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Brain and Behavior Oct 2019The hippocampus is linked to the formation and retrieval of episodic memories and spatial navigation. In rats, it is an elongated structure divided into dorsal (septal)...
INTRODUCTION
The hippocampus is linked to the formation and retrieval of episodic memories and spatial navigation. In rats, it is an elongated structure divided into dorsal (septal) and ventral (temporal) regions paralleling the respective division in the posterior and anterior hippocampus in humans. The dorsal hippocampus has been suggested to be more important for spatial processing and the ventral to processing anxiety-based behaviors. Far less is known regarding the degree to which these different regions interact during information processing. The anatomical connectivity suggests a flow of information between the dorsal and ventral regions; conversely, there are also commissural connections to the contralateral hippocampus. The current study examined the extent to which information from the dorsal hippocampus interacts with processing in the ipsilateral and contralateral ventral hippocampus following the acquisition of a spatial task.
METHODS
Rats were well-trained on a spatial reference version of the water maze, followed by muscimol inactivation of different hippocampal subregions in a within-animal repeated design. Various combinations of bilateral, ipsilateral, and contralateral infusions were used.
RESULTS
Combined dorsal and ventral inactivation produced a severe impairment in spatial performance. Inactivation of only the dorsal or ventral regions resulted in intermediate impairment with performance levels falling between controls and combined inactivation. Performance was impaired during contralateral inactivation and was almost equivalent to bilateral dorsal and ventral hippocampus inactivation, while ipsilateral inactivation resulted in little impairment.
CONCLUSIONS
Taken together, results indicate that for spatial processing, the hippocampus functions as a single integrated structure along the longitudinal axis.
Topics: Animals; Behavior, Animal; Hippocampus; Male; Maze Learning; Models, Animal; Muscimol; Rats; Rats, Inbred F344; Spatial Navigation
PubMed: 31571397
DOI: 10.1002/brb3.1410 -
Frontiers in Pharmacology 2022As a nonspecific antagonist of the adenosine A receptor (AR), caffeine enhances learning and improves memory impairment. Simultaneously, the consumption of caffeine...
As a nonspecific antagonist of the adenosine A receptor (AR), caffeine enhances learning and improves memory impairment. Simultaneously, the consumption of caffeine correlates with a feeling of anxiety. The hippocampus is functionally differentiated along its dorsal/ventral axis and plays a crucial role both in memory and anxiety. Whether caffeine exerts its regulation by inhibiting ARs in different subregions of the hippocampus is still unknown. In the present study, we found that after chronic intake of drinking water containing caffeine (1 g/L, 3 weeks), mice exhibited aggravated anxiety-like behavior and enhanced memory function. Tissue-specific, functional disruption of dorsal hippocampal ARs by the CRE-LoxP system prevented the memory-enhancing effect of caffeine, while selective disruption of ventral hippocampal ARs blocked the impact of caffeine on anxiety. These results, together with the enhanced memory of dorsal hippocampus AR knockout mice and greater anxiety-like behavior of ventral hippocampus AR knockout mice without caffeine, indicates a dissociation between the roles of ventral and dorsal hippocampal A receptors in caffeine's effects on anxiety-like and memory-related behavioral measures, respectively. Furthermore, optogenetic activation of dorsal or ventral hippocampal ARs reversed the behavioral alterations caused by drinking caffeine, leading to impaired memory or decreased anxiety-like behaviors, respectively. Taken together, our findings suggest that the memory- and anxiety-enhancing effects of caffeine are related to the differential effects of inhibiting ARs in the dorsal and ventral hippocampus, respectively.
PubMed: 35185566
DOI: 10.3389/fphar.2022.807330 -
Journal of Wrist Surgery Dec 2021The dorsal intercarpal ligament, whose role in dorsal stability of the wrist has been shown, can be harmed in case of injury to the dorsal scapholunate complex....
The dorsal intercarpal ligament, whose role in dorsal stability of the wrist has been shown, can be harmed in case of injury to the dorsal scapholunate complex. However, dorsal intercarpal ligament injury also seems to exist isolated posttraumatic forms of dorsal intercarpal ligament rupture, much rarer, through bony avulsion on its scaphoid insertion. The authors report the first description of this lesion, and propose a technique for arthroscopic repair. Radiocarpal arthroscopy will confirm the bony avulsion of the dorsal intercarpal ligament from the scaphoid. Under arthroscopic control, an anchor can be placed into the dorsal aspect of the scaphoid and the ligament can be reattached along with the dorsal capsule. Between 2018 and 2020, seven patients underwent arthroscopic repair of this particular injury. They presented a painful preoperative wrist with decreased range of motion, and were treated arthroscopically, with anchored reinsertion of the ligament on the scaphoid. After a mean follow-up period of 12 months, arthroscopic repair showed decreased pain (6.7 to 0.2), improved range of motion in flexion (66 to 82 degrees) and extension (57 to 87 degrees°), and improved Disabilities of the Arm, Shoulder, and Hand (DASH) score (68.45 to 2.23). This lesion has so far never been reported in the literature, and seems mechanically different from more common injuries of the scapholunate complex and dorsal capsulo-scapholunate septum with which dorsal intercarpal ligament ruptures are frequently associated. Arthroscopic repair with an anchor is possible without difficulty and seems to give very good results at 1-year follow-up (normal strength and range of motion).
PubMed: 34881111
DOI: 10.1055/s-0041-1728803 -
Plastic and Reconstructive Surgery.... Sep 2022Dorsal preservation techniques as a means of addressing the dorsal hump have been popularized recently to avoid midvault disruption or dorsal resection. The pitfall of...
Dorsal preservation techniques as a means of addressing the dorsal hump have been popularized recently to avoid midvault disruption or dorsal resection. The pitfall of these techniques is the higher rate of dorsal hump recurrence of up to 15%. We present the use of the upper lateral cartilages (ULCs) as a turn-in flap and as a cutting guide during classic dorsal hump takedown. The cutting guide provides the perfect dorsal angulation and dictates the amount of resection needed. This translates to aesthetically pleasing dorsal lines, avoidance of dorsal irregularities, and decreased risk of hump recurrence.
PubMed: 36148028
DOI: 10.1097/GOX.0000000000004518 -
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 -
Journal of Wrist Surgery Apr 2023The aim of this study was to compare the rates of recurrence and wound infection in patients with primary dorsal wrist ganglion treated with aspiration (with or...
The aim of this study was to compare the rates of recurrence and wound infection in patients with primary dorsal wrist ganglion treated with aspiration (with or without an injection of an additive), open excision, or arthroscopic resection. This systematic review was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines and registered on PROSPERO. Systematic electronic searches in PubMed (MEDLINE), EMBASE, Web of Science, and the Cochrane Library of Controlled Trials were performed on May 5, 2020, and June 1, 2021, respectively. All clinical studies written in English determining the recurrence and wound infection rates after treatment of primary dorsal wrist ganglion with aspiration, open excision, or arthroscopic resection in patients over the age of 16 years were eligible for inclusion. Quality assessment was guided by the Cochrane Collaboration's tool for randomized controlled trials (RCTs) and the methodological index for nonrandomized studies (MINORS) tool for observational studies. The literature searches resulted in 1,691 studies. After screening, five RCTs, enrolling 233 patients, and six observational studies, enrolling 316 patients with primary dorsal wrist ganglions were included. Quality assessment of the included RCTs and observational studies determined the existing level of evidence pertaining to primary dorsal wrist ganglion treatment to be low. About 11 studies reported on recurrence rate, which ranged between 7 and 72% for patients initially treated with aspiration (with or without an injection of an additive). In comparison, the recurrence rate for the open excision and arthroscopic resection groups ranged between 6 to 41% and 0 to 16%, respectively. Four studies investigated wound-related complications, for which zero infections were reported, irrespective of treatment. The evidence summarized in this systematic review demonstrates a considerable variability in recurrence rate following aspiration and open or arthroscopic resection of a primary dorsal wrist ganglion. The greatest variability in recurrence was displayed among studies on aspiration. The overall infection rate after treatment of dorsal wrist ganglions seems to be low regardless of the treatment type. However, the divergent results of individual studies highlight a pressing need for prospective controlled trials assessing outcomes following dorsal wrist ganglion treatment. Systematic review on level 1 to 4 clinical therapeutic studies.
PubMed: 36926205
DOI: 10.1055/s-0042-1753542 -
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 -
The Journal of Pain Jul 2023Depression and thermal hypersensitivity share pathogenic features and symptomology, but their pathophysiologic interactions have not been fully elucidated. Dopaminergic...
Depression and thermal hypersensitivity share pathogenic features and symptomology, but their pathophysiologic interactions have not been fully elucidated. Dopaminergic systems in the ventrolateral periaqueductal gray (vlPAG) and dorsal raphe nucleus have been implicated in these conditions due to their antinociception and antidepression effects, although their specific roles and underlying mechanisms remain obscure. In this study, chronic unpredictable mild stress (CMS) was used to induce depression-like behaviors and thermal hypersensitivity in C57BL/6J (wild-type) or dopamine transporter promoter mice to establish a mouse model of pain and depression comorbidity. Microinjections of quinpirole, a dopamine D2 receptor agonist, up-regulated D2 receptor expression in dorsal raphe nucleus and reduced depressive behaviors and thermal hypersensitivity with CMS, while dorsal raphe nucleus injections of JNJ-37822681, an antagonist of D2 receptors, had the reciprocal effect on dopamine D2 receptor expression and behaviors. Moreover, using a chemical genetics approach to activate or inhibit dopaminergic neurons in vlPAG ameliorated or exacerbated depression-like behaviors and thermal hypersensitivity, respectively, in dopamine transporter promoter-Cre CMS mice. Collectively these results demonstrated the specific role of vlPAG and dorsal raphe nucleus dopaminergic systems in the regulation of pain and depression comorbidity in mice. PERSPECTIVE: The current study provides insights into the complex mechanisms underlying thermal hypersensitivity induced by depression, and the findings suggest that pharmacological and chemogenetic modulation of dopaminergic systems in the vlPAG and dorsal raphe nucleus may be a promising therapeutic strategy to simultaneously mitigate pain and depression.
Topics: Mice; Animals; Dorsal Raphe Nucleus; Periaqueductal Gray; Dopamine Plasma Membrane Transport Proteins; Depression; Mice, Inbred C57BL; Pain
PubMed: 36796500
DOI: 10.1016/j.jpain.2023.02.004