Antibacterial activity of biosynthesized silver nanoparticles (AgNps) against Pectobacterium carotovorum.

In a bioprospecting study of paramo soils cultivated with potato (Solanum tuberosum), 50 fungal isolates were obtained and evaluated for their nitrate reductase (NR) activity, given the role played by this enzyme in the biosynthesis of silver nanoparticles (AgNps). Five isolates strain with high NR activity belonging to Penicillium simplicissimum, Aspergillus niger, and Fusarium oxysporum species were selected, verifying the presence of the NR enzyme in their enzymatic extract. Later, these strains showed the ability to biosynthesize AgNps with distorted spherical shapes and sizes ranging from 15 to 45 nm. Subsequently, an antibiosis test was carried out by the agar diffusion method using glass fiber disks against the phytopathogenic agent Pectobacterium carotovorum, finding halos of inhibition of bacterial growth up to 15.3 mm using a 100 ppm solution of the AgNps obtained from F. oxysporum. These results contribute to generating the basis of a new alternative for the control of this phytopathogenic agent of potato, challenging to manage by traditional methods and of relevance at the post-harvest level.

Experiencia de la aplicación de homeopatía contra el tabaquismo / Experience of the application of homeopathy against smoking

Existen diferentes procedimientos para tratar la dependencia a la nicotina, y, entre los no conductuales se incluye la Terapia Homeopática, que utiliza sustancias de origen animal, vegetal o mineral diluidas en alcohol capaces de curar diferentes patologías a un individuo enfermo prestando una información que pone en funcionamiento los mecanismos autocurativos del organismo.

Tratamiento profiláctico en extracciones dentarias con la terapia floral de bach (crab apple) / Prophylactic treatment in tooth extractions with bach flower therapy (crab apple)

Introducción: La terapia floral de Bach es una terapia medicamentosa no farmacológica que brinda un conjunto de remedios vibracionales; es un remedio de limpieza por excelencia, se le considera el antibiótico de elección del citado sistema floral. Objetivo: caracterizar a los pacientes atendidos en el Servicio de Estomatología de la Facultad de Ciencias Médicas de Morón tarados con Terapia Floral de Bach (Crab Apple), como profilaxis en extracciones dentarias. Método: se realizó un estudio experimental (cuasi experimento), para el mismo se crearon dos grupos uno experimental y otro control en el período comprendido de Junio 2019 a Enero de 2020. La población la constituyó 370 pacientes que acudieron al Servicio de Estomatología de la Facultad de Ciencias Médicas "Arley Hernández Moreira" para realizarse extracciones dentarias; la muestra se seleccionó utilizando el método probabilístico aleatorio simple la cual quedó conformada por 260 pacientes. Resultados: la respuesta preoperatoria del 100 % de los pacientes del grupo experimental fue satisfactoria, el 9,5 % perteneciente al grupo control fue no satisfactoria. El 100 % de los pacientes del grupo experimental y el 89,1 % del grupo control durante el transoperatorio presentaron respuesta satisfactoria. Durante el posoperatorio solo el 2,5% del grupo experimental alcanzó resultados no satisfactorios y en el grupo control el 9,4 %. Conclusiones: El estudio mostro la efectividad de la terapia floral de Bach como profilaxis ante la extracción dentaria presentando un menor número de complicaciones y respondiendo con mayor efectividad su uso durante el posoperatorio el transoperatorio y el posoperatorio.

Alterations in Brain Structure and Amplitude of Low-frequency after 8 weeks of Mindfulness Meditation Training in Meditation-Naïve Subjects.

Increasing neuroimaging evidence suggests that mindfulness meditation expertise is related to different functional and structural configurations of the default mode network (DMN), the salience network (SN) and the executive network at rest. However, longitudinal studies observing resting network plasticity effects in brains of novices who started to practice meditation are scarce and generally related to one dimension, such as structural or functional effects. The purpose of this study was to investigate structural and functional brain network changes (e.g. DMN) after 40 days of mindfulness meditation training in novices and set these in the context of potentially altered depression symptomatology and anxiety. We found overlapping structural and functional effects in precuneus, a posterior DMN region, where cortical thickness increased and low-frequency amplitudes (ALFF) decreased, while decreased ALFF in left precuneus/posterior cingulate cortex correlates with the reduction of (CES-D) depression scores. In conclusion, regional overlapping of structural and functional changes in precuneus may capture different components of the complex changes of mindfulness meditation training.

Modulation of Functional Connectivity in Auditory-Motor Networks in Musicians Compared with Nonmusicians.

Correlation of spontaneous fluctuations at rest between anatomically distinct brain areas are proposed to reflect the profile of individual a priori cognitive biases, coded as synaptic efficacies in cortical networks. Here, we investigate functional connectivity at rest (rs-FC) in musicians and nonmusicians to test for differences in auditory, motor, and audiomotor connectivity. As expected, musicians had stronger rs-FC between the right auditory cortex (AC) and the right ventral premotor cortex than nonmusicians, and this stronger rs-FC was greater in musicians with more years of practice. We also found reduced rs-FC between the motor areas that control both hands in musicians compared with nonmusicians, which was more evident in the musicians whose instrument required bimanual coordination and as a function of hours of practice. Finally, we replicated previous morphometric data to show an increased volume in the right AC in musicians, which was greater in those with earlier musical training, and that this anatomic feature was in turn related to greater rs-FC between auditory and motor systems. These results show that functional coupling within the motor system and between motor and auditory areas is modulated as a function of musical training, suggesting a link between anatomic and functional brain features.

State and Training Effects of Mindfulness Meditation on Brain Networks Reflect Neuronal Mechanisms of Its Antidepressant Effect.

The topic of investigating how mindfulness meditation training can have antidepressant effects via plastic changes in both resting state and meditation state brain activity is important in the rapidly emerging field of neuroplasticity. In the present study, we used a longitudinal design investigating resting state fMRI both before and after 40 days of meditation training in 13 novices. After training, we compared differences in network connectivity between rest and meditation using common resting state functional connectivity methods. Interregional methods were paired with local measures such as Regional Homogeneity. As expected, significant differences in functional connectivity both between states (rest versus meditation) and between time points (before versus after training) were observed. During meditation, the internal consistency in the precuneus and the temporoparietal junction increased, while the internal consistency of frontal brain regions decreased. A follow-up analysis of regional connectivity of the dorsal anterior cingulate cortex further revealed reduced connectivity with anterior insula during meditation. After meditation training, reduced resting state functional connectivity between the pregenual anterior cingulate and dorsal medical prefrontal cortex was observed. Most importantly, significantly reduced depression/anxiety scores were observed after training. Hence, these findings suggest that mindfulness meditation might be of therapeutic use by inducing plasticity related network changes altering the neuronal basis of affective disorders such as depression.

Bilingualism at the core of the brain. Structural differences between bilinguals and monolinguals revealed by subcortical shape analysis.

Naturally acquiring a language shapes the human brain through a long-lasting learning and practice process. This is supported by previous studies showing that managing more than one language from early childhood has an impact on brain structure and function. However, to what extent bilingual individuals present neuroanatomical peculiarities at the subcortical level with respect to monolinguals is yet not well understood, despite the key role of subcortical gray matter for a number of language functions, including monitoring of speech production and language control - two processes especially solicited by bilinguals. Here we addressed this issue by performing a subcortical surface-based analysis in a sample of monolinguals and simultaneous bilinguals (N=88) that only differed in their language experience from birth. This analysis allowed us to study with great anatomical precision the potential differences in morphology of key subcortical structures, namely, the caudate, accumbens, putamen, globus pallidus and thalamus. Vertexwise analyses revealed significantly expanded subcortical structures for bilinguals compared to monolinguals, localized in bilateral putamen and thalamus, as well as in the left globus pallidus and right caudate nucleus. A topographical interpretation of our results suggests that a more complex phonological system in bilinguals may lead to a greater development of a subcortical brain network involved in monitoring articulatory processes.

Top-down attention regulates the neural expression of audiovisual integration.

The interplay between attention and multisensory integration has proven to be a difficult question to tackle. There are almost as many studies showing that multisensory integration occurs independently from the focus of attention as studies implying that attention has a profound effect on integration. Addressing the neural expression of multisensory integration for attended vs. unattended stimuli can help disentangle this apparent contradiction. In the present study, we examine if selective attention to sound pitch influences the expression of audiovisual integration in both behavior and neural activity. Participants were asked to attend to one of two auditory speech streams while watching a pair of talking lips that could be congruent or incongruent with the attended speech stream. We measured behavioral and neural responses (fMRI) to multisensory stimuli under attended and unattended conditions while physical stimulation was kept constant. Our results indicate that participants recognized words more accurately from an auditory stream that was both attended and audiovisually (AV) congruent, thus reflecting a benefit due to AV integration. On the other hand, no enhancement was found for AV congruency when it was unattended. Furthermore, the fMRI results indicated that activity in the superior temporal sulcus (an area known to be related to multisensory integration) was contingent on attention as well as on audiovisual congruency. This attentional modulation extended beyond heteromodal areas to affect processing in areas classically recognized as unisensory, such as the superior temporal gyrus or the extrastriate cortex, and to non-sensory areas such as the motor cortex. Interestingly, attention to audiovisual incongruence triggered responses in brain areas related to conflict processing (i.e., the anterior cingulate cortex and the anterior insula). Based on these results, we hypothesize that AV speech integration can take place automatically only when both modalities are sufficiently processed, and that if a mismatch is detected between the AV modalities, feedback from conflict areas minimizes the influence of this mismatch by reducing the processing of the least informative modality.

Involvement of the human midbrain and thalamus in auditory deviance detection.

Prompt detection of unexpected changes in the sensory environment is critical for survival. In the auditory domain, the occurrence of a rare stimulus triggers a cascade of neurophysiological events spanning over multiple time-scales. Besides the role of the mismatch negativity (MMN), whose cortical generators are located in supratemporal areas, cumulative evidence suggests that violations of auditory regularities can be detected earlier and lower in the auditory hierarchy. Recent human scalp recordings have shown signatures of auditory mismatch responses at shorter latencies than those of the MMN. Moreover, animal single-unit recordings have demonstrated that rare stimulus changes cause a release from stimulus-specific adaptation in neurons of the primary auditory cortex, the medial geniculate body (MGB), and the inferior colliculus (IC). Although these data suggest that change detection is a pervasive property of the auditory system which may reside upstream cortical sites, direct evidence for the involvement of subcortical stages in the human auditory novelty system is lacking. Using event-related functional magnetic resonance imaging during a frequency oddball paradigm, we here report that auditory deviance detection occurs in the MGB and the IC of healthy human participants. By implementing a random condition controlling for neural refractoriness effects, we show that auditory change detection in these subcortical stations involves the encoding of statistical regularities from the acoustic input. These results provide the first direct evidence of the existence of multiple mismatch detectors nested at different levels along the human ascending auditory pathway.

Reading salt activates gustatory brain regions: fMRI evidence for semantic grounding in a novel sensory modality.

Because many words are typically used in the context of their referent objects and actions, distributed cortical circuits for these words may bind information about their form with perceptual and motor aspects of their meaning. Previous work has demonstrated such semantic grounding for sensorimotor, visual, auditory, and olfactory knowledge linked to words, which is manifest in activation of the corresponding areas of the cortex. Here, we explore the brain basis of gustatory semantic links of words whose meaning is primarily related to taste. In a blocked functional magnetic resonance imaging design, Spanish taste words and control words matched for a range of factors (including valence, arousal, image-ability, frequency of use, number of letters and syllables) were presented to 59 right-handed participants in a passive reading task. Whereas all the words activated the left inferior frontal (BA44/45) and the posterior middle and superior temporal gyri (BA21/22), taste-related words produced a significantly stronger activation in these same areas and also in the anterior insula, frontal operculum, lateral orbitofrontal gyrus, and thalamus among others. As these areas comprise primary and secondary gustatory cortices, we conclude that the meaning of taste words is grounded in distributed cortical circuits reaching into areas that process taste sensations.

[Involvement of the thalamic-cortical-striatal circuit in patients with obsessive-compulsive disorder during an inhibitory control task with reward and punishment contingencies]. / Implicación del circuito corticoestriadotalámico en pacientes con trastorno obsesivo-compulsivo durante una tarea de control inhibitorio con contingencias de recompensa y castigo.

INTRODUCTION: Recent neuroimaging studies conducted on obsessive-compulsive disorder (OCD) show alterations in the fronto-thalamic-striatal circuit, which would give rise to an executive dysfunction. This could be the neurocognitive substrate underlying the main symptoms of OCD, i.e. obsessions and compulsions. SUBJECTS AND METHODS: Both brain activity and behavioural performance of a group of 13 patients with OCD were compared with a control group of 13 healthy subjects by means of functional magnetic resonance imaging while performing an inhibitory control task with reward and punishment contingencies. The effects of medication were also analysed. RESULTS: The intra-group analyses showed a longer reaction time during the go/no go condition in both groups, although there were no differences between the groups in the performance of the task. With regard to this task, significant activation of large areas of the cerebellum and the occipital, temporal and parietal lobes was observed in the healthy subjects. In comparison with the controls, the obsessive patients showed lower activation in the right-side frontal medial and superior gyri, the anterior cingulate cortex and the caudate nucleus, and greater activation in the inferior parietal convolution and the fusiform gyrus. The effects of medication were found in the frontal cortex and basal structures. CONCLUSIONS: These results agree with the argument claiming that the dysfunction in the corticostriatal system in OCD is associated to diminished brain activity in response to cognitive tasks.

Anatomical and functional differences between the Paced Auditory Serial Addition Test and the Symbol Digit Modalities Test.

The Paced Auditory Serial Addition Test (PASAT) and the Symbol Digit Modalities Test (SDMT) are generally used to detect cognitive impairments in multiple sclerosis patients. Although both seem to be sensitive to the slow information-processing speed, some results suggest that they do not involve the same cognitive functions. The aim of the present study is to observe possible differences between these tasks to help understand their utility to cognitive assessment. A total of 17 participants were recruited for the study and completed a block-design version of each task. Comparisons between tasks were calculated using an analysis of variance (ANOVA; p < .05, familywise error, FWE, corrected). We observed activations in the left frontal and parietal areas during both tasks; however, the PASAT activated more frontal areas than did the SDMT. These tasks require an efficient transfer of information among large areas. Moreover, the PASAT requires more executive functions to be executed.

Differential dorsolateral prefrontal cortex activation during a verbal n-back task according to sensory modality.

Functional neuroimaging studies carried out on healthy volunteers while performing different n-back tasks have shown a common pattern of bilateral frontoparietal activation, especially of the dorsolateral prefrontal cortex (DLPFC). Our objective was to use functional magnetic resonance imaging (fMRI) to compare the pattern of brain activation while performing two similar n-back tasks which differed in their presentation modality. Thirteen healthy volunteers completed a verbal 2-back task presenting auditory stimuli, and a similar 2-back task presenting visual stimuli. A conjunction analysis showed bilateral activation of frontoparietal areas including the DLPFC. The left DLPFC and the superior temporal gyrus showed a greater activation in the auditory than in the visual condition, whereas posterior brain regions and the anterior cingulate showed a greater activation during the visual than during the auditory task. Thus, brain areas involved in the visual and auditory versions of the n-back task showed an important overlap between them, reflecting the supramodal characteristics of working memory. However, the differences found between the two modalities should be considered in order to select the most appropriate task for future clinical studies.

A comparison of brain activation patterns during covert and overt paced auditory serial addition test tasks.

The Paced Auditory Serial Addition test (PASAT) is a sensitive task for evaluating cognitive impairment in patients with diffuse brain disorders, such as multiple sclerosis patients. Brain areas involved in this task have been investigated in diverse fMRI studies using different methodologies to control the subjects' responses during scanning. Here, we examined the possible differences between overt and covert responses during the PASAT task in 13 volunteers. Results showed similar activations in parietal and frontal brain areas during both versions of the task. The contrast between the two conditions (overt and covert) indicated that differences in these two methodologies were minimal. Unlike the covert condition, the overt version of the task obtained significant activations in the left superior and inferior frontal gyrus, bilateral occipital cortex, caudate nucleus and cerebellum. As expected, no significant overactivations were observed in the covert when compared with the overt condition. Discussion focuses on the lower cost of using verbal responses to monitor performance during the PASAT task, which might be generalisable to other frontal lobe tasks requiring discrete responses.

Compensatory activations in patients with multiple sclerosis during preserved performance on the auditory N-back task.

Recent fMRI studies have suggested that multiple sclerosis (MS) patients show adaptive cortical changes (i.e., compensatory mechanisms) during motor and cognitive tasks to limit the clinical impact of tissue injury. In this study, we investigated the activation pattern during the auditory n-back working memory (WM) paradigm in a group of 17 MS patients and 10 healthy controls with preserved performance in WM tasks. Compared with healthy controls, MS patients showed significantly greater bilateral activation in prefrontal cortex (BA 44), and the insula. These findings were similar to those obtained in previous studies showing that compensatory mechanisms during WM tasks in MS may be based on the use of prefrontal areas adjacent to those involved in the task.

Reading cinnamon activates olfactory brain regions.

Some words immediately and automatically remind us of odours, smells and scents, whereas other language items do not evoke such associations. This study investigated, for the first time, the abstract linking of linguistic and odour information using modern neuroimaging techniques (functional MRI). Subjects passively read odour-related words ('garlic', 'cinnamon', 'jasmine') and neutral language items. The odour-related terms elicited activation in the primary olfactory cortex, which include the piriform cortex and the amygdala. Our results suggest the activation of widely distributed cortical cell assemblies in the processing of olfactory words. These distributed neuron populations extend into language areas but also reach some parts of the olfactory system. These distributed neural systems may be the basis of the processing of language elements, their related conceptual and semantic information and the associated sensory information.

Selective alteration of native, but not second language articulation in a patient with foreign accent syndrome.

The present study deals with a right-handed female polyglot suffering from a Foreign Accent Syndrome (FAS) which affects her native language (L1), but not her other languages learnt since the age of 12. She had a small infarct in the left corona radiata as the result of a carotid occlusion. Her L1 was Spanish, but she also had a good command of French, English and Catalan (L2). Aphasia tests did not reveal any other significant alteration in any language. Analyses of pre-morbid and post-morbid voice recordings revealed that FAS affected Spanish dramatically, but no important changes were observed for French. Results were interpreted as showing that different brain areas control articulation of L1 and L2 learnt after a critical period.