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OBJECTIVE: To evaluate the clinical relevance of intraocular pressure (IOP) measured with three different rebound tonometers in an ex vivo analysis and clinical trials in dogs. ANIMALS AND PROCEDURES: Ex vivo analysis and clinical trials were performed separately. For the ex vivo analysis, eight enucleated eyes were obtained from four Beagle dogs. IOP values measured with TONOVET® (TV-IOP), TONOVET-Plus® (TVP-IOP), and SW-500® (SW-IOP) were compared with manometric IOPs. For clinical trials, each tonometer was evaluated separately, depending on whether TVP-IOP was higher or lower than 14 mm Hg. One-way repeatedmeasures analysis of variance, simple linear regression analysis, and Bland-Altman plots were used for statistical analyses. RESULTS: In ex vivo analysis, TV-IOP and TVP-IOP were not significantly different from manometric IOP. However, SW-IOP underestimated IOP compared to manometry. Higher discrepancy was observed in TV-IOP and SW-IOP with an increase in manometric IOP. In clinical trials, no significant difference was observed between TV-IOP (9.73 ± 2.92) and TVP-IOP (11.36 ± 2.23) when TVP-IOP was lower than 14 mm Hg, but SW-IOP (8.70 ± 3.03) was significantly lower than TVP-IOP. TV-IOP (15.96 ± 6.47) and SW-IOP (13.09 ± 3.72) were significantly lower than TVP-IOP (20.08 ± 6.60) when the IOP was higher than 14 mm Hg of TVP-IOP. CONCLUSIONS: This study demonstrates that the TONOVET® and TONOVET-Plus® provide a useful approach for ex vivo analysis. In clinical trials, results of TV-IOP and SW-IOP were significantly lower than of TVP-IOP when IOP was higher than 14 mm Hg of TVP-IOP. The characteristics of rebound tonometers should be considered in clinical settings.
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Pressão Intraocular , Tonometria Ocular/veterinária , Animais , Cães , Técnicas In Vitro , Tonometria Ocular/instrumentação , Tonometria Ocular/métodosRESUMO
The array invariant technique has been recently proposed for passive source localization in the ocean. It has successfully estimated the source-receiver horizontal range in multipath-dominant shallow-water waveguides. However, it requires a relatively large-scale hydrophone array. This study proposes an array invariant method that uses acoustic intensity, which is a vector quantity that has the same direction as the sound wave propagating through a water medium. This method can be used to estimate not only the source-receiver horizontal range, but also the azimuth to an acoustic source. The feasibility of using a vector quantity for the array invariant method is examined through a simulation and an acoustic experiment in which particle velocity signals are obtained using a finite difference approximation of the pressure signals at two adjacent points. The source localization results estimated using acoustic intensity are compared with those obtained from beamforming of the acoustic signals acquired by the vertical line array.
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OBJECTIVE: The authors' goal was to study avian motor brain mapping via wireless stimulation to induce certain behaviors. In this paper, the authors propose an electrode design that is suitable for avian brain stimulation as well as a stereotactic implant procedure for the proposed electrode. METHODS: An appropriate breed for avian brain study was chosen. A fully implantable remote-controlled electrical stimulation system was inserted to minimize discomfort. A suitable electrode design and stereotactic surgery method based on the electrode design were investigated. RESULTS: Using a wireless stimulation system, flapping and rotation behaviors were induced by stimulating the ventral part of the nucleus intercollicularis and formatio reticularis medialis mesencephali both on the ground and during flight. CONCLUSIONS: The authors were able to implant the entire brain stimulation system inside the avian body without any surgical complications. Postoperative observations suggested that the bird did not find the implant uncomfortable.
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Encéfalo/fisiologia , Encéfalo/cirurgia , Estimulação Encefálica Profunda , Técnicas Estereotáxicas , Animais , Aves , Mapeamento Encefálico/métodos , Estimulação Encefálica Profunda/métodos , Estimulação Elétrica/métodos , Eletrodos Implantados , Humanos , Imageamento TridimensionalRESUMO
Underwater acoustic sensor networks have recently attracted considerable attention as demands on the Internet of Underwater Things (IoUT) increase. In terms of efficiency, it is important to achieve the maximum communication coverage using a limited number of sensor nodes while maintaining communication connectivity. In 2017, Kim and Choi proposed a new deployment algorithm using the communication performance surface, which is a geospatial information map representing the underwater acoustic communication performance of a targeted underwater area. In that work, each sensor node was a vertically separated hydrophone array, which measures acoustic pressure (a scalar quantity). Although an array receiver is an effective system to eliminate inter-symbol interference caused by multipath channel impulse responses in underwater communication environments, a large-scale receiver system degrades the spatial efficiency. In this paper, single-vector sensors measuring the particle velocity are used as underwater sensor nodes. A single-vector sensor can be considered to be a single-input multiple-output communication system because it measures the three directional components of particle velocity. Our simulation results show that the optimal deployment obtained using single-vector sensor nodes is more effective than that obtained using a hydrophone (three-channel vertical-pressure sensor) array.
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This study was conducted to compare the effects of 3 different sedative agents on electroretinography (ERG) in domestic pigeons (Columba livia). Six pigeons were sedated with alfaxalone, xylazine, and medetomidine at separate times with a 1-week washout period between sedative administration. After sedation with each agent, pigeons underwent the modified ERG protocol adapted from the standardized protocol for dogs. The scotopic mixed rod and cone response was recorded after 20 minutes of dark adaptation, and the photopic cone response and photopic flicker response were recorded after 10 minutes of light adaptation. Either a 1-way analysis of variance or a Kruskall-Wallis test was used to compare the a-wave and b-wave implicit time and amplitude. No significant differences were observed in the scotopic mixed rod and cone response among all 3 sedatives used. Compared with alfaxalone, medetomidine significantly prolonged the a-wave implicit time, depressed the b-wave amplitude of photopic cone response, and prolonged the peak implicit time of the photopic flicker response (P < .05). These results show that medetomidine has a depressant effect on photopic ERG in pigeons at a dosage that produces light sedation.
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Columbidae , Eletrorretinografia/veterinária , Medetomidina/farmacologia , Pregnanodionas/farmacologia , Xilazina/farmacologia , Anestésicos/farmacologia , Animais , Estudos Cross-Over , Hipnóticos e Sedativos/farmacologiaRESUMO
The underwater acoustic sensor network (UWASN) is a system that exchanges data between numerous sensor nodes deployed in the sea. The UWASN uses an underwater acoustic communication technique to exchange data. Therefore, it is important to design a robust system that will function even in severely fluctuating underwater communication conditions, along with variations in the ocean environment. In this paper, a new algorithm to find the optimal deployment positions of underwater sensor nodes is proposed. The algorithm uses the communication performance surface, which is a map showing the underwater acoustic communication performance of a targeted area. A virtual force-particle swarm optimization algorithm is then used as an optimization technique to find the optimal deployment positions of the sensor nodes, using the performance surface information to estimate the communication radii of the sensor nodes in each generation. The algorithm is evaluated by comparing simulation results between two different seasons (summer and winter) for an area located off the eastern coast of Korea as the selected targeted area.
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We previously showed that NDP52 (also known as calcoco2) plays a role as an autophagic receptor for phosphorylated tau facilitating its clearance via autophagy. Here, we examined the expression and association of NDP52 with autophagy-regulated gene (ATG) proteins including LC3, as well as phosphorylated tau and amyloid-beta (Aß) in brains of an AD mouse model. NDP52 was expressed not only in neurons, but also in microglia and astrocytes. NDP52 co-localized with ATGs and phosphorylated tau as expected since it functions as an autophagy receptor for phosphorylated tau in brain. Compared to wild-type mice, the number of autophagic vesicles (AVs) containing NDP52 in both cortex and hippocampal regions was significantly greater in AD model mice. Moreover, the protein levels of NDP52 and phosphorylated tau together with LC3-II were also significantly increased in AD model mice, reflecting autophagy impairment in the AD mouse model. By contrast, a significant change in p62/SQSTM1 level was not observed in this AD mouse model. NDP52 was also associated with intracellular Aß, but not with the extracellular Aß of amyloid plaques. We conclude that NDP52 is a key autophagy receptor for phosphorylated tau in brain. Further our data provide clear evidence for autophagy impairment in brains of AD mouse model, and thus strategies that result in enhancement of autophagic flux in AD are likely to be beneficial.
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Doença de Alzheimer/metabolismo , Encéfalo/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Proteínas Nucleares/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Proteínas tau/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Animais , Autofagia/fisiologia , Encéfalo/patologia , Modelos Animais de Doenças , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas Associadas aos Microtúbulos/metabolismo , Neuroglia/metabolismo , Neurônios/metabolismo , Fosforilação , Placa Amiloide/metabolismo , Placa Amiloide/patologia , Distribuição Tecidual , Proteínas tau/químicaRESUMO
MicroRNAs (miRNAs) have been implicated in various cellular processes, such as cell fate determination, cell death, and tumorigenesis. In the present study, we investigated the role of miRNA-34a (miR-34a) in the reorganization of the actin cytoskeleton, which is essential for chondrocyte differentiation. miRNA arrays to identify genes that appeared to be up-regulated or down-regulated during chondrogenesis were applied with chondrogenic progenitors treated with JNK inhibitor. PNA-based antisense oligonucleotides and miRNA precursor were used for investigation of the functional roles of miR-34a. We found that, in chick chondroprogenitors treated with JNK inhibitor, which suppresses chondrogenic differentiation, the expression levels of miR-34a and RhoA1 are up-regulated through modulation of Rac1 expression. Blockade of miR-34a via the use of PNA-based antisense oligonucleotides was associated with decreased protein expression of RhoA (a known modulator of stress fiber expression), down-regulation of stress fibers, up-regulation of Rac1, and recovery of protein level of type II collagen. miR-34a regulates RhoA/Rac1 cross-talk and negatively modulates reorganization of the actin cytoskeleton, which is one of the essential processes for establishing chondrocyte-specific morphology.
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Condrócitos/metabolismo , MicroRNAs/fisiologia , Receptor Cross-Talk , Proteínas rac1 de Ligação ao GTP/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo , Animais , Diferenciação Celular , Células Cultivadas , Embrião de Galinha , Condrogênese , Expressão Gênica , Regulação da Expressão Gênica , Proteínas Quinases JNK Ativadas por Mitógeno/antagonistas & inibidores , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Mesoderma/citologia , MicroRNAs/genética , MicroRNAs/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Fibras de Estresse/metabolismo , Proteína rhoA de Ligação ao GTP/genéticaRESUMO
Cell shape change and cytoskeletal reorganization are known to be involved in the chondrogenesis. Negative role of RhoA, a cytoskeleton-regulating protein, and its downstream target, Rho-associated protein kinase (ROCK) in the chondrogenesis has been studied in many different culture systems including primary chondrocytes, chondrogenic cell lines, dedifferentiated chondrocytes, and micromass culture of mesenchymal cells. To further investigate the role of RhoA and ROCK in the chondrogenesis, we examined the RhoA-ROCK-myosin light chains (MLC) pathway in low density culture of chick limb bud mesenchymal cells. We observed for the first time that inhibition of RhoA by C3 cell-permeable transferase, CT04, induced chondrogenesis of undifferentiated mesenchymal single cells following dissolution of actin stress fibers. Inhibition of RhoA activity by CT04 was confirmed by pull down assay using the Rho-GTP binding domain of Rhotekin. CT04 also inhibited ROCK activity. In contrast, inhibition of ROCK by Y27632 neither altered the actin stress fibers nor induced chondrogenesis. In addition, inhibition of RhoA or ROCK did not affect the phosphorylation of MLC. Inhibition of myosin light chain kinase (MLCK) by ML-7 or inhibition of myosin ATPase with blebbistatin dissolved actin stress fibers and induced chondrogenesis. ML-7 reduced the MLC phosphorylation. Taken together, our current study suggests that RhoA uses other pathway than ROCK/MLC in the modulation of actin stress fibers and chondrogenesis. Our data also imply that, irrespective of mechanisms, dissolution of actin stress fibers is crucial for chondrogenesis.
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Condrogênese , Mesoderma/enzimologia , Fibras de Estresse/fisiologia , Quinases Associadas a rho/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo , Animais , Forma Celular , Células Cultivadas , Embrião de Galinha , Extremidades/embriologia , Mesoderma/citologia , Cadeias Leves de Miosina/metabolismo , Fosforilação , Fibras de Estresse/enzimologia , Transferases/metabolismo , Quinases Associadas a rho/genética , Proteína rhoA de Ligação ao GTP/genéticaRESUMO
Numerous studies have reported conflicting results associated with cow's milk intake and coronary heart disease (CHD). However, studies involving postmenopausal women are very limited. This study was therefore undertaken to identify the relationship between cow's milk intake and CHD risk in postmenopausal women, using data from the 6th period of the Korea National Health and Nutrition Examination Survey (2013−2015). A total of 1825 postmenopausal women, aged 50−64 years old, were included in the final analysis. The frequency of cow's milk consumption for each subject was determined using the semi-quantitative food frequency questionnaire, and was classified into four groups (Q1−Q4): Q1, group that did not drink milk (no milk, n = 666); Q2, 0 < frequency of milk intake per week ≤ 1 (n = 453); Q3, 1 < frequency of milk intake per week ≤ 3 (n = 319); and Q4, frequency of milk intake >3 times per week (n = 387). General characteristics, such as education, living area, household income, and obesity level, were compared between the four groups. Percentages of daily nutrient intake compared to the dietary reference intake for Koreans (KDRIs) were determined, and the Framingham Risk Score (FRS), atherogenic index (AI), and atherogenic index of plasma (AIP) were determined as the CHD risk indicators. Except household income, no significant difference was obtained among the four groups with respect to age, education, living area, or obesity. Compared to KDRIs, the intake ratio of calcium, phosphorus, and riboflavin were significantly higher in the Q4 group than in the Q1−Q3 groups. Blood HDL-cholesterol was significantly higher in Q4 than in Q1. The CHD risk factors FRS (%), AI, and AIP were significantly lower in the Q4 group as compared to the other groups (CHD risk (%): Q1 9.4, Q4 8.5; AI: Q1 3.06, Q4 2.83; API: Q1 0.37, Q2 0.31, Q4 0.32). FRS was determined to be significantly and positively correlated to AI or AIP, and negatively correlated with the cow's milk intake frequency and calcium intake. In conclusion, compared to women who do not consume cow's milk, postmenopausal women who consume cow's milk frequently have a better nutritional status of calcium, phosphorus, and vitamin B12, higher HDL levels, and a lower level of CHD risk indicators, such as FRS, AI, and AIP, contributing to decreased CHD risk in a 10-year period. Therefore, to prevent the risk of CHD in postmenopausal women, there needs to be a greater emphasis for cow's milk consumption four or more times per week.
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Doença das Coronárias , Leite , Animais , Bovinos , Doença das Coronárias/epidemiologia , Doença das Coronárias/etiologia , Doença das Coronárias/prevenção & controle , Feminino , Leite/efeitos adversos , Inquéritos Nutricionais , Estado Nutricional , Pós-MenopausaRESUMO
BACKGROUND: Dry eye disease (DED) cannot be diagnosed by a single test because it is a multifactorial disorder of the ocular surface. Although studies on various dry eye tests (DETs) in dogs have been reported, standard criteria have not been established except for the Schirmer tear test 1 (STT-1). OBJECTIVES: To establish reference values for DETs in dogs with normal STT-1 values (≥ 15 mm/min) and to analyze the correlation between DETs. METHODS: The STT-1 was performed in 10 healthy Beagle dogs (20 eyes). After 20 min, interferometry (IF) for estimating the lipid layer thickness (LLT) of the tear film, tear meniscus height (TMH), non-invasive tear breakup time (NIBUT), and meibomian gland loss rate of the upper eyelid (MGLRU) and lower eyelid (MGLRL), were measured using an ocular surface analyzer. RESULTS: Mean values for STT-1, TMH, and NIBUT were as follows: 21.7 ± 3.4 mm/min, 0.41 ± 0.21 mm, and 19.1 ± 9.5 sec, respectively. The most frequent LLT range, measured by IF, was 30-80 nm (11 eyes), followed by 80 nm (5 eyes) and 80-140 nm (4 eyes). MGLRU ≤ 25% was measured in 11 eyes and 26%-50% in 9 eyes; MGLRL ≤ 25% in 8 eyes and 26%-50% in 12 eyes. Besides positive correlation between TMH and NIBUT (P = 0.038), there were no significant associations between DETs. CONCLUSIONS: Data obtained in this study provided normative references that could be useful for diagnosing DED and for further research into correlation between DETs in dogs with DED.
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Doenças do Cão , Síndromes do Olho Seco , Animais , Doenças do Cão/diagnóstico , Cães , Síndromes do Olho Seco/diagnóstico , Síndromes do Olho Seco/veterinária , Lipídeos , Glândulas Tarsais , Projetos Piloto , Valores de Referência , LágrimasRESUMO
Position-dependent chondrogenesis is regulated by processes that are both common to and differ among all limb types and limb skeletal elements. Despite intrinsic differences between wing and leg bud mesenchyme, the exact regulatory molecules and mechanisms involved in these processes have not been elucidated. Here, we show the limb type-specific role of TGF-ß3 during chondrogenic differentiation of chick limb mesenchymal cells. Exposure of wing cells to TGF-ß3 stimulated chondrogenic differentiation, whereas in leg bud mesenchymal cells, TGF-ß3 induced apoptotic cell death via G2M arrest. Consistent with a limb type-specific effect of TGF-ß3 on chondrogenic differentiation, we found different levels of miR-142-3p induction. Inhibition of miR-142-3p via PNA-based antisense oligonucleotides (ASOs) markedly promoted cell migration and precartilage condensation, while exogenous induction of miR-142-3p reduced cell survival and increased cell death. Overexpression of ADAM9 significantly reduced chondrogenic differentiation via downregulation of cell migration and cell survival and upregulation of apoptotic cell death. Limb type-specific expression levels of ADAM9 induced by TGF-ß3 were observed. Collectively, this study demonstrates that differential induction of miR-142-3p is involved in the limb type-specific effect of TGF-ß3 on wing vs. leg mesenchymal cells through direct modulation of ADAM9 transcription.
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Proteínas ADAM/genética , Diferenciação Celular , Condrogênese/genética , Regulação da Expressão Gênica no Desenvolvimento , Mesoderma/citologia , MicroRNAs/metabolismo , Animais , Células Cultivadas , Embrião de Galinha , Condrogênese/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Extremidade Inferior/embriologia , Mesoderma/efeitos dos fármacos , Mesoderma/enzimologia , MicroRNAs/genética , Fator de Crescimento Transformador beta3/farmacologia , Asas de Animais/embriologiaRESUMO
MicroRNAs function as an endogenous mode of fine gene regulation and have been implicated in multiple differentiation and developmental processes. In the present study, we investigated the role of miRNA-34 during chondrogenic differentiation of chick limb mesenchymal cells. We found that the expression of miR-34a increased upon chondrogenic inhibition. Blockade of miR-34a via PNA-based antisense oligonucleotides (ASOs) recovered the chondro-inhibitory actions of JNK inhibitor on migration of chondrogenic progenitors and the formation of precartilage condensation. Furthermore, we determined that EphA5 is a relevant target of miR-34a during chondrogenesis. MiR-34a was necessary and sufficient to down-regulate EphA5 expression, and up-modulation of EphA5 is sufficient to overcome inhibitory actions of miR-34 inhibition on cell migration and condensation of chick limb mesenchymal cells on collagen substrate. Taken together, our data suggest that miR-34a is a negative modulator of chondrogenesis, particularly in migration of chondroblasts, by targeting EphA5 and resulting inhibition of cellular condensation during chondrogenesis of chick limb mesenchymal cells.
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Movimento Celular , Condrócitos/fisiologia , Condrogênese , Interleucina-1beta/fisiologia , MicroRNAs/metabolismo , Receptor EphA5/metabolismo , Animais , Células Cultivadas , Galinhas , Condrócitos/efeitos dos fármacos , Condrócitos/metabolismo , Humanos , Interleucina-1beta/farmacologia , MAP Quinase Quinase 4/metabolismo , Mesoderma/citologia , RatosRESUMO
BACKGROUND: To assess the normal retina of the pigeon eye using spectral domain optical coherence tomography (SD-OCT) and establish a normative reference. METHODS: Twelve eyes of six ophthalmologically normal pigeons (Columba livia) were included. SD-OCT images were taken with dilated pupils under sedation. Four meridians, including the fovea, optic disc, red field, and yellow field, were obtained in each eye. The layers, including full thickness (FT), ganglion cell complex (GCC), thickness from the retinal pigmented epithelium to the outer nuclear layer (RPE-ONL), and from the retinal pigmented epithelium to the inner nuclear layer (RPE-INL), were manually measured. RESULTS: The average FT values were significantly different among the four meridians (p < 0.05), with the optic disc meridian being the thickest (294.0 ± 13.9 µm). The average GCC was thickest in the optic disc (105.3 ± 27.1 µm) and thinnest in the fovea meridian (42.8 ± 15.3 µm). The average RPE-INL of the fovea meridian (165.5 ± 18.3 µm) was significantly thicker than that of the other meridians (p < 0.05). The average RPE-ONL of the fovea, optic disc, yellow field, and red field were 91.2 ± 5.2 µm, 87.7 ± 5.3 µm, 87.6 ± 6.5 µm, and 91.4 ± 3.9 µm, respectively. RPE-INL and RPE-ONL thickness of the red field meridian did not change significantly with measurement location (p > 0.05). CONCLUSIONS: Measured data could be used as normative references for diagnosing pigeon retinopathies and further research on avian fundus structure.
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Columbidae/anatomia & histologia , Retina/anatomia & histologia , Tomografia de Coerência Óptica/veterinária , Animais , Columbidae/fisiologia , Valores de Referência , Retina/fisiologia , Epitélio Pigmentado da Retina/anatomia & histologia , Epitélio Pigmentado da Retina/fisiologiaRESUMO
This study aimed to investigate the effect of mydriasis using topical rocuronium bromide on electroretinography (ERG) in domestic pigeons (Columba livia). Scotopic mixed rod and cone, photopic cone, and photopic flicker ERG were performed on nine eyes of nine healthy adult pigeons under sedation. Each pigeon underwent two sets of ERG recordings. First, without the induction of mydriasis (control) and the second time with the induction of mydriasis using topical rocuronium bromide (treatment). The results were compared using either the Student's t-test or Wilcoxon rank-sum test, where a P-value of <0.05 was considered statistically significant. No significant differences were observed in the a- and b-wave implicit times and amplitudes during scotopic ERG between the two groups. The a- and b-wave amplitudes in the photopic cone were significantly higher in the treatment group (63.83 ± 32.33 and 191.75 ± 94.46 µV) compared to the control group (46.15 ± 27.60 and 116.76 ± 70.65 µV; P=0.045 and P=0.032, respectively). The photopic flicker amplitude was also significantly higher in the treatment group (76.23 ± 48.56 µV) than in the control group (42.18 ± 31.18 µV; P=0.044). No statistically significant differences were observed in the photopic cone and flicker implicit times between both groups. In conclusions, mydriasis induced by rocuronium bromide in pigeon resulting in higher amplitudes during the photopic ERG but not scotopic ERG.
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Eletrorretinografia , Midríase , Animais , Columbidae , Midríase/induzido quimicamente , Midríase/veterinária , RocurônioRESUMO
Animals digest food to fuel brain neurometabolism via cellular respiration. This study demonstrates the combination of a biofuel cell (BFC) and an animal brain stimulator (ABS) implanted in a pigeon. Glucose oxidation and oxygen reduction in an enzymatic BFC supplied electrical power to the ABS. Power from the BFC reached 0.12 mW in vitro and 0.08 mW in vivo using only the natural glucose and oxygen in the pigeon's body. A power management integrated circuit is used to harvest energy from the in vivo BFC at a rate of 28.4 mJ over 10 min, which is sufficient for intermittent neurostimulation.
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Fontes de Energia Bioelétrica , Técnicas Biossensoriais , Animais , Aves , Encéfalo , Comunicação , Eletrodos , Glucose , OxigênioRESUMO
A number of research attempts to understand and modulate sensory and motor skills that are beyond the capability of humans have been underway. They have mainly been expounded in rodent models, where numerous reports of controlling movement to reach target locations by brain stimulation have been achieved. However, in the case of birds, although basic research on movement control has been conducted, the brain nuclei that are triggering these movements have yet to be established. In order to fully control flight navigation in birds, the basic central nervous system involved in flight behavior should be understood comprehensively, and functional maps of the birds' brains to study the possibility of flight control need to be clarified. Here, we established a stable stereotactic surgery to implant multi-wire electrode arrays and electrically stimulated several nuclei of the pigeon's brain. A multi-channel electrode array and a wireless stimulation system were implanted in thirteen pigeons. The pigeons' flight trajectories on electrical stimulation of the cerebral nuclei were monitored and analyzed by a 3D motion tracking program to evaluate the behavioral change, and the exact stimulation site in the brain was confirmed by the postmortem histological examination. Among them, five pigeons were able to induce right and left body turns by stimulating the nuclei of the tractus occipito-mesencephalicus (OM), nucleus taeniae (TN), or nucleus rotundus (RT); the nuclei of tractus septo-mesencephalicus (TSM) or archistriatum ventrale (AV) were stimulated to induce flight aviation for flapping and take-off with five pigeons.
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An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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BACKGROUND: Animal learning based on brain stimulation is an application in a brain-computer interface. Especially for birds, such a stimulation system should be sufficiently light without interfering with movements of wings. OBJECTIVE: We proposed a fully-implantable system for wirelessly navigating a pigeon. In this paper, we report a handheld neural stimulation controller for this avian navigation guided by remote control. METHODS: The handheld controller employs ZigBee to control pigeon's behaviors through brain stimulation. ZigBee can manipulate brain stimulation remotely while powered by batteries. Additionally, simple switches enable users to customize parameters of stimuli like a gamepad. These handheld and user-friendly interfaces make it easy to use the controller while a pigeon flies in open areas. RESULTS: An electrode was inserted into a nucleus (formatio reticularis medialis mesencephalic) of a pigeon and connected to a stimulator fully-implanted in the pigeon's back. Receiving signals sent from the controller, the stimulator supplied biphasic pulses with a duration of 0.080 ms and an amplitude of 0.400 mA to the nucleus. When the nucleus was stimulated, a 180-degree turning-left behavior of the pigeon was consistently observed. CONCLUSIONS: The feasibility of remote avian navigation using the controller was successfully verified.