Effect of Acute Sodium Bicarbonate and Caffeine Coingestion on Repeated-Sprint Performance in Recreationally Trained Individuals: A Randomized Controlled Trial.

INTRODUCTION: The acute and isolated ingestion of sodium bicarbonate (NaHCO3) and caffeine (CAF) improves performance and delays fatigue in high-intensity tasks. However, it remains to be elucidated if the coingestion of both dietary supplements stimulates a summative ergogenic effect. This study aimed to examine the effect of the acute coingestion of NaHCO3 and CAF on repeated-sprint performance. METHODS: Twenty-five trained participants (age: 23.3 [4.0] y; sex [female/male]: 12/13; body mass: 69.6 [12.5] kg) participated in a randomized, double-blind, placebo (PLA) -controlled, crossover study. Participants were assigned to 4 conditions: (1) NaHCO3 + CAF, (2) NaHCO3, (3) CAF, or (4) PLA. Thus, they ingested 0.3 g/kg of NaHCO3, 3 mg/kg of CAF, or PLA. Then, participants performed 4 Wingate tests (Wt), consisting of a 30-second all-out sprint against an individualized resisted load, interspersed by a 1.5-minute rest period between sprints. RESULTS: Peak (Wpeak) and mean (Wmean) power output revealed a supplement and sprint interaction effect (P = .009 and P = .049, respectively). Compared with PLA, NaHCO3 + CAF and NaHCO3 increased Wpeak performance in Wt 3 (3%, P = .021) and Wt 4 (4.5%, P = .047), while NaHCO3 supplementation increased mean power performance in Wt 3 (4.2%, P = .001). In Wt 1, CAF increased Wpeak (3.2%, P = .054) and reduced time to Wpeak (-8.5%; P = .008). Plasma lactate showed a supplement plus sprint interaction (P < .001) when NaHCO3 was compared with CAF (13%, P = .031) and PLA (23%, P = .021). CONCLUSION: To summarize, although the isolated ingestion of CAF and NaHCO3 improved repeated-sprint performance, the coingestion of both supplements did not stimulate a synergic ergogenic effect.

Gold nanorods derivatized with CTAB and hydroquinone or ascorbic acid: spectroscopic investigation of anisotropic nanoparticles of different shapes and sizes.

Gold nanorods stabilized by binary ligand mixtures of cetyltrimethylammonium bromide (CTAB, primary ligand) and ascorbic acid or hydroquinone were investigated by complementary synchrotron radiation-induced spectroscopies and microscopies, with the aim to find evidence of the influence of the secondary ligand molecular and chemical structure on the nanorod shapes and size ratios. Indeed, as it is well known that the CTAB interaction with Ag(i) ions at the NR surface plays a key role in directing the anisotropic growth of nanorods, the possibility to finely control the NR shape and dimension by opportunely selecting the secondary ligands opens new perspectives in the design and synthesis of anisotropic nanoparticles.

An Affordable NIR Spectroscopic System for Fraud Detection in Olive Oil.

Adulterations of olive oil are performed by adding seed oils to this high-quality product, which are cheaper than olive oils. Food safety controls have been established by the European Union to avoid these episodes. Most of these methodologies require expensive equipment, time-consuming procedures, and expert personnel to execute. Near-infrared spectroscopy (NIRS) technology has many applications in the food processing industry. It analyzes food safety and quality parameters along the food chain. Using principal component analysis (PCA), the differences and similarities between olive oil and seed oils (sesame, sunflower, and flax oil) have been evaluated. To quantify the percentage of adulterated seed oil in olive oils, partial least squares (PLS) have been employed. A total of 96 samples of olive oil adulterated with seed oils were prepared. These samples were used to build a spectra library covering various mixtures containing seed oils and olive oil contents. Eighteen chemometric models were developed by combining the first and second derivatives with Standard Normal Variable (SNV) for scatter correction to classify and quantify seed oil adulteration and percentage. The results obtained for all seed oils show excellent coefficients of determination for calibration higher than 0.80. Because the instrumental aspects are not generally sufficiently addressed in the articles, we include a specific section on some key aspects of developing a high-performance and cost-effective NIR spectroscopy solution for fraud detection in olive oil. First, spectroscopy architectures are introduced, especially the Texas Instruments Digital Light Processing (DLP) technology for spectroscopy that has been used in this work. These results demonstrate that the portable prototype can be used as an effective tool to detect food fraud in liquid samples.

Beetroot juice ingestion does not improve neuromuscular performance and match-play demands in elite female hockey players: a randomized, double-blind, placebo-controlled study.

PURPOSE: Beetroot juice is a dietary supplement that contains high levels of inorganic nitrate (NO3-) and that its intake has proven effective at increasing blood nitric oxide (NO) concentrations improving endurance performance. However, the effect of this supplement in team sport performance, especially in female athletes, has been barely studied. This study aimed to compare the acute effects of beetroot juice supplementation on neuromuscular performance and match-play demands in elite female field hockey players. METHODS: Eleven elite female hockey players (22.8 ± 5.1 years) belonging to a bronze team medal in Eurohockey Club Champions Cup participated in this study. Participants were randomly divided into two groups undergoing a test battery with beetroot juice (70 mL, 6.4 mmol NO3-) or placebo (70 mL, 0.04 mmol NO3-) in two different days with one week between protocols. The neuromuscular test battery consisted of a countermovement jump, isometric handgrip strength (i.e., dominant hand), 20 m-sprint and repeated sprint ability test (RSA). Afterward, a simulated hockey match play (2 × 12.5 min) was performed and recorded by Global Positioning System (GPS). RESULTS: No statistically significant improvements were observed in any physical parameters analysed comparing beetroot juice compared to placebo ingestion, countermovement jump (p = 0.776, ES = 0.16), isometric handgrip strength (p = 0.829; ES = - 0.08), 20 m sprint test (p = 0.227; ES = - 0.23), mean repeated sprint ability (p = 0.955, ES = 0.03) and in any physical match demands measured by GPS (p = 0.243-1.000; ES = 0.02-0.47). CONCLUSION: Acute beetroot juice supplementation did not produce any statistically significant improvement in neuromuscular performance or match-play demands in elite female field hockey players. TRIAL REGISTRATION: The study was registered in ClinicalTrials.gov with the following ID: NCT05209139. The study was retrospectively registered by 26 January 2022.

Establishing and maintaining a remote vascular surgery aortic program: A single-center 5-year experience at the Veterans Affairs.

OBJECTIVE: We sought to detail the process of establishing a surgical aortic telehealth program and report the outcomes of a 5-year experience. METHODS: A telehealth program was established between two regional Veterans Affairs hospitals, one of which was without a comprehensive aortic surgical program, until such a program was established at the referring institution. A retrospective review was performed of all patients who underwent aortic surgery from 2014 to 2019. The operative data, demographics, perioperative complications, and follow-up data were reviewed. RESULTS: From 2014 to 2019, 109 patients underwent aortic surgery for occlusive and aneurysmal disease. Preoperative evaluation and postoperative follow-up were done remotely via telehealth. The median age of the patients was 68 years, 107 were men (98.2%), 28 (25.7%) underwent open aortic repair, and 81 (74.3%) underwent endovascular repair. Of the 109 patients, 101 (92.7%) had a median follow-up of 24.3 months, 5 (4.6%) were lost to follow-up or were noncompliant, 2 (1.8%) were noncompliant with their follow-up imaging studies but responded to telephone interviews, and 1 (0.9%) moved to another state. At the 30-day follow-up, eight patients (7.3%) required readmission. Four complications were managed locally, and four patients (3.6%) required transfer back to the operative hospital for additional care. CONCLUSIONS: Telehealth is a great tool to provide perioperative care and long-term follow-up for patients with aortic pathologies in remote locations. Most postoperative care and complications can be managed remotely, and patient compliance for long-term follow-up is high.

Acute Beetroot Juice Supplementation Does Not Improve Match-Play Activity in Professional Tennis Players.

ObjectiveBeetroot juice is a source of dietary nitrate (NO3-) recognized as a potential ergogenic aid to enhance tolerance during endurance exercise of submaximal-to-maximal intensity. However, little is known about the effects of beetroot juice on exercise performance in intermittent sports such as tennis. The present study aimed to determine the effect of acute beetroot juice supplementation on movement patterns during a competitive tennis match in professional players.MethodsIn a double-blind and randomized experiment, nine professional tennis players performed two experimental trials 3 h after ingesting either 70 mL of a commercially-available concentrated beetroot juice (6.4 mmol NO3-) or placebo (0.005 mmol NO3-). In each experimental trial, players completed a 3-set tennis match and two performance tests (i.e., serve speed and isometric handgrip strength) before and after the match. Match-play running performance was recorded using wearable GPS and accelerometer units.ResultsIn comparison to the placebo trial, the acute beetroot juice supplementation did not modify any match-play running performance (p = 0.178 to 0.997, d = 0.01 to 0.42). Furthermore, beetroot juice supplementation did not alter the pre-to-post match change in serve speed (p = 0.663, ηp2 = 0.03) or isometric handgrip strength (p = 0.219, ηp2 = 0.18).Conclusions: The current results indicated that acute ingestion of a commercialized shot of nitrate-rich beetroot juice (70 mL containing 6.4 mmol of NO3-) did not produce any performance benefit on tennis matchplay. Thus, acute beetroot juice supplementation seems an ergogenic aid with little value to enhance physical performance in professional tennis players.

Effects of Beetroot Juice Ingestion on Physical Performance in Highly Competitive Tennis Players.

Beetroot juice (BJ) contains high levels of inorganic nitrate (NO3-) and its intake has good evidence in increasing blood nitrate/nitrite concentrations. The ingestion of BJ has been associated with improvements in physical performance of endurance sports, however the literature in intermittent sports is scarce. The aim of this study was to investigate whether BJ could improve physical performance in tennis players. Thirteen well-trained tennis players (25.4 ± 5.1 years) participated in the study during their preparatory period for the tennis season. Subjects were randomly divided into two groups and performed a neuromuscular test battery after either BJ or placebo (PLA) consumption. Both trials were executed on two separate days, in randomized order, with one week of wash out period. The test battery consisted of serve velocity test (SVT), countermovement jump (CMJ), isometric handgrip strength (IHS), 5-0-5 agility test (5-0-5), and 10 m sprint (10-m). No significant differences were found in SVT (1.19%; p = 0.536), CMJ (0.96%; p = 0.327), IHS (4.06%; p = 0.069), 5-0-5 dominant and nondominant side (1.11-2.02%; p = 0.071-0.191) and 10-m (1.05%; p = 0.277) when comparing BJ and PLA ingestion. Thus, our data suggest that low doses of BJ (70 mL) consumption do not enhance tennis physical performance.

Caffeine Supplementation Improves Anaerobic Performance and Neuromuscular Efficiency and Fatigue in Olympic-Level Boxers.

BACKGROUND: this study examined the effects of caffeine supplementation on anaerobic performance, neuromuscular efficiency and upper and lower extremities fatigue in Olympic-level boxers. METHODS: Eight male athletes, members of the Spanish National Olympic Team, were enrolled in the study. In a randomized double-blind, placebo-controlled, counterbalanced, crossover design, the athletes completed 2 test sessions after the intake of caffeine (6 mg·kg-1) or placebo. Sessions involved initial measures of lactate, handgrip and countermovement jump (CMJ) performance, followed by a 30-seconds Wingate test, and then final measures of the previous variables. During the sessions, electromiography (EMG) data were recorded on the gluteus maximus, biceps femoris, vastus lateralis, gastrocnemius lateral head and tibialis anterior. RESULTS: caffeine enhanced peak power (6.27%, p < 0.01; Effect Size (ES) = 1.26), mean power (5.21%; p < 0.01; ES = 1.29) and reduced the time needed to reach peak power (-9.91%, p < 0.01; ES = 0.58) in the Wingate test, improved jump height in the CMJ (+2.4 cm, p < 0.01), and improved neuromuscular efficiency at peak power in the vastus lateralis (ES = 1.01) and gluteus maximus (ES = 0.89), and mean power in the vastus lateralis (ES = 0.95) and tibialis anterior (ES = 0.83). CONCLUSIONS: in these Olympic-level boxers, caffeine supplementation improved anaerobic performance without affecting EMG activity and fatigue levels in the lower limbs. Further benefits observed were enhanced neuromuscular efficiency in some muscles and improved reaction speed.

Enhancement of Exercise Performance by 48 Hours, and 15-Day Supplementation with Mangiferin and Luteolin in Men.

The natural polyphenols mangiferin and luteolin have free radical-scavenging properties, induce the antioxidant gene program and down-regulate the expression of superoxide-producing enzymes. However, the effects of these two polyphenols on exercise capacity remains mostly unknown. To determine whether a combination of luteolin (peanut husk extract containing 95% luteolin, PHE) and mangiferin (mango leave extract (MLE), Zynamite®) at low (PHE: 50 mg/day; and 140 mg/day of MLE containing 100 mg of mangiferin; L) and high doses (PHE: 100 mg/day; MLE: 420 mg/day; H) may enhance exercise performance, twelve physically active men performed incremental exercise to exhaustion, followed by sprint and endurance exercise after 48 h (acute effects) and 15 days of supplementation (prolonged effects) with polyphenols or placebo, following a double-blind crossover design. During sprint exercise, mangiferin + luteolin supplementation enhanced exercise performance, facilitated muscle oxygen extraction, and improved brain oxygenation, without increasing the VO2. Compared to placebo, mangiferin + luteolin increased muscle O2 extraction during post-exercise ischemia, and improved sprint performance after ischemia-reperfusion likely by increasing glycolytic energy production, as reflected by higher blood lactate concentrations after the sprints. Similar responses were elicited by the two doses tested. In conclusion, acute and prolonged supplementation with mangiferin combined with luteolin enhances performance, muscle O2 extraction, and brain oxygenation during sprint exercise, at high and low doses.

Protein synthesis signaling in skeletal muscle is refractory to whey protein ingestion during a severe energy deficit evoked by prolonged exercise and caloric restriction.

BACKGROUND: Exercise and protein ingestion preserve muscle mass during moderate energy deficits. OBJECTIVE: To determine the molecular mechanisms by which exercise and protein ingestion may spare muscle mass during severe energy deficit (5500 kcal/day). DESIGN: Fifteen overweight, but otherwise healthy men, underwent a pre-test (PRE), caloric restriction (3.2 kcals/kg body weight/day) + exercise (45 min one-arm cranking + 8 h walking) for 4 days (CRE), followed by a control diet (CD) for 3 days, with a caloric content similar to pre-intervention while exercise was reduced to less than 10,000 steps per day. During CRE, participants ingested either whey protein (PRO, n = 8) or sucrose (SU, n = 7) (0.8 g/kg body weight/day). Muscle biopsies were obtained from the trained and untrained deltoid, and vastus lateralis. RESULTS: Following CRE and CD, serum concentrations of leptin, insulin, and testosterone were reduced, whereas cortisol and the catabolic index (cortisol/total testosterone) increased. The Akt/mTor/p70S6K pathway and total eIF2α were unchanged, while total 4E-BP1 and Thr37/464E-BP1 were higher. After CRE, plasma BCAA and EAA were elevated, with a greater response in PRO group, and total GSK3ß, pSer9GSK3ß, pSer51eIF2α, and pSer51eIF2α/total eIF2α were reduced, with a greater response of pSer9GSK3ß in the PRO group. The changes in signaling were associated with the changes in leptin, insulin, amino acids, cortisol, cortisol/total testosterone, and lean mass. CONCLUSIONS: During severe energy deficit, pSer9GSK3ß levels are reduced and human skeletal muscle becomes refractory to the anabolic effects of whey protein ingestion, regardless of contractile activity. These effects are associated with the changes in lean mass and serum insulin, testosterone, and cortisol concentrations.

Effects of Beetroot Juice Supplementation on Performance and Fatigue in a 30-s All-Out Sprint Exercise: A Randomized, Double-Blind Cross-Over Study.

As a nitric oxide precursor, beetroot juice (BJ) is known to enhance high-intensity exercise performance (80⁻100% VO2max) yet its impacts on higher intensity sprint exercise (>100% VO2max) remain to be established. This study sought to examine the effects of BJ supplementation on performance and subsequent fatigue during an all-out sprint exercise. Using a randomized cross-over, double-blind, placebo-controlled design, 15 healthy resistance-trained men (22.4 ± 1.6 years) ingested 70 mL of either BJ or placebo. Three hours later, participants undertook a 30-s all-out Wingate test. Before and after the sprint exercise and at 30 s and 180 s post-exercise, three countermovement jumps (CMJ) were performed and blood lactate samples were obtained. Compared to placebo, BJ consumption improved peak (placebo vs. BJ, 848 ± 134 vs. 881 ± 135 W; p = 0.049) and mean (641 ± 91 vs. 666 ± 100 W; p = 0.023) power output and also reduced the time taken to reach Wpeak in the Wingate test (8.9 ± 1.4 vs. 7.3 ± 0.9 s; p = 0.003). No differences were detected in the fatigue index. In addition, while over time CMJ height and power diminished (ANOVA p < 0.001) and blood lactate levels increased (ANOVA p < 0.001), no supplementation effect was observed. Our findings indicate that while BJ supplementation improved performance at the 30-s cycling sprint, this improvement was not accompanied by differences in fatigue during or after this type of exercise.

Effects of an Acute Exercise Bout on Serum Hepcidin Levels.

Iron deficiency is a frequent and multifactorial disorder in the career of athletes, particularly in females. Exercise-induced disturbances in iron homeostasis produce deleterious effects on performance and adaptation to training; thus, the identification of strategies that restore or maintain iron homeostasis in athletes is required. Hepcidin is a liver-derived hormone that degrades the ferroportin transport channel, thus reducing the ability of macrophages to recycle damaged iron, and decreasing iron availability. Although it has been suggested that the circulating fraction of hepcidin increases during early post-exercise recovery (~3 h), it remains unknown how an acute exercise bout may modify the circulating expression of hepcidin. Therefore, the current review aims to determine the post-exercise expression of serum hepcidin in response to a single session of exercise. The review was carried out in the Dialnet, Elsevier, Medline, Pubmed, Scielo and SPORTDiscus databases, using hepcidin (and "exercise" or "sport" or "physical activity") as a strategy of search. A total of 19 articles were included in the review after the application of the inclusion/exclusion criteria. This search found that a single session of endurance exercise (intervallic or continuous) at moderate or vigorous intensity (60-90% VO2peak) stimulates an increase in the circulating levels of hepcidin between 0 h and 6 h after the end of the exercise bout, peaking at ~3 h post-exercise. The magnitude of the response of hepcidin to exercise seems to be dependent on the pre-exercise status of iron (ferritin) and inflammation (IL-6). Moreover, oxygen disturbances and the activation of a hypoxia-induced factor during or after exercise may stimulate a reduction of hepcidin expression. Meanwhile, cranberry flavonoids supplementation promotes an anti-oxidant effect that may facilitate the post-exercise expression of hepcidin. Further studies are required to explore the effect of resistance exercise on hepcidin expression.

First record and range extension of the Galapagos slipper lobster, Scyllarides astori (Decapoda, Scyllaridae) in the central Pacific coast of Mexico mainland.

The Galapagos slipper lobster Scyllarides astori was found for the first time off western Mexico mainland. A male and two female specimens were collected in south Jalisco and north Colima. This represents a new record from central Pacific coast of Mexico and a range extension of 700 km southwards, as the species was previously reported from the Gulf of California, 780 km eastwards from Revillagigedo Archipelago and 2400 km northwestwards from Isla del Coco and Galapagos Archipelago.

Dolor anal crónico idiopático. Evaluación de los resultados diagnóstico-terapéuticos en una unidad de referencia de coloproctología / Chronic idiopathic anal pain. Results of a diagnostic-therapeutic protocol in a colorectal referral unit

INTRODUCCIÓN: En la actualidad, el dolor anal crónico idiopático (DACI) sigue siendo un diagnóstico de exclusión, cuyo estudio y manejo permanece carente de un protocolo estandarizado. El objetivo del presente estudio es evaluar los resultados obtenidos con el protocolo diagnóstico-terapéutico establecido en nuestro servicio. MATERIAL Y MÉTODOS: Realizamos un estudio retrospectivo de los pacientes diagnosticados de DACI en la Unidad de Coloproctología del Hospital General Universitario de Elche entre 2005 y 2011. RESULTADOS: Se evaluó a 57 pacientes, remitidos con el diagnóstico de dolor anal crónico (DAC) por trastornos funcionales anorrectales (TFAR). Tras la aplicación del protocolo diagnóstico establecido, se llegó a un diagnóstico en 43 casos (75%), incluyendo 22 casos de síndrome del periné descendente, 12 de proctalgia fugax, 2 de neuritis pudenda, 7 de coccigodinia; en 14 casos se realizó un diagnóstico de exclusión de DACI.Entre las medidas terapéuticas empleadas en los pacientes con DACI, el biofeedback combinado con medidas conservadoras mejoró la sintomatología en el 43% de los casos, valorándose la neuroestimulación de raíces sacras en pacientes resistentes a otros tratamientos. CONCLUSIÓN: Mediante una protocolizada anamnesis, exploración física y con ayuda de pruebas complementarias pudo especificarse el diagnóstico de DAC por TFAR, reduciéndose el diagnóstico de exclusión de DACI al 25% de los casos. Las medidas conservadoras junto con el biofeedback consiguieron una mejoría de los síntomas en más del 40% de los casos de DACI. En el resto de pacientes debe valorarse de forma individualizada la neuroestimulación de raíces sacras

INTRODUCTION: Chronic idiopathic anal pain (CIAP) remains a diagnosis of exclusion. Its study and management still lack a standardized protocol. The aim of this study is to evaluate the results obtained with the diagnostic-therapeutic protocol established in our service. MATERIAL AND METHODS: We performed a retrospective study of patients diagnosed with CIAP at the Colorectal Unit of the General University Hospital of Elche, between 2005 and 2011.ResultsWe evaluated 57 patients with a diagnosis of chronic anal pain for functional anorectal disease (FAD). After the application of our diagnostic protocol, final diagnosis of chronic anal pain (CAP) was achieved in 43 cases (75%), including 22 cases of descending perineum syndrome, 12 of proctalgia fugax, 2 of pudendal neuritis and 7 of coccydynia. In 14 patients exclusion diagnosis of CIAP was established. Among the therapies used on patients with CIAP, biofeedback combined with conservative measures improved symptoms in 43% of the cases. Sacral nerve stimulation was assessed in patients who did not respond to other treatments. CONCLUSION: Through proper anamnesis, physical examination and complementary tests, a specific diagnosis of the cause of CAP by FAD can be achieved, reducing exclusion diagnosis of CIAP to 25% of cases. Conservative measures combined with biofeedback achieved an improvement in pain in more than 40% of the cases of CIAP in our study. Sacral nerve stimulation can be considered as a treatment option in refractory cases

Percutaneous posterior tibial nerve stimulation (PPTNS) in faecal incontinence associated with an anal sphincter lesion: results of a prospective study.

PURPOSE: Establish the efficacy of posterior tibial nerve stimulation in treating faecal incontinence associated to sphincter defect. METHODS: Prospective study that included patients with faecal incontinence associated to sphincter lesions between 90 and 180°. Clinical anamnesis, physical examination, reverse visual analogic scale, incontinence diary and Wexner score were recorded at baseline and 6 months. Anal manometry was realized at baseline and 6 months. Subjects underwent one 30-min session every week for 12 consecutive weeks and was continued with 6 additional sessions every 2 weeks. RESULTS: Sixteen patients were analysed, 15 women and 1 men, with a mean age of 56.5 years. The incontinence were obstetric origin (50%) and perineal surgeries (50%). Four patients who did not continue with the second stage. Referring to the retention time, at baseline 12 patients (75%) did not bear even 1 min. At 6 months the retention time was <1 min in only 2 patients (p = 0.008). Median Wexner baseline values were 10; at 6 months decrease to 5 (p = 0.006). The visual analogical scale (VAS) increased from 6 to 7.5 (p > 0.05). After 6 months, maximum resting pressure increased from 40.9 to 51 mmHg (p < 0.001) and maximum squeeze pressure from 82.5 to 94 mmHg (p < 0.001). CONCLUSION: PTNS is an effective treatment for faecal incontinence associated to sphincter lesions because the number of incontinence episodes per week, the Wexner Score, the ability to defer defaecation and the manometric determinations improved significantly.

Sócrates: útil en la práctica médica / Socrates: useful in medical practice

Sócrates fue un filósofo griego famoso por su facilidad de palabra y su sabiduría. Creador de la mayéutica, método mediante el que estimulaba a sus alumnos para la resolución de problemas mediante la formulación de hábiles preguntas, su influencia en la aplicación actual del método clínico es indiscutible(AU)

Dynamic changes in single unit activity and γ oscillations in a thalamocortical circuit during rapid instrumental learning.

The medial prefrontal cortex (mPFC) and mediodorsal thalamus (MD) together form a thalamocortical circuit that has been implicated in the learning and production of goal-directed actions. In this study we measured neural activity in both regions simultaneously, as rats learned to press a lever to earn food rewards. In both MD and mPFC, instrumental learning was accompanied by dramatic changes in the firing patterns of the neurons, in particular the rapid emergence of single-unit neural activity reflecting the completion of the action and reward delivery. In addition, we observed distinct patterns of changes in the oscillatory LFP response in MD and mPFC. With learning, there was a significant increase in theta band oscillations (6-10 Hz) in the MD, but not in the mPFC. By contrast, gamma band oscillations (40-55 Hz) increased in the mPFC, but not in the MD. Coherence between these two regions also changed with learning: gamma coherence in relation to reward delivery increased, whereas theta coherence did not. Together these results suggest that, as rats learned the instrumental contingency between action and outcome, the emergence of task related neural activity is accompanied by enhanced functional interaction between MD and mPFC in response to the reward feedback.

Síndrome da fase atrasada do sono: efeitos dos usos isolados e combinados de melatonina e de fototerapia / Sleep delayed phase syndrome: the effects of melatonin and bright light alone, or in combination

OBJETIVO: Avaliar, por meio de um estudo duplo cego e aleatório, os efeitos do uso isolado e do uso combinado de melatonina (3 mg) e de fototerapia (10.000 lux) no horário de início do sono, na variação do horário de início da secreção do hormônio melatonina e na fase do valor mínimo da temperatura corporal central em voluntários com o diagnóstico de síndrome da fase atrasada do sono. MÉTODOS: Vinte voluntários foram submetidos ao uso do actígrafo e preencheram o diário de sono, antes e durante os tratamentos, e à coleta de melatonina plasmática e de temperatura retal durante 24 horas, antes e após os tratamentos. Os tratamentos consistiram no uso de fototerapia pela manhã e placebo à noite, de placebo de fototerapia pela manhã e melatonina à noite e fototerapia pela manhã e melatonina à noite durante 4 semanas. RESULTADOS: Houve o avanço no horário do início do sono nos voluntários que usaram fototerapia pela manhã e placebo à noite (n=7) e nos que usaram placebo de fototerapia e melatonina à noite (n=6), entre a semana do pré-tratamento e a semana 4 do tratamento, mas não naqueles que utilizaram a fototerapia pela manhã e ingeriram melatonina à noite. Não houve diferenças estatisticamente significativas entre os três tratamentos. Não houve alteração nos horários de início de secreção da melatonina e do nadir. CONCLUSÕES: Os tratamentos com o uso isolado de fototerapia e de melatonina avançaram o horário de início do sono, o que não ocorreu com a associação de ambos