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ELife Nov 2023Participant-specific, functionally defined brain areas are usually mapped with functional localizers and estimated by making contrasts between responses to single...
Participant-specific, functionally defined brain areas are usually mapped with functional localizers and estimated by making contrasts between responses to single categories of input. Naturalistic stimuli engage multiple brain systems in parallel, provide more ecologically plausible estimates of real-world statistics, and are friendly to special populations. The current study shows that cortical functional topographies in individual participants can be estimated with high fidelity from naturalistic stimuli. Importantly, we demonstrate that robust, individualized estimates can be obtained even when participants watched different movies, were scanned with different parameters/scanners, and were sampled from different institutes across the world. Our results create a foundation for future studies that allow researchers to estimate a broad range of functional topographies based on naturalistic movies and a normative database, making it possible to integrate high-level cognitive functions across datasets from laboratories worldwide.
Topics: Humans; Motion Pictures; Academies and Institutes; Brain; Cognition; Databases, Factual
PubMed: 37994909
DOI: 10.7554/eLife.86037 -
Cancers Oct 2021Wire-guided localisation (WGL) has been the gold-standard for localising non-palpable breast lesions before excision. Due to its drawbacks, various wireless alternatives... (Review)
Review
Wire-guided localisation (WGL) has been the gold-standard for localising non-palpable breast lesions before excision. Due to its drawbacks, various wireless alternatives have been developed, including LOCalizer™, which is based on radio-frequency identification (RFID) technology. In this systematic review, we consulted EMBASE, Medline and PubMed databases using appropriate search terms regarding the use of RFID technology in the localisation of occult breast lesions. Retrospective and prospective studies were included if they quoted the number of patients, rate of successful placement, retrieval rate, margin positivity rate and the re-excision rate. In addition, studies comparing RFID to WGL were also included and analysed separately. Seven studies were included in this systematic review spanning 1151 patients and 1344 tags. The pooled deployment rate was 99.1% and retrieval rate was 100%. Re-excision rate was 13.9%. One complication was identified. Two studies compared RFID with WGL (128 vs. 282 patients respectively). For both techniques the re-excision rate was 15.6% (20/128 vs. 44/282 respectively, value is 0.995). Based on our review, LOCalizer™ is safe and non-inferior to WGL in terms of successful localisation and re-excision rates. However, further research is required to assess the cost effectiveness of this approach and its impact on the aesthetic outcome compared with WGL and other wire free technologies to better inform decision making in service planning and provision.
PubMed: 34638480
DOI: 10.3390/cancers13194996 -
The British Journal of Radiology Oct 2020As tomosynthesis is rapidly adopted by breast imaging practices, tomosynthesis-guided procedures are increasingly being performed. Tomosynthesis-guided needle... (Review)
Review
As tomosynthesis is rapidly adopted by breast imaging practices, tomosynthesis-guided procedures are increasingly being performed. Tomosynthesis-guided needle localizations are feasible and efficient and allow for localization of tomosynthesis-only findings or one-view findings, which may be difficult to localize under standard digital mammography. In this review, we describe our step-by-step approach for performing tomosynthesis-guided localizations of the breast and axilla using a standard tomosynthesis unit.
Topics: Axilla; Breast Neoplasms; Female; Humans; Image-Guided Biopsy; Mammography; Radiographic Image Enhancement
PubMed: 32667855
DOI: 10.1259/bjr.20200495 -
Molecular Biology of the Cell May 2022Protein localization is intrinsic to cellular function and specialized activities, such as migration or proliferation. Many localized proteins enrich at defined...
Protein localization is intrinsic to cellular function and specialized activities, such as migration or proliferation. Many localized proteins enrich at defined organelles, forming subdomains of functional activity further specified by interacting protein assemblies. One well-studied organelle showing dynamic, functional changes in protein composition is the centrosome. Centrosomes are microtubule-organizing centers with diverse cellular functions largely defined by the composition of the pericentriolar material, an ordered matrix of proteins organized around a central pair of centrioles. Also localizing to the pericentriolar material are mRNAs. Although RNA was identified at centrosomes decades ago, the characterization of specific RNA transcripts and their functional contributions to centrosome biology remained largely unstudied. While the identification of RNA localized to centrosomes accelerated with the development of high-throughput screening methods, this discovery still outpaces functional characterization. Recent work indicates RNA localized to centrosomes is biologically significant and further implicates centrosomes as sites for local protein synthesis. Distinct RNA localization and translational activities likely contribute to the diversity of centrosome functions within cells.
Topics: Centrioles; Centrosome; Cilia; Microtubule-Organizing Center; Proteins; RNA
PubMed: 35420887
DOI: 10.1091/mbc.E21-03-0128 -
NeuroImage Mar 2010Functional localizers are routinely used in neuroimaging studies to test hypotheses about the function of specific brain areas. The specific tasks and stimuli used to... (Review)
Review
Functional localizers are routinely used in neuroimaging studies to test hypotheses about the function of specific brain areas. The specific tasks and stimuli used to localize particular regions vary widely from study to study even when the same cortical region is targeted. Thus, it is important to ask whether task and stimulus changes lead to differences in localization or whether localization procedures are largely immune to differences in tasks and contrasting stimuli. We present two experiments and a literature review that explore whether face localizer tasks yield differential localization in the fusiform gyrus as a function of task and contrasting stimuli. We tested standard localization tasks-passive viewing, 1-back, and 2-back memory tests--and did not find differences in localization based on task. We did, however, find differences in the extent, strength and patterns/reliabilities of the activation in the fusiform gyrus based on comparison stimuli (faces vs. houses compared to faces vs. scrambled stimuli).
Topics: Brain; Brain Mapping; Cues; Face; Female; Humans; Magnetic Resonance Imaging; Male; Memory; Neuropsychological Tests; Photic Stimulation; Reaction Time; Signal Processing, Computer-Assisted; Temporal Lobe; Visual Perception; Young Adult
PubMed: 20025980
DOI: 10.1016/j.neuroimage.2009.12.024 -
Developmental Biology Dec 1995Although there are many differences, mRNA localisations in the Xenopus oocyte show some tantalizing similarities to those occurring in Drosophila development. As in... (Review)
Review
Although there are many differences, mRNA localisations in the Xenopus oocyte show some tantalizing similarities to those occurring in Drosophila development. As in Drosophila, transcripts localise to opposite poles of the oocyte, this localisation is hierarchical and occurs in a multistep process in which localisation is followed by anchoring at the cortex. This distinction between initial transport and long-term maintenance reflects the dynamic nature of the cytoskeleton: the microtubule tracks form and reform according to the needs of the cell so that stable localisation must be mediated by a more constant structure--the cortex. A possible exception is the localisation of gurken mRNA where it is unknown whether there are separate mechanisms for transport to and maintenance at the oocyte nucleus. However, gurken is responsible for the transmission of a transitory signal; once this has been received, and the fate of the recipient follicle cells determined, there is no further need for localisation. It is possible that the time scale over which the localisation machinery is stable is sufficient for transmission of this signal without the need for a separate maintenance phase. The existence of a nanos homologue, Xcat-2 (Mosquera et al., 1993), associated with the Xenopus germ plasm is particularly interesting because of the morphological and functional similarities between Drosophila polar granules, Caenorhabditis P-granules, and Xenopus germ plasm. These electron-dense protein-RNA complexes are maternally supplied and in each case segregate with the germ line. These granules may represent a fundamental conserved pathway to germ-cell specification and it is now at least a possibility that they are also involved in establishing the embryonic axis through translational repression. In the case of Drosophila, this occurs through localised nanos acting (via Pumilio) on nanos response elements in hunchback mRNA. No such regulatory pair has yet been demonstrated in C. elegans or X. laevis, but each contains a candidate for one half of the interaction: glp-1 could be a target for an unidentified nanos-like protein; Xcat-2 may control translation of an unknown NRE-containing mRNA. Another common feature of mRNA localisation is that in every case where the targeting signal has been determined, it has been mapped to a region of the 3' UTR capable of forming an extensive secondary structure (e.g., David and Ish-Horowicz, 1991; Dalby and Glover, 1992; Gavis and Lehmann, 1992; Kim-Ha et al., 1993; Kislauskis et al., 1993, 1994; Lantz and Schedl, 1994). In several cases, translational control and transcript stability signals have also been mapped to these regions (Jackson and Standart, 1990; Standart et al., 1990; Standart and Hunt, 1990; Davis and Ish-Horowicz, 1991; Wharton and Struhl, 1991; Dalby and Glover, 1993; Evans et al., 1994; Kim-Ha et al., 1995). The large secondary structures may provide a means for stably exposing sequence-specific regions of RNA to proteins. Due to the ease with which RNA forms base pairs, it is likely that rather than remaining single-stranded, RNA within the cell forms some sort of secondary structure. The geometry of purely double-stranded RNA does not permit sequence specific interactions between proteins and the bases because the major groove is inaccessible to amino acid side chains (Weeks and Crothers, 1993). However, the distortions to the dsRNA helix provided by bulges, pseudoknots, and the single-strand loop regions in stem-loop structures do present sequence information that can be "read" by proteins. The extensive 3'UTRs may produce a stable secondary structure which ensures that regulatory elements remain exposed in such regions rather than hidden in double-stranded stems. (ABSTRACT TRUNCATED)
Topics: Animals; Drosophila melanogaster; Oocytes; Proteins; RNA, Messenger; Xenopus
PubMed: 8612958
DOI: 10.1006/dbio.1995.8048 -
Frontiers in Human Neuroscience 2023Transcranial electrical stimulation (TES) is limited in focally stimulating deep-brain regions, even with optimized stimulation montages. Recently, interferential...
INTRODUCTION
Transcranial electrical stimulation (TES) is limited in focally stimulating deep-brain regions, even with optimized stimulation montages. Recently, interferential stimulation (IFS), also known as transcranial temporal interference stimulation (TI, TIS, or tTIS), has drawn much attention in the TES community as both computational and experimental studies show that IFS can reach deep-brain areas. However, the underlying electrodynamics of IFS is complicated and difficult to visualize. Existing literature only shows static visualization of the interfered electric field induced by IFS. These could result in a simplified understanding that there is always one static focal spot between the two pairs of stimulation electrodes. This static visualization can be frequently found in the IFS literature. Here, we aimed to systematically visualize the entire dynamics of IFS.
METHODS AND RESULTS
Following the previous study, the lead field was solved for the MNI-152 head, and optimal montages using either two pairs of electrodes or two arrays of electrodes were found to stimulate a deep-brain region close to the left striatum with the highest possible focality. We then visualized the two stimulating electrical currents injected with similar frequencies. We animated the instant electric field vector at the target and one exemplary off-target location both in 3D space and as a 2D Lissajous curve. We finally visualized the distribution of the interfered electric field and the amplitude modulation envelope at an axial slice going through the target location. These two quantities were visualized in two directions: radial-in and posterior-anterior.
DISCUSSION
We hope that with intuitive visualization, this study can contribute as an educational resource to the community's understanding of IFS as a powerful modality for non-invasive focal deep-brain stimulation.
PubMed: 37954939
DOI: 10.3389/fnhum.2023.1239114 -
European Archives of... Apr 2022To investigate sound localization in patients bilaterally fitted with bone conduction devices (BCDs). Additionally, clinically applicable methods to improve localization...
PURPOSE
To investigate sound localization in patients bilaterally fitted with bone conduction devices (BCDs). Additionally, clinically applicable methods to improve localization accuracy were explored.
METHODS
Fifteen adults with bilaterally fitted percutaneous BCDs were included. At baseline, sound localization, (un)aided pure-tone thresholds, device use, speech, spatial and qualities of hearing scale (SSQ) and York hearing-related quality of life (YHRQL) questionnaire were measured. Settings to optimize sound localizing were added to the BCDs. At 1 month, sound localization was assessed again and localization was practiced with a series of sounds with visual feedback. At 3 months¸ localization performance, device use and questionnaire scores were determined again.
RESULTS
At baseline, one patient with congenital hearing loss demonstrated near excellent localization performance and four other patients (three with congenital hearing loss) localized sounds (quite) accurately. Seven patients with acquired hearing loss were able to lateralize sounds, i.e. identify whether sounds were coming from the left or right side, but could not localize sounds accurately. Three patients (one with congenital hearing loss) could not even lateralize sounds correctly. SSQ scores were significantly higher at 3 months. Localization performance, device use and YHRQL scores were not significantly different between visits.
CONCLUSION
In this study, the majority of experienced bilateral BCD users could lateralize sounds and one third was able to localize sounds (quite) accurately. The localization performance was robust and stable over time. Although SSQ scores were increased at the last visit, optimizing device settings and a short practice session did not improve sound localization.
Topics: Adult; Bone Conduction; Hearing Aids; Hearing Loss, Conductive; Humans; Quality of Life; Sound Localization; Speech Perception
PubMed: 33956208
DOI: 10.1007/s00405-021-06842-1 -
Cureus Jun 2021The N-localizer is generally utilized in a 3-panel or, more rarely, a 4-panel system for computing stereotactic positions. However, a stereotactic frame that...
INTRODUCTION
The N-localizer is generally utilized in a 3-panel or, more rarely, a 4-panel system for computing stereotactic positions. However, a stereotactic frame that incorporates a 2-panel (bipanel) N-localizer system with panels affixed to only the left and right sides of the frame offers several advantages: improved ergonomics to attach the panels, reduced claustrophobia for the patient, mitigation of posterior panel contact with imaging systems, and reduced complexity. A bipanel system that comprises two standard N-localizer panels yields only two three-dimensional (3D) coordinates, which are insufficient to solve for the stereotactic matrix without further information. While additional information to determine the stereotactic positions could include scalar distances from Digital Imaging and Communications in Medicine (DICOM) metadata or 3D regression across the imaging volume, both have risks related to noise and error propagation. Therefore, we sought to develop new stereotactic localizers that comprise only lateral fiducials (bipanel) that leave the front and back regions of the patient accessible but that contain enough information to solve for the stereotactic matrix using each image independently. Methods: To solve the stereotactic matrix, we assumed the need to compute three or more 3D points from a single image. Several localizer options were studied using Monte Carlo simulations to understand the effect of errors on the computed target location. The simulations included millions of possible combinations for computing the stereotactic matrix in the presence of random errors of 1mm magnitude. The matrix then transformed coordinates for a target that was placed 50mm anterior, 50mm posterior, 50mm lateral, or 50mm anterior and 50mm lateral to the centre of the image. Simulated cross-sectional axial images of the novel localizer systems were created and converted into DICOM images representing computed tomography (CT) images. Results: Three novel models include the M-localizer, F-localizer, and Z-localizer. For each of these localizer systems, optimized results were obtained using an overdetermined system of equations made possible by more than three diagonal bars. In each case, the diagonal bar position was computed using standard N-localizer mathematics. Additionally, the M-localizer allowed adding a computation using the Sturm-Pastyr method. Monte Carlo simulation demonstrated that the Z-localizer provided optimal results.
CONCLUSION
The three proposed novel models meet our design objectives. Of the three, the Z-localizer produced the least propagation of error. The M-localizer was simpler and had slightly more error than the Z-localizer. The F-localizer produced more error than either the Z-localizer or M-localizer. Further study is needed to determine optimizations using these novel models.
PubMed: 34277238
DOI: 10.7759/cureus.15620 -
Wellcome Open Research 2022Myosin 7a is an actin-binding motor protein involved in the formation of hair-cell stereocilia both in the cochlea and in the vestibular system. Mutations in myosin 7a...
Myosin 7a is an actin-binding motor protein involved in the formation of hair-cell stereocilia both in the cochlea and in the vestibular system. Mutations in myosin 7a are linked to congenital hearing loss and are present in 50% of Type-1 Usher syndrome patients who suffer from progressive hearing loss and vestibular system dysfunction. Myosin 7a is often used to visualise sensory hair cells due to its well characterised and localised expression profile. We thus conducted myosin-7a immunostaining across all three turns of the adult rat organ of Corti to visualise hair cells. As expected, we observed myosin 7a staining in both inner and outer hair cells. Unexpectedly, we also observed strong myosin 7a staining in the medial olivocochlear efferent synaptic boutons contacting the outer hair cells. Efferent bouton myosin-7a staining was present across all three turns of the cochlea. We verified this localisation by co-staining with a known efferent bouton marker, the vesicular acetylcholine transporter. In addition to its role in stereocilia formation and maintenance, myosin 7a or certain myosin-7a expression variants might play a role in efferent synaptic transmission in the cochlea and thus ultimately influence cochlear gain regulation. Our immunohistochemistry results should be validated with other methods to confirm these serendipitous findings.
PubMed: 35224213
DOI: 10.12688/wellcomeopenres.17428.2