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1
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Altered electrophysiological pattern of target detection in schizophrenia in the Continous Attention Test

100%
Basinska A.
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vol. 58
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issue 3
207-220
EN
Visual evoked potentials were examined in 50 male schizophrenic patients and 50 age-matched healthy male volunteers during performance of the Continous Attention Test (CAT). In the patients emerged an evident deterioration of attentional processes: much higher index of errors and longre reaction time than in he healthy subjects. On the other hand, in patients the following alternations is evoked potentials were found:(1) in the non-target condition lower amplitudes ofcomponents; left- sided P1, bilateral N1 as well as frontal P3a; (2) a distinct electrophysiological pattern of target detection, consisting of an increase in amplitudes of either N1 or P3a as compared to the response to the non-target stimulus. Electrophysiological features were related to behavioural data. An increase in the amplitude of N1 during detection of the target, as well as a lower non-target amplitude of P3a, correlated with poor CAT performance, while an increase in the amplitude of P3a during detection of the target correlated with relatively shorter reaction time, and showed no correlation with an index of errors. The results suggest an underlying primary hyperarousability at lower stages of visual data processing (up to N1 latency range) accompanied by several secondary pathological and compensatory mechanisms at the higher stages.
2
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Aging and the time course of inhibition of return in a static environment

80%
Bao Y., Zhou J., Fu L.
Acta Neurobiologiae Experimentalis
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2004
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vol. 64
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issue 3
403-414
EN
Age-related differences on the time course of inhibition of return (IOR), a phenomenon that refers to a slowed response time for targets appearing at a previously attended location, were examined in 30 young and 30 elderly adults. Stimulus onset asynchronies (SOAs) between peripheral cues and targets were systematically manipulated on a detection task with a double-cue procedure to capture the onset and offset of IOR. Results show that IOR in elderly people developed 50 ms later as compared to young adults, at an approximately 200 ms cue-target interval. The magnitude of IOR for elderly people was also weaker than that for young adults during short SOAs. Similar magnitude and dissipation of IOR at an approximately 3.5 s cue-target interval during long SOAs were observed for both young and elderly people. Possible reasons underlying the age effects on the time course of IOR and the involvement of temporal processing mechanisms are discussed.
3
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Conscious control of movements: increase of temporal precision in voluntarily delayed actions?

80%
Szelag E., Rymarczyk K., Poppel E.
Acta Neurobiologiae Experimentalis
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2001
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vol. 61
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issue 3
175-179
EN
The variability of simple actions with response to auditory stimuli was studied under different delay conditions. Subjects reacted as fast as possible or with a defined time delay (from 250 to 750 ms) to a tone switching off by pressing a response-key with the left index finger (controlled by the right hemisphere) or with the right one (left hemisphere). For short delays (requested response times below 350 ms) variability of responses was much larger then for longer delays (above 350 ms), especially for the right hand. Thus, precise temporal control on consciously mediated actions sets only in after a rather long delay (in some cases after half a second). Neuronal mechanisms underlying conscious temporal control of actions appear to be different for the two hemispheres.
4
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Event-related current density in primary insomnia

80%
Szelenberger W., Niemcewicz S.
Acta Neurobiologiae Experimentalis
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2001
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vol. 61
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issue 4
299-308
EN
Using Low Resolution Electromagnetic Tomography (LORETA), event-related current density was investigated in 14 patients with primary insomnia and 14 controls matched for age, gender and education level. All subjects were rated on the Athens Insomnia Scale, the Hyperarousal Scale, the Hamilton Depression Rating Scale and the Beck Depression Inventory. They also completed the Selective Reminding Test and the Continuous Attention Test. Only minor elevations on depression scales were found in patients. The Continuous Attention Test did not reveal any between group differences. However, insomniacs required more trials before all the Selective Reminding Test items were learned. Insomniacs showed less event-related current density in orbitofrontal, medial prefrontal and anterior cingulate cortex, i.e. brain regions of relevance for cognition and affect. Earliest group differences appeared in the P1 time range and then were observed at the N1, N2 and P3 stages of stimulus processing. These stimulus processing differences correlated most consistently with severity of insomnia. Neuropsychological impairment correlated most strongly with less current density in Brodmann area 10.
5
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Pathology and compensation during visual signal processing in schizophrenia - spatial analysis of event-related potentials

80%
Basinska-Starzycka A.
Acta Neurobiologiae Experimentalis
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2000
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vol. 60
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issue 3
345-359
EN
Correlations between measures of attention and topographical abnormalities of evoked cortical potentials elicited during the Continuous Attention Test (CAT) were assessed in 50 schizophrenic patients, compared to 50 healthy subjects. For each group and for each CAT condition evoked responses consisted of six successive epochs (segments) of stable spatially configured potentials. Quantitative descriptors of those configurations (Lehmann 1987) were referred to the CAT data. In patients: (1) segments III-V were delayed, (2) in the non-target condition, diminished global field power (GFP) emerged, coexisting either with lower amplitude of posterior potentials in segment I and II or with lower amplitude of a central positive potential in segment V, (3) an altered topographic pattern of responses to the target stimulus occurred. In healthy subjects detection of the target (as compared to the non-target condition) was associated with a shift of the location of the positive potential in segments IV and V from a central towards the prefrontal area. In patients, in segment V a similar shift reached frontal, but not prefrontal areas, and additionally, the central areas remained active. Delayed latency and low GFP in segment V in the non-target condition in patients correlated with poor CAT performance. A more posterior location of the positive centroid in segment V during detection of the target correlated with better CAT results, and the associated GFP increase with less prolonged reaction time. The data revealed a possible compensatory role of central and frontal areas in the face of weakened prefrontal functions in schizophrenia.
6
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Visual and auditory attentional capture are both sluggish in children with developmental dyslexia

80%
Facoetti A., Lorusso M. L., Cattaneo C., Galli R., Molteni M.
Acta Neurobiologiae Experimentalis
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2005
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vol. 65
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issue 1
61-72
EN
Automatic multimodal spatial attention was studied in 12 dyslexic children (SRD), 18 chronological age matched (CA) and 9 reading level matched (RL) normally reading children by measuring reaction times (RTs) to lateralized visual and auditory stimuli in cued detection tasks. The results show a slower time course of focused multimodal attention (FMA) in SRD children than in both CA and RL controls. Specifically, no cueing effect (i.e., RTs difference between cued?uncued) was found in SRD children at 100 ms cue-target delay, while it was present at 250 ms cue-target delay. In contrast, in both CA and RL controls, a cueing effect was found at the shorter cue-target delay but it disappeared at the longer cue-target delay, as predicted by theories of automatic capture of attention. Our results suggest that FMA may be crucial for learning to read, and we propose a possible causal explanation of how a FMA deficit leads to specific reading disability, suggesting that sluggish FMA in dyslexic children could be caused by a specific parietal dysfunction.
7
Content available remote

Two types of anticipation in synchronization tapping

80%
Miyake Y., Onishi Y., Poppel E.
Acta Neurobiologiae Experimentalis
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2004
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vol. 64
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issue 3
415-426
EN
The time perception mechanism in anticipatory timing control was investigated in a synchronization tapping task. An especially negative asynchrony phenomenon in which the tap onset precedes the stimulus onset was used as an anticipatory response. In this experiment, to clarify the effects of higher brain functions, such as attention, a dual-task method was applied and a word memory task was used as a secondary task. The results revealed two types of anticipatory mechanisms from the standpoint of attentional resources involved in time perception. One is the anticipatory tapping that is influenced by attention and seen in the interstimulus-onset interval (ISI) range of 1 800 to 3 600 ms. In this region, the magnitude of synchronization error (SE) between tap onset and stimulus onset was scaled by the ISI. The other is the automatic anticipation that is not affected by attention and is seen in the 450 to 1 500 ms range. SE in this region was constant and independent of the ISI. Accordingly, this anticipatory timing mechanism in synchronous tapping is thought to be a dual process including the attention processing of temporal information and the embodied automatic anticipation.
8
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Time perception depends on accurate clock mechanisms as well as unimpaired attention and memory processes

70%
Pouthas V., Perbal S.
Acta Neurobiologiae Experimentalis
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2004
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vol. 64
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issue 3
367-385
EN
We report a series of studies aimed at characterizing the relationships between duration judgments and slowing down of the internal clock, attention and memory deficits. Different groups of participants (elderly people, patients with Parkinson's disease, patients with severe traumatic brain injury, and patients with temporal lobe lesions) performed a duration reproduction task and a duration production task in two conditions: a control counting condition and a concurrent reading condition. Participants were also administered reaction time tasks, tapping tasks, and a battery of attention and memory tests. The results allow us to characterize the relationships between cognitive deficits and impaired duration reproductions and productions in each group. Moreover, results as a whole clarify the respective weight of processing speed, attention and memory in both tasks, and allow better insight into the theoretical models of psychological time
9
Content available remote

Limits of learning enhancements with nicotine in old male rats

61%
Taylor G. T., Bassi C., Weiss J.
Acta Neurobiologiae Experimentalis
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2005
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vol. 65
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issue 2
125-136
EN
Findings with young adult humans and animal models suggest that nicotine may serve both neuroprotective and cognition enhancing roles in old animals. A pair of experiments was conducted to examine drug-induced modification of the cholinergic nicotinic receptor subtype on rates of learning by young and aged rats. In experiment 1 males (4-7 months or 20-25 months old) were administered nicotine (0.0, 0.3 or 0.7 mg/ kg bwt SC injected daily) and tested in both a T-maze non-spatial discrimination paradigm and a hole board spatial task. Nicotine failed to improve acquisition by young animals on either task. Nicotine also failed to improve non-spatial learning by old animals. However, both dosages of nicotine improved performance by the old males in the spatial paradigm. In experiment 2, a 5-choice serial discrimination paradigm designed to better evaluate visual attention and spatial working memory in aging was used. Groups of old male rats were administered nicotine or mecamylamine (2 or 8mg/ kg), an antagonist of the nicotinic cholinergic receptor. Results were that the 0.3mg nicotine group learned the task fastest and achieved the highest learning asymptote. Both learning rates and final levels of performance were worst in the 8mg mecamylamine group. However, the 2mg mecamylamine rats were the equals of the control group and both reached a higher asymptote than the 0.7mg nicotine group. These data suggest that healthy old animals can accrue benefits from nicotinic activation but that the benefits are complex, being limited to certain dosages and to specific cognitive skills.
10
Content available remote

Cognitive subtypes of dyslexia

51%
Heim S., Tschierse J., Amunts K., Wilms M., Vossel S., Willmes K., Grabowska A., Huber W.
Acta Neurobiologiae Experimentalis
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2008
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vol. 68
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issue 1
73-82
EN
Different theories conceptualise dyslexia as either a phonological, attentional, auditory, magnocellular, or automatisation deficit. Such heterogeneity suggests the existence of yet unrecognised subtypes of dyslexics suffering from distinguishable deficits. The purpose of the study was to identify cognitive subtypes of dyslexia. Out of 642 children screened for reading ability 49 dyslexics and 48 controls were tested for phonological awareness, auditory discrimination, motion detection, visual attention, and rhythm imitation. A combined cluster and discriminant analysis approach revealed three clusters of dyslexics with different cognitive deficits. Compared to reading-unimpaired children cluster no. 1 had worse phonological awareness; cluster no. 2 had higher attentional costs; cluster no. 3 performed worse in the phonological, auditory, and magnocellular tasks. These results indicate that dyslexia may result from distinct cognitive impairments. As a consequence, prevention and remediation programmes should be specifically targeted for the individual child's deficit pattern.
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