Biology subjects

Jeon, J. Y.

Publications and source records attributed to Jeon, J. Y..

4 recordsLinked to original sources

bioRxiv2025

Motion-corrected eye tracking (MoCET) improves gaze accuracy during visual fMRI experiments

Human eye movements are essential for understanding cognition, yet achieving high-precision eye tracking in fMRI remains challenging. Even slight head shifts from the initial calibration position can introduce drift in eye tracking data, leading to substantial gaze inaccuracies. To address this, we introduce Motion-Corrected Eye Tracking (MoCET), a novel approach that corrects drift using head motion parameters derived from the preprocessing of fMRI data. MoCET requires no additional hardware and can be applied retrospectively to existing datasets. We show that it outperforms traditional detrending methods with respect to accuracy of gaze estimation and offers higher spatial and temporal precision compared to MR-based eye tracking approaches. By overcoming a key limitation in integrating eye tracking with fMRI, MoCET facilitates investigations of naturalistic vision and cognition in fMRI research.

neuroscience↗

bioRxiv2024

Improved vascularized lymph node transfer by periodic injection of hyaluronidase in a rodent model

BackgroundVascularized lymph node transfer (VLNT) is an advanced surgical approach for secondary lymphedema (SLE) treatment, but tissue fibrosis around the lymph node flap (VLNF) inhibiting lymphangiogenesis is the biggest challenge undermining its therapeutic efficacy. Hyaluronidase (HLD), which is an enzyme that breaks down hyaluronic acid, may have the efficacy of reducing fibrosis and increasing the chance of lymphangiogenesis in the injury site. Materials and methods52 Sprague-Dawley rats with VLNF were divided into a group injected periodically with HLD and a control group and followed up. A follow-up study was performed for 13 weeks starting 1 week after model formation was examined. The limb volume and dermal backflow pattern were observed to evaluate the degree of lymphedema. The real-time ICG fluorescence intensity changes were measured to evaluate the degree of lymphatic drainage to the flap. Lastly, the number of regenerative lymphatic vessels and the degree of fibrosis were investigated. ResultsIn the group injected with HLD periodically (VLNF+HLD group), swelling reduction and dermal backflow pattern recovery occurred rapidly in the 3rd week of follow-up compared to the only VLNF group. Moreover, the efficiency of lymphatic drainage into the flap was also improved in the VLNF+HLD group. They significantly had more newly formed lymphatic vessels along with a decrease in collagen fiber decomposition in the tissue around the VLNF by up to 26%. ConclusionThese encouraging results pave the way for developing a combination strategy for SLE treatment involving HLD and VLNT. Furthermore, this finding may guide future research on the development of new drugs that could enhance the efficacy of VLNT surgery for SLE patients. Graphic abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=96 SRC="FIGDIR/small/586511v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@12b4c7forg.highwire.dtl.DTLVardef@1ab4538org.highwire.dtl.DTLVardef@14d93adorg.highwire.dtl.DTLVardef@1a6b87_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

bioRxiv2024

Impact of Cervical Lymphatic Obstruction on Brain Pathophysiology in Cervical Lymphedema Animal Models

BackgroundInjury to the cervical lymph nodes can lead to cervical lymphedema and subsequent fluid accumulation in the head and neck region, potentially causing pathophysiological alteration in the brain. This condition is thought to be linked with various neurological diseases, although the direct connection between cervical lymphatic obstruction and its effect on the brain has been difficult to establish. MethodsWe produced the disease animal models through lymph node dissection and radiation in fifteen male Sprague-Dawley rats aged 8 weeks and weighing 280-320 g. The models were specifically designed to induce lymphatic obstruction in the cervical region only, with no direct interventions applied to the brain. We evaluated swelling and lymphatic drainage in the head and neck for follow-up. The size of the lateral ventricles was verified through MRI, and changes in water content in brain tissue were directly measured. At 2 and 8 weeks, we observed immune cell infiltration, ventricular enlargement, and pathohistological changes in the harvested brain tissues. ResultsThe experimental animals exhibited lymphatic obstruction in the cervical region, with swelling, abnormal lymphatic drainage, and immune cell infiltration into the brains white matter, reminiscent of extremities lymphedema. MRI revealed lateral ventricular enlargement in these animals, indicative of increased cerebrospinal fluid levels compared to the control group. This increase in cerebrospinal fluid was associated with an increase in brain tissue water content, leading to pathophysiological changes akin to those seen in hydrocephalus and cerebral edema. ConclusionThe outcomes in this study underscore a significant link between lymphatic circulatory dysfunction and the onset of neurophysiological diseases. Cervical lymphedema showed pathophysiological changes similar to those seen in extremities lymphedema. However, these changes in the brain could be more critical than in the extremities. Our finding highlights the importance of understanding lymphatic system health in preventing and managing neurological conditions.

physiology↗

bioRxiv2023

Static and dynamic analysis of in-vivo imaging for early-detection of lymphedema via near-infrared fluorescence indocyanine green lymphangiography

BackgroundNear-infrared fluorescence indocyanine green (NIRF-ICG) lymphangiography, a primary modality for detecting lymphedema, which is a disease due to lymphatic obstruction, enables real-time observations of lymphatic flow and reveals not only the spatial distribution of drainage (static analysis), but also information on the lymphatic contraction (dynamic analysis). MethodsWe have produced lymphatic obstruction models in upper limbs through the dissection of proximal lymph nodes (LNs) and radiation (dissection limbs). After the model formation during 1 week, the static and dynamic analysis using NIRF-ICG lymphangiography were performed for six weeks. The drainage pattern and leakage of lymph fluid were observed and time-domain signals of lymphatic contraction were measured in the distal lymph vessels. The obtained signals were converted to the frequency-domain spectrums using the signal processing. ResultsThe results of both static and dynamic analyses proved to be effective in accurately identify the extent of lymphatic disruption in the dissection limbs. The static analysis showed abnormal drainage patterns and an increased leakage of lymph fluid to the periphery of the vessels compared to the control limbs. Meanwhile, the waveforms were changed and the frequency of the contractile signals was increased by 58% in the dynamic analysis. Specifically, our findings revealed that regular lymphatic contractions, observed at a frequency range of 0.08 [~] 0.13 Hz in the control limbs, were absent in the dissection limbs. The contractile regularity was not fully restored until the end of the follow-up, indicating a persistent lymphatic disruption in the dissected limbs. ConclusionThe dynamic analysis was consistent with the static analysis, and it could detect the abnormalities of lymphatic circulation by observing the characteristics of signals without the need for a control group. As NIRF-ICG lymphangiography is currently used in clinical practice, our findings may be useful for the early detection of the lymphatic circulation problem.

bioengineering↗