (but not in the far space), neglect can appears also in the far space when the subjects used a tool to perform the task. Methods Fifteen right-handed healthy subjects ex…
The Right Frontopolar Cortex Is Involved in Visual-Spatial Prospective Memory
2013
The involvement of frontopolar cortex in mediating prospective memory processes has been evidenced by various studies, mainly by means of neuroimaging techniques. Recently, one transcranial magnetic stimulation study documented that transient inhibition of left Brodmann Area (BA) 10 impaired verbal prospective memory. This result raises the issue of whether the BA 10 involvement in prospective memory functioning may be modulated by the physical characteristics of the stimuli used. The present study aimed to investigate the role of the frontopolar cortex in visual-spatial PM by means of the application of inhibitory theta-burst stimulation. Twelve volunteers were evaluated after inhibitory t…
Musicians--same or different?
2009
In the neuroscience of music, musicians have traditionally been treated as a unified group, as if the demands set by their musical activities would be more or less equal in terms of perceptual, cognitive, and motor functions. However, obviously, their musical preferences differentiate them to a higher degree, for instance, in terms of the instrument they choose and the music genre they are mostly engaged with as well as their practicing style. This diversity in musicians' profiles has been recently taken into account in several empirical endeavors. The present contribution will review the evidence available about the various neurocognitive profiles these different kinds of musicians display.
Analysis of a spatial orientation memory in Drosophila.
2008
Flexible goal-driven orientation requires that the position of a target be stored, especially in case the target moves out of sight. The capability to retain, recall and integrate such positional information into guiding behaviour has been summarized under the term spatial working memory. This kind of memory contains specific details of the presence that are not necessarily part of a long-term memory. Neurophysiological studies in primates indicate that sustained activity of neurons encodes the sensory information even though the object is no longer present. Furthermore they suggest that dopamine transmits the respective input to the prefrontal cortex, and simultaneous suppression by GABA s…
Mathematical description of the stimuli to the lateral line system of fish derived from a three-dimensional flow field analysis
1992
The spatial distributions of the stimuli to the lateral line system of a fish moving alongside or above a plane surface are derived mathematically. The derivation was done from the analysis of the three-dimensional potential flow field on the surface of fish with bodies of circular cross-section with different shapes.
Collision with and avoidance of obstacles by blind cave fish Anoptichthys jordani (Characidae).
1985
Blind Mexican cave fish (Anoptichthys jordani) were released into unknown surroundings and their swimming tracks were recorded. During the first 24 h in a new tank, i.e., in unfamiliar environments, the average swimming velocity of the fish was higher than during the remaining time in the tank. Collision with obstacles was recorded by an electrical contact detection method. Single frame analysis of video-recordings revealed that collision can be correlated with tail movements when the fish is close to an obstacle, whereas avoidance correlates with gliding during approach to an obstacle. These behavior patterns are discussed in the context of the flow field hypothesis and inhibition of the l…
Integration of local features into a global shape
2001
AbstractIt is a well-established fact that the cortical filters selective for spatial frequency and orientation have a limited spatial extent. The present study investigated how information from local filters is integrated into global shapes. Specifically, we were interested in whether identification of a global pattern consisting of small oriented, spatially-bandpass features (Gabor patches) depends on the orientations of those features. The observer was presented with a C-like stimulus shape comprised of oriented Gabor elements on a blank background, and the performance measure was the threshold contrast for identifying the global orientation of the C-shape (four possible rotated orientat…
Space information is important for reading
2009
AbstractReading a text without spaces in an alphabetic language causes disruption at the levels of word identification and eye movement control. In the present experiment, we examined how word discriminability affects the pattern of eye movements when reading unspaced text in an alphabetic language. More specifically, we designed an experiment in which participants read three types of sentences: normally written sentences, regular unspaced sentences, and alternatingbold unspaced sentences. Although there was a reading cost in the unspaced sentences relative to the normally written sentences, this cost was much smaller in alternatingbold unspaced sentences than in regular unspaced sentences.
Extraction of objects from structured backgrounds in the cat superior colliculus. Part II
1980
Specific changes occur in the cells of the uppers layers of the cat's superior colliculus when a two dimensional noise (background) is superimposed onto a deterministic signal (spot of light). Some of the measurements can be interpreted as meaning that some cells only react to certain relative movements of object (spot) and background (noise). The movement of the visual background is interpreted as environmental movement occurring due to the animal's own movement. The results of the measurements provide all the necessary presuppositions for a distinction between the animal's own velocity and that of the object (Part I). The experimental results can be interpreted with a model. The essential…