Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 68
Filtrar
Mais filtros











Intervalo de ano de publicação
1.
Curr Issues Mol Biol ; 46(7): 6885-6902, 2024 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-39057053

RESUMO

Pereskia sacharosa Griseb. is a plant used in traditional herbal medicine to treat inflammation. We analyzed the phenolic content of P. sacharosa leaves (EEPs) by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and investigated the anti-inflammatory properties of EEPs and its flavonoid fraction (F10) in animal models subjected to acute neuroinflammation induced by bacterial lipopolysaccharide (LPS). Coronal brain sections of C57BL/6JN male mice or Wistar male rats administered with EEPs or F10 before LPS were subjected to in situ hybridization to determine c-fos and CD14 mRNA levels in the hypothalamus or GABAA γ2 mRNA levels in the hippocampus. Theta oscillations were recorded every 6 h in the hippocampus of Wistar rats. In total, five flavonoids and eight phenolic acids were identified and quantified in P. sacharosa leaves. Either EEPs or F10 crossed the blood-brain barrier (BBB) into the brain and reduced the mRNA expression of c-fos, CD14, and GABAA γ2. A decrease in theta oscillation was observed in the hippocampus of the LPS group, while the F10 + LPS group overrode the LPS effect on theta activity. We conclude that the bioactive compounds of P. sacharosa reduce the central response to inflammation, allowing the early return of ambulatory activity and well-being of the animal.

2.
Asian J Psychiatr ; 96: 104013, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38554561

RESUMO

BACKGROUND: Transcranial magnetic stimulation (TMS) has been shown to improve response and remission in patients with treatment resistant depression. The objective of this study was to compare the efficacy of two bilateral rTMS protocols with different protocols in patients with treatment resistant depression and comorbid severe anxiety. METHODS: A retrospective cohort study involving 67 patients who underwent two different bilateral TMS protocols and who met the specified eligibility criteria was conducted. Group 1 received stimulation with 85% RMT intermittent theta burst (iTBS) in the left DLPFC + 120% RMT (1 Hz) in the right DLPFC. Group 2 received stimulation with 100% RMT (iTBS) in the left DLPFC + 110% RMT (1 Hz) in the left DLPFC. RESULTS: After the magnetic stimulation treatment, 55% (n=22) achieved response to depression symptoms in group 1 and 62% (n=18) in group 2. Remission of depression symptoms was achieved in 13% in group 1 (n=5) and 24% in group 2 (n=7). There were no significant differences between the two protocols after TMS CONCLUSIONS: Different bilateral protocol parameters in individuals undergoing TMS may have an impact on symptom response and remission. Further studies with larger sample sizes are needed.


Assuntos
Transtorno Depressivo Resistente a Tratamento , Estimulação Magnética Transcraniana , Humanos , Estimulação Magnética Transcraniana/métodos , Masculino , Feminino , Transtorno Depressivo Resistente a Tratamento/terapia , Estudos Retrospectivos , Adulto , Pessoa de Meia-Idade , Transtornos de Ansiedade/terapia , Resultado do Tratamento , Córtex Pré-Frontal Dorsolateral/fisiologia , Avaliação de Resultados em Cuidados de Saúde
3.
Med Biol Eng Comput ; 62(6): 1869-1885, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38403862

RESUMO

Since the first electroencephalogram (EEG) was obtained, there have been many possibilities to use it as a tool to access brain cognitive dynamics. Mathematical (Math) problem solving is one of the most important cortical processes, but it is still far from being well understood. EEG is an inexpensive and simple indirect measure of brain operation, but only recently has low-cost equipment (mobile EEG) allowed sophisticated analyses in non-clinical settings. The main purpose of this work is to study EEG activation during a Math task in a realistic environment, using mobile EEG. A matching pursuit (MP)-based signal analysis technique was employed, since MP properties render it a priori suitable to study induced EEG activity over long time sequences, when it is not tightly locked to a given stimulus. The study sample comprised sixty healthy volunteers. Unlike the majority of previous studies, subjects were studied in a sitting position with their eyes open. They completed a written Math task outside the EEG lab, wearing a mobile EEG device (EPOC+). Theta [4 Hz-7.5 Hz], alpha (7.5 Hz-13 Hz] and 0.5 Hz micro-bands in the [0.5 Hz-20 Hz] range were studied with a low-density stochastic MP dictionary. Over 1-min windows, ongoing EEG alpha and theta activity was decomposed into numerous MP atoms with median duration around 3 s, similar to the duration of induced, time-locked activity obtained with event-related (des)synchronization (ERS/ERD) studies. Relative to Rest, there was lower right-side and posterior MP alpha atom/min during Math, whereas MP theta atom/min was significantly higher on anteriorly located electrodes, especially on the left side. MP alpha findings were particularly significant on a narrow range around 10 Hz-10.5 Hz, consistent with FFT alpha peak findings from ERS/ERD studies. With a streamlined protocol, these results replicate previous findings of EEG alpha and theta activation obtained during Math tasks with different signal analysis techniques and in different time frames. The efficient application to real-world, noisy EEG data with a low-resolution stochastic MP dictionary shows that this technique is very encouraging. These results provide support for studies of mathematical cognition with mobile EEG and matching pursuit.


Assuntos
Ritmo alfa , Eletroencefalografia , Humanos , Eletroencefalografia/métodos , Feminino , Masculino , Adulto , Ritmo alfa/fisiologia , Processamento de Sinais Assistido por Computador , Ritmo Teta/fisiologia , Adulto Jovem , Encéfalo/fisiologia , Matemática
4.
Colomb. med ; 54(4): e2005766, Oct.-Dec. 2023. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1574799

RESUMO

Abstract Background: Intermittent theta-burst stimulation and repetitive peripheral magnetic stimulation can improve motor function in poststroke patients, but the therapeutic effect of this combination remains unclear. Objective: To determine the effects of central intermittent theta-burst stimulation and repetitive peripheral magnetic stimulation on upper limb function. Methods: Fifty-six subacute stroke patients were randomly assigned to three groups: the CMS (n = 18), peripheral magnetic stimulation (PMS) (n = 19) and CPS (n = 19) groups. The CMS group received intermittent theta-burst stimulation and peripheral false stimulation, while the PMS group received repetitive peripheral magnetic stimulation and central false stimulation once a day for five days a week over four weeks. The CPS group received intermittent theta-burst stimulation and repetitive peripheral magnetic stimulation simultaneously once daily for four weeks. The Fugl-Meyer Assessment, Action Research Arm Test, Modified Barthel Index and Modified Ashworth Scale evaluated outcomes before and after four weeks of treatment. Results: The motor function scores of all groups were significantly increased after treatment compared with before treatment, while the Modified Ashworth Scale score showed no significant change. There was a significant difference in the motor function score of the CPS group compared with that of the CMS and PMS groups, but there was no significant improvement in the Modified Ashworth Scale score. Conclusion: Combining the two treatment methods can improve patients' motor function and daily living abilities but cannot improve muscle tone.


Resumen Antecedentes: La estimulación intermitente de theta-burst y la estimulación magnética periférica repetitiva pueden mejorar la función motora en pacientes postictus, pero el efecto terapéutico de esta combinación sigue sin estar claro. Objetivo: Determinar el efecto de la estimulacion central intermitente theta-burst y la estimulación magnética repetitiva periférica en la función del miembro superior. Métodos: Se asignaron aleatoriamente a tres grupos 56 pacientes con ictus subagudo: CMS (n = 18), estimulación magnética periferica (PMS) (n = 19) y CPS(Cm1) (n = 19). El grupo CMS recibió estimulación intermitente de theta-burst y falsa estimulación periférica, el grupo PMS recibió estimulación magnética periférica repetitiva y falsa estimulación central una vez al día durante cinco días a la semana a lo largo de cuatro semanas. El grupo SPC recibió estimulación intermitente theta-burst y estimulación magnética periférica repetitiva simultáneamente una vez al día durante cuatro semanas. Se utilizaron la Fugl-Meyer Assessment, Action Research Arm Test, Modified Barthel Index and Modified Ashworth Scale para evaluar losresultados antes y después de cuatro semanas de tratamiento. Resultados: Las puntuaciones de la función motora de todos los grupos aumentaron significativamente después del tratamiento en comparación con antes del tratamiento, mientras que la puntuación de la Escala de Ashworth Modificada no mostró cambios significativos. Hubo una diferencia significativa en la puntuación de la función motora del grupo CPS en comparación con la de los grupos CMS y PMS, pero no hubo una mejora significativa en la puntuación de la Escala de Ashworth Modificada. Conclusiones: La combinación de los dos métodos de tratamiento puede mejorar la función motora y las capacidades de la vida diaria de los pacientes, pero no puede mejorar el tono muscular.

5.
Front Psychiatry ; 14: 1160209, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37520238

RESUMO

Introduction: Decision-making is a process that can be strongly affected by social factors. Evidence has shown how people deviate from traditional rational-choice predictions under different levels of social interactions. The emergence of prosocial decision-making, defined as any action that is addressed to benefit another individual even at the expense of personal benefits, has been reported as an example of such social influence. Furthermore, brain evidence has shown the involvement of structures such as the prefrontal cortex, anterior insula, and midcingulate cortex during decision settings in which a decision maker interacts with others under physical pain or distress or while being observed by others. Methods: Using a slightly modified version of the dictator game and EEG recordings, we tested the hypothesis that the inclusion of another person into the decision setting increases prosocial decisions in young adults and that this increase is higher when the other person is associated with others in need. At the brain level, we hypothesized that the increase in prosocial decisions correlates with frontal theta activity. Results and Discussion: The results showed that including another person in the decision, setting increased prosocial behavior only when this presence was associated with someone in need. This effect was associated with an increase in frontocentral theta-oscillatory activity. These results suggest that the presence of someone in need enhances empathy concerns and norm compliance, raising the participants' prosocial decision-making.

6.
Front Hum Neurosci ; 17: 1116890, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37520930

RESUMO

To the best of our knowledge, neurophysiological markers indicating changes induced by non-invasive brain stimulation (NIBS) on cognitive performance, especially one of the most investigated under these procedures, working memory (WM), are little known. Here, we will briefly introduce frontal midline theta (FM-theta) oscillation (4-8 Hz) as a possible indicator for NIBS effects on WM processing. Electrophysiological recordings of FM-theta oscillation seem to originate in the medial frontal cortex and the anterior cingulate cortex, but they may be driven more subcortically. FM-theta has been acknowledged to occur during memory and emotion processing, and it has been related to WM and sustained attention. It mainly occurs in the frontal region during a delay period, in which specific information previously shown is no longer perceived and must be manipulated to allow a later (delayed) response and observed in posterior regions during information maintenance. Most NIBS studies investigating effects on cognitive performance have used n-back tasks that mix manipulation and maintenance processes. Thus, if considering FM-theta as a potential neurophysiological indicator for NIBS effects on different WM components, adequate cognitive tasks should be considered to better address the complexity of WM processing. Future research should also evaluate the potential use of FM-theta as an index of the therapeutic effects of NIBS intervention on neuropsychiatric disorders, especially those involving the ventral medial prefrontal cortex and cognitive dysfunctions.

7.
Brain Topogr ; 36(5): 671-685, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37490130

RESUMO

The impact of binaural beats (BBs) on human cognition and behavior remains and various methods have been used to measure their effect, including neurophysiological, psychometric, and human performance evaluations. The few approaches where the level of neural synchronicity and connectivity were measured by neuroimaging techniques have only been undertaken in spontaneous mode. The present research proposes an approach based on the oddball paradigm to study BB effect by estimating the level of attention induced by BBs. Evoked activity of 25 young adults between 19 and 24 years old with no hearing impairments nor clinical neurological history were analyzed. The experiment was conducted in two different sessions of 24.5 min. The first part consisted of 20-min BB stimulation in either theta (BBθ) or beta (BBß). After the BB stimulation, an oddball paradigm was applied in each BB condition to assess the attentional effect induced by BBs. Attention enhancement is expected for BBß with respect to BBθ. Target event related potentials (ERPs) were mainly analyzed in the time and time-frequency domains. The frequency analysis was based on continuous wavelet transform (CWT), event-related spectral perturbation (ERSP), and inter-trial phase coherence (ITPC). The study revealed that the P300 component was not significantly different between conditions (BBθ vs. BBß). However, the target grand average ERP in BBθ condition was mainly composed of 8 Hz-frequency components, appearing before 400 ms post-stimulus, and mainly on the centro-parietal regions. In contrast, the target grand average ERP in BBß condition was mainly composed of frequency components below 6 Hz, mainly appearing at 400 ms post-stimulus on the parieto-occipital regions. Furthermore, ERPs in the BBθ condition were more phase locked than the BBß condition.


Assuntos
Eletroencefalografia , Potenciais Evocados Auditivos , Adulto Jovem , Humanos , Adulto , Potenciais Evocados Auditivos/fisiologia , Estimulação Acústica/métodos , Eletroencefalografia/métodos , Potenciais Evocados/fisiologia , Atenção
8.
Brain Sci ; 13(4)2023 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-37190540

RESUMO

Preschool children show neural responses and make behavioral adjustments immediately following an error. However, there is a lack of evidence regarding how neural responses to error predict subsequent behavioral adjustments during childhood. The aim of our study was to explore the neural dynamics of error processing and associated behavioral adjustments in preschool children from unsatisfied basic needs (UBN) homes. Using EEG recordings during a go/no-go task, we examined within-subject associations between the error-related negativity (ERN), frontal theta power, post-error slowing, and post-error accuracy. Post-error accuracy increased linearly with post-error slowing, and there was no association between the neural activity of error processing and post-error accuracy. However, during successful error recovery, the frontal theta power, but not the ERN amplitude, was associated positively with post-error slowing. These findings indicated that preschool children from UBN homes adjusted their behavior following an error in an adaptive form and that the error-related theta activity may be associated with the adaptive forms of post-error behavior. Furthermore, our data support the adaptive theory of post-error slowing and point to some degree of separation between the neural mechanisms represented by the ERN and theta.

9.
Front Cell Neurosci ; 17: 1132121, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37025696

RESUMO

Introduction: Neuronal Ca2+ signals generated through the activation of Ca2+-induced Ca2+ release in response to activity-generated Ca2+ influx play a significant role in hippocampal synaptic plasticity, spatial learning, and memory. We and others have previously reported that diverse stimulation protocols, or different memory-inducing procedures, enhance the expression of endoplasmic reticulum-resident Ca2+ release channels in rat primary hippocampal neuronal cells or hippocampal tissue. Methods and Results: Here, we report that induction of long-term potentiation (LTP) by Theta burst stimulation protocols of the CA3-CA1 hippocampal synapse increased the mRNA and protein levels of type-2 Ryanodine Receptor (RyR2) Ca2+ release channels in rat hippocampal slices. Suppression of RyR channel activity (1 h preincubation with 20 µM ryanodine) abolished both LTP induction and the enhanced expression of these channels; it also promoted an increase in the surface expression of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor subunits GluR1 and GluR2 and caused a moderate but significant reduction of dendritic spine density. In addition, training rats in the Morris water maze induced memory consolidation, which lasted for several days after the end of the training period, accompanied by an increase in the mRNA levels and the protein content of the RyR2 channel isoform. Discussion: We confirm in this work that LTP induction by TBS protocols requires functional RyR channels. We propose that the increments in the protein content of RyR2 Ca2+ release channels, induced by LTP or spatial memory training, play a significant role in hippocampal synaptic plasticity and spatial memory consolidation.

10.
Int J Psychophysiol ; 188: 55-61, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36965672

RESUMO

Emotion and working memory are key components in daily life experiences. Previous research has already established a connection between these processes but the neural substrates of this relationship remain an open discussion. The present study aimed to investigate the effects of the use of pictures with emotional valence on the performance of a working memory task as well as the neuronal response during the task. For this purpose, 32 participants performed a 2-back task with negative, positive, and neutral images selected from the International Affective Pictures System (IAPS). No significant difference was found in the performance or in the response time related to the valence of the images. Repeated-measures ANOVA with hemisphere and valence as factors revealed an increase of the activity in the right hemisphere for the amplitude of the ERP P3 component and for the time-locked theta power for all the images. The P3 component in the right hemisphere additionally showed greater mean amplitude for the negative images as compared to the neutral and positive ones. Together, these results suggest a predominant role of the right hemisphere for the processing of both working memory and emotional information, as well as a higher neuronal resource allocation to the processing of negative valence images which enabled a proper performance of the working memory task for the negative images.


Assuntos
Emoções , Memória de Curto Prazo , Humanos , Emoções/fisiologia , Eletroencefalografia/métodos
11.
Front Hum Neurosci ; 16: 941981, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36118977

RESUMO

Introduction: Transcranial magnetic stimulation (TMS) is a consolidated procedure for the treatment of depression, with several meta-analyses demonstrating its efficacy. Theta-burst stimulation (TBS) is a modification of TMS with similar efficacy and shorter session duration. The geriatric population has many comorbidities and a high prevalence of depression, but few clinical trials are conducted specifically for this age group. TBS could be an option in this population, offering the advantages of few side effects and no pharmacological interactions. Therefore, our aim is to investigate the efficacy of TBS in geriatric depression. Clinical trial registration: [https://clinicaltrials.gov/ct2/], identifier [NCT04842929].

12.
Neuroimage ; 262: 119516, 2022 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-35931308

RESUMO

Detection of novel stimuli that violate statistical regularities in the sensory scene is of paramount importance for the survival of biological organisms. Event-related potentials, phasic increases in pupil size, and evoked changes in oscillatory power have been proposed as markers of sensory novelty detection. However, how conscious access to novelty modulates these different brain responses is not well understood. Here, we studied the neural responses to sensory novelty in the auditory modality with and without conscious access. We identified individual thresholds for conscious auditory discrimination and presented to our participants sequences of tones, where the last stimulus could be another standard, a subthreshold target or a suprathreshold target. Participants were instructed to report whether the last tone of each sequence was the same or different from those preceding it. Results indicate that attentional orientation to behaviorally relevant stimuli and overt decision-making mechanisms, indexed by the P3 event-related response and reaction times, best predict whether a novel stimulus will be consciously accessed. Theta power and pupil size do not predict conscious access to novelty, but instead reflect information maintenance and unexpected sensory uncertainty. These results highlight the interplay between bottom-up and top-down mechanisms and how the brain weights neural responses to novelty and uncertainty during perception and goal-directed behavior.


Assuntos
Estado de Consciência , Eletroencefalografia , Estimulação Acústica , Atenção/fisiologia , Percepção Auditiva/fisiologia , Estado de Consciência/fisiologia , Eletroencefalografia/métodos , Potenciais Evocados/fisiologia , Humanos
13.
eNeurologicalSci ; 27: 100407, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35669231

RESUMO

During a social evaluation, the right temporo-parietal junction (rTPJ) plays an important role according to its contribution in making inferences about the mental states of others. However, what is the neural response if rTPJ function is inhibited during a mentalizing task? In this study, participants played the Dictator Game with two confederates: one playing cooperation (C) and other playing non-cooperation (NC) role and then they were scanned during a mentalizing test. However, we inhibited rTPJ using transcranial magnetic stimulation (TMS) after they played the game and before they were scanned. In this test, participants read negative (Neg) or positive (Pos) personal situations and then they watched confederate's pictures. Images from the TMS group were compared against controls with no TMS stimulation. After statistical comparison, we found a significantly higher activity in right and left visual association areas (BA 18) during the NCPos > NCNeg condition in the TMS group compared with the No-TMS group. Same visual association areas have been described before when participants are processing visual emotional information or when making a fast social categorization. This could reflect a neural mechanism of socio - emotional categorization that emerges after rTPJ inhibition.

14.
Mol Brain ; 15(1): 50, 2022 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-35672792

RESUMO

Theta is one of the most prominent extracellular synchronous oscillations in the mammalian brain. Hippocampal theta relies on an intact medial septum (MS) and has been consistently recorded during the training phase of some learning paradigms, suggesting that it may be implicated in hippocampus-dependent long-term memory processing. Object recognition memory (ORM) allows animals to identify familiar items and is essential for remembering facts and events. In rodents, long-term ORM formation requires a functional hippocampus but the involvement of the MS in this process remains controversial. We found that training adult male Wistar rats in a long-term ORM-inducing learning task involving exposure to two different, but behaviorally equivalent novel stimuli objects increased hippocampal theta power, and that suppressing theta via optogenetic MS inactivation caused amnesia. Importantly, the amnesia was specific to the object the animals were exploring when the MS was inactivated. Taken together, our results indicate that the MS is necessary for long-term ORM formation and suggest that hippocampal theta activity is causally linked to this process.


Assuntos
Optogenética , Ritmo Teta , Amnésia , Animais , Hipocampo/fisiologia , Masculino , Mamíferos , Memória de Longo Prazo , Optogenética/métodos , Ratos , Ratos Wistar , Ritmo Teta/fisiologia
15.
Proc Natl Acad Sci U S A ; 119(20): e2203024119, 2022 05 17.
Artigo em Inglês | MEDLINE | ID: mdl-35561217

RESUMO

Remembering life episodes is a complex process that requires interaction among multiple brain areas. It is thought that contextual information provided by the hippocampus (HPC) can trigger the recall of a past event through the activation of medial prefrontal cortex (mPFC) neuronal ensembles, but the underlying mechanisms remain poorly understood. However, little is known about the coordinated activity between these structures during recall. We performed electrophysiological recordings in behaving rats during the retrieval phase of the object-in-context (OIC) memory task. Context-guided recognition of objects in this task requires the activity of both the mPFC and the ventral HPC (vHPC). Coherence, phase locking, and theta amplitude correlation analysis showed an increase in vHPC-mPFC LFP synchronization in the theta range when animals explore contextually mismatched objects. Moreover, we identified ensembles of putative pyramidal cells in the mPFC that encode specific object­context associations. Interestingly, the increase of vHPC-mPFC synchronization during exploration of the contextually mismatched object and the preference of mPFC incongruent object neurons predicts the animals' performance during the resolution of the OIC task. Altogether, these results identify changes in vHPC-mPFC synchronization and mPFC ensembles encoding specific object­context associations likely involved in the recall of past events.


Assuntos
Hipocampo , Rememoração Mental , Córtex Pré-Frontal , Animais , Hipocampo/fisiologia , Rememoração Mental/fisiologia , Córtex Pré-Frontal/fisiologia , Ratos
16.
Forensic Sci Int Genet ; 58: 102678, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35168016

RESUMO

When DNA profile comparisons between a crime scene trace and a reference sample generate correspondence, the match probability has to be estimated, so that evaluation of the strength of the forensic DNA evidence can be made. The random match probability estimations require information on allele frequencies and an adjustment factor, referred to as theta (θ) or Fst, a co-ancestry correction factor for subpopulation effects. The θ value has been standardized for urban and isolated populations, but inconsistencies have been reported when it is specifically calculated for smaller and isolated populations, including Amerindian populations. Notably, attempts to characterize forensic markers of these minor populations have been extensively limited and more conservative estimates of the correction factor may be generated for each of them. Therefore, we estimate allele frequencies of 21 autosomal STR markers used for forensic testing and calculated relevant forensic parameters for the set. In addition, we featured the possible structure of five Brazilian Amerindian populations that have been genetically isolated for centuries so we could obtain the appropriate θ value for them. The sample consisted of 319 individuals: (1) 121 Kaingang, from two communities: Ivaí (KIV=61) and Rio das Cobras (KRC=60); and (2) 198 Guaranis from three communities: Mbya from Rio das Cobras (GRC=51), Guarani Ñandeva (GND=71) and Guarani Kaiowá (GKW=76). Between Guarani populations low (Rst=0.0402, p < 10-4) to high (Rst=0.1557, p < 10-5) differentiation was found. Regarding Guarani and Kaingang populations, intermediate (Rst=0.0590, p < 10-5) to high (Rst=0.1604, p < 10-5) differentiation was found. The two Kaingang populations showed very low differentiation between them (Rst=0.0017, p = 0.27), which justifies the union of both genetic data for forensic databases and calculations. The combined power of discrimination (PD) and the combined power of exclusion (PE) were calculated for each population, demonstrating the usefulness of this set of markers in forensic and kinship analysis regarding these populations. Considering the demographic heterogeneity of Amerindian populations in general, the Fst mean value (0.03) was evaluated regarding 43 different indigenous populations from the Americas, including Guaranis and Kaingangs. This result confirms the adequacy of the standardized θ value for the forensic random match probability estimations involving Amerindian populations.


Assuntos
Genética Forense , Indígenas Sul-Americanos , Brasil , Frequência do Gene , Genética Populacional , Humanos , Indígenas Sul-Americanos/genética
17.
Brain Sci ; 13(1)2022 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-36671983

RESUMO

The septal complex regulates both motivated and innate behaviors, chiefly by the action of its diverse population of long-range projection neurons. A small population of somatostatin-expressing GABAergic cells in the lateral septum projects deep into subcortical regions, yet on its way it also targets neighboring medial septum neurons that profusely innervate cortical targets by ascending synaptic pathways. Here, we used optogenetic stimulation and extracellular recordings in acutely anesthetized transgenic mice to show that lateral septum somatostatin neurons can disinhibit the cholinergic septo-hippocampal pathway, thus enhancing the amplitude and synchrony of theta oscillations while depressing sharp-wave ripple episodes in the dorsal hippocampus. These results suggest that septal somatostatin cells can recruit ascending cholinergic pathways to promote hippocampal theta oscillations.

18.
Hippocampus ; 32(1): 38-54, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34843143

RESUMO

The hippocampus has been linked to memory encoding and spatial navigation, while the prefrontal cortex is associated with cognitive functions such as decision-making. These regions are hypothesized to communicate in tasks that demand both spatial navigation and decision-making processes. However, the electrophysiological signatures underlying this communication remain to be better elucidated. To investigate the dynamics of the hippocampal-prefrontal interactions, we have analyzed their local field potentials and spiking activity recorded from rats performing a spatial alternation task on a figure eight-shaped maze. We found that the phase coherence of theta peaked around the choice point area of the maze. Moreover, Granger causality revealed a hippocampus → prefrontal cortex directionality of information flow at theta frequency, peaking at starting areas of the maze, and on the reverse direction at delta frequency, peaking near the turn onset. Additionally, the patterns of phase-amplitude cross-frequency coupling within and between the regions also showed spatial selectivity, and hippocampal theta and prefrontal delta modulated not only gamma amplitude but also inter-regional gamma synchrony. Finally, we found that the theta rhythm dynamically modulated neurons in both regions, with the highest modulation at the choice area; interestingly, prefrontal cortex neurons were more strongly modulated by the hippocampal theta rhythm than by their local field rhythm. In all, our results reveal maximum electrophysiological interactions between the hippocampus and the prefrontal cortex near the decision-making period of the spatial alternation task, corroborating the hypothesis that a dynamic interplay between these regions takes place during spatial decisions.


Assuntos
Hipocampo , Ritmo Teta , Animais , Cognição , Hipocampo/fisiologia , Neurônios , Córtex Pré-Frontal/fisiologia , Ratos , Ritmo Teta/fisiologia
19.
Int J Neurosci ; 132(6): 563-573, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32962509

RESUMO

AIM: The study investigated the cortical activity changes and time production task performance induced by changes in motion speed of a non-immersive 3D virtual stimulus. MATERIAL AND METHODS: Twenty-one individuals were participated in the crossover study with the visual-time reproduction task under three-speed conditions: original, slow and fast virtual stimulus. In addition, the electroencephalographic analysis of the theta band power in the dorsolateral prefrontal cortex was done simultaneously with time production task execution. RESULTS: The results demonstrated that in the slow speed condition, there is an increase in the error in the time production task after virtual reality (p < 0.05). There is also increased EEG theta power in the right dorsolateral prefrontal cortex in all speed conditions (p < 0.05). CONCLUSIONS: We propose that the modulations of speed of virtual stimulus may underlie the accumulation of temporal pulses, which could be responsible for changes in the performance of the production task of the time intervals and a substantial increase in right dorsolateral prefrontal cortex activity related to attention and memory, acting in cognitive domains of supraseconds.


Assuntos
Córtex Pré-Frontal Dorsolateral , Eletroencefalografia , Análise e Desempenho de Tarefas , Atenção , Estudos Cross-Over , Eletroencefalografia/métodos , Humanos , Córtex Pré-Frontal , Percepção do Tempo , Realidade Virtual
20.
Front Psychol ; 12: 764068, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34867666

RESUMO

Binaural beats (BB) consist of two slightly distinct auditory frequencies (one in each ear), which are differentiated with clinical electroencephalographic (EEG) bandwidths, namely, delta, theta, alpha, beta, or gamma. This auditory stimulation has been widely used to module brain rhythms and thus inducing the mental condition associated with the EEG bandwidth in use. The aim of this research was to investigate whether personalized BB (specifically those within theta and beta EEG bands) improve brain entrainment. Personalized BB consisted of pure tones with a carrier tone of 500 Hz in the left ear together with an adjustable frequency in the right ear that was defined for theta BB (since f c for theta EEG band was 4.60 Hz ± 0.70 SD) and beta BB (since f c for beta EEG band was 18.42 Hz ± 2.82 SD). The adjustable frequencies were estimated for each participant in accordance with their heart rate by applying the Brain-Body Coupling Theorem postulated by Klimesch. To achieve this aim, 20 healthy volunteers were stimulated with their personalized theta and beta BB for 20 min and their EEG signals were collected with 22 channels. EEG analysis was based on the comparison of power spectral density among three mental conditions: (1) theta BB stimulation, (2) beta BB stimulation, and (3) resting state. Results showed larger absolute power differences for both BB stimulation sessions than resting state on bilateral temporal and parietal regions. This power change seems to be related to auditory perception and sound location. However, no significant differences were found between theta and beta BB sessions when it was expected to achieve different brain entrainments, since theta and beta BB induce relaxation and readiness, respectively. In addition, relative power analysis (theta BB/resting state) revealed alpha band desynchronization in the parieto-occipital region when volunteers listened to theta BB, suggesting that participants felt uncomfortable. In conclusion, neural resynchronization was met with both personalized theta and beta BB, but no different mental conditions seemed to be achieved.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA