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1.
Reprod Domest Anim ; 57 Suppl 5: 4-13, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-35500162

RESUMO

The establishment of a successful pregnancy can only occur through a concerted functioning of the entire female reproductive system, allowing for fertilization, subsequent embryo development and implantation of the conceptus. In this context, the uterine immunological responses responsible for rejection or tolerance of the conceptus are of critical importance. The aim of the present review is to summarize our current knowledge about those cellular and molecular immunological events occurring at the uterine level during pre-implantation and implantation stages of pregnancy in the pig. Advancing our understanding of the immune mechanisms involved in the success or failure of pregnancy will provide cues to develop novel strategies augmenting endometrial receptivity, finally increasing the efficiency of assisted reproductive technologies in pigs.


Assuntos
Implantação do Embrião , Útero , Animais , Implantação do Embrião/fisiologia , Embrião de Mamíferos , Desenvolvimento Embrionário , Endométrio , Feminino , Gravidez , Suínos , Útero/fisiologia
2.
J Cardiothorac Vasc Anesth ; 35(5): 1371-1380, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-32888799

RESUMO

OBJECTIVE: To demonstrate that the analysis of the atrioventricular, intraventricular, and interventricular asynchrony by point-of-care ultrasound (POCUS) could be an alternative tool for assessing complex arrhythmias in pediatric patients with congenital heart diseases, mainly when an epicardial register or electrophysiology study is not available. DESIGN: Descriptive, retrospective case series study. SETTING: The pediatric intensive care unit of a university-affiliated tertiary hospital in Spain. PATIENTS: The authors included 12 patients with congenital heart disease younger than 18 years admitted to the authors' pediatric intensive care unit (PICU) from January 2018 to December 2019, with complex arrhythmias after surgery, managed by performing a bedside echocardiography when an electrophysiology test or epicardial auriculogram was unavailable. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The authors included a total of 14 complex arrhythmias in 12 postsurgical patients in whom a comprehensive transthoracic electrocardiogram was not conclusive. The presence of atrioventricular, intraventricular, or interventricular asynchrony was assessed in standard echo views by performing M-mode and Doppler mitral inflow analysis, checking the heart motion. The final POCUS diagnoses were atrial flutter (n = 5), postsurgical atrioventricular block (n = 4), asynchrony induced by pacemaker (n = 2), junctional ectopic tachycardia (n = 1), nodal rhythm plus ventricular extrasystole (n = 1), and supraventricular tachycardia (n = 1). In all patients, regardless of the type of arrhythmia, detecting motion asynchrony was crucial for making the correct diagnosis. Offline cardiologist analysis of the POCUS scans showed full agreement. CONCLUSIONS: POCUS is a useful tool for initial diagnosis and management of complex arrhythmias in the PICU, mainly when epicardial auriculogram or electrophysiology studies are unavailable.


Assuntos
Flutter Atrial , Sistemas Automatizados de Assistência Junto ao Leito , Criança , Ecocardiografia , Humanos , Unidades de Terapia Intensiva Pediátrica , Estudos Retrospectivos
3.
J Paediatr Child Health ; 56(3): 367-371, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31482635

RESUMO

AIM: The aim of this study is to determine the most useful diagnostic tools to differentiate appendicitis from non-specific abdominal pain (NSAP) in pre-school children. METHODS: We prospectively evaluated all children aged 5 years or younger admitted for suspected appendicitis at a paediatric emergency department during 5 years. Cases of NSAP and appendicitis were enrolled according to inclusion and exclusion criteria. The different variables collected were assessed by statistic and diagnostic accuracy studies. RESULTS: A total of 82 patients were studied: 27 cases of NSAP and 55 cases of appendicitis. We found no symptoms or signs with a high power of discrimination between both processes. Complicated cases of appendicitis begin to appear when the duration of symptoms exceeds 12 h. Among laboratory tests, C-reactive protein (CRP) value >34 mg/L was the variable with a greater association to appendicitis (odds ratio 9.8). Abdominal ultrasound (US) had high sensitivity and specificity to differentiate appendicitis, significantly improving its diagnostic accuracy when the duration of symptoms exceeds 12 h. CONCLUSIONS: A good history and physical examination are important in the diagnostic process, but reliable physical signs can be difficult to elicit in pre-school children. CRP and abdominal US are useful investigations that can improve diagnostic accuracy. According to our results, abdominal pain duration longer than 12 h or CRP value >34 mg/L should be an indication to perform an abdominal US in pre-school children with right lower quadrant tenderness.


Assuntos
Apendicite , Dor Abdominal/diagnóstico por imagem , Dor Abdominal/etiologia , Apendicite/diagnóstico por imagem , Proteína C-Reativa/análise , Criança , Pré-Escolar , Humanos , Estudos Prospectivos , Ultrassonografia
4.
J Neurosci ; 38(15): 3643-3656, 2018 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-29530988

RESUMO

The coupling of energy homeostasis to thermoregulation is essential to maintain homeothermy in changing external environments. We studied the role of the cold thermoreceptor TRPM8 in this interplay in mice of both sexes. We demonstrate that TRPM8 is required for a precise thermoregulation in response to cold, in fed and fasting. Trpm8-/- mice exhibited a fall of 0.7°C in core body temperature when housed at cold temperatures, and a deep hypothermia (<30°C) during food deprivation. In both situations, TRPM8 deficiency induced an increase in tail heat loss. This, together with the presence of TRPM8-sensory fibers innervating the main tail vessels, unveils a major role of this ion channel in tail vasomotor regulation. Finally, TRPM8 deficiency had a remarkable impact on energy balance. Trpm8-/- mice raised at mild cold temperatures developed late-onset obesity and metabolic dysfunction, with daytime hyperphagia and reduction of fat oxidation as plausible causal factors. In conclusion, TRPM8 fine-tunes eating behavior and fuel utilization during thermoregulatory adjustments to mild cold. Persistent imbalances in these responses result in obesity.SIGNIFICANCE STATEMENT The thermosensitive ion channel TRPM8 is required for a precise thermoregulatory response to cold and fasting, playing an important role in tail vasoconstriction, and therefore heat conservation, as well as in the regulation of ingestive behavior and metabolic fuel selection upon cooling. Indeed, TRPM8-deficient mice, housed in a mild cold environment, displayed an increase in tail heat loss and lower core body temperature, associated with the development of late-onset obesity with glucose and lipid metabolic dysfunction. A persistent diurnal hyperphagia and reduced fat oxidation constitute plausible underlying mechanisms in the background of a deficient thermoregulatory adjustment to mild cold ambient temperatures.


Assuntos
Regulação da Temperatura Corporal , Hiperfagia/genética , Obesidade/genética , Canais de Cátion TRPM/genética , Animais , Ingestão de Alimentos , Metabolismo Energético , Deleção de Genes , Hiperfagia/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Obesidade/metabolismo , Cauda/irrigação sanguínea
5.
J Org Chem ; 84(5): 2523-2541, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30701973

RESUMO

We took advantage of the chemoselective meso-functionalization of 2,3,5,6-tetrabromo-8-methylthioBODIPY 6 to prepare a series of 2,3,5,6-tetrabromo-8-arylBODIPY derivatives suitable for SNAr substitution reactions with phenols exclusively at positions 3 and 5. Pd(0)-catalyzed intramolecular arylation reaction ensued on the remaining brominated positions 2 and 6 to give a new family of benzofuran-fused BODIPY dyes. This method utilizes readily available starting materials and allows for the preparation of the title compounds with excellent functional group tolerance. Moreover, it was demonstrated that the methodology described herein is amenable for the incorporation of biomolecules. The photophysical and lasing properties of the benzofuran-fused BODIPY dyes were thoroughly analyzed with the aid of electrochemical measurements and quantum mechanical simulations. These dyes show bright and intriguing emission (both fluorescence and laser) toward the red edge of the visible spectrum with remarkable tolerance under strong and continuous irradiation.

6.
Reprod Domest Anim ; 54 Suppl 4: 4-13, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31625238

RESUMO

Commercial embryo transfer (ET) has unprecedented productive and economic implications for the pig sector. However, pig ET has been considered utopian for decades mainly because of the requirements of surgical techniques for embryo collection and embryo deposition into recipients, alongside challenges to preserve embryos. This situation has drastically changed in the last decade since the current technology allows non-surgical ET and short- and long-term embryo preservation. Here, we provide a brief review of the improvements in porcine ET achieved by our laboratory in the past 20 years. This review includes several aspects of non-surgical ET technology and different issues affecting ET programmes and embryo preservation systems. The future perspectives of ET technology are also considered. We will refer only to embryos produced in vivo since they are the only type of embryos with possible short-term use in pig production.


Assuntos
Transferência Embrionária/veterinária , Suínos/embriologia , Animais , Criopreservação/métodos , Criopreservação/veterinária , Técnicas de Cultura Embrionária/veterinária , Transferência Embrionária/métodos , Embrião de Mamíferos , Feminino
7.
Bioprocess Biosyst Eng ; 41(6): 859-869, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29536177

RESUMO

Acinetobacter species are identified as producing surface-active and emulsifying molecules known as bioemulsifiers. Production, characterization and stability of bioemulsifiers produced by Acinetobacter bouvetii UAM25 were studied. A. bouvetii UAM25 grew in three different carbon and energy sources: ethanol, a glycerol-hexadecane mixture and waste cooking oil in an airlift bioreactor, showing that bioemulsifier production was growth associated. The three purified bioemulsifiers were lipo-heteropolysaccharides of high molecular weight (4866 ± 533 and 462 ± 101 kDa). The best carbon source and energy for bioemulsifier production was wasted cooking oil, with a highest emulsifying capacity (76.2 ± 3.5 EU mg-1) as compared with ethanol (46.6 ± 7.1 EU mg-1) and the glycerol-hexadecane mixture (49.5 ± 4.2 EU mg-1). The three bioemulsifiers in our study displayed similar macromolecular structures, regardless of the nature (hydrophobic or hydrophilic) of the carbon and energy source. Bioemulsifiers did not decrease surface tension, but the emulsifying capacity of all of them was retained under extreme variation in salinity (0-50 g NaCl L-1), pH (3-10) and temperature (25-121 °C), indicative of remarkable stability. These findings contribute to understanding of the relationship between: production, physical properties, chemical composition and stability of bioemulsifiers for their potential applications in biotechnology, such as bioremediation of hydrocarbon-contaminated soil and water.


Assuntos
Acinetobacter/crescimento & desenvolvimento , Alcanos/farmacologia , Meios de Cultura/farmacologia , Emulsificantes/metabolismo , Etanol/farmacologia , Glicerol/farmacologia , Alcanos/química , Meios de Cultura/química , Etanol/química , Glicerol/química
8.
Phys Chem Chem Phys ; 19(21): 13746-13755, 2017 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-28503687

RESUMO

A modified Stöber method is used to synthesize spherical core-shell silica nanoparticles (NPs) with an external surface functionalized by amino groups and with an average size around 50 nm. Fluorescent dyes and photosensitizers of singlet oxygen were fixed, either separately or conjointly, respectively in the core or in the shell. Rhodamines were encapsulated in the core with relatively high fluorescence quantum yields (Φfl ≥ 0.3), allowing fluorescence tracking of the particles. Various photosensitizers of singlet oxygen (PS) were covalenty coupled to the shell, allowing singlet oxygen production. The stability of NP suspensions strongly deteriorated upon grafting the PS, affecting their apparent singlet oxygen quantum yields. Agglomeration of NPs depends both on the type and on the amount of grafted photosensitizer. New, lab-made, halogenated 4,4-difluoro-4-bora-3a,4a-diaza-s-indacenes (BODIPY) grafted to the NPs achieved higher singlet oxygen quantum yields (ΦΔ âˆ¼ 0.35-0.40) than Rose Bengal (RB) grafted NPs (ΦΔ âˆ¼ 0.10-0.27). Finally, we combined both fluorescence and PS functions in the same NP, namely a rhodamine in the silica core and a BODIPY or RB grafted in the shell, achieving the performance Φfl ∼ 0.10-0.20, ΦΔ âˆ¼ 0.16-0.25 with a single excitation wavelength. Thus, proper choice of the dyes, of their concentrations inside and on the NPs and the grafting method enables fine-tuning of singlet oxygen production and fluorescence emission.

9.
PLoS Comput Biol ; 11(11): e1004502, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26556807

RESUMO

Estimating the difficulty of a decision is a fundamental process to elaborate complex and adaptive behaviour. In this paper, we show that the movement time of behaving monkeys performing a decision-making task is correlated with decision difficulty and that the activity of a population of neurons in ventral Premotor cortex correlates with the movement time. Moreover, we found another population of neurons that encodes the discriminability of the stimulus, thereby supplying another source of information about the difficulty of the decision. The activity of neurons encoding the difficulty can be produced by very different computations. Therefore, we show that decision difficulty can be encoded through three different mechanisms: 1. Switch time coding, 2. rate coding and 3. binary coding. This rich representation reflects the basis of different functional aspects of difficulty in the making of a decision and the possible role of difficulty estimation in complex decision scenarios.


Assuntos
Biologia Computacional/métodos , Tomada de Decisões/fisiologia , Modelos Neurológicos , Córtex Motor/fisiologia , Desempenho Psicomotor/fisiologia , Algoritmos , Animais , Macaca mulatta , Masculino , Fatores de Tempo
10.
J Org Chem ; 80(11): 5771-82, 2015 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-25965325

RESUMO

Several new examples of meso-(het)arylBODIPY were prepared via the Liebeskind-Srogl (L-S) cross-coupling reaction of the Biellmann BODIPYs (1a,b) and aryl- and heteroarylboronic acids in good to excellent yield. It was shown that this reaction could be carried out under microwave heating to shorten reaction times and/or increase the yield. It was illustrated that organostannanes also participate in the L-S reaction to give the corresponding BODIPY analogues in short reaction times and also with good to excellent yields. We analyze the role of the substituent at the sensitive meso position in the photophysical signatures of these compounds. In particular, the rotational motion of the aryl ring and the electron donor ability of the anchored moieties rule the nonradiative pathways and, hence, have a deep impact in the fluorescence efficiency.

11.
Proc Natl Acad Sci U S A ; 109(48): 19828-33, 2012 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-23150557

RESUMO

No previous research has tuned the temporal characteristics of light-emitting devices to enhance brightness perception in human vision, despite the potential for significant power savings. The role of stimulus duration on perceived contrast is unclear, due to contradiction between the models proposed by Bloch and by Broca and Sulzer over 100 years ago. We propose that the discrepancy is accounted for by the observer's "inherent expertise bias," a type of experimental bias in which the observer's life-long experience with interpreting the sensory world overcomes perceptual ambiguities and biases experimental outcomes. By controlling for this and all other known biases, we show that perceived contrast peaks at durations of 50-100 ms, and we conclude that the Broca-Sulzer effect best describes human temporal vision. We also show that the plateau in perceived brightness with stimulus duration, described by Bloch's law, is a previously uncharacterized type of temporal brightness constancy that, like classical constancy effects, serves to enhance object recognition across varied lighting conditions in natural vision-although this is a constancy effect that normalizes perception across temporal modulation conditions. A practical outcome of this study is that tuning light-emitting devices to match the temporal dynamics of the human visual system's temporal response function will result in significant power savings.


Assuntos
Luz , Percepção Visual , Humanos , Variações Dependentes do Observador
12.
eNeuro ; 10(5)2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-37230769

RESUMO

Encoding and processing sensory information is key to understanding the environment and to guiding behavior accordingly. Characterizing the behavioral and neural correlates of these processes requires the experimenter to have a high degree of control over stimuli presentation. For auditory stimulation in animals with relatively large heads, this can be accomplished by using headphones. However, it has proven more challenging in smaller species, such as rats and mice, and has been only partially solved using closed-field speakers in anesthetized or head-restrained preparations. To overcome the limitations of such preparations and to deliver sound with high precision to freely moving animals, we have developed a set of miniature headphones for rats. The headphones consist of a small, skull-implantable base attached with magnets to a fully adjustable structure that holds the speakers and keeps them in the same position with respect to the ears.


Assuntos
Localização de Som , Som , Ratos , Animais , Camundongos , Estimulação Acústica/métodos , Localização de Som/fisiologia
13.
Animals (Basel) ; 13(9)2023 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-37174605

RESUMO

The combination of estrus synchronization and superovulation (SS) treatments causes alterations in ovarian and endometrial gene expression patterns, resulting in abnormal follicle and oocyte growth, fertilization, and embryo development. However, the impact of combined SS treatments on the transcriptome of the surviving embryos remains unidentified. In this study, we examined gene expression changes in day 6 blastocysts that survived a brief regimen of synchronization treatment combined with superovulation. The sows were included in one of three groups: SS7 group (n = 6), sows were administered Altrenogest (ALT) 7 days from the day of weaning and superovulated with eCG 24 h after the end of ALT treatment and hCG at the onset of estrus; SO group (n = 6), ALT nontreated sows were superovulated with eCG 24 h postweaning and hCG at the onset of estrus; control group (n = 6), weaned sows displaying natural estrus. Six days after insemination, the sows underwent a surgical intervention for embryo collection. Transcriptome analysis was performed on blastocyst-stage embryos with good morphology. Differentially expressed genes (DEGs) between groups were detected using one-way ANOVA with an un-adjusted p-value < 0.05 and a fold change 1.5. The effect of SO treatment on the number of altered pathways and DEGs within each pathway was minimal. Only four pathways were disrupted comprising only a total of four altered transcripts, which were not related to reproductive functions or embryonic development. On the other hand, the surviving blastocysts subjected to SS7 treatments exhibited moderate gene expression changes in terms of DEGs and fold changes, with seven pathways disrupted containing a total of 10 transcripts affected. In this case, the up-regulation of certain pathways, such as the metabolic pathway, with two up-regulated genes associated with reproductive functions, namely RDH10 and SPTLC2, may suggest suboptimal embryo quality, while the down-regulation of others, such as the glutathione metabolism pathway, with down-regulated genes related to cellular detoxification of reactive oxygen species, namely GSTK1 and GSTO1, could depress the embryos' response to oxidative stress, thereby impairing subsequent embryo development. The gene expression changes observed in the present study in SS7 embryos, along with previous reports indicating SS7 can negatively affect fertilization, embryo production, and reproductive tract gene expression, make its use in embryo transfer programs unrecommendable.

14.
ACS Omega ; 8(51): 48843-48854, 2023 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-38162790

RESUMO

Peptide synthesis has opened new frontiers in the quest for bioactive molecules with limitless biological applications. This study presents the synthesis of a series of novel isoquinoline dipeptides using advanced spectroscopic techniques for characterization. These compounds were designed with the goal of discovering unexplored biological activities that could contribute to the development of novel pharmaceuticals. We evaluated the biological activities of novel compounds including their antimicrobial, antibacterial, and antifungal properties. The results show promising activity against Escherichia coli and potent antibacterial activity against MTCC 443 and MTCC 1688. Furthermore, these compounds demonstrate strong antifungal activity, outperforming existing standard drugs. Computational binding affinity studies of tetrahydroisoquinoline-conjugated dipeptides against E. coli DNA gyrase displayed significant binding interactions and binding affinity, which are reflected in antimicrobial activities of compounds. Our integrative significant molecular findings from both wet and dry laboratories would help pave a path for the development of antimicrobial therapeutics. The findings suggest that these isoquinoline-conjugated dipeptides could be excellent candidates for drug development, with potential applications in the fight against bacterial and fungal infections. This research represents an exciting step forward in the field of peptide synthesis and its potential to discover novel bioactive molecules with significant implications for human health.

15.
Pediatr Radiol ; 42(10): 1197-204, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22875204

RESUMO

BACKGROUND: The ultimate goal in the management of paediatric ileocolic intussusception is to achieve non-operative reduction and therefore patient cure. The standard non-surgical treatment consists of enema (air or liquid media). OBJECTIVE: The purpose of this study is to present external manual reduction for paediatric ileocolic intussusception. We present a new manoeuvre that is standardised, simple, safe and effective for the radiologist in the non-surgical management of this pathology. MATERIALS AND METHODS: External manual reduction is performed under sedation. Execution of the manoeuvre is detailed and illustrated. The procedure was carried out 15 times in 13 paediatric patients with idiopathic ileocolic intussusception. RESULTS: Complete reduction exclusively by external manual reduction was accomplished on 12 occasions (80%). In the remaining three procedures, partial reduction to the cecum was obtained. Subsequent enema achieved complete reduction in two. Overall non-surgical reduction rate was 93%. CONCLUSION: External manual reduction is a radiation-free, safe and effective procedure. In case of incomplete reduction, it facilitates enema performance. External manual reduction incorporates and additional initial step in the non-surgical reduction of intussusception and should be considered a first-line procedure.


Assuntos
Doenças do Íleo/diagnóstico por imagem , Doenças do Íleo/terapia , Intussuscepção/diagnóstico por imagem , Intussuscepção/terapia , Massagem/métodos , Massagem/normas , Ultrassonografia de Intervenção/normas , Pré-Escolar , Humanos , Lactente , Masculino , Guias de Prática Clínica como Assunto , Espanha , Resultado do Tratamento
16.
Proc Natl Acad Sci U S A ; 106(44): 18815-9, 2009 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-19846763

RESUMO

Depending on the circumstances, decision making requires either comparing current sensory information with that showed recently or with that recovered from long-term memory (LTM). In both cases, to learn from past decisions and adapt future ones, memories and outcomes have to be available after the report of a decision. The ventral premotor cortex (PMv) is a good candidate for integrating memory traces and outcomes because it is involved in working-memory, decision-making, and encoding the outcomes. To test this hypothesis we recorded the extracellular unit activity while monkeys performed 2 variants of a visual discrimination task. In one task, the decision was based on the comparison of the orientation of a current stimulus with that of another stimulus recently shown. In the other task, the monkeys had to compare the current orientation of the stimulus with the correct one retrieved from LTM. Here, we report that when the task required retrieval of the stimulus and its use in the following trials, the neurons continue encoding this internal representation together with the outcomes after the monkey has emitted the motor response. However, this codification did not occur when the stimulus was shown recently and updated every trial. These results suggest that the PMv activity represents the information needed to evaluate the consequences of a decision. We interpret these results as evidence that the PMv plays a role in evaluating the outcomes that can serve to learn and thus adapt future decision to environmental demands.


Assuntos
Córtex Cerebral/fisiologia , Análise e Desempenho de Tarefas , Animais , Comportamento Animal , Tomada de Decisões , Discriminação Psicológica , Haplorrinos/fisiologia , Memória/fisiologia , Neurônios/fisiologia , Estimulação Física , Fatores de Tempo
17.
Span J Psychol ; 15(3): 881-90, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23156898

RESUMO

Despite the existence of numerous studies that examined the relationship between working memory capacity and performance in complex cognitive tasks, it remains unclear whether this capacity is domain specific or domain general. In addition, the available empirical evidence is somewhat contradictory. In this work we have studied the role of verbal working memory capacity in a non-verbal task--mental image rotation. If this capacity were domain specific it would be expected that high and low verbal span participants would obtain similar results in the mental rotation task. We have found that this is not the case as the high span participants performed better in terms of both speed and accuracy. Moreover, these differences depended on the processing component of the mental rotation task: the higher the processing requirements the higher the differences as a function of the working memory capacity. Therefore, the evidence presented here supports the domain general hypothesis.


Assuntos
Imaginação/fisiologia , Memória de Curto Prazo/fisiologia , Desempenho Psicomotor/fisiologia , Adolescente , Adulto , Humanos , Individualidade , Masculino , Memória de Curto Prazo/classificação , Testes Neuropsicológicos , Rotação , Percepção Espacial/fisiologia , Adulto Jovem
18.
Eur J Neurosci ; 33(12): 2338-48, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21554429

RESUMO

The relationship between neuronal activity and psychophysical judgments is central to understanding the brain mechanisms responsible for perceptual decisions. The ventral premotor cortex is known to be involved in representing different components of the decision-making process. In this cortical area, however, neither the neuronal ability to discriminate nor the trial-to-trial relationship between neuronal activity and behavior have been studied during visual decision-making. We recorded from single neurons while monkeys reported a decision based on the comparison of the orientation of two lines shown sequentially and separated by a delay. Analyses based on signal detection theory provided both the behavioral and neuronal sensitivities (d') and the coherence between behavioral and neuronal choices. To determine the temporal evolution of neuronal sensitivity and of coherence, the optimal size and position of the encoding windows were assessed. For a subset of neurons from the premotor ventral cortex, neuronal sensitivity was close to behavioral sensitivity and the trial-to-trial coherence between the neuronal and behavioral choices was close to 100%. By comparing these results with those obtained in a motor control task we ruled out the possibility of this activity being explained by the motor component of the task. These results suggest that activity in the ventral premotor cortex explains behavioral performance and predicts trial-to-trial subject choices.


Assuntos
Tomada de Decisões/fisiologia , Córtex Motor/fisiologia , Neurônios/fisiologia , Percepção Visual/fisiologia , Potenciais de Ação/fisiologia , Animais , Discriminação Psicológica/fisiologia , Movimentos Oculares/fisiologia , Macaca mulatta , Masculino , Orientação/fisiologia , Desempenho Psicomotor/fisiologia
19.
Stat Med ; 30(14): 1695-711, 2011 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-21433050

RESUMO

It is well established that neural activity is stochastically modulated over time. Therefore, direct comparisons across experimental conditions and determination of change points or maximum firing rates are not straightforward. This study sought to compare temporal firing probability curves that may vary across groups defined by different experimental conditions. Odds-ratio (OR) curves were used as a measure of comparison, and the main goal was to provide a global test to detect significant differences of such curves through the study of their derivatives. An algorithm is proposed that enables ORs based on generalized additive models, including factor-by-curve-type interactions to be flexibly estimated. Bootstrap methods were used to draw inferences from the derivatives curves, and binning techniques were applied to speed up computation in the estimation and testing processes. A simulation study was conducted to assess the validity of these bootstrap-based tests. This methodology was applied to study premotor ventral cortex neural activity associated with decision-making. The proposed statistical procedures proved very useful in revealing the neural activity correlates of decision-making in a visual discrimination task.


Assuntos
Potenciais de Ação/fisiologia , Encéfalo/fisiologia , Tomada de Decisões/fisiologia , Neurônios/fisiologia , Algoritmos , Animais , Bioestatística , Córtex Cerebral/fisiologia , Simulação por Computador , Interpretação Estatística de Dados , Discriminação Psicológica/fisiologia , Haplorrinos , Modelos Logísticos , Modelos Neurológicos , Razão de Chances , Estimulação Luminosa , Estatísticas não Paramétricas
20.
Front Syst Neurosci ; 15: 709337, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34566589

RESUMO

Currently, the role of hypothermia in electroencephalography (EEG) is well-established. However, few studies have investigated the effect of hyperthermia on EEG, an important physiological parameter governing brain function. The aim of this work was to determine how neuronal activity in anesthetized mice is affected when the temperature rises above the physiological threshold mandatory to maintain the normal body functions. In this study, a temperature-elevation protocol, from 37 to 42°C, was applied to four female mice of 2-3 months old while EEG was recorded simultaneously. We found that hyperthermia reduces EEG amplitude by 4.36% when rising from 37 to 38 degrees and by 24.33% when it is increased to 42 degrees. Likewise, increasing the body temperature produces a very large impact on the EEG spectral parameters, reducing the frequency power at the delta, theta, alpha, and beta bands. Our results show that hyperthermia has a global effect on the EEG, being able to change the electrical activity of the brain.

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