Independent Effects of Attentional Gain Control and Competitive Interactions on Visual Stimulus Processing

Abstract The capacity-limited human brain is constantly confronted with a huge amount of sensory information. Selective attention is needed for biasing neural processing towards relevant information and consequently allows meaningful interaction with the environment. Activity in the alpha-band has been proposed to be related to top-down modulation of neural inhibition and could thus represent a viable candidate to control the priority of stimulus processing. It is, however, unknown whether modulations in the alpha-band directly relate to changes in the sensory gain control of the early visual cortex. Here, we used a spatial cueing paradigm while simultaneously measuring ongoing alpha-band oscillations and steady-state visual evoked potentials (SSVEPs) as a marker of continuous early sensory processing in the human visual cortex. Thereby, the effects of spatial attention for both of these signals and their potential interactions were assessed. As expected, spatial attention modulated both alpha-band and SSVEP responses. However, their modulations were independent of each other and the corresponding activity profiles differed across task demands. Thus, our results challenge the view that modulations of alpha-band activity represent a mechanism that directly alters or controls sensory gain. The potential role of alpha-band oscillations beyond sensory processing will be discussed in light of the present results.

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Panum’s phenomenon and the confluence of signals from the two eyes in stereoscopy

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1986.0056 ◽

1986 ◽

Vol 228 (1252) ◽

pp. 289-305 ◽

Cited By ~ 21

Keyword(s):

Nervous System ◽

Visual Stimulus ◽

Spatial Extent ◽

Repulsive Interaction ◽

Apparent Depth ◽

Stimulus Processing ◽

Neural Ensemble ◽

Length Constant ◽

Processing Mechanisms ◽

Time Information

The signals from the two eyes must be routed to allow either eye to have access to the processing mechanisms for position, shape, colour, etc.; at the same time, information as to the eye of origin must be retained for the purposes of stereoscopy. The study of this confluence of signals from the two eyes was approached psychophysically by studying induced position and depth changes of adjacent binocular and monocular stimuli in the human fovea. It was demonstrated that a monocular visual stimulus located near a binocular one acquires a depth signal, according to a scheme originally proposed by Panum. The effect is unspecific as regards feature shape and brightness, and falls off with a length constant of about 15 minutes of arc in the fovea. A monocular stimulus also affects the apparent depth of its binocular neighbour in a centre—surround manner; disparity pooling changes to disparity repulsion when features are separated by distances of about 3 minutes of arc in the fovea. The findings led to the development of a scheme of uniocular connectivity to a matrix of depth units. Excitation patterns here would depend on the state of the input lines, the intrinsic neuronal interaction properties, and contextural configuring influences from other parts of the nervous system. Experiments showing the spatial extent of pooling and repulsive interaction within the disparity domain help to characterize the stimulus processing in this neural ensemble.

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Associations between neural correlates of visual stimulus processing and set-shifting in ill and recovered women with anorexia nervosa

Psychiatry Research Neuroimaging ◽

10.1016/j.pscychresns.2016.07.004 ◽

2016 ◽

Vol 255 ◽

pp. 35-42 ◽

Cited By ~ 7

Author(s):

Hedvig Sultson ◽

Floor van Meer ◽

Nicole Sanders ◽

Annemarie A. van Elburg ◽

Unna N. Danner ◽

...

Keyword(s):

Anorexia Nervosa ◽

Visual Stimulus ◽

Neural Correlates ◽

Set Shifting ◽

Stimulus Processing

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Video-Enhanced Microscopy--Better Visibility of Plant Cell Structures

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100053589 ◽

1982 ◽

Vol 40 ◽

pp. 182-185

Author(s):

N.S. Allen ◽

R.D. Allen

Keyword(s):

Diffraction Pattern ◽

Theoretical Basis ◽

Numerical Aperture ◽

Gain Control ◽

Control Unit ◽

Camera Control ◽

Variable Gain ◽

Contrast Method ◽

Fine Detail ◽

Cell Structures

Various methods of video-enhanced microscopy combine TV cameras with light microscopes creating images with improved resolution, contrast and visibility of fine detail, which can be recorded rapidly and relatively inexpensively. The AVEC (Allen Video-enhanced Contrast) method avoids polarizing rectifiers, since the microscope is operated at retardations of λ/9- λ/4, where no anomaly is seen in the Airy diffraction pattern. The iris diaphram is opened fully to match the numerical aperture of the condenser to that of the objective. Under these conditions, no image can be realized either by eye or photographically. Yet the image becomes visible using the Hamamatsu C-1000-01 binary camera, if the camera control unit is equipped with variable gain control and an offset knob (which sets a clamp voltage of a D.C. restoration circuit). The theoretical basis for these improvements has been described.

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Both Antiangiogenesis- and Angiogenesis-Independent Effects Are Responsible for Hepatocellular Carcinoma Growth Arrest by Tyrosine kinase Inhibitor PTK787/ZK222584

Yearbook of Oncology ◽

10.1016/s1040-1741(08)70211-2 ◽

2006 ◽

Vol 2006 ◽

pp. 309-310

Author(s):

P.J. Loehrer

Keyword(s):

Hepatocellular Carcinoma ◽

Tyrosine Kinase ◽

Tyrosine Kinase Inhibitor ◽

Kinase Inhibitor ◽

Growth Arrest ◽

Independent Effects

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Orienting and Focusing in Voluntary and Involuntary Visuospatial Attention Conditions

Journal of Psychophysiology ◽

10.1027/0269-8803/a000010 ◽

2010 ◽

Vol 24 (3) ◽

pp. 198-209 ◽

Cited By ~ 8

Author(s):

Yan Wang ◽

Jianhui Wu ◽

Shimin Fu ◽

Yuejia Luo

Keyword(s):

Gain Control ◽

Event Related Potentials ◽

Stimulus Onset ◽

Orientation Discrimination ◽

Involuntary Attention ◽

Attention Condition ◽

Voluntary Attention ◽

Visual Spatial ◽

Related Potentials ◽

Underlying Mechanisms

In the present study, we used event-related potentials (ERPs) and behavioral measurements in a peripherally cued line-orientation discrimination task to investigate the underlying mechanisms of orienting and focusing in voluntary and involuntary attention conditions. Informative peripheral cue (75% valid) with long stimulus onset asynchrony (SOA) was used in the voluntary attention condition; uninformative peripheral cue (50% valid) with short SOA was used in the involuntary attention condition. Both orienting and focusing were affected by attention type. Results for attention orienting in the voluntary attention condition confirmed the “sensory gain control theory,” as attention enhanced the amplitude of the early ERP components, P1 and N1, without latency changes. In the involuntary attention condition, compared with invalid trials, targets in the valid trials elicited larger and later contralateral P1 components, and smaller and later contralateral N1 components. Furthermore, but only in the voluntary attention condition, targets in the valid trials elicited larger N2 and P3 components than in the invalid trials. Attention focusing in the involuntary attention condition resulted in larger P1 components elicited by targets in small-cue trials compared to large-cue trials, whereas in the voluntary attention condition, larger P1 components were elicited by targets in large-cue trials than in small-cue trials. There was no interaction between orienting and focusing. These results suggest that orienting and focusing of visual-spatial attention are deployed independently regardless of attention type. In addition, the present results provide evidence of dissociation between voluntary and involuntary attention during the same task.

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