Publications by authors named "Aaron Loh"

Article Synopsis
  • - Two specific strains (SCP14 and SCP15) were extracted from coral remains in Singapore, particularly in high-temperature conditions.
  • - The genomes of these strains were sequenced, which means their genetic makeup was analyzed and recorded.
  • - The genetic information revealed important elements that contribute to the health of coral, especially when they face temperature-related stress.
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A sp. was isolated from the skeleton of the heat resilient coral . Genome analysis revealed the presence of the complete denitrification pathway and potential dimethylsulfoniopropionate metabolism which enhance coral resilience and production of tropodithietic acid, an antibiotic implicated in host defense.

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Objective: Optimized deep brain stimulation (DBS) is fast becoming a therapy of choice for the treatment of Parkinson's disease (PD). However, the post-operative optimization (aimed at maximizing patient clinical benefits and minimizing adverse effects) of all possible DBS parameter settings using the standard-of-care clinical protocol requires numerous clinical visits, which substantially increases the time to optimization per patient (TPP), patient cost burden and limit the number of patients who can undergo DBS treatment. The TPP is further elongated in electrodes with stimulation directionality or in diseases with latency in clinical feedback.

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Background: Cerebellar mutism syndrome (CMS) is a common and debilitating complication of posterior fossa tumor surgery in children. Affected children exhibit communication and social impairments that overlap phenomenologically with subsets of deficits exhibited by children with Autism spectrum disorder (ASD). Although both CMS and ASD are thought to involve disrupted cerebro-cerebellar circuitry, they are considered independent conditions due to an incomplete understanding of their shared neural substrates.

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Spatial normalization-the process of mapping subject brain images to an average template brain-has evolved over the last 20+ years into a reliable method that facilitates the comparison of brain imaging results across patients, centers & modalities. While overall successful, sometimes, this automatic process yields suboptimal results, especially when dealing with brains with extensive neurodegeneration and atrophy patterns, or when high accuracy in specific regions is needed. Here we introduce WarpDrive, a novel tool for manual refinements of image alignment after automated registration.

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Article Synopsis
  • Deep brain stimulation (DBS) is a recognized treatment for various neurological and psychiatric disorders, but disparities in access to this procedure exist based on demographic factors.
  • The study analyzed 104,356 DBS cases from 1993 to 2017 using the National Inpatient Sample to identify trends and predictors affecting procedure utilization among different patient groups.
  • Findings indicate significant disparities in DBS access, especially concerning age, sex, and race, with noticeable variations in these factors depending on the specific indication for treatment.
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Article Synopsis
  • Cognitive flexibility is essential for effective attention control, but its neural mechanisms remain unclear, especially in children with epilepsy.
  • Using advanced techniques like intracranial recordings and deep learning, researchers analyzed brain activity during attention tasks, revealing important brain regions and patterns associated with task performance.
  • The study highlighted the dorsal default mode network's key involvement in cognitive flexibility, demonstrating that even with varied electrode placements, consistent networks can be observed, showcasing deep learning's potential in understanding human attention.
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Background: The loss of the ability to swim following deep brain stimulation (DBS), although rare, poses a worrisome risk of drowning. It is unclear what anatomic substrate and neural circuitry underlie this phenomenon. We report a case of cervical dystonia with lost ability to swim and dance during active stimulation of globus pallidus internus.

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Machine-learning models for medical tasks can match or surpass the performance of clinical experts. However, in settings differing from those of the training dataset, the performance of a model can deteriorate substantially. Here we report a representation-learning strategy for machine-learning models applied to medical-imaging tasks that mitigates such 'out of distribution' performance problem and that improves model robustness and training efficiency.

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Deep brain stimulation targeting the posterior hypothalamus (pHyp-DBS) is being investigated as a treatment for refractory aggressive behavior, but its mechanisms of action remain elusive. We conducted an integrated imaging analysis of a large multi-centre dataset, incorporating volume of activated tissue modeling, probabilistic mapping, normative connectomics, and atlas-derived transcriptomics. Ninety-one percent of the patients responded positively to treatment, with a more striking improvement recorded in the pediatric population.

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Deep brain stimulation (DBS) to the fornix is an investigational treatment for patients with mild Alzheimer's Disease. Outcomes from randomized clinical trials have shown that cognitive function improved in some patients but deteriorated in others. This could be explained by variance in electrode placement leading to differential engagement of neural circuits.

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Introduction: Magnetic resonance-guided focused ultrasound (MRgFUS) is an emerging treatment for tremor and other movement disorders. An incisionless therapy, it is becoming increasingly common worldwide. However, given MRgFUS' relative novelty, there remain limited data on its benefits and adverse effects.

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Deep brain stimulation (DBS) and non-invasive neuromodulation are currently being investigated for treating network dysfunction in Alzheimer's Disease (AD). However, due to heterogeneity in techniques and targets, the cognitive outcome and brain network connectivity remain unknown. We performed a systematic review, meta-analysis, and normative functional connectivity to determine the cognitive outcome and brain networks of DBS and non-invasive neuromodulation in AD.

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We report the case of a patient with craniopharyngioma who demonstrated ectopic spread to the right temporal lobe and concurrent local recurrence, 10 years after her initial diagnosis. The patient additionally demonstrated new-onset psychotic symptoms of uncertain etiology during her admission. Lesion network mapping identified the ectopic lesion as a putative cause for her psychosis.

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Background: MR-guided focused ultrasound (MRgFUS) thalamotomy has been shown to be a safe and effective treatment for essential tremor (ET).

Objective: To investigate the effects of MRgFUS in patients with ET with an emphasis on ipsilateral-hand and axial tremor subscores.

Methods: Tremor scores and adverse effects of 100 patients treated between 2012 and 2018 were assessed at 1 week, 3, 12, and 24 months.

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A total of 15 individuals with cervical dystonia and good outcome after pallidal deep brain stimulation underwent resting-state functional magnetic resonance imaging under three conditions: stimulation using a priori clinically determined optimal settings (ON-Op), non-optimal settings (ON-NOp), and stimulation off (OFF). ON-Op > OFF and ON-Op > ON-NOp were both associated with significant deactivation within sensorimotor cortex (changes not seen with ON-NOp > OFF). Brain responses to stimulation were related to individual long-term clinical improvement (R = 0.

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Deep brain stimulation is a treatment option for patients with drug-resistant epilepsy. The precise mechanism of neuromodulation in epilepsy is unknown, and biomarkers are needed for optimizing treatment. The aim of this study was to describe the neural network associated with deep brain stimulation targets for epilepsy and to explore its potential application as a novel biomarker for neuromodulation.

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Background: Deep brain stimulation (DBS) is an established treatment for certain movement disorders and has additionally shown promise for various psychiatric, cognitive, and seizure disorders. However, the mechanisms through which stimulation exerts therapeutic effects are incompletely understood. A technique that may help to address this knowledge gap is functional magnetic resonance imaging (fMRI).

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Background: Obsessive-compulsive disorder (OCD) is a debilitating disease with a lifetime prevalence of 2-3%. Neuromodulatory treatments have been successfully used in severe cases. Deep brain stimulation (DBS) targeting the inferior thalamic peduncle (ITP) has been shown to successfully alleviate symptoms in OCD patients; however, the brain circuits implicated remain unclear.

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The habenula (Hb) is a small, evolutionarily conserved epithalamic structure implicated in functions such as reward and mood regulation. Prior imaging work suggests that Hb's structural and functional properties may relate to treatment response in depression and other mood disorders. We used multimodal MRI techniques to investigate the potential involvement of Hb in response to subcallosal cingulate area deep brain stimulation (SCC-DBS) for treatment-resistant mood disorders.

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Objective: Peripheral nerve field stimulation (PNFS) is a tool in the armamentarium of treatment options for trigeminal pain. The efficacy of this modality in mitigating trigeminal pain remains unclear. The aim of this study was to examine the existing literature on PNFS and elucidate pain score outcomes associated with its use in patients with trigeminal pain.

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