Wyniki wyszukiwania - Biblioteka Nauki

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Functional neuromarkers for neuropsychology

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Kropotov J. D.

Acta Neuropsychologica

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2018

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tom 16(1)

1-7

EN

This article is written to commemorate the 40th year of the scientific career of Professor Maria Pąchalska, Head of the Department of Neuropsychology and Neurorehabilitation at Krakow University, President of the Polish Neuropsychological Society, and the Editor-in-chief of Acta Neuropsychologica, with whom I have been collaborating for over ten years. The subject matter of our work includes the introduction of HBI methodology to clinics and the search for neuromarkers in particular disease entities. What is the new methodology we are talking about? In general, we think of a biomarker (or biological marker) as a characteristic that can be objectively measured and evaluated as an index of normal or pathological biological processes. For disorders of the central nervous system, biomarkers can be classified as clinical, neuroimaging, biochemical or genetic, according to the type of information they provide. Expectations for the development of biomarkers are high, since they could lead to a significant improvement in diagnosing and possibly preventing neurological and psychiatric diseases. Neuroimaging is an array of neuroscience methods that include the techniques of magnetic resonance imaging (MRI), functional MRI (fMRI), and PET (positron emission tomography), as well as Electroencephalogram (EEG) and Magnetoencephalogram (MEG) techniques, such as quantitative EEG (QEEG), event related de/synchronization (ERD/ERS) and event-related potentials (ERPs).

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The role of spatial and temporal information in biological motion perception

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Lange J. , Lappe M.

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2007

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tom 3

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nr 4

419-428

EN

Point-light biological motion stimuli provide spa-tio-temporal information about the structure of the human body in motion. Manipulation of the spatial structure of point-light stimuli reduces the ability of human observers to perceive biological motion. A recent study has reported that interference with the spatial structure of point-light walkers also reduces the evoked event-related potentials over the occipitotemporal cortex, but that interference with the temporal structure of the stimuli evoked event-related potentials similar to normal biological motion stimuli. We systematically investigated the influence of spatial and temporal manipulation on 2 common discrimination tasks and compared it with predictions of a neurocomputational model previously proposed. This model first analyzes the spatial structure of the stimulus independently of the temporal information to derive body posture and subsequently analyzes the temporal sequence of body postures to derive movement direction. Similar to the model predictions, the psychophysical results show that human observers need only intact spatial configuration of the stimulus to discriminate the facing direction of a point-light walker. In contrast, movement direction discrimination needs a fully intact spatio-temporal pattern of the stimulus. The activation levels in the model predict the observed event-related potentials for the spatial and temporal manipulations.

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Emotion and memory: Event-related potential indices predictive for subsequent successful memory depend on the emotional mood state

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Kiefer M. , Schuch S. , Schenck W. , Fiedler K.

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2007

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tom 3

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nr 3

363-373

EN

The present research investigated the influences of emotional mood states on cognitive processes and neural circuits during long-term memory encoding using event-related potentials (ERPs). We assessed whether the subsequent memory effect (SME), an electrophysiological index of successful memory encoding, varies as a function of participants' current mood state. ERPs were recorded while participants in good or bad mood states were presented with words that had to be memorized for subsequent recall. In contrast to participants in bad mood, participants in good mood most frequently applied elaborative encoding styles. At the neurophysiological level, ERP analyses showed that potentials to subsequently recalled words were more positive than to forgotten words at central electrodes in the time interval of 500-650 ms after stimulus onset (SME). At fronto-central electrodes, a polarity-reversed SME was obtained. The strongest modulations of the SME by participants' mood state were obtained at fronto-temporal electrodes. These differences in the scalp topography of the SME suggest that successful recall relies on partially separable neural circuits for good and bad mood states. The results are consistent with theoretical accounts of the interface between emotion and cognition that propose mood-dependent cognitive styles.

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Developmental Trajectory of Audiovisual Speech Integration in Early Infancy. A Review of Studies Using the McGurk Paradigm

88%

Tomalski P.

Psychology of Language and Communication

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2015

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tom 19

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nr 2

77-100

EN

Apart from their remarkable phonological skills young infants prior to their first birthday show ability to match the mouth articulation they see with the speech sounds they hear. They are able to detect the audiovisual conflict of speech and to selectively attend to articulating mouth depending on audiovisual congruency. Early audiovisual speech processing is an important aspect of language development, related not only to phonological knowledge, but also to language production during subsequent years. Th is article reviews recent experimental work delineating the complex developmental trajectory of audiovisual mismatch detection. Th e central issue is the role of age-related changes in visual scanning of audiovisual speech and the corresponding changes in neural signatures of audiovisual speech processing in the second half of the first year of life. Th is phenomenon is discussed in the context of recent theories of perceptual development and existing data on the neural organisation of the infant ‘social brain’.

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Disentangling neural processing of masked and masking stimulus by means of event-related contralateral — ipsilateral differences of EEG potentials

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Verleger R. , Jaśkowski P.

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2007

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tom 3

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nr 1-2

193-210

EN

In spite of the excellent temporal resolution of event-related EEG potentials (ERPs), the overlapping potentials evoked by masked and masking stimuli are hard to disentangle. However, when both masked and masking stimuli consist of pairs of relevant and irrelevant stimuli, one left and one right from fixation, with the side of the relevant element varying between pairs, effects of masked and masking stimuli can be distinguished by means of the contralateral preponderance of the potentials evoked by the relevant elements, because the relevant elements may independently change sides in masked and masking stimuli. Based on a reanalysis of data from which only selected contralateral-ipsilateral effects had been previously published, the present contribution will provide a more complete picture of the ERP effects in a masked-priming task. Indeed, effects evoked by masked primes and masking targets heavily overlapped in conventional ERPs and could be disentangled to a certain degree by contralateral-ipsilateral differences. Their major component, the N2pc, is interpreted as indicating preferential processing of stimuli matching the target template, which process can neither be identified with conscious perception nor with shifts of spatial attention. The measurements showed that the triggering of response preparation by the masked stimuli did not depend on their discriminability, and their priming effects on the processing of the following target stimuli were qualitatively different for stimulus identification and for response preparation. These results provide another piece of evidence for the independence of motor-related and perception-related effects of masked stimuli.