Body representation in infants: Categorical boundaries of body parts as assessed by somatosensory mismatch negativity.

There is growing interest in developing and using novel measures to assess how the body is represented in human infancy. Various lines of evidence with adults and older children show that tactile perception is modulated by a high-level representation of the body. For instance, the distance between two points of tactile stimulation is perceived as being greater when these points cross a joint boundary than when they are within a body part, suggesting that the representation of the body is structured with joints acting as categorical boundaries between body parts. Investigating the developmental origins of this categorical effect has been constrained by infants' inability to verbally report on the properties of tactile stimulation. Here we made novel use of an infant brain measure, the somatosensory mismatch negativity (sMMN), to explore categorical aspects of tactile body processing in infants aged 6-7 months. Amplitude of the sMMN elicited by tactile stimuli across the wrist boundary was significantly greater than for stimuli of equal distance that were within the boundary, suggesting a categorical effect in body processing in infants. We suggest that an early-appearing, structured representation of the body into 'parts' may play a role in mapping correspondences between self and other

Brain‑correlates of processing local dependencies within a statistical learning paradigm

Statistical learning refers to the implicit mechanism of extracting regularities in our environment. Numerous studies have investigated the neural basis of statistical learning. However, how the brain responds to violations of auditory regularities based on prior (implicit) learning requires further investigation. Here, we used functional magnetic resonance imaging (fMRI) to investigate the neural correlates of processing events that are irregular based on learned local dependencies. A stream of consecutive sound triplets was presented. Unbeknown to the subjects, triplets were either (a) standard, namely triplets ending with a high probability sound or, (b) statistical deviants, namely triplets ending with a low probability sound. Participants (n = 33) underwent a learning phase outside the scanner followed by an fMRI session. Processing of statistical deviants activated a set of regions encompassing the superior temporal gyrus bilaterally, the right deep frontal operculum including lateral orbitofrontal cortex, and the right premotor cortex. Our results demonstrate that the violation of local dependencies within a statistical learning paradigm does not only engage sensory processes, but is instead reminiscent of the activation pattern during the processing of local syntactic structures in music and language, reflecting the online adaptations required for predictive coding in the context of statistical learning.publishedVersio

Error Signals from the Brain: 7th Mismatch Negativity Conference

The 7th Mismatch Negativity Conference presents the state of the art in methods, theory, and application (basic and clinical research) of the MMN (and related error signals of the brain). Moreover, there will be two pre-conference workshops: one on the design of MMN studies and the analysis and interpretation of MMN data, and one on the visual MMN (with 20 presentations). There will be more than 40 presentations on hot topics of MMN grouped into thirteen symposia, and about 130 poster presentations. Keynote lectures by Kimmo Alho, Angela D. Friederici, and Israel Nelken will round off the program by covering topics related to and beyond MMN

The Aha! Experience of Spatial Reorientation

The experience of spatial re-orientation is investigated as an instance of the wellknown phenomenon of the Aha! moment. The research question is: What are the visuospatial conditions that are most likely to trigger the spatial Aha! experience? The literature suggests that spatial re-orientation relies mainly on the geometry of the environment and a visibility graph analysis is used to quantify the visuospatial information. Theories from environmental psychology point towards two hypotheses. The Aha! experience may be triggered by a change in the amount of visual information, described by the isovist properties of area and revelation, or by a change in the complexity of the visual information associated with the isovist properties of clustering coefficient and visual control. Data from participants’ exploratory behaviour and EEG recordings are collected during wayfinding in virtual reality urban environments. Two types of events are of interest here: (a) sudden changes of the visuospatial information preceding subjects' response to investigate changes in EEG power; and (b) participants brain dynamics (Aha! effect) just before the response to examine differences in isovist values at this location. Research on insights, time-frequency analysis of the P3 component and findings from navigation and orientation studies suggest that the spatial Aha! experience may be reflected by: a parietal alpha power decrease associated with the switch of the representation and a frontocentral theta increase indexing spatial processing during decision-making. Single-trial time-frequency analysis is used to classify trials into two conditions based on the alpha/theta power differences between a 3s time-period before participants’ response and a time-period of equal duration before that. Behavioural results show that participants are more likely to respond at locations with low values of clustering coefficient and high values of visual control. The EEG analysis suggests that the alpha decrease/theta increase condition occurs at locations with significantly lower values of clustering coefficient and higher values of visual control. Small and large decreases in clustering coefficient, just before the response, are associated with significant differences in delta/theta power. The values of area and revelation do not show significant differences. Both behavioural and EEG results suggest that the Aha! experience of re-orientation is more likely to be triggered by a change in the complexity of the visual-spatial environment rather than a change in the amount, as measured by the relevant isovist properties

Stimulus-specific adaptation and deviance detection in the auditory cortex

Tesis por compendio de publicaciones[EN] Neurons in primary auditory cortex, thalamus and midbrain show stimulus-specific adaptation (SSA), a reduction in response to repetitive stimuli that does not affect neuronal responses to deviant tones. This has been proposed as a neuronal correlate of the mismatch negativity (MMN), a special evoked potential in response to deviant tones. However, three important requirements remain to be demonstrated in order to support the SSA-MMN link: (1) MMN is generated mainly within higher-order auditory cortical areas, whereas cortical SSA has only been recorded in A1 of different species. (2) MMN is a mid-long latency response, peaking between 100-200 ms in humans, whereas SSA has only been observed in early responses of A1 neurons. And finally, (3) neuronal responses to oddball stimulation have not been tested for deviance detection–enhancement of responses to deviant events—in addition to SSA, which is an essential property of any bona-fide mismatch response. In this study, I set specific objectives to investigate the relation between SSA and MMN, and moreover, I will test the Hierarchical Predictive Coding account for the MMN at the neuronal level, showing that single neuron responses to oddball stimulation represent prediction error, which is hierarchically organized along the auditory system

Brain maturation throughout adolescence : an EEG study

Objective: Adolescence is characterised by a genuine interest in new experiences and an increased sense of responsibility. The aim of this study was to investigate changes in brain maturation that underlie task-relevant behaviour and the relation of these changes to novel impressions during the transition from childhood into adolescence and then young adulthood. We hypothesized that, with development, improved target detection abilities and reduced distractibility will be characterised by an increased involvement of frontal brain regions within the fronto-parietal brain network during novel processing and target detection. Methods: In a cross-sectional study, a classical visual oddball task (n = 159) and a novelty visual oddball task (n = 84) were utilized in combination with EEG measurements to investigate brain maturation between late childhood and young adulthood (8 to 30 years of age). Developmental changes of late ERP components and concurrent delta (0.5 - 4 Hz) and theta (4 - 7 Hz) oscillations were analysed using regression models. Pre-stimulus amplitude and post-stimulus amplitude modulation, inter-trial phase coherence of local maxima and inter-electrode spatial phase coherence were assessed. Results and Discussion: A general decline in reaction time and late ERP latency (novelty N2, P3a and P3b) with age was observed and may depend on task performance. The frontal novelty N2 amplitude decreased while the P3a amplitude increased with age. This opposing developmental trend may relate to a compensatory mechanism for immature P3a-related cognitive functions, such as attention control. The pre-stimulus amplitudes of delta and theta oscillations decreased while post-stimulus amplitude enhancements and inter-trial phase coherence increased with age. Both effects seem to underlie maturation of the P3b amplitude, even though this cannot be observed directly in ERP amplitude measurements. Post-stimulus theta inter-electrode spatial phase coherence originating from frontal electrode sites increased with age during novel and target stimulus processing, indicating prolonged maturation of the fronto-parietal network that underlies target detection and novel processing. Conclusion: Functional brain networks involving the frontal cortex, such as the fronto-parietal network, mature until young adulthood, thereby affecting slow-wave oscillations on a local and global scale alongside late frontal ERP components. Brain maturation during adolescence may lead to a reduction of spontaneous slow-wave oscillations and an enhancement of amplitude modulation and regional and inter-regional precision of timing of event-related oscillations within the P3 time-window. Thus, brain maturation underlying task-related behaviour and reduced distractibility is versatile. Significance: Combined analysis of developmental trajectories of late ERPs, concurrent changes in spontaneous and task-modulated brain oscillations and their embedding within functional brain networks (e.g., the fronto-parietal network) is important to estimate how brain maturation relates to abilities of cognitive control during the transition into adolescence and young adulthood. It is critical to extend our understanding of healthy brain maturation as excessive brain plasticity during adolescence raises the sensitivity to the environment and learning experiences, and its outcome may have long-term positive or negative impact on personal opportunities in life and mental health

Detecting integration of top-down information using the mismatch negativity: Preliminary evidence from phoneme restoration

The current study utilizes mismatch negativity in the phenomenon of phoneme restoration to investigate the critical debate regarding the integration of top down (lexical) and bottom up (acoustic) processing in spoken word recognition. Phoneme restoration, which occurs when phonemes missing from a speech signal are restored by the brain and may appear to be heard, was examined in a multi-standard oddball paradigm. Participants heard stimuli while watching a quiet animated film. Stimuli were divided into word and non- word conditions, with noise added to some stimuli to make them ambiguous. The many-to-one ratio of standards to deviants for generation of mismatch negativity (MMN) was achieved only if the brain could recover the missing phoneme in the ambiguous, noise-spliced stimuli. Both word and nonword conditions were compared to verify that an elicited MMN among words was contingent on involvement of the lexicon in the grouping of standards, and not some more general cognitive grouping procedure. Results from seven participants show preliminary support for the predicted effect: i.e., mismatch negativity for words but not for nonwords. This effect is contingent on phoneme restoration, and thus is consistent with recent literature suggesting that MMN is sensitive to higher information structures such as the mental lexicon. Keywords: phoneme restoration, MMN, lexical access, top-down informatio

Concurrent affective and linguistic prosody with the same emotional valence elicits a late positive ERP response

Change in linguistic prosody generates a mismatch negativity response (MMN), indicating neural representation of linguistic prosody, while change in affective prosody generates a positive response (P3a), reflecting its motivational salience. However, the neural response to concurrent affective and linguistic prosody is unknown. The present paper investigates the integration of these two prosodic features in the brain by examining the neural response to separate and concurrent processing by electroencephalography (EEG). A spoken pair of Swedish words—[ˈfɑ́ːsɛn] phase and [ˈfɑ̀ːsɛn] damn—that differed in emotional semantics due to linguistic prosody was presented to 16 subjects in an angry and neutral affective prosody using a passive auditory oddball paradigm. Acoustically matched pseudowords—[ˈvɑ́ːsɛm] and [ˈvɑ̀ːsɛm]—were used as controls. Following the constructionist concept of emotions, accentuating the conceptualization of emotions based on language, it was hypothesized that concurrent affective and linguistic prosody with the same valence—angry [ˈfɑ̀ːsɛn] damn—would elicit a unique late EEG signature, reflecting the temporal integration of affective voice with emotional semantics of prosodic origin. In accordance, linguistic prosody elicited an MMN at 300–350 ms, and affective prosody evoked a P3a at 350–400 ms, irrespective of semantics. Beyond these responses, concurrent affective and linguistic prosody evoked a late positive component (LPC) at 820–870 ms in frontal areas, indicating the conceptualization of affective prosody based on linguistic prosody. This study provides evidence that the brain does not only distinguish between these two functions of prosody but also integrates them based on language and experience

Detecting integration of top-down information using the mismatch negativity: Preliminary evidence from phoneme restoration

The current study utilizes mismatch negativity in the phenomenon of phoneme restoration to investigate the critical debate regarding the integration of top down (lexical) and bottom up (acoustic) processing in spoken word recognition. Phoneme restoration, which occurs when phonemes missing from a speech signal are restored by the brain and may appear to be heard, was examined in a multi-standard oddball paradigm. Participants heard stimuli while watching a quiet animated film. Stimuli were divided into word and non- word conditions, with noise added to some stimuli to make them ambiguous. The many-to-one ratio of standards to deviants for generation of mismatch negativity (MMN) was achieved only if the brain could recover the missing phoneme in the ambiguous, noise-spliced stimuli. Both word and nonword conditions were compared to verify that an elicited MMN among words was contingent on involvement of the lexicon in the grouping of standards, and not some more general cognitive grouping procedure. Results from seven participants show preliminary support for the predicted effect: i.e., mismatch negativity for words but not for nonwords. This effect is contingent on phoneme restoration, and thus is consistent with recent literature suggesting that MMN is sensitive to higher information structures such as the mental lexicon. Keywords: phoneme restoration, MMN, lexical access, top-down information