Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Pedagogiczna Biblioteka Wojewódzka im. Komisji Edukacji Narodowej w Lublinie Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaPedagogiczna Biblioteka Wojewódzka im. Komisji Edukacji Narodowej w Lublinie
Zmień bibliotekę

Wyszukujesz frazę "Verleger, Rolf" wg kryterium: Autor

  Lista filtrów
Wyrównaj
    Wyświetlanie 1-8 z 8
    Tytuł:
    Differences between visual hemifields in identifying rapidly presented target stimuli: letters and digits, faces, and shapes
    Autorzy:
    Asanowicz, Dariusz
    Verleger, Rolf
    Śmigasiewicz, Kamila
    Opis:
    The right hemisphere has been shown to play a dominant role in processing of visuo-spatial information. Recently, this role has been studied in the two-stream rapid serial visual presentation task. In this task, two alphanumerical targets are embedded in left and right simultaneous streams of rapidly changing letters. The second target (T2) is identified better in the left than in the right visual field. This difference has been interpreted as advantage of the right hemisphere (RH). However, a disadvantage of the left hemisphere (LH) could not be excluded so far. The LH, specialized for processing of verbal stimuli, might be overloaded due to constant input of letters from both visual fields. In the present study, this overload hypothesis was tested by reducing demands on verbal processing (Experiment 1), and by overloading the RH with non-verbal stimuli: faces (Experiment 2) and irregular shapes (Experiment 3). The left visual field advantage proved to be largely independent from the level of verbal load and from stimulus type. Therefore, although not entirely disproving the overload hypothesis, these results suggest as the most parsimonious explanation this asymmetry reflects a RH advantage, presumably in perceptual and attentional processing, rather than a LH disadvantage caused by verbal overload
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    Biased odds for heads or tails : outcome-evoked P3 depends on frequencies of guesses
    Autorzy:
    Asanowicz, Dariusz
    Werner, Lucas
    Śmigasiewicz, Kamila
    Verleger, Rolf
    Opis:
    Events that had to be predicted evoke large P3 components of the event-related EEG potential. There is conflicting evidence whether these P3s are moderated by participants' preceding guesses. In the present study, participants made one prediction frequently and the other rarely because one stimulus was presented frequently and the other rarely. Thereby, effects on stimulus-evoked P3s of both guess frequency and stimulus frequency could be tested. Indeed, P3s were not only larger with rare than frequent stimuli but also larger after rare than frequent guesses. This result pattern may have additionally been affected by expectancies for payoff. In any case, the modification of outcome-evoked P3 by what had been guessed may reflect that each of the four guess-stimulus combinations is encoded as a separate event category. In terms of the stimulus-response link hypothesis of P3b, it is suggested that P3s are evoked by these events because internal responses (right or wrong) are associated to each of these event categories and need to be reactivated with rare guess-stimulus combinations
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    Bias for the left visual field in rapid serial visual presentation : effects of additional salient cues suggest a critical role of attention
    Autorzy:
    Śmigasiewicz, Kamila
    Westphal, Nicole
    Verleger, Rolf
    Asanowicz, Dariusz
    Opis:
    Everyday experience suggests that people are equally aware of stimuli in both hemifields. However, when two streams of stimuli are rapidly presented left and right, the second target (T2) is better identified in the left hemifield than in the right hemifield. This left visual field (LVF) advantage may result from differences between hemifields in attracting attention. Therefore, we introduced a visual cue shortly before T2 onset to draw attention to one stream. Thus, to identify T2, attention was correctly positioned with valid cues but had to be redirected to the other stream with invalid ones. If the LVF advantage is caused by differences between hemifields in attracting attention, invalid cues should increase, and valid cues should reduce the LVF advantage as compared with neutral cues. This prediction was confirmed. ERP analysis revealed that cues evoked an early posterior negativity, confirming that attention was attracted by the cue. This negativity was earlier with cues in the LVF, which suggests that responses to salient events are faster in the right hemisphere than in the left hemisphere. Valid cues speeded up, and invalid cues delayed T2-evoked N2pc; in addition, valid cues enlarged T2-evoked P3. After N2pc, right-side T2 evoked more sustained contralateral negativity than left T2, least long-lasting after valid cues. Difficulties in identifying invalidly cued right T2 were reflected in prematurely ending P3 waveforms. Overall, these data provide evidence that the LVF advantage is because of different abilities of the hemispheres in shifting attention to relevant events in their contralateral hemifield.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    Lateralization of spatial rather than temporal attention underlies the left hemifield advantage in rapid serial visual presentation
    Autorzy:
    Śmigasiewicz, Kamila
    Verleger, Rolf
    Kruse, Lena
    Asanowicz, Dariusz
    Opis:
    In bilateral rapid serial visual presentation (RSVP), the second of two targets, T1 and T2, is better identified in the left visual field (LVF) than in the right visual field (RVF). This LVF advantage may reflect hemispheric asymmetry in temporal attention or/and in spatial orienting of attention. Participants performed two tasks: the "standard" bilateral RSVP task (Exp.1) and its unilateral variant (Exp.1 & 2). In the bilateral task, spatial location was uncertain, thus target identification involved stimulus-driven spatial orienting. In the unilateral task, the targets were presented block-wise in the LVF or RVF only, such that no spatial orienting was needed for target identification. Temporal attention was manipulated in both tasks by varying the T1-T2 lag. The results showed that the LVF advantage disappeared when involvement of stimulus-driven spatial orienting was eliminated, whereas the manipulation of temporal attention had no effect on the asymmetry. In conclusion, the results do not support the hypothesis of hemispheric asymmetry in temporal attention, and provide further evidence that the LVF advantage reflects right hemisphere predominance in stimulus-driven orienting of spatial attention. These conclusions fit evidence that temporal attention is implemented by bilateral parietal areas and spatial attention by the right-lateralized ventral frontoparietal network.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    Testing the S-R link hypothesis of P3b : the oddball effect on S1-evoked P3 gets reduced by increased task relevance of S2
    Autorzy:
    Asanowicz, Dariusz
    Śmigasiewicz, Kamila
    Hamann, Lin Marlena
    Verleger, Rolf
    Opis:
    We had previously reported that the oddball effect on the P3b EEG potential evoked by infrequent vs. frequent S1 presented in a sequence of two stimuli, S1 and S2, gets reduced in a "combination task". In this task, responses were determined by the combinations of S1 and S2 rather than by S1 only. We had attributed this reduction of the oddball effect to increased task difficulty. The present study investigated possible reasons for this reduction of S1-evoked P3b in more detail, by making the combination task easier in several respects: allowing for forming associations from S1 to responses (Experiment 1), reducing the complexity of stimulus-response (S-R) mappings (Experiment 2), and decreasing S2 relevance in defining responses (Experiment 3). The results showed that only S2 relevance affected the oddball effect on S1-evoked P3b. Namely, when S2 attained some relevance by inducing a go/no-go decision for S1-defined responses, the oddball effect on S1-evoked P3b was intermediate between the large effect in the simple oddball task and the small effect in the combination task. The results may be explained in terms of the S-R link hypothesis of P3b which interprets P3b as reflecting reactivation of well-established S-R links
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    A right hemisphere advantage at early cortical stages of processing alphanumeric stimuli : evidence from electrophysiology
    Autorzy:
    Verleger, Rolf
    Kruse, Lena
    Beier, Kathrin
    Asanowicz, Dariusz
    Śmigasiewicz, Kamila
    Opis:
    This study investigates hemispheric asymmetry evoked by non-target alphanumeric stimuli in a bilateral rapid serial visual presentation (RSVP) task. Our indicators of asymmetry are shorter latencies and larger amplitudes of the right hemisphere (RH) P1 and N1 components of visual evoked potentials (VEPs). This VEP asymmetry might reflect either a RH advantage, possibly in early perceptual processing, or for familiar stimuli, or for directing attention, or might be a paradoxical reflection of left hemisphere specialization in letter processing. Experiment 1 showed that the VEP asymmetry decreased, though remained present, with unfamiliar stimuli (Tibetan letters), as compared to familiar stimuli (Latin letters and Arabic digits). Experiment 2 showed that while leftward and rightward attentional biases affected the relation between hemispheres contra- and ipsilateral to attended visual fields, the VEP asymmetry remained independent of attention. As the most parsimonious explanation, the primary cause of the VEP asymmetry seems to be a general predominance of the RH in early perceptual processing.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    On how the motor cortices resolve an inter-hemispheric response conflict : an event-related EEG potential-guided TMS study of the flankers task
    Autorzy:
    Verleger, Rolf
    Siebner, Hartwig Roman Oman
    Fritzmannova, Michaela
    Kuniecki, Michał
    Möller, Frederike
    Opis:
    An important aspect of human motor control is the ability to resolve conflicting response tendencies. Here we used single-pulse transcranial magnetic stimulation (TMS) to track the time course of excitability changes in the primary motor hand areas (M1HAND) while the motor system resolved response conflicts. Healthy volunteers had to respond fast with their right and left index fingers to right- and left-pointing arrows. These central target stimuli were preceded by flanking arrows, inducing premature response tendencies which competed with correct response activation. The time point of maximum premature activation was individually measured as peak latency of the lateralized readiness potential (LRP) in the EEG. In the subsequent TMS experiment, single pulses were applied to left or right M1HAND during the same flanker task. The amplitude of the motor evoked potentials in the contralateral first dorsal interosseus muscle was taken as an index of corticospinal excitability. Guided by the previous LRP measurement, magnetic stimuli were applied 0-90 ms after the individual LRP peak, to cover the epoch of conflict resolution. When flankers were incompatible with the target, excitability of the prematurely activated M1HAND gradually decreased during this 90 ms period. This decrease was paralleled by a mirror-symmetrical increase in excitability in the other M1HAND. These results show that the inappropriate response tendency is cancelled in one M1HAND simultaneously with activation of the correct response in the other. This integrated implementation of response activation and cancellation at the level of the M1HAND presumably represents a downstream effect orchestrated by premotor brain regions.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
    Tytuł:
    The left visual-field advantage in rapid visual presentationis amplified rather than reduced by posterior-parietal rTMS
    Autorzy:
    Verleger, Rolf
    Siebner, Hartwig Roman Oman
    Möller, Frederike
    Kuniecki, Michał
    Groppa, Sergiu
    Śmigasiewicz, Kamila
    Opis:
    In the present task, series of visual stimuli are rapidly presented left and right, containing two target stimuli, T1 and T2. In previous studies, T2 was better identified in the left than in the right visual field. This advantage of the left visual field might reflect dominance exerted by the right over the left hemisphere. If so, then repetitive transcranial magnetic stimulation (rTMS) to the right parietal cortex might release the left hemisphere from right-hemispheric control, thereby improving T2 identification in the right visual field. Alternatively or additionally, the asymmetry in T2 identification might reflect capacity limitations of the left hemisphere, which might be aggravated by rTMS to the left parietal cortex. Therefore, rTMS pulses were applied during each trial, beginning simultaneously with T1 presentation. rTMS was directed either to P4 or to P3 (right or left parietal cortex) either as effective or as sham stimulation. In two experiments, either one of these two factors, hemisphere and effectiveness of rTMS, was varied within or between participants. Again, T2 was much better identified in the left than in the right visual field. This advantage of the left visual field was indeed modified by rTMS, being further increased by rTMS to the left hemisphere rather than being reduced by rTMS to the right. It may be concluded that superiority of the right hemisphere in this task implies that this hemisphere is less irritable by external interference than the left hemisphere.
    Dostawca treści:
    Repozytorium Uniwersytetu Jagiellońskiego
    Artykuł
      Wyświetlanie 1-8 z 8

      Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies