Wyniki wyszukiwania - Biblioteka Nauki

1

ATTENTION! - BRAIN IN ACTION. ON NEURONAL BASIS OF ATTENTION MECHANISM

100%

Wronka E.

Psychological Studies

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2004

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tom 41

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nr 1

11-24

EN

The following article review the issues concerning neuronal basis of attention. Attention is not treated by author as a single entity but as a name given to a finite set of brain processes interacting with each other and influencing other brain processes in the performance of perceptual, motor and cognitive actions. At the most general level one could state that function of attention is to allow and to maintain specific reaction of the organism in the face of incoming information. In this meaning attention system of the brain is cooperating with sensory systems by selecting information based on its semantic meaning. From the other hand, attention system serves as a mechanism, decides about the priorities of motor activity and controls motor planning, providing the efficient response to the environmental changes.

2

The P3 produced by auditory stimuli presented in a passive and active condition: Modulation by visual stimuli

51%

Wronka E. , Kuniecki M. , Kaiser J. , Coenen A. M. L.

Acta Neurobiologiae Experimentalis

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2007

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tom 67

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nr 2

EN

The aim of this study was to investigate how the processing of auditory stimuli is affected by the simultaneous presentation of visual stimuli. This was approached in an active and passive condition, during which a P3 was elicited in the human EEG by single auditory stimuli. Subjects were presented tones, either alone or accompanied by the simultaneous exposition of pictures. There were two different sessions. In the first, the presented tones demanded no further cognitive activity from the subjects (passive or ""ignore"" session), while in the second session subjects were instructed to count the tones (active or "count" session). The central question was whether inter-modal influences of visual stimulation in the active condition would modulate the auditory P3 in the same way as in the passive condition. Brain responses in the ignore session revealed only a small P3-like component over the parietal and frontal cortex, however, when the auditory stimuli co-occurred with the visual stimuli, an increased frontal activity in the window of 300-500 ms was observed. This could be interpreted as the reflection of a more intensive involuntary attention shift, provoked by the preceding visual stimulation. Moreover, it was found that cognitive load caused by the count instruction, resulted in an evident P3, with maximal amplitude over parietal locations. This effect was smaller when auditory stimuli were presented on the visual background. These findings might support the thesis that available resources were assigned to the analysis of visual stimulus, and thus were not available to analyze the subsequent auditory stimuli. This reduction in allocation of resources for attention was restricted to the active condition only, when the matching of a template with incoming information results in a distinct P3 component. It is discussed whether the putative source of this effect is a change in the activity of the frontal cortex.

3

Evoked cardiac response as a correlate of cognitive processing in the cases of central motor system impairment

51%

Kaiser J. , Wronka E. , Tomik B. , Szkudlik A.

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1997

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tom 57

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nr 5

4

Neural generators of the auditory evoked potential components P3a and P3b

51%

Wronka E. , Kaiser J. , Coenen A. M. L.

Acta Neurobiologiae Experimentalis

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2012

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tom 72

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nr 1

EN

The aim of the present study was to define the scalp topography of the two subcomponents of the P3 component of the auditory evoked potential elicited in a three-stimulus oddball paradigm and to identify their cortical generators using the standardized low resolution electromagnetic tomography (sLORETA). Subjects were presented with a random sequence of auditory stimuli and instructed to respond to an infrequently occurring target stimulus inserted into a sequence of frequent standard and rare non-target stimuli. Results show that the magnitude of the frontal P3a is determined by the relative physical difference among stimuli, as it was larger for the stimulus more deviant from the standard. Major neural generators of the P3a were localized within frontal cortex and anterior cingulate gyrus. In contrast to this, the P3b, showing maximal amplitude at parietal locations, was larger for stimuli demanding a response than for the rare non-target. Major sources of the P3b included the superior parietal lobule and the posterior part of the cingulate gyrus. Our findings are in line with the hypothesis that P3a is related to alerting activity during the initial allocation of attention, while P3b is related to activation of a posterior network when the neuronal model of perceived stimulation is compared with the attentional trace.

5

Evoked cardiac response components in cognitive processing: differential effects of amyotrophic lateral sclerosis

51%

Kaiser J. , Wronka E. , Barry R. J. , Szczudlik A.

Acta Neurobiologiae Experimentalis

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1999

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tom 59

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nr 4