Now showing 1 - 6 of 6
  • Publication
    Open Access
    Violation of expectation: neural correlates reflect bases of prediction
    (MIT Pr. Journals, 2009-01)
    Bubic, Andreja
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    von Cramon, D. Yves
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    ;
    Schröger, Erich
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    Schubotz, Ricarda I.
    Setting perceptual expectations can be based on different sources of information that determine which functional networks will be involved in implementing preparatory top-down influences and dealing with situations in which expectations are violated. The goal of the present study was to investigate and directly compare brain activations triggered by violating expectations within two different task contexts. In the serial prediction task, participants monitored ordered perceptual sequences for predefined sequential deviants. In contrast, the target detection task entailed a presentation of stimuli which had to be monitored for predefined nonsequential deviants. Detection of sequential deviants triggered an increase of activity in premotor and cerebellar components of the "standard" sequencing network and activations in additional frontal areas initially not involved in sequencing. This pattern of activity reflects the detection of a mismatch between the expected and presented stimuli, updating of the underlying sequence representation (i.e., forward model), and elaboration of the violation. In contrast, target detection elicited activations in posterior temporal and parietal areas, reflecting an increase in perceptual processing evoked by the nonsequential deviant. The obtained results suggest that distinct functional networks involved in detecting deviants in different contexts reflect the origin and the nature of expectations being violated.
  • Publication
    Open Access
    Localizing pre-attentive auditory memory-based comparison: magnetic mismatch negativity to pitch change
    (Academic Press, 2007-08-15)
    Maess, Burkhard
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    ;
    Schröger, Erich
    ;
    Friederici, Angela D.
    Changes in the pitch of repetitive sounds elicit the mismatch negativity (MMN) of the event-related brain potential (ERP). There exist two alternative accounts for this index of automatic change detection: (1) A sensorial, non-comparator account according to which ERPs in oddball sequences are affected by differential refractory states of frequency-specific afferent cortical neurons. (2) A cognitive, comparator account stating that MMN reflects the outcome of a memory comparison between a neuronal model of the frequently presented standard sound with the sensory memory representation of the changed sound. Using a condition controlling for refractoriness effects, the two contributions to MMN can be disentangled. The present study used whole-head MEG to further elucidate the sensorial and cognitive contributions to frequency MMN. Results replicated ERP findings that MMN to pitch change is a compound of the activity of a sensorial, non-comparator mechanism and a cognitive, comparator mechanism which could be separated in time. The sensorial part of frequency MMN consisting of spatially dipolar patterns was maximal in the late N1 range (105-125 ms), while the cognitive part peaked in the late MMN-range (170-200 ms). Spatial principal component analyses revealed that the early part of the traditionally measured MMN (deviant minus standard) is mainly due to the sensorial mechanism while the later mainly due to the cognitive mechanism. Inverse modeling revealed sources for both MMN contributions in the gyrus temporales transversus, bilaterally. These MEG results suggest temporally distinct but spatially overlapping activities of non-comparator-based and comparator-based mechanisms of automatic frequency change detection in auditory cortex.
  • Publication
    Open Access
    Bridging the arts and sciences: a framework for the psychology of aesthetics
    (MIT Press, 2006)
    The investigation of aesthetic processing has constituted a longstanding tradition in experimental psychology, of which experimental aesthetics is the second-oldest branch. The status of this psychology of aesthetics, the science of aesthetic processing, is briefly reviewed here Building on this heritage and drawing on a host of related scientific disciplines, a framework for a strongly interdisciplinary psychology of aesthetics is proposed. It is argued that the topic can be fruitfully approached from at least seven different perspectives, each with multiple levels of analysis. diachroma, ipsichroma, mind, body, content, person and situation. Eventually, this work may coalesce into a unified theory of aesthetic processing.
  • Publication
    Open Access
    Brain correlates of aesthetic judgment of beauty
    (Academic Press, 2006) ;
    Schubotz, Ricarda I.
    ;
    Höfel, Lea
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    Cramon, D. Yves V.
    Functional MRI was used to investigate the neural correlates of aesthetic judgments of beauty of geometrical shapes. Participants performed evaluative aesthetic judgments (beautiful or not?) and descriptive symmetry judgments (symmetric or not?) on the same stimulus material. Symmetry was employed because aesthetic judgments are known to be often guided by criteria of symmetry. Novel, abstract graphic patterns were presented to minimize influences of attitudes or memory-related processes and to test effects of stimulus symmetry and complexity. Behavioral results confirmed the influence of stimulus symmetry and complexity on aesthetic judgments. Direct contrasts showed specific activations for aesthetic judgments in the frontomedian cortex (BA 9/10), bilateral prefrontal BA 45/47, and posterior cingulate, left temporal pole, and the temporoparietal junction. In contrast, symmetry judgments elicited specific activations in parietal and premotor areas subserving spatial processing. Interestingly, beautiful judgments enhanced BOLD signals not only in the frontomedian cortex, but also in the left intraparietal sulcus of the symmetry network. Moreover, stimulus complexity caused differential effects for each of the two judgment types. Findings indicate aesthetic judgments of beauty to rely on a network partially overlapping with that underlying evaluative judgments on social and moral cues and substantiate the significance of symmetry and complexity for our judgment of beauty.
  • Publication
    Open Access
    Familiarity affects the processing of task-irrelevant auditory deviance
    (MIT Pr. Journals, 2005-11) ;
    Schröger, Erich
    ;
    Winkler, István
    ;
    Horváth, János
    The effects of familiarity on auditory change detection on the basis of auditory sensory memory representations were investigated by presenting oddball sequences of sounds while participants ignored the auditory stimuli. Stimulus sequences were composed of sounds that were familiar and sounds that were made unfamiliar by playing the same sounds backward. The roles of frequently presented stimuli (standards) and infrequently presented ones (deviants) were fully crossed. Deviants elicited the mismatch negativity component of the event-related brain potential. We found an enhancement in detecting changes when deviant sounds appeared among familiar standard sounds compared when they were delivered among unfamiliar standards. Familiarity with the deviant sounds also enhanced the change-detection process. We suggest that tuning to familiar items sets up preparatory processes that affect change detection in familiar sound sequences.