Developmental light deprivation transiently reduces the expression of vGluT2 and GluN2B in the rat ventral suprachiasmatic nucleus.

The suprachiasmatic nucleus (SCN) is the most important circadian clock in mammals. The SCN synchronizes to environmental light via the retinohypothalamic tract (RHT), which is an axon cluster derived from melanopsin-expressing intrinsic photosensitive retinal ganglion cells. Investigations on the development of the nonimage-forming pathway and the RHT are scarce. Previous studies imply that light stimulation during postnatal development is not needed to make the RHT functional at adult stages. Here, we examined the effects of light deprivation (i.e., constant darkness (DD) rearing) during postnatal development on the expression in the ventral SCN of two crucial proteins for the synchronization of circadian rhythms to light: the presynaptic vesicular glutamate transporter type 2 (vGluT2) and the GluN2B subunit of the postsynaptic NMDA receptor. We found that animals submitted to DD conditions exhibited a transitory reduction in the expression of vGluT2 (at P12-19) and of GluN2B (at P7-9) that was compensated at older stages. These findings support the hypothesis that visual stimulation during early ages is not decisive for normal development of the RHT-SCN pathway.

Design and Fabrication of Embroidered Textile Strain Sensors: An Alternative to Stitch-Based Strain Sensors.

Smart textile sensors have been gaining popularity as alternative methods for the continuous monitoring of human motion. Multiple methods of fabrication for these textile sensors have been proposed, but the simpler ones include stitching or embroidering the conductive thread onto an elastic fabric to create a strain sensor. Although multiple studies have demonstrated the efficacy of textile sensors using the stitching technique, there is almost little to no information regarding the fabrication of textile strain sensors using the embroidery method. In this paper, a design guide for the fabrication of an embroidered resistive textile strain sensor is presented. All of the required design steps are explained, as well as the different embroidery design parameters and their optimal values. Finally, three embroidered textile strain sensors were created using these design steps. These sensors are based on the principle of superposition and were fabricated using a stainless-steel conductive thread embroidered onto a polyester-rubber elastic knit structure. The three sensors demonstrated an average gauge factor of 1.88±0.51 over a 26% working range, low hysteresis (8.54±2.66%), and good repeatability after being pre-stretched over a certain number of stretching cycles.

Malnutrition management of hospitalized patients with diabetes/hyperglycemia and COVID-19 infection.

Diabetes mellitus and/or hyperglycemia are highly prevalent medical conditions in patients hospitalized for coronavirus disease 2019 (COVID-19) and are associated with adverse outcomes. In addition, COVID-19 itself can provoke fluctuating and high glucose levels that can be difficult to manage upon hospitalization. Hospitalized patients with COVID-19 are at high risk of malnutrition due to an increase in nutritional requirements and a severe acute inflammatory response. The management of patients with diabetes/hyperglycemia and COVID-19 is challenging and requires a specific nutritional approach, the purpose of which is to fulfill the nutritional requirements while maintaining an optimal glycemic control. In this study, an expert group of nutritional endocrinologists carried out a qualitative literature review and provided recommendations based on evidence and guidelines, when available, or on their own experience. The optimal care based on these recommendations was compared with the routine bedside care as reported by a panel of physicians (mainly, endocrinologists, geriatricians, and internists) treating patients with diabetes/hyperglycemia and COVID-19 in their daily practice. Early screening and diagnosis, a diabetes-specific therapeutic approach, and a close malnutrition monitoring are essential to improve the clinical outcomes of these patients. In conclusion, the proposed recommendations are intended to provide a useful guide on the clinical management of malnutrition in patients with COVID-19 and diabetes/hyperglycemia, in order to improve their outcomes and accelerate their recovery. The comparison of the recommended optimal care with routine clinical practice could aid to identify gaps in knowledge, implementation difficulties, and areas for improvement in the management of malnutrition in this population.

Using an on-site laboratory for fecal steroid analysis in wild white-faced capuchins.

Hormone laboratories located "on-site" where field studies are being conducted have a number of advantages. On-site laboratories allow hormone analyses to proceed in near-real-time, minimize logistics of sample permits/shipping, contribute to in-country capacity-building, and (our focus here) facilitate cross-site collaboration through shared methods and a shared laboratory. Here we provide proof-of-concept that an on-site hormone laboratory (the Taboga Field Laboratory, located in the Taboga Forest Reserve, Costa Rica) can successfully run endocrine analyses in a remote location. Using fecal samples from wild white-faced capuchins (Cebus imitator) from three Costa Rican forests, we validate the extraction and analysis of four steroid hormones (glucocorticoids, testosterone, estradiol, progesterone) across six assays (DetectX® and ISWE, all from Arbor Assays). Additionally, as the first collaboration across three long-term, wild capuchin field sites (Lomas Barbudal, Santa Rosa, Taboga) involving local Costa Rican collaborators, this laboratory can serve as a future hub for collaborative exchange.

User-Independent Hand Gesture Recognition Classification Models Using Sensor Fusion.

Recently, it has been proven that targeting motor impairments as early as possible while using wearable mechatronic devices for assisted therapy can improve rehabilitation outcomes. However, despite the advanced progress on control methods for wearable mechatronic devices, the need for a more natural interface that allows for better control remains. To address this issue, electromyography (EMG)-based gesture recognition systems have been studied as a potential solution for human-machine interface applications. Recent studies have focused on developing user-independent gesture recognition interfaces to reduce calibration times for new users. Unfortunately, given the stochastic nature of EMG signals, the performance of these interfaces is negatively impacted. To address this issue, this work presents a user-independent gesture classification method based on a sensor fusion technique that combines EMG data and inertial measurement unit (IMU) data. The Myo Armband was used to measure muscle activity and motion data from healthy subjects. Participants were asked to perform seven types of gestures in four different arm positions while using the Myo on their dominant limb. Data obtained from 22 participants were used to classify the gestures using three different classification methods. Overall, average classification accuracies in the range of 67.5-84.6% were obtained, with the Adaptive Least-Squares Support Vector Machine model obtaining accuracies as high as 92.9%. These results suggest that by using the proposed sensor fusion approach, it is possible to achieve a more natural interface that allows better control of wearable mechatronic devices during robot assisted therapies.

Light stimulation during postnatal development is not determinant for glutamatergic neurotransmission from the retinohypothalamic tract to the suprachiasmatic nucleus in rats.

The hypothalamic suprachiasmatic nucleus (SCN) is the leading circadian pacemaker in mammals, which synchronizes with environmental light through the retinohypothalamic tract (RHT). Although the SCN regulates circadian rhythms before birth, postnatal synaptic changes are needed for the RHT-SCN pathway to achieve total functional development. However, it is unknown whether visual experience affects developmental maturation. Here, we studied the effects of constant darkness (DD) rearing on the physiology (at pre- and postsynaptic levels) of glutamatergic neurotransmission between RHT and SCN during postnatal development in rats. Upon recording spontaneous and evoked excitatory postsynaptic currents (EPSCs) by electrical stimulation of RHT fibers, we found that DD animals at early postnatal ages (P3-19) exhibited different frequencies of spontaneous EPSCs and lower synaptic performance (short-term depression, release sites, and recruitment of RHT fibers) when compared with their normal light/dark (LD) counterparts. At the oldest age evaluated (P30-35), there was a synaptic response strengthening (probability of release, vesicular re-filling rate, and reduced synaptic depression) in DD rats, which functionally equaled (or surmounted) that of LD animals. Control experiments evaluating EPSCs in ventral SCN neurons of LD rats during day and night revealed no significant differences in spontaneous or evoked EPSCs by high-frequency trains in the RHT at any postnatal age. Our results suggest that DD conditions induce a compensatory mechanism in the glutamatergic signaling of the circadian system to increase the chances of synchronization to light at adult ages, and that the synaptic properties of RHT terminals during postnatal development are not critically influenced by environmental light.

Combination of a Probiotic and an Antispasmodic Increases Quality of Life and Reduces Symptoms in Patients with Irritable Bowel Syndrome: A Pilot Study.

BACKGROUND: Probiotics and antispasmodics have been tested extensively in the management of symptoms of irritable bowel syndrome (IBS), but they have rarely been evaluated in combination. The objective of this pilot study was to assess the efficacy of treatment with the probiotic formulation i3.1 (Lactobacillus plantarum CECT7484 and CECT7485 and Pediococcus acidilactici CECT7483), with or without the addition of the antispasmodic alverine/simethicone, in improving IBS-related quality of life (QoL) and reducing abdominal pain and diarrhea in patients with IBS. METHODS: This was a randomized, placebo-controlled clinical trial with 3 parallel arms (probiotic, probiotic plus antispasmodic, and placebo). Patients with IBS (N = 55) were recruited at the Gastroenterology Department of the Juárez Hospital (México City). QoL was assessed with the IBS-QoL questionnaire, abdominal pain with a visual analog scale, and stool consistency with the Bristol scale. RESULTS: The IBS-QoL rate of response (ITT analysis) was 50.0% for patients in the group with probiotic alone, 68.4% in the group with probiotic plus antispasmodic, and 16.7% in the group with placebo after 6 weeks of treatment (p = 0.005). Response to abdominal pain was reported by 38.9% of patients treated with probiotic, 57.9% with probiotic plus antispasmodic, and 16.7% with placebo (p = 0.035). Regarding stool consistency, a response to treatment was reported by 44.4% of patients treated with probiotic, 57.9% with probiotic plus antispasmodic, and 16.7% with placebo (p = 0.032). CONCLUSION: The results are consistent with previous studies on the use of the i3.1 probiotic formulation for the management of symptoms in IBS patients, and the addition of an antispasmodic improves its observed effects.

The Eya1 Phosphatase Mediates Shh-Driven Symmetric Cell Division of Cerebellar Granule Cell Precursors.

During neural development, stem and precursor cells can divide either symmetrically or asymmetrically. The transition between symmetric and asymmetric cell divisions is a major determinant of precursor cell expansion and neural differentiation, but the underlying mechanisms that regulate this transition are not well understood. Here, we identify the Sonic hedgehog (Shh) pathway as a critical determinant regulating the mode of division of cerebellar granule cell precursors (GCPs). Using partial gain and loss of function mutations within the Shh pathway, we show that pathway activation determines spindle orientation of GCPs, and that mitotic spindle orientation correlates with the mode of division. Mechanistically, we show that the phosphatase Eya1 is essential for implementing Shh-dependent GCP spindle orientation. We identify atypical protein kinase C (aPKC) as a direct target of Eya1 activity and show that Eya1 dephosphorylates a critical threonine (T410) in the activation loop. Thus, Eya1 inactivates aPKC, resulting in reduced phosphorylation of Numb and other components that regulate the mode of division. This Eya1-dependent cascade is critical in linking spindle orientation, cell cycle exit and terminal differentiation. Together these findings demonstrate that a Shh-Eya1 regulatory axis selectively promotes symmetric cell divisions during cerebellar development by coordinating spindle orientation and cell fate determinants.

Song structure and singing activity of two separate humpback whales populations wintering off the coast of Caño Island in Costa Rica.

Central American (CA) and Breeding Stock-G (BSG) humpback whales are known to winter off Caño Island, Costa Rica at different times of the year. To study their singing behavior, autonomous underwater recorders were used to record the whales. Song detection for BSG whales was higher than CA whales, and song structure was distinct for each population. No strong evidence for cross-equatorial connectivity was found. This study provides the first humpback whale song reference for both populations in Costa Rica, which can help advance understanding of CA and BSG whale song rate of change and connectivity with other wintering areas.

An automated Y-maze based on a reduced instruction set computer (RISC) microcontroller for the assessment of continuous spontaneous alternation in rats.

Continuous spontaneous alternation behavior (SAB) in a Y-maze is used for evaluating working memory in rodents. Here, the design of an automated Y-maze equipped with three infrared optocouplers per arm, and commanded by a reduced instruction set computer (RISC) microcontroller is described. The software was devised for recording only true entries and exits to the arms. Experimental settings are programmed via a keyboard with three buttons and a display. The sequence of arm entries and the time spent in each arm and the neutral zone (NZ) are saved as a text file in a non-volatile memory for later transfer to a USB flash memory. Data files are analyzed with a program developed under LabVIEW® environment, and the results are exported to an Excel® spreadsheet file. Variables measured are: latency to exit the starting arm, sequence and number of arm entries, number of alternations, alternation percentage, and cumulative times spent in each arm and NZ. The automated Y-maze accurately detected the SAB decrease produced in rats by the muscarinic antagonist trihexyphenidyl, and its reversal by caffeine, having 100 % concordance with the alternation percentages calculated by two trained observers who independently watched videos of the same experiments. Although the values of time spent in the arms and NZ measured by the automated system had small discrepancies with those calculated by the observers, Bland-Altman analysis showed 95 % concordance in three pairs of comparisons, while in one it was 90 %, indicating that this system is a reliable and inexpensive alternative for the study of continuous SAB in rodents.

Neurotensin-polyplex-mediated brain-derived neurotrophic factor gene delivery into nigral dopamine neurons prevents nigrostriatal degeneration in a rat model of early Parkinson's disease.

BACKGROUND: The neurotrophin Brain-Derived Neurotrophic Factor (BDNF) influences nigral dopaminergic neurons via autocrine and paracrine mechanisms. The reduction of BDNF expression in Parkinson's disease substantia nigra (SN) might contribute to the death of dopaminergic neurons because inhibiting BDNF expression in the SN causes parkinsonism in the rat. This study aimed to demonstrate that increasing BDNF expression in dopaminergic neurons of rats with one week of 6-hydroxydopamine lesion recovers from parkinsonism. The plasmids phDAT-BDNF-flag and phDAT-EGFP, coding for enhanced green fluorescent protein, were transfected using neurotensin (NTS)-polyplex, which enables delivery of genes into the dopaminergic neurons via neurotensin-receptor type 1 (NTSR1) internalization. RESULTS: Two weeks after transfections, RT-PCR and immunofluorescence techniques showed that the residual dopaminergic neurons retain NTSR1 expression and susceptibility to be transfected by the NTS-polyplex. phDAT-BDNF-flag transfection did not increase dopaminergic neurons, but caused 7-fold increase in dopamine fibers within the SN and 5-fold increase in innervation and dopamine levels in the striatum. These neurotrophic effects were accompanied by a significant improvement in motor behavior. CONCLUSIONS: NTS-polyplex-mediated BDNF overexpression in dopaminergic neurons has proven to be effective to remit hemiparkinsonism in the rat. This BDNF gene therapy might be helpful in the early stage of Parkinson's disease.

Papillary Tumor of the Pineal Gland: Series of Four Clinical Cases.

The papillary tumor of the pineal region (PTPR) is a rare neuroepithelial tumor originating from specialized ependymocytes. It primarily affects structures within the pineal region, including the pineal gland, epithalamus, quadrigeminal cistern, and posterior wall of the third ventricle. Here, we present a series of four cases characterized by symptoms associated with obstructive hydrocephalus such as headaches, seizures, visual disturbances, gait disturbances, and Parinaud syndrome. Imaging studies revealed lesions in the pineal region, prompting surgical intervention. Histopathological examination, including biopsy and intraoperative analysis, confirmed the diagnosis of PTPR. Despite advancements, the etiology and pathogenesis of PTPR remain incompletely understood, warranting further research to refine management strategies.

Effects of a mindfulness-based program on the occupational balance and mental health of university students. Protocol for a randomized controlled trial.

OBJECTIVE: The aim is to examine whether the addition of Virtual Reality (VR) meditation training to a standard 8-week Mindfulness-Based Health Care Program (MBHC-VR) results in a significantly increased improvement in occupational, mental health, and psychological functioning versus MBHC-only in university students. MATERIALS AND METHODS: A randomized controlled clinical trial with three arms (MBHC, MBHC-VR, Control Group), four assessment time points (pre-intervention, inter-session, post-intervention, and 3-month follow-up), and mixed methodology will be proposed. University students (undergraduate, master, or doctoral) interested in participating and who meet the inclusion/exclusion criteria will be included over two years. Data will be collected from different ad hoc questionnaires, several standardized tests, and an Ecological Momentary Assessment. We will use R software to carry out descriptive analyses (univariate and bivariate), multilevel modeling, and structural equation models to respond to the proposed objective. The qualitative analysis will be carried out using the MAXQDA program and the technique of focus groups. DISCUSSION: It is expected that with the proposed intervention university students will learn to relate in a healthier way with their mental processes, so as to improve their occupational balance (OB) and their psychological well-being. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT05929430.

A system for automatic recording and analysis of motor activity in rats.

We describe the design and evaluation of an electronic system for the automatic recording of motor activity in rats. The device continually locates the position of a rat inside a transparent acrylic cube (50 cm/side) with infrared sensors arranged on its walls so as to correspond to the x-, y-, and z-axes. The system is governed by two microcontrollers. The raw data are saved in a text file within a secure digital memory card, and offline analyses are performed with a library of programs that automatically compute several parameters based on the sequence of coordinates and the time of occurrence of each movement. Four analyses can be made at specified time intervals: traveled distance (cm), movement speed (cm/s), time spent in vertical exploration (s), and thigmotaxis (%). In addition, three analyses are made for the total duration of the experiment: time spent at each x-y coordinate pair (min), time spent on vertical exploration at each x-y coordinate pair (s), and frequency distribution of vertical exploration episodes of distinct durations. User profiles of frequently analyzed parameters may be created and saved for future experimental analyses, thus obtaining a full set of analyses for a group of rats in a short time. The performance of the developed system was assessed by recording the spontaneous motor activity of six rats, while their behaviors were simultaneously videotaped for manual analysis by two trained observers. A high and significant correlation was found between the values measured by the electronic system and by the observers.

Effect of flunixin meglumine on pain-related behaviours following cautery disbudding in dairy goat kids.

The aim of this research was to evaluate the physiological and behavioural parameters in Saanen goat kids treated with flunixin meglumine compared with no analgesic treatment after cautery disbudding using a device fueled by propane gas. At 7 days of age, 30 goat kids were randomly allocated to three groups: Sham (Sh) control, (i.e., simulating disbudding); Disbudding (Di), using thermal cauterization; Disbudding + Flunixin (DiFl), thermal cauterization + flunixin meglumine (2.2 mg/kg body weight, 15 min before treatment). Each kid was video-recorded for 30 min before and after treatment to evaluate the frequency of head shaking, head scratching, body shaking, grooming, head rubbing, jumping, running, and bleating. Blood samples were taken 30 min after disbudding to evaluate serum cortisol concentrations and white blood cell count. Heart rate (HR) and respiratory rate (RR) were measured using a stethoscope. Liveweight of goat kids was recorded at birth, -24 h and 7 days after treatment, and at 25 days of age. The mean frequency of head shaking and head scratching was higher (p = 0.0001) after disbudding in Di (37.5 ± 47.8 and 33.32 ± 31.2) group compared to Sh (3.42 ± 3.58 and 2.2 ± 1.8) and DiFl, (4.02 ± 2.76 and 4.42 ± 3.72) groups. The frequency of jumping was higher (p = 0.022) for Di (3.74 ± 2.24) than that of DiFl (0.39 ± 0.92). The remaining behaviours did not show differences (p > 0.05). HR and RR were higher (HR: p < 0.0048; RR: p < 0.035) in group Di (HR: 156 ± 13.6; RR: 66 ± 14.8) than in Sh (HR: 138 ± 8.48; RR: 55.6 ± 5.4) and in DiFl (HR: 136 ± 6.38; RR: 52.8 ± 4.13). No differences were detected between live weight, serum cortisol and white blood cell count data (p > 0.05). Results show that flunixin meglumine was effective at reducing pain-related behaviours when given at the time of disbudding.

Using waste poly(vinyl chloride) to synthesize chloroarenes by plasticizer-mediated electro(de)chlorination.

New approaches are needed to both reduce and reuse plastic waste. In this context, poly(vinyl chloride) (PVC) is an appealing target as it is the least recycled high-production-volume polymer due to its facile release of plasticizers and corrosive HCl gas. Herein, these limitations become advantageous in a paired-electrolysis reaction in which HCl is intentionally generated from PVC to chlorinate arenes in an air- and moisture-tolerant process that is mediated by the plasticizer. The reaction proceeds efficiently with other plastic waste present and a commercial plasticized PVC product (laboratory tubing) can be used directly. A simplified life-cycle assessment reveals that using PVC waste as the chlorine source in the paired-electrolysis reaction has a lower global warming potential than HCl. Overall, this method should inspire other strategies for repurposing waste PVC and related polymers using electrosynthetic reactions, including those that take advantage of existing polymer additives.

Neuroprotective and Immunomodulatory Effects of Probiotics in a Rat Model of Parkinson's Disease.

It is now well recognized that a bidirectional relationship between gut microbiota and the brain, referred to as the gut-brain axis, plays a prominent role in maintaining homeostasis and that a disruption in this axis can result in neuroinflammatory response and neurological disorders such as Parkinson's disease (PD). The protective action of probiotics such as Bifidobacterium animalis ssp. lactis Bb12 and Lactobacillus rhamnosus GG in various animal models of PD has been reported. Therefore, in this study, we used an inflammatory model of PD to assess the effects of a combination of these two probiotics (Microbiot®) on motor behavior as well as on the response of microglia, including microglia morphology, to gain a better understanding of their mechanism of action. Microbiot® (300 µL) was administered orally once daily for 15 days in a lipopolysaccharide-induced PD model using male Wistar rats. Although LPS-induced motor asymmetry in cylinder test was not affected by Microbiot®, impairment of motor coordination in the narrow-beam test was significantly reduced by this probiotic. Moreover, Microbiot® treatment reduced microglial activation suggesting an anti-inflammatory effect. While further mechanistic investigation of Microbiot® in neurodegenerative diseases is warranted, our results support the potential utility of probiotics in PD.

Whistle repertoire and structure reflect ecotype distinction of pantropical spotted dolphins in the Eastern Tropical Pacific.

The pantropical spotted dolphin in the Eastern Tropical Pacific (ETP) is found in two genetically and phenotypically diverged ecotypes, coastal and offshore. These habitats have distinct acoustic characteristics, which can lead to the evolution of distinct acoustic communication. Whistles are sounds widely used by dolphins to mediate species and individual recognition and social interactions. Here, we study the whistle acoustic structure and repertoire diversity of offshore and coastal pantropical spotted dolphins. Our results show that there is significantly more within- and across-group variation in whistle fundamental frequency between ecotypes than between offshore groups and between coastal groups. A Random Forest classification analysis performed with an accuracy of 83.99% and identified duration, peak and minimum frequency as the most informative variables for distinguishing between ecotypes. Overall, coastal spotted dolphins produced significantly shorter whistles that were significantly lower in frequency (peak, minimum and maximum, and start and end) than offshore dolphins. Ecotypes produced whistle repertoires that were similar in diversity, but different in contour composition, with the coastal ecotype producing more upsweep whistles than offshore dolphins. The results of this study suggest that acoustic adaptations to coastal and offshore environments could be important contributors to intraspecific variation of dolphin whistle repertoires.

Explanatory model of symptoms of stress, anxiety and depression in the general population: Cross-sectional study during the COVID-19 pandemic.

COVID-19 pandemic has had a great impact worldwide, specially affecting mental health and has undoubtedly taken part in human behaviour modification, increasing global health burden and with stress, anxiety and depression being the main contributors to this load. Because of the importance of this issue, the objective of this study was the creation of an explanatory model for the causal relationship of the main psychological variables: stress, anxiety and depression in the COVID-19 pandemic context. A cross-sectional study was carried out with a sample of 709 volunteers, sociodemographic variables and psychological symptoms were measured through a virtual DASS-21 questionnaire, during the COVID-19 pandemic, dated from November 2 to 6, 2020. A structural equation model using the weighted least squares means and the adjusted variance was employed for the creation and adjustment of the explanatory relational model. The results showed the presence of stress, anxiety and depression symptoms among the general population. The model showed an adequate fit (CFI = 0.94; TLI = 0.94; RMSEA = 0.06; P = 0.000) and was able to explain more than 80% of depressive symptoms (R2 = 0.86) and more than 70% of anxiety symptoms (R2 = 0.72), in addition to showing a unidirectional causal relationship of long-term stress on anxiety, and anxiety on depressive symptoms, showing a linked behaviour of the same, in the adjusted model. It was also outlined that this model was characterized by being expressed mainly in women, with lower quality of sleep and at a younger age.

Septal medial/diagonal band of Broca citalopram infusion reduces place learning efficiency and alters septohippocampal theta learning-related activity in rats.

Increases in power and frequency of hippocampal theta activity have been related to efficient place learning and memory acquisition in hippocampal-dependent tests. The complex medial septum-diagonal band of Broca (MS/DBB) is the pacemaker of hippocampal theta activity, influenced by the ascending synchronizing system, and modulated by serotonergic raphe medial afferents, acting on cholinergic and GABAergic septal neurons. The suppression of hippocampal theta expression and the modulation of hippocampal learning and memory are attributed to serotonin. To simultaneously test these hypotheses, a daily local serotonin increase was induced by citalopram (CIT) infusion (100 µM, 0.88 µl, 0.2 µl/m) 15 min before training in the Morris water maze. The theta activity was recorded in the MS/DBB, dentate gyrus (DG) and CA1 of one group infused with artificial cerebrospinal liquid (ACL) and the other with CIT on Days 1-6 of training. After a probe trial (Day 7) and one resting day, the treatments were reversed (Days 8-11). The CIT MS/DBB infusion in the first 6 training days reduced the efficiency of spatial learning in association with reduced power in the DG, reduced MS/DBB-DG coherence, increased DG-CA1 coherence, and a lack of a negative correlation between MS/DBB power and swam distances. No effect of the CIT occurred once the information was acquired under ACL training. These results support a role of serotonin, in acting on the MS/DBB in the fine tuning of hippocampal learning and memory efficiency through the modulation of learning-related theta activity power and septohipocampal synchronization.