Biology subjects

Manting, C. L.

Publications and source records attributed to Manting, C. L..

5 recordsLinked to original sources

bioRxiv2025

Fast voxel and structural MRI realignment to mitigate inter-acquisition motion for spectroscopy

Magnetic resonance spectroscopy (MRS) non-invasively measures the biochemical composition within a predefined brain region, enabling quantification of neurochemicals with biological and clinical relevance, such as N-acetylaspartate, creatine, choline, glutamate, and gamma-aminobutyric acid. However, accurate MRS quantification is compromised by subject motion displacing the prescribed location, a common problem during long scans or with motion-prone populations such as children and patients. Furthermore, displacement into bone tissue contaminates MRS data with noisy artifacts, often rendering them unusable. While promising solutions exist to address motion-related issues, many rely on specialized infrastructure and expertise available only at a limited number of research centers. We propose a fast and straightforward method that acquires a head scout (18 s) MRI sequence following potential motion, automatically repositions the prescribed voxel with the scanners built-in AutoAlign function, and realigns the T1-weighted image to the updated position for anatomical segmentation. Using voxels prescribed in the prefrontal cortex, thalamus, and left superior temporal gyrus, we demonstrated that this realignment method successfully restored displaced voxels to their intended locations, eliminating bone contamination while improving voxel targeting through greater overlap with intended regions and more consistent voxel placement across subjects. This solution offers a quick and practical way for correcting subject motion between scans by combining available tools that are readily accessible even to new users, while more sophisticated motion correction technologies continue to develop towards broader adoption.

neuroscience↗

bioRxiv2025

Spatiotemporal Dynamics of Invariant Face Representations in the Human Brain

The human brain can effortlessly extract a familiar faces age, gender, and identity despite dramatic changes in appearance, such as head orientation, lighting, or expression. Yet, the spatiotemporal dynamics underlying this ability, and how they depend on task demands, remain unclear. Here, we used multivariate decoding of magnetoencephalography (MEG) responses and source localization to characterize the emergence of invariant face representations. Human participants viewed natural images of highly familiar celebrities that systematically varied in viewpoint, gender, and age, while performing a one-back task on the identity or the image. Time-resolved decoding revealed that identity information emerged rapidly and became increasingly invariant to viewpoint over time. We observed a temporal hierarchy: view-specific identity information appeared at 64 ms, followed by mirror-invariant representations at 75 ms and fully view-invariant identity at 89 ms. Identity-invariant age and gender information emerged around the same time as view-invariant identity. Task demands modulated only late-stage identity and gender representations, suggesting that early face processing is predominantly feedforward. Source localization at peak decoding times showed consistent involvement of the occipital face area (OFA) and fusiform face area (FFA), with stronger identity and age signals than gender. Our findings reveal the spatiotemporal dynamics by which the brain extracts view-invariant identity from familiar faces, suggest that age and gender are processed in parallel, and show that task demands modulate later processing stages. Together, these results offer new constraints on computational models of face perception.

neuroscience↗

bioRxiv2024

Musicality enhances selective attention: spatiotemporal insights from precise separation of simultaneous neural responses

1.Natural environments typically contain a blend of simultaneous sounds. A significant challenge in neuroscience is identifying specific neural signals corresponding to each sound and analyzing them separately. Combining frequency-tagging and machine learning, we achieved high-precision separation of neural responses to mixed melodies, classifying them by selective attention towards specific melodies. Across two magnetoencephalography datasets, individual musicality and task performance heavily influenced the attentional recruitment of cortical regions, correlating positively with top-down attention in the left parietal cortex, but negatively with bottom-up attention in the right. In prefrontal areas, neural responses indicating higher sustained selective attention reflected better performance and musicality. These results suggest musical training enhances neural mechanisms in the frontoparietal regions, boosting performance via improving top-down attention, reducing bottom-up distractions, and maintaining selective attention over time. Importantly, this work establishes the effectiveness of combining frequency-tagging with machine learning to capture cognitive and behavioral effects with stimulus precision, applicable to other studies involving simultaneous stimuli.

neuroscience↗

bioRxiv2020

Auditory Steady-State Responses During And After A Stimulus: Cortical Sources, and the Influence of Attention and Musicality

The auditory steady-state response (ASSR) is an oscillatory brain response generated by periodic auditory stimuli and originates mainly from the temporal auditory cortices. Recent data show that while the auditory cortices are indeed strongly activated by the stimulus when it is present (ON ASSR), the anatomical distribution of ASSR sources involves also parietal and frontal cortices, indicating that the ASSR is a more complex phenomenon than previously believed. Furthermore, while the ASSR typically continues to oscillate even after the stimulus has stopped (OFF ASSR), very little is known about the characteristics of the OFF ASSR and how it compares to the ON ASSR. Here, we assessed whether the OFF and ON ASSR powers are modulated by the stimulus properties (i.e. volume and pitch), selective attention, as well as individual musical sophistication. We also investigated the cortical source distribution of the OFF ASSR using a melody tracking task, in which attention was directed between uniquely amplitude-modulated melody streams that differed in pitch. The ON and OFF ASSRs were recorded with magnetoencephalography (MEG) on a group of participants varying from low to high degree of musical sophistication. Our results show that the OFF ASSR is distinctly different from the ON ASSR in nearly every aspect. While the ON ASSR was modulated by the stimulus properties and selective attention, the OFF ASSR was not influenced by any of these factors. Furthermore, while the ON ASSR was generated primarily from temporal sources, the OFF ASSR originated mainly from the frontal cortex. These findings challenge the notion that the OFF ASSR is merely a continuation of the ON ASSR. Rather, they suggest that the OFF ASSR is an internally-driven signal that develops from an initial sensory processing state (ON ASSR), with both types of ASSRs clearly differing in cortical representation and character. Furthermore, our results show that the ON ASSR power was enhanced by selective attention at cortical sources within each of the bilateral frontal, temporal, parietal and insular lobes. Finally, the ON ASSR proved sensitive to musicality, demonstrating positive correlations between musical sophistication and ASSR power, as well as with the degree of attentional ASSR modulation at the left and right parietal cortices. Taken together, these results show new aspects of the ASSR response, and demonstrate its usefulness as an effective tool for analysing how selective attention interacts with individual abilities in music perception.

neuroscience↗

bioRxiv2019

Attentional Modulation of the Auditory Steady-State Response across the Cortex

Selective auditory attention allows us to focus on relevant sounds within noisy or complex auditory environments, and is essential for the processing of speech and music. The auditory steady-state response (ASSR) has been proposed as a neural measure for tracking selective auditory attention, even within continuous and complex soundscapes. However, the current literature is inconsistent on how the ASSR is influenced by selective attention, with findings based primarily on attention being directed to either ear rather than to sound content. In this experiment, a mixture of melody streams was presented to both ears identically (diotically) as we examined if selective auditory attention to sound content influences the ASSR. Using magnetoencephalography (MEG), we assessed the stream-specific ASSRs from three frequency-tagged melody streams when attention was directed between each melody stream, based on their respective pitch and timing. Our main results showed that selective attention enhances the ASSR power of an attended melody stream by 15 % at a general sensor level. This ability to readily capture attentional changes in a stimuli-precise manner makes the ASSR a useful tool for studying selective auditory attention, especially in complex auditory environments. Furthermore, as a secondary aim, we explored the distribution of cortical ASSR sources and their respective attentional modulation. A novel finding using distributed source modelling revealed that the ASSR is modulated by attention in many areas across the cortex, with frontal regions experiencing the strongest enhancement of up to ~ 80 %. ASSRs in the temporal and parietal cortices were enhanced by approximately 20 - 25 %. For future studies, this work can serve as a template to narrow-down possible sites of ASSR attentional modulation for further investigation.

neuroscience↗