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Vision Research Sep 2021Rubin's face-vase illusion demonstrates how one can switch back and forth between two different interpretations depending on how the figure outlines are assigned. In the...
Rubin's face-vase illusion demonstrates how one can switch back and forth between two different interpretations depending on how the figure outlines are assigned. In the primate visual system, assigning ownership along figure borders is encoded by neurons called the border ownership (BO) cells. Studies show that the responses of these neurons not only depend on the local features within their receptive fields, but also on contextual information. Despite two decades of studies on BO neurons, the ownership assignment mechanism in the brain is still unknown. Here, we propose a hierarchical recurrent model grounded on the hypothesis that neurons in the dorsal stream provide the context required for ownership assignment. Our proposed model incorporates early recurrence from the dorsal pathway as well as lateral modulations within the ventral stream. While dorsal modulations initiate the response difference to figure on either side of the border, lateral modulations enhance the difference. We found responses of our dorsally-modulated BO cells, similar to their biological counterparts, are invariant to size, position and solid/outlined figures. Moreover, our model BO cells exhibit comparable levels of reliability in the ownership signal to biological BO neurons. We found dorsal modulations result in high levels of accuracy and robustness for BO assignments in complex scenes compared to previous models based on ventral feedback. Finally, our experiments with illusory contours suggest that BO encoding could explain the perception of such contours in higher processing stages in the brain.
Topics: Animals; Ownership; Pattern Recognition, Visual; Photic Stimulation; Reproducibility of Results; Visual Cortex
PubMed: 34023589
DOI: 10.1016/j.visres.2021.04.009 -
Neuromodulation : Journal of the... Aug 2023In the practice of intrathecal drug delivery, consensus exists regarding the cephalad to caudad location of the catheter tip relative to dermatomal distribution of pain.... (Clinical Trial)
Clinical Trial
OBJECTIVES
In the practice of intrathecal drug delivery, consensus exists regarding the cephalad to caudad location of the catheter tip relative to dermatomal distribution of pain. However, data are lacking on the importance of dorsal vs ventral tip location relative to the spinal cord. We hypothesize that a dorsally placed catheter tip improves efficacy because of closer proximity to nociceptive pathways.
MATERIALS AND METHODS
A retrospective review of 298 patients with cancer with intrathecal drug delivery systems implanted at the Huntsman Cancer Institute from May 2014 to June 2020 was performed. Patients were stratified by catheter tip location zones based on available radiographic studies. Patient-controlled intrathecal medication dose requirements and rate of change were compared with catheter zone and other variables, including the presence of adjuncts such as bupivacaine and ziconotide.
RESULTS
A total of 158 patients were suitable for analysis demonstrating a dorsal tip in 63.9% (n = 101) and ventral tip in 36.1% (n = 57), with a median follow-up of 17 days (interquartile range [IQR], 10-24). There was no difference in daily dose change from implant to discharge between the dorsal group 8.2% (IQR, 0.0-41.5) and ventral group 20.8% (IQR, 0.0-66.7; p = 0.12). Daily dose change from discharge to follow-up was 2.6% (IQR, 0.0-7.1) in the dorsal group and 1.8% (IQR, 0.0-5.7) in the ventral group (p = 0.92). Catheter tip location had no impact on systemic opioid use.
CONCLUSIONS
We did not find significant associations between dorsal vs ventral catheter tip location and measures of pain relief, including change in intrathecal dose or systemic opioid use.
Topics: Humans; Analgesics, Opioid; Cancer Pain; Catheters; Injections, Spinal; Neoplasms; Opioid-Related Disorders; Pain
PubMed: 35393238
DOI: 10.1016/j.neurom.2022.02.230 -
Annales de Chirurgie Plastique Et... Aug 2021Rhinoplasty is one of the most commonly performed aesthetic surgeries among patients who are admitted to plastic surgeons. Recent research has focused on dorsal...
PURPOSE
Rhinoplasty is one of the most commonly performed aesthetic surgeries among patients who are admitted to plastic surgeons. Recent research has focused on dorsal preservation in hump reduction and consequently dorsal preservation techniques have become more popular. The current study aimed to revise the push down technique by adding ostectomy.
PATIENTS AND METHODS
In the present retrospective study, data from patients who underwent rhinoplasty to fix a nasal hump were assessed. All patients were administered the push down technique with ostectomy. Following these inclusion and exclusion criteria, the records of 52 patients were assessed (45 females and 7 males). The median age of the patients was 22.2 years. Patients were evaluated using the "Rhinoplasty Outcome Evaluation" (ROE) questionnaire both before surgery and 12 months after surgery. The follow-up period ranged between 13 and 21 months (median of 15.1 months).
RESULTS
Patients were evaluated before surgery and after one year of surgery by the ROE scale. The median of the ROE score before surgery was 63.4. The median score after one year of surgery was 91.6. Thus, the ROE score significantly increased 12 months after surgery (P<0.001).
CONCLUSIONS
This study was the first to demonstrate the benefits of performing the push down technique with ostectomy in terms of obtaining a wider nasal cavity. In addition, it can be assumed that the disadvantage of using the push down technique can be overcome with ostectomy.
Topics: Adult; Esthetics; Female; Humans; Male; Nasal Septum; Plastic Surgery Procedures; Retrospective Studies; Rhinoplasty; Young Adult
PubMed: 32978019
DOI: 10.1016/j.anplas.2020.08.004 -
Facial Plastic Surgery : FPS Dec 2016Revision rhinoplasty in Asian patients is associated with problems related to the use of grafts or implant materials. Moreover, the septal cartilage of Asian individuals... (Review)
Review
Revision rhinoplasty in Asian patients is associated with problems related to the use of grafts or implant materials. Moreover, the septal cartilage of Asian individuals is generally weak and small, which makes it particularly vulnerable to injury or secondary deformity during primary surgery. Hence, there is an increased demand for major reconstruction of the septal cartilage framework during revision surgery in Asian patients. In revision rhinoplasty of the nose in Asian patients, appropriate management of the graft or implant is vital. The common problems resulting in the need for revision surgery include displacement, malposition, extrusion, recurrent inflammation, and infection of dorsally implanted alloplastic material. A short-nose deformity following silicone rhinoplasty is also a common problem that is difficult to manage. Furthermore, residual or recurrent deviation of the deviated nose, undercorrection of the convex nasal dorsum, and tip graft-related complications are frequently encountered problems that require revision. In revision rhinoplasty for Asian patients, autologous tissues, such as conchal cartilage and costal cartilage, play a pivotal role for use as a new dorsal implant or building block for major septal reconstruction. Therefore, it is imperative for surgeons to familiarize themselves with the appropriate use of autologous tissues, particularly costal cartilage.
Topics: Asian People; Costal Cartilage; Humans; Nasal Cartilages; Nose Deformities, Acquired; Prostheses and Implants; Prosthesis Failure; Reoperation; Rhinoplasty
PubMed: 28033636
DOI: 10.1055/s-0036-1594254 -
Movement Disorders : Official Journal... Feb 2021The aim of this study is to identify anatomical regions related to stimulation-induced dyskinesia (SID) after pallidal deep brain stimulation (DBS) in Parkinson's...
OBJECTIVES
The aim of this study is to identify anatomical regions related to stimulation-induced dyskinesia (SID) after pallidal deep brain stimulation (DBS) in Parkinson's disease (PD) patients and to analyze connectivity associated with SID.
METHODS
This retrospective study analyzed the clinical and imaging data of PD patients who experienced SID during the monopolar review after pallidal DBS. We analyzed structural and functional connectivity using normative connectivity data with the volume of tissue activated (VTA) modeling. Each contact was assigned to either that producing SID (SID VTA) or that without SID (non-SID VTA). Structural and functional connectivity was compared between SID and non-SID VTAs. "Optimized VTAs" were also estimated using the DBS settings at 6 months after implantation.
RESULTS
Of the 68 consecutive PD patients who underwent pallidal implantation, 20 patients (29%) experienced SID. SID VTAs were located more dorsally and anteriorly compared with non-SID and optimized VTAs and were primarily in the dorsal globus pallidus internus (GPi) and dorsal globus pallidus externus (GPe). SID VTAs showed significantly higher structural connectivity than non-SID VTAs to the associative cortex and supplementary motor area/premotor cortex (P < 0.0001). Simultaneously, non-SID VTAs showed greater connectivity to the primary sensory cortex, cerebellum, subthalamic nucleus, and motor thalamus (all P < 0.0004). Functional connectivity analysis showed significant differences between SID and non-SID VTAs in multiple regions, including the primary motor, premotor, and prefrontal cortices and cerebellum.
CONCLUSION
SID VTAs were primarily in the dorsal GPi/GPe. The connectivity difference between the motor-related cortices and subcortical regions may explain the presence and absence of SID. © 2020 International Parkinson and Movement Disorder Society.
Topics: Deep Brain Stimulation; Dyskinesias; Globus Pallidus; Humans; Parkinson Disease; Retrospective Studies
PubMed: 33002233
DOI: 10.1002/mds.28324 -
ELife May 2022The dorsal axial muscles, or epaxial muscles, are a fundamental structure covering the spinal cord and vertebrae, as well as mobilizing the vertebrate trunk. To date,...
The dorsal axial muscles, or epaxial muscles, are a fundamental structure covering the spinal cord and vertebrae, as well as mobilizing the vertebrate trunk. To date, mechanisms underlying the morphogenetic process shaping the epaxial myotome are largely unknown. To address this, we used the medaka -enhancer mutant (), which exhibits ventralized dorsal trunk structures resulting in impaired epaxial myotome morphology and incomplete coverage over the neural tube. In wild type, dorsal dermomyotome (DM) cells reduce their proliferative activity after somitogenesis. Subsequently, a subset of DM cells, which does not differentiate into the myotome population, begins to form unique large protrusions extending dorsally to guide the epaxial myotome dorsally. In , by contrast, DM cells maintain the high proliferative activity and mainly form small protrusions. By combining RNA- and ChIP-sequencing analyses, we revealed direct targets of Zic1, which are specifically expressed in dorsal somites and involved in various aspects of development, such as cell migration, extracellular matrix organization, and cell-cell communication. Among these, we identified as a crucial factor regulating both cell proliferation and protrusive activity of DM cells. We propose that dorsal extension of the epaxial myotome is guided by a non-myogenic subpopulation of DM cells and that empowers the DM cells to drive the coverage of the neural tube by the epaxial myotome.
Topics: Animals; Embryonic Development; Gene Expression Regulation, Developmental; Morphogenesis; Oryzias; Somites; Wnt Proteins
PubMed: 35522214
DOI: 10.7554/eLife.71845 -
Injury Dec 2022Hand wounds account for 35 to 51% of hand traumas. Damage to underlying anatomical structures depends on the location of the wound. The objective of this study is to...
INTRODUCTION
Hand wounds account for 35 to 51% of hand traumas. Damage to underlying anatomical structures depends on the location of the wound. The objective of this study is to describe the topographic distribution of hand wounds allowing for subsequent evaluation of the link between affected surface area and underlying lesion.
METHODS
We retrospectively reviewed the medical records of 1058 patients with a total of 1319 wounds over a period of 2 years. Wound location was described according to the cutaneous projection of IFSSH zones for flexors and extensors. Any associated deep lesions were evaluated. Topographical distribution was modeled graphically using a heat-map. We compared the proportion of underlying lesions between each cutaneous zone. Sub-group analysis for lesions' rate regarding zone groups were performed.
RESULTS
58.9% of wounds were located on the palmar surface and 41.1% on the dorsal surface. 71% of wounds affected only the digits. The index finger was the most affected. The most damaged region was zone 2 for palmar wounds and zone 3 for dorsal wounds. 45.5% of wounds resulted in injury to a significant underlying anatomical structure. This frequency was 36.4% and 58.5% for palmar and dorsal wounds respectively. More than 50% of wounds in palmar zone 5 and dorsal zones 1, 3, 5, 6 and 7 presented at least one lesion. A lesion of major structure was more frequently found in palmar zone 5 (p <0.001). Dorsally, no zone predominated. Subgroup analysis for dorsal wounds revealed that wounds overlying joints had more major lesions including more tendons injuries and more articular violations with zone 3 presenting a rate of 68%.
CONCLUSION
We provided the first graphical representation for the topographical distribution of hand wounds. Dorsal wounds have a higher association with injury to underlying structures. These results generally support surgical exploration of all hand wounds regardless of their location.
LEVEL OF EVIDENCE
IV Study type: Epidemiological study.
Topics: Humans; Retrospective Studies; Hand Injuries; Tendon Injuries; Hand; Upper Extremity
PubMed: 36424689
DOI: 10.1016/j.injury.2022.10.022 -
Journal of Anatomy Jul 2021Although the development of the sympathetic trunks was first described >100 years ago, the topographic aspect of their development has received relatively little...
Although the development of the sympathetic trunks was first described >100 years ago, the topographic aspect of their development has received relatively little attention. We visualised the sympathetic trunks in human embryos of 4.5-10 weeks post-fertilisation, using Amira 3D-reconstruction and Cinema 4D-remodelling software. Scattered, intensely staining neural crest-derived ganglionic cells that soon formed longitudinal columns were first seen laterally to the dorsal aorta in the cervical and upper thoracic regions of Carnegie stage (CS)14 embryos. Nerve fibres extending from the communicating branches with the spinal cord reached the trunks at CS15-16 and became incorporated randomly between ganglionic cells. After CS18, ganglionic cells became organised as irregular agglomerates (ganglia) on a craniocaudally continuous cord of nerve fibres, with dorsally more ganglionic cells and ventrally more fibres. Accordingly, the trunks assumed a "pearls-on-a-string" appearance, but size and distribution of the pearls were markedly heterogeneous. The change in position of the sympathetic trunks from lateral (para-aortic) to dorsolateral (prevertebral or paravertebral) is a criterion to distinguish the "primary" and "secondary" sympathetic trunks. We investigated the position of the trunks at vertebral levels T2, T7, L1 and S1. During CS14, the trunks occupied a para-aortic position, which changed into a prevertebral position in the cervical and upper thoracic regions during CS15, and in the lower thoracic and lumbar regions during CS18 and CS20, respectively. The thoracic sympathetic trunks continued to move further dorsally and attained a paravertebral position at CS23. The sacral trunks retained their para-aortic and prevertebral position, and converged into a single column in front of the coccyx. Based on our present and earlier morphometric measurements and literature data, we argue that differential growth accounts for the regional differences in position of the sympathetic trunks.
Topics: Embryo, Mammalian; Embryonic Development; Humans; Sympathetic Nervous System
PubMed: 33641166
DOI: 10.1111/joa.13415 -
Hand (New York, N.Y.) Jan 2019The anatomy of the scapholunate interosseous ligament (SLIL) has been described qualitatively in great detail, with recognition of the dorsal component's importance for...
BACKGROUND
The anatomy of the scapholunate interosseous ligament (SLIL) has been described qualitatively in great detail, with recognition of the dorsal component's importance for carpal stability. The purpose of this study was to define the quantitative anatomy of the dorsal SLIL and to assess the use of high-frequency ultrasound to image the dorsal SLIL.
METHODS
We used high-frequency ultrasound imaging to evaluate 40 wrists in 20 volunteers and recorded the radial-ulnar (length) and dorsal-volar (thickness) dimensions of the dorsal SLIL and the dimensions of the scapholunate interval. We assessed the use of high-frequency ultrasound by comparing the length and thickness of the dorsal SLIL on ultrasound evaluation and open dissection of 12 cadaveric wrists. Student's t test was used to assess the relationship between measurements obtained on cadaver ultrasound and open dissection.
RESULTS
In the volunteer wrists, the mean dorsal SLIL length was 7.5 ± 1.4 mm and thickness was 1.8 ± 0.4 mm; the mean scapholunate interval was 5.0 mm dorsally and 2.5 mm centrally. In the cadaver wrists, there was no difference in dorsal SLIL length or thickness between ultrasound and open dissection.
CONCLUSIONS
The dorsal SLIL is approximately 7.5 mm long and 1.8 mm thick. These parameters may be useful in treatment of SLIL injuries to restore the native anatomy. High-frequency ultrasound is a useful imaging technique to assess the dorsal SLIL, although further study is needed to assess the use of high-frequency ultrasound in detection of SLIL pathology.
Topics: Adult; Aged; Aged, 80 and over; Cadaver; Dissection; Female; Healthy Volunteers; Humans; Ligaments, Articular; Lunate Bone; Male; Middle Aged; Scaphoid Bone; Ultrasonography; Young Adult
PubMed: 30205714
DOI: 10.1177/1558944718798846 -
Hand Surgery & Rehabilitation Dec 2023In volar distal radius fixation, conventional and additional fluoroscopic views could not be sufficient to assess dorsal screw penetration. Ultrasound (US) has been...
OBJECTIVES
In volar distal radius fixation, conventional and additional fluoroscopic views could not be sufficient to assess dorsal screw penetration. Ultrasound (US) has been suggested as a technique to improve this assessment. The objective was to determine the agreement between these two explorations in a clinical study. Quantify time-consuming of intraoperative US was the secondary objective.
MATERIAL AND METHODS
A prospective descriptive study was performed. Thirty patients with a surgical distal radius fracture were treated with volar fixation by five consultant surgeons in a level I Trauma Centre. Final intraoperative fluoroscopic views: AP, lateral, 20º tilted lateral and Dorsal Tangential views (DTV) were performed assessing for dorsal screw protrusion. Then, ultrasound was performed to reassess dorsal cortex integrity. Those protruding screws were registered and changed.
RESULTS
A total of 153 screws were examined. Four protruding screws were observed with no multiple protruding screws in the same fixation. Intraoperative ultrasound detected a dorsal screw protrusion in one fixation, assessed as correct by radiological projections. Almost perfect agreement was found between DTV and US examination k = 0.83 (p < 0.001). The mean surgical time was 63 ± 20.3 min while the addition of the ultrasound, supposed an average of 4 ± 1 min more.
CONCLUSION
Ultrasound did not show a clinically significant improvement in the assessment dorsal screw penetration in distal radius fixation. A high agreement was observed between US and the described fluoroscopic views. The addition of intraoperative US was a non-significant time-consuming procedure.
Topics: Humans; Radius; Radius Fractures; Bone Plates; Fracture Fixation, Internal; Fluoroscopy
PubMed: 37499797
DOI: 10.1016/j.hansur.2023.07.010