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Markus Hausmann - One of the best experts on this subject based on the ideXlab platform.

  • Cognitive sex differences and Hemispheric Asymmetry: A critical review of 40 years of research.
    Laterality, 2018
    Co-Authors: Marco Hirnstein, Kenneth Hugdahl, Markus Hausmann
    Abstract:

    According to a longstanding view, sex differences in cognitive abilities such as mental rotation or verbal memory arise from sex differences in Hemispheric Asymmetry: males are thought to be more lateralized than females which boosts their spatial but hampers their verbal skills. This idea sparked great interest and, even though it lost support in the 1990s, it is still put forward in contemporary (popular) scientific papers and textbooks. We aimed to provide a comprehensive review that summarizes the last 40 years of research. First, we confirm previous findings that the stronger Hemispheric Asymmetry in males is very small but robust. Second, we conclude that stronger Hemispheric Asymmetry, in general, does not enhance spatial and reduce verbal performance. Crucially, we carried out a systematic literature review showing that cognitive sex differences often emerge in the absence of sex differences in Hemispheric Asymmetry (and vice versa), implying the two phenomena are at least partly independent of each other. At present, there is insufficient data to conclude that sex differences in Hemispheric Asymmetry and cognitive performance are uncorrelated. However, we can conclude that sex differences in Hemispheric Asymmetry are certainly not the driving force behind sex differences in cognitive functioning.

  • Disentangling the relationship between Hemispheric Asymmetry and cognitive performance
    Brain and cognition, 2010
    Co-Authors: Marco Hirnstein, S.j. Leask, Jonas Rose, Markus Hausmann
    Abstract:

    It is widely believed that advantages of Hemispheric asymmetries originated in better cognitive processing, hence it is often implied that the relationship between Hemispheric Asymmetry and cognitive performance is linearly positive: the higher the degree of lateralization in a specific cognitive domain, the better the performance in a corresponding task. Yet, the empirical evidence for this notion is mixed and the statistical methods to analyze this relationship have been criticized. The present study therefore investigated the relationship between Hemispheric asymmetries and cognitive performance in two behavioral tasks (a left-lateralized word-matching task and a right-lateralized face-decision task) in 230 participants (140 women, 90 men) by using two different approaches. Both methods correspondingly revealed that a relationship between Hemispheric asymmetries and cognitive performance does exist. Contrary to a positive (linear) relationship however, the data could be best described by an inverted U-shaped curve. Although the optimal degree of lateralization seemed to be task-specific, a slight or moderate degree of Hemispheric Asymmetry achieved best cognitive performance in all tasks. Moreover, performances deteriorated towards extreme ends of lateralization (i.e., participants with either extreme left or right Hemispheric biases). Taken together, the present study provides evidence against the notion that higher lateralization is related to enhanced cognitive performance.

  • Hemispheric Asymmetry in spatial attention across the menstrual cycle
    Neuropsychologia, 2005
    Co-Authors: Markus Hausmann
    Abstract:

    Functional cerebral asymmetries (FCAs) are known to fluctuate across the menstrual cycle. The mechanisms of these sex hormonal modulations are poorly understood. It has been suggested that gonadal steroid hormones might suppress or specifically activate one hemisphere. However, recent studies suggest that high levels of gonadal steroid hormones reduce FCAs by its modulating effects on cortico-cortical transmission. To investigate the activating effects of gonadal steroid hormones on the interHemispheric interaction, a visual line-bisection task was administered to normally cycling women during menses and the midluteal cycle phase as well as to similar-aged healthy men. The results replicate previous findings of a sex difference in line-bisection as a function of hand-use and show that the hand-use effect fluctuates across the menstrual cycle. High levels of estradiol during the midluteal phase were related to a decrease of the hand-use effect. It is concluded that cycle-related fluctuations in levels of gonadal steroid hormones affect Hemispheric Asymmetry of spatial attention, presumably by interHemispheric spreading of neuronal activation.

Hari Om Vats - One of the best experts on this subject based on the ideXlab platform.

  • Evidence of a strong relationship between Hemispheric Asymmetry in solar coronal rotation and solar activity during solar cycle 24
    Monthly Notices of the Royal Astronomical Society, 2020
    Co-Authors: Jaidev Sharma, Anil K. Malik, Brajesh Kumar, Hari Om Vats
    Abstract:

    ABSTRACT In this paper, we report evidence of a very strong and statistically significant relationship between Hemispheric Asymmetry in the solar coronal rotation rate and solar activity. Our approach is based on the cross-correlation of the Hemispheric Asymmetry index (AI) in the rotation rate with annual solar activity indicators. To obtain the Hemispheric Asymmetry in the solar rotation rate, we use solar full disc (SFD) images at 30.4-, 19.5- and 28.4-nm wavelengths for the 24th solar cycle, that is, for the period from 2008 to 2018, as recorded by the Solar Terrestrial Relations Observatory (STEREO) space mission. Our analysis shows that the Hemispheric Asymmetry in rotation rate is high during the solar maxima from 2011 to 2014. However, Hemispheric Asymmetry decreases gradually on both sides (i.e. from 2008 to 2011 and from 2014 to 2018). The results show that the AI leads sunspot numbers by ∼ 1.56 yr. This is a clear indication that Hemispheric Asymmetry triggers the formation of sunspots in conjunction with the differential rotation of the Sun.

  • Evidence of strong relationship between Hemispheric Asymmetry in solar coronal rotation and solar activity during solar cycle 24.
    arXiv: Solar and Stellar Astrophysics, 2020
    Co-Authors: Jaidev Sharma, Anil K. Malik, Brajesh Kumar, Hari Om Vats
    Abstract:

    In this article, we report an evidence of very high and statistically significant relationship between Hemispheric Asymmetry in solar coronal rotation rate and solar activity. Our approach is based on cross correlation of Hemispheric Asymmetry index (AI) in rotation rate with annual solar activity indicators. To obtain Hemispheric Asymmetry in solar rotation rate, we use solar full disc (SFD) images at 30.4 nm, 19.5 nm, and 28.4 nm wavelengths for 24th Solar Cycle i.e., for the period from 2008 to 2018, as recorded by the Solar Terrestrial Relations Observatory (STEREO) space mission. Our analysis shows that Hemispheric Asymmetry in rotation rate is high during the solar maxima from 2011 to 2014. On the other hand, Hemispheric Asymmetry drops gradually on both sides (i.e., from 2008 to 2011 and from 2014 to 2018). The results show that Asymmetry index (AI) leads sunspot numbers by ~1.56 years. This gives a clear indication that Hemispheric Asymmetry triggers the formation of sunspots working together with the differential rotation of the Sun.

An-suey Shiao - One of the best experts on this subject based on the ideXlab platform.

  • Neuromagnetic index of Hemispheric Asymmetry predicting long-term outcome in sudden hearing loss.
    NeuroImage, 2012
    Co-Authors: Kuang-chao Chen, Po-lei Lee, David M. Niddam, Jen-chuen Hsieh, Chou-ming Cheng, Chih-cher Chou, An-suey Shiao
    Abstract:

    Abstract The neuromagnetic index of Hemispheric Asymmetry in terms of ipsilateral/contralateral ratio at acute stage was previously revealed to prognosticate the 1-month hearing outcome of acute unilateral idiopathic sudden sensorineural hearing loss (ISSNHL), showing a dynamic relationship between top- and down-levels of auditory pathway. However, the prognostic effect of reorganization pattern for the long-term results remained elusive. This study aimed to probe the prognosticating relevance of Hemispheric Asymmetry to the hearing at chronic stage of ISSNHL. Using magnetoencephalography (MEG), inter-Hemispheric differences in peak dipole of N100m responses to monaural tones were evaluated in 21 controls and 21 ISSNHL patients at initial and final (12 months later) stages. Predictive value of Hemispheric Asymmetry was assessed by correlating hearing level and ipsilateral/contralateral ratio (I/C) of N100m latency and amplitude. Healthy-side dominance of N100m was observed in ISSNHL initially, and remained in three final prognostic subgroups (complete, partial, and no recovery) of ISSNHL. The initial I/C amplitude on affected-ear stimulation strongly correlated with the hearing level of final stage in ISSNHL. However, there was no prognostic effect of Hemispheric Asymmetry pattern for the 12-month hearing improvement. The heterogeneity between neuromagnetic index and hearing levels possibly echoed different pathogeneses of ISSNHL. Since a restored hearing status did not necessarily lead toward a normal functional organization, the dynamics of Hemispheric Asymmetry could actually index a central resilient reorganization in the brain for sound processing in ISSNHL. Our finding showed not only a clinically relevant measure to predict final hearing of ISSNHL, but also a linkage between central plasticity and cochlear lesion. This finding suggests a new perspective, and perhaps new interventions, to diagnose and treat unilateral ISSNHL.

  • Neuromagnetic Index of Hemispheric Asymmetry Prognosticating the Outcome of Sudden Hearing Loss
    PloS one, 2012
    Co-Authors: An-suey Shiao, Kuang-chao Chen, Po-lei Lee, David M. Niddam, Shyue-yih Chang, Jen-chuen Hsieh
    Abstract:

    The longitudinal relationship between central plastic changes and clinical presentations of peripheral hearing impairment remains unknown. Previously, we reported a unique plastic pattern of “healthy-side dominance” in acute unilateral idiopathic sudden sensorineural hearing loss (ISSNHL). This study aimed to explore whether such Hemispheric Asymmetry bears any prognostic relevance to ISSNHL along the disease course. Using magnetoencephalography (MEG), inter-Hemispheric differences in peak dipole amplitude and latency of N100m to monaural tones were evaluated in 21 controls and 21 ISSNHL patients at two stages: initial and fixed stage (1 month later). Dynamics/Prognostication of Hemispheric Asymmetry were assessed by the interplay between hearing level/hearing gain and ipsilateral/contralateral ratio (I/C) of N100m latency and amplitude. Healthy-side dominance of N100m amplitude was observed in ISSNHL initially. The pattern changed with disease process. There is a strong correlation between the hearing level at the fixed stage and initial I/Camplitude on affected-ear stimulation in ISSNHL. The optimal cut-off value with the best prognostication effect for the hearing improvement at the fixed stage was an initial I/Clatency on affected-ear stimulation of 1.34 (between subgroups of complete and partial recovery) and an initial I/Clatency on healthy-ear stimulation of 0.76 (between subgroups of partial and no recovery), respectively. This study suggested that a dynamic process of central auditory plasticity can be induced by peripheral lesions. The Hemispheric Asymmetry at the initial stage bears an excellent prognostic potential for the treatment outcomes and hearing level at the fixed stage in ISSNHL. Our study demonstrated that such brain signature of central auditory plasticity in terms of both N100m latency and amplitude at defined time can serve as a prognostication predictor for ISSNHL. Further studies are needed to explore the long-term temporal scenario of auditory Hemispheric Asymmetry and to get better psychoacoustic correlates of pathological Hemispheric Asymmetry in ISSNHL.

Jen-chuen Hsieh - One of the best experts on this subject based on the ideXlab platform.

  • Neuromagnetic index of Hemispheric Asymmetry predicting long-term outcome in sudden hearing loss.
    NeuroImage, 2012
    Co-Authors: Kuang-chao Chen, Po-lei Lee, David M. Niddam, Jen-chuen Hsieh, Chou-ming Cheng, Chih-cher Chou, An-suey Shiao
    Abstract:

    Abstract The neuromagnetic index of Hemispheric Asymmetry in terms of ipsilateral/contralateral ratio at acute stage was previously revealed to prognosticate the 1-month hearing outcome of acute unilateral idiopathic sudden sensorineural hearing loss (ISSNHL), showing a dynamic relationship between top- and down-levels of auditory pathway. However, the prognostic effect of reorganization pattern for the long-term results remained elusive. This study aimed to probe the prognosticating relevance of Hemispheric Asymmetry to the hearing at chronic stage of ISSNHL. Using magnetoencephalography (MEG), inter-Hemispheric differences in peak dipole of N100m responses to monaural tones were evaluated in 21 controls and 21 ISSNHL patients at initial and final (12 months later) stages. Predictive value of Hemispheric Asymmetry was assessed by correlating hearing level and ipsilateral/contralateral ratio (I/C) of N100m latency and amplitude. Healthy-side dominance of N100m was observed in ISSNHL initially, and remained in three final prognostic subgroups (complete, partial, and no recovery) of ISSNHL. The initial I/C amplitude on affected-ear stimulation strongly correlated with the hearing level of final stage in ISSNHL. However, there was no prognostic effect of Hemispheric Asymmetry pattern for the 12-month hearing improvement. The heterogeneity between neuromagnetic index and hearing levels possibly echoed different pathogeneses of ISSNHL. Since a restored hearing status did not necessarily lead toward a normal functional organization, the dynamics of Hemispheric Asymmetry could actually index a central resilient reorganization in the brain for sound processing in ISSNHL. Our finding showed not only a clinically relevant measure to predict final hearing of ISSNHL, but also a linkage between central plasticity and cochlear lesion. This finding suggests a new perspective, and perhaps new interventions, to diagnose and treat unilateral ISSNHL.

  • Neuromagnetic Index of Hemispheric Asymmetry Prognosticating the Outcome of Sudden Hearing Loss
    PloS one, 2012
    Co-Authors: An-suey Shiao, Kuang-chao Chen, Po-lei Lee, David M. Niddam, Shyue-yih Chang, Jen-chuen Hsieh
    Abstract:

    The longitudinal relationship between central plastic changes and clinical presentations of peripheral hearing impairment remains unknown. Previously, we reported a unique plastic pattern of “healthy-side dominance” in acute unilateral idiopathic sudden sensorineural hearing loss (ISSNHL). This study aimed to explore whether such Hemispheric Asymmetry bears any prognostic relevance to ISSNHL along the disease course. Using magnetoencephalography (MEG), inter-Hemispheric differences in peak dipole amplitude and latency of N100m to monaural tones were evaluated in 21 controls and 21 ISSNHL patients at two stages: initial and fixed stage (1 month later). Dynamics/Prognostication of Hemispheric Asymmetry were assessed by the interplay between hearing level/hearing gain and ipsilateral/contralateral ratio (I/C) of N100m latency and amplitude. Healthy-side dominance of N100m amplitude was observed in ISSNHL initially. The pattern changed with disease process. There is a strong correlation between the hearing level at the fixed stage and initial I/Camplitude on affected-ear stimulation in ISSNHL. The optimal cut-off value with the best prognostication effect for the hearing improvement at the fixed stage was an initial I/Clatency on affected-ear stimulation of 1.34 (between subgroups of complete and partial recovery) and an initial I/Clatency on healthy-ear stimulation of 0.76 (between subgroups of partial and no recovery), respectively. This study suggested that a dynamic process of central auditory plasticity can be induced by peripheral lesions. The Hemispheric Asymmetry at the initial stage bears an excellent prognostic potential for the treatment outcomes and hearing level at the fixed stage in ISSNHL. Our study demonstrated that such brain signature of central auditory plasticity in terms of both N100m latency and amplitude at defined time can serve as a prognostication predictor for ISSNHL. Further studies are needed to explore the long-term temporal scenario of auditory Hemispheric Asymmetry and to get better psychoacoustic correlates of pathological Hemispheric Asymmetry in ISSNHL.

Yves D Von Cramon - One of the best experts on this subject based on the ideXlab platform.

  • Hemispheric Asymmetry for auditory processing in the human auditory brain stem thalamus and cortex
    Cerebral Cortex, 2006
    Co-Authors: Marc Schonwiesner, Rudolf Rubsamen, Katrin Krumbholz, Gereon R Fink, Yves D Von Cramon
    Abstract:

    We report evidence for a context- and not stimulus-dependent functional Asymmetry in the left and right human auditory midbrain, thalamus, and cortex in response to monaural sounds. Neural activity elicited by left- and right-ear stimulation was measured simultaneously in the cochlear nuclei, inferior colliculi (ICs), medial geniculate bodies (MGBs), and auditory cortices (ACs) in 2 functional magnetic resonance imaging experiments. In experiment 1, pulsed noise was presented monaurally to either ear, or binaurally, simulating a moving sound source. In experiment 2, only monaural sounds were presented. The results show a modulation of the neural responses to monaural sounds by the presence of binaural sounds at a time scale of tens of seconds: In the absence of binaural stimulation, the left and right ICs, MGBs, and ACs responded stronger to stimulation of the contralateral ear. When blocks of binaural stimuli were interspersed in the sound sequence, the contralateral preference vanished in those structures in the right hemisphere. The resulting Hemispheric Asymmetry was similar to the Asymmetry demonstrated for spatial sound processing. Taken together, the data demonstrate that functional asymmetries in auditory processing are modulated by context. The observed long time constant suggests that this effect results from a "top-down" mechanism.

  • Hemispheric Asymmetry for spectral and temporal processing in the human antero lateral auditory belt cortex
    European Journal of Neuroscience, 2005
    Co-Authors: Marc Schonwiesner, Rudolf Rubsamen, Yves D Von Cramon
    Abstract:

    The present study investigates the acoustic basis of the Hemispheric Asymmetry for the processing of speech and music. Experiments on this question ideally involve stimuli that are perceptually unrelated to speech and music, but contain acoustic characteristics of both. Stimuli in previous studies were derived from speech samples or tonal sequences. Here we introduce a new class of noise-like sound stimuli with no resemblance of speech or music that permit independent parametric variation of spectral and temporal acoustic complexity. Using these stimuli in a functional MRI experiment, we test the hypothesis of a Hemispheric Asymmetry for the processing of spectral and temporal sound structure by seeking cortical areas in which the blood oxygen level dependent (BOLD) signal covaries with the number of simultaneous spectral components (spectral complexity) or the temporal modulation rate (temporal complexity) of the stimuli. BOLD-responses from the left and right Heschl's gyrus (HG) and part of the right superior temporal gyrus covaried with the spectral parameter, whereas covariation analysis for the temporal parameter highlighted an area on the left superior temporal gyrus. The portion of superior temporal gyrus in which asymmetrical responses are apparent corresponds to the antero-lateral auditory belt cortex, which has been implicated with spectral integration in animal studies. Our results support a similar function of the anterior auditory belt in humans. The findings indicate that asymmetrical processing of complex sounds in the cerebral hemispheres does not depend on semantic, but rather on acoustic stimulus characteristics.