Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 79
Filtrar
1.
J Neurosci ; 2024 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-38527807

RESUMEN

Adaptive behavior relies both on specific rules that vary across situations and stable long-term knowledge gained from experience. The frontoparietal control network (FPCN) is implicated in the brain's ability to balance these different influences on action. Here, we investigate how the topographical organization of the cortex supports behavioral flexibility within the FPCN. Functional properties of this network might reflect its juxtaposition between the dorsal attention network (DAN) and the default mode network (DMN), two large-scale systems implicated in top-down attention and memory-guided cognition, respectively. Our study tests whether subnetworks of FPCN are topographically proximal to the DAN and the DMN, respectively, and how these topographical differences relate to functional differences: the proximity of each subnetwork is anticipated to play a pivotal role in generating distinct cognitive modes relevant to working memory and long-term memory. We show that FPCN subsystems share multiple anatomical and functional similarities with their neighboring systems (DAN and DMN) and that this topographic architecture supports distinct interaction patterns that give rise to different patterns of functional behavior. The FPCN acts as a unified system when long-term knowledge supports behavior but becomes segregated into discrete subsystems with different patterns of interaction when long term memory is less relevant. In this way, our study suggests that the topographic organization of the FPCN, as well as the connections it forms with distant regions of cortex, are important influences on how this system supports flexible behavior.Significance Statement Adaptive behavior depends on adjudicating between specific rules that vary across situations. The frontoparietal control network (FPCN) helps guide this process through its interactions with other brain regions. We examined how local topographical features support this function of the FPCN. Subnetworks within the FPCN share key anatomical and functional features with adjacent systems linked to external attention and long-term knowledge. This topographic architecture supports the emergence of distinct interaction patterns: FPCN subnetworks act cohesively when long-term memory can support behavior, but segregate when long-term memory is not aligned with current goals. Our study shows that, in addition to dynamic interaction with spatially distant cortical regions, local topographical features of the FPCN play a significant role in flexible behavior.

2.
Neuropsychologia ; 196: 108824, 2024 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-38387554

RESUMEN

Using a creative production task, jazz improvisation, we tested alternative hypotheses about the flow experience: (A) that it is a state of domain-specific processing optimized by experience and characterized by minimal interference from task-negative default-mode network (DMN) activity versus (B) that it recruits domain-general task-positive DMN activity supervised by the fronto-parietal control network (FPCN) to support ideation. We recorded jazz guitarists' electroencephalograms (EEGs) while they improvised to provided chord sequences. Their flow-states were measured with the Core Flow State Scale. Flow-related neural sources were reconstructed using SPM12. Over all musicians, high-flow (relative to low-flow) improvisations were associated with transient hypofrontality. High-experience musicians' high-flow improvisations showed reduced activity in posterior DMN nodes. Low-experience musicians showed no flow-related DMN or FPCN modulation. High-experience musicians also showed modality-specific left-hemisphere flow-related activity while low-experience musicians showed modality-specific right-hemisphere flow-related deactivations. These results are consistent with the idea that creative flow represents optimized domain-specific processing enabled by extensive practice paired with reduced cognitive control.


Asunto(s)
Encéfalo , Música , Humanos , Mapeo Encefálico/métodos , Electroencefalografía , Música/psicología
3.
Cortex ; 172: 141-158, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38330778

RESUMEN

BACKGROUND: Cognitive control processes, including those involving frontoparietal networks, are highly variable between individuals, posing challenges to basic and clinical sciences. While distinct frontoparietal networks have been associated with specific cognitive control functions such as switching, inhibition, and working memory updating functions, there have been few basic tests of the role of these networks at the individual level. METHODS: To examine the role of cognitive control at the individual level, we conducted a within-subject excitatory transcranial magnetic stimulation (TMS) study in 19 healthy individuals that targeted intrinsic ("resting") frontoparietal networks. Person-specific intrinsic networks were identified with resting state functional magnetic resonance imaging scans to determine TMS targets. The participants performed three cognitive control tasks: an adapted Navon figure-ground task (requiring set switching), n-back (working memory), and Stroop color-word (inhibition). OBJECTIVE: Hypothesis: We predicted that stimulating a network associated with externally oriented control [the "FPCN-B" (fronto-parietal control network)] would improve performance on the set switching and working memory task relative to a network associated with attention (the Dorsal Attention Network, DAN) and cranial vertex in a full within-subjects crossover design. RESULTS: We found that set switching performance was enhanced by FPCN-B stimulation along with some evidence of enhancement in the higher-demand n-back conditions. CONCLUSION: Higher task demands or proactive control might be a distinguishing role of the FPCN-B, and personalized intrinsic network targeting is feasible in TMS designs.


Asunto(s)
Memoria a Corto Plazo , Estimulación Magnética Transcraneal , Humanos , Memoria a Corto Plazo/fisiología , Imagen por Resonancia Magnética , Inhibición Psicológica , Cognición/fisiología , Encéfalo/fisiología
4.
Cogn Affect Behav Neurosci ; 24(1): 111-125, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38253775

RESUMEN

The mechanisms for how large-scale brain networks contribute to sustained attention are unknown. Attention fluctuates from moment to moment, and this continuous change is consistent with dynamic changes in functional connectivity between brain networks involved in the internal and external allocation of attention. In this study, we investigated how brain network activity varied across different levels of attentional focus (i.e., "zones"). Participants performed a finger-tapping task, and guided by previous research, in-the-zone performance or state was identified by low reaction time variability and out-of-the-zone as the inverse. In-the-zone sessions tended to occur earlier in the session than out-of-the-zone blocks. This is unsurprising given the way attention fluctuates over time. Employing a novel method of time-varying functional connectivity, called the quasi-periodic pattern analysis (i.e., reliable, network-level low-frequency fluctuations), we found that the activity between the default mode network (DMN) and task positive network (TPN) is significantly more anti-correlated during in-the-zone states versus out-of-the-zone states. Furthermore, it is the frontoparietal control network (FPCN) switch that differentiates the two zone states. Activity in the dorsal attention network (DAN) and DMN were desynchronized across both zone states. During out-of-the-zone periods, FPCN synchronized with DMN, while during in-the-zone periods, FPCN switched to synchronized with DAN. In contrast, the ventral attention network (VAN) synchronized more closely with DMN during in-the-zone periods compared with out-of-the-zone periods. These findings demonstrate that time-varying functional connectivity of low frequency fluctuations across different brain networks varies with fluctuations in sustained attention or other processes that change over time.


Asunto(s)
Mapeo Encefálico , Imagen por Resonancia Magnética , Humanos , Imagen por Resonancia Magnética/métodos , Encéfalo/diagnóstico por imagen , Tiempo de Reacción
5.
J Neurosci ; 44(2)2024 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-37963765

RESUMEN

Recently, multi-voxel pattern analysis has verified that information can be removed from working memory (WM) via three distinct operations replacement, suppression, or clearing compared to information being maintained ( Kim et al., 2020). While univariate analyses and classifier importance maps in Kim et al. (2020) identified brain regions that contribute to these operations, they did not elucidate whether these regions represent the operations similarly or uniquely. Using Leiden-community-detection on a sample of 55 humans (17 male), we identified four brain networks, each of which has a unique configuration of multi-voxel activity patterns by which it represents these WM operations. The visual network (VN) shows similar multi-voxel patterns for maintain and replace, which are highly dissimilar from suppress and clear, suggesting this network differentiates whether an item is held in WM or not. The somatomotor network (SMN) shows a distinct multi-voxel pattern for clear relative to the other operations, indicating the uniqueness of this operation. The default mode network (DMN) has distinct patterns for suppress and clear, but these two operations are more similar to each other than to maintain and replace, a pattern intermediate to that of the VN and SMN. The frontoparietal control network (FPCN) displays distinct multi-voxel patterns for each of the four operations, suggesting that this network likely plays an important role in implementing these WM operations. These results indicate that the operations involved in removing information from WM can be performed in parallel by distinct brain networks, each of which has a particular configuration by which they represent these operations.


Asunto(s)
Encéfalo , Memoria a Corto Plazo , Masculino , Humanos , Encéfalo/diagnóstico por imagen , Encéfalo/cirugía , Mapeo Encefálico , Estimulación Luminosa , Imagen por Resonancia Magnética/métodos
6.
Acta Neuropsychiatr ; 36(1): 39-43, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-37622320

RESUMEN

OBJECTIVE: Rumination is a passive form of negative self-focused cognition that predicts depressive episodes for individuals with bipolar disorder (BD). Individuals with BD also have impaired inhibitory executive control; rumination in BD may therefore reflect executive dysfunction. We investigated the relationship between a neural measure of executive functioning (functional connectivity between the frontoparietal control network [FPCN] and the default mode network [DMN] during an effortful task), behavioural measures of executive functioning (the Behavior Rating Inventory of Executive Function) and rumination (the Ruminative Responses Scale). METHODS: Fifteen individuals with BD and fifteen healthy controls underwent MRI scans during mental distraction. Using CONN toolbox, between-network FPCN-DMN connectivity values were calculated. We conducted Pearson's r bivariate correlations between connectivity values, BRIEF and RRS scores. RESULTS: RRS scores were positively correlated with BRIEF Behavioral Regulation Index (BRI) scores. In individuals with BD, there was a positive correlation between FPCN-DMN functional connectivity during distraction and BRIEF BRI scores. FPCN-DMN functional connectivity was also positively correlated with RRS ruminative brooding scores. Healthy controls did not show significant correlations between these behavioural and neural measures of executive functioning and rumination. CONCLUSION: For individuals with BD, the greater the tendency to ruminate and the higher the executive dysfunction, the stronger the connectivity between an executive control network and a network involved in rumination during an unrelated cognitive task. This could reflect continual attempts to inhibit ruminative thinking and shift back to the distraction task. Therefore, engagement in rumination may reflect failed inhibitory executive control.


Asunto(s)
Trastorno Bipolar , Función Ejecutiva , Humanos , Función Ejecutiva/fisiología , Mapeo Encefálico , Encéfalo/diagnóstico por imagen , Cognición , Imagen por Resonancia Magnética
7.
Front Psychol ; 14: 1264221, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37965648

RESUMEN

Background: Rumination impedes problem solving and is one of the most important factors in the onset and maintenance of multiple psychiatric disorders. The current study aims to investigate the impact of social rejection on rumination and explore the underlying neural mechanisms involved in this process. Methods: We utilized psychological questionnaire and resting-state brain imaging data from a sample of 560 individuals. The predictive model for rumination scores was constructed using resting-state functional connectivity data through connectome-based predictive modeling. Additionally, a mediation analysis was conducted to investigate the mediating role of the prediction network in the relationship between social rejection and rumination. Results: A positive correlation between social rejection and rumination was found. We obtained the prediction model of rumination and found that the strongest contributions came from the intra- and internetwork connectivity within the default mode network (DMN), dorsal attention network (DAN), frontoparietal control network (FPCN), and sensorimotor networks (SMN). Analysis of node strength revealed the significance of the supramarginal gyrus (SMG) and angular gyrus (AG) as key nodes in the prediction model. In addition, mediation analysis showed that the strength of the prediction network mediated the relationship between social rejection and rumination. Conclusion: The findings highlight the crucial role of functional connections among the DMN, DAN, FPCN, and SMN in linking social rejection and rumination, particular in brain regions implicated in social cognition and emotion, namely the SMG and AG regions. These results enhance our understanding of the consequences of social rejection and provide insights for novel intervention strategies targeting rumination.

8.
Front Neurol ; 14: 1273935, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-38020657

RESUMEN

Objective: Primary blepharospasm (BSP) is a clinically heterogeneous disease that manifests not only as spasmodic closure of the eyelids but also sometimes with apraxia of eyelid opening (AEO). This cross-sectional study aimed to investigate differences in the neural mechanisms of isolated BSP and BSP-associated AEO subtypes, which may reveal the pathophysiology underlying different phenotypes. Methods: A total of 29 patients manifested as isolated BSP, 17 patients manifested as BSP associated with AEO, and 28 healthy controls underwent resting-state functional near-infrared spectroscopy (fNIRS). We assessed functional connectivity (FC) between regions of interest (ROIs) in the fronto-parietal control network (PFCN) and sensorimotor network (SMN). We also examined the relationship between altered FC and behavioral data. Results: In the FPCN, ROI- analyses showed decreased FC between the left premotor cortex and supramarginal gyrus in the BSP with AEO group compared to the isolated BSP group. In the SMN, both subgroups showed hypoconnectivity of the left premotor cortex with the right primary motor cortex, primary sensory cortex, and somatosensory association cortex. This hypoconnectivity was positively correlated with the total number of botulinum toxin A treatments, which suggests that long-term botulinum toxin A treatment may modulate motor sequence planning and coordination. Conclusion: These findings showed different connectivity alterations in neural networks associated with motor and cognitive control among different behavioral phenotypes of BSP. The identification of specific alterations in various networks that correspond to clinical heterogeneity may inform the identification of potential biomarkers for early diagnosis and personalized neuromodulation targets for treating different BSP subphenotypes.

9.
Neuroimage ; 283: 120386, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37820860

RESUMEN

Cognitive control (CC) is essential for problem-solving in everyday life, and CC-related deficits occur alongside costly and debilitating disorders. The tri-partite model suggests that CC comprises multiple behaviors, including switching, inhibiting, and updating. Activity within the fronto-parietal control network B (FPCN-B), the dorsal attention network (DAN), the cingulo-opercular network (CON), and the lateral default-mode network (L-DMN) is related to switching and inhibiting behaviors. However, our understanding of how these brain regions interact to bring about cognitive switching and inhibiting in individuals is unclear. In the current study, subjects performed two in-scanner tasks that required switching and inhibiting. We used support vector regression (SVR) models containing individually-estimated functional connectivity between the FPCN-B, DAN, CON and L-DMN to predict switching and inhibiting behaviors. We observed that: inter-network connectivity can predict inhibiting and switching behaviors in individuals, and the L-DMN plays a role in switching and inhibiting behaviors. Therefore, individually estimated inter-network connections are markers of CC behaviors, and CC behaviors may arise due to interactions between a set of networks.


Asunto(s)
Mapeo Encefálico , Disfunción Cognitiva , Humanos , Imagen por Resonancia Magnética , Encéfalo , Cognición
10.
Geroscience ; 45(5): 3079-3093, 2023 10.
Artículo en Inglés | MEDLINE | ID: mdl-37814198

RESUMEN

Limited research exists on the association between resting-state functional network connectivity in the brain and learning and memory processes in advanced age. This study examined within-network connectivity of cingulo-opercular (CON), frontoparietal control (FPCN), and default mode (DMN) networks, and verbal and visuospatial learning and memory in older adults. Across domains, we hypothesized that greater CON and FPCN connectivity would associate with better learning, and greater DMN connectivity would associate with better memory. A total of 330 healthy older adults (age range = 65-89) underwent resting-state fMRI and completed the Hopkins Verbal Learning Test-Revised (HVLT-R) and Brief Visuospatial Memory Test-Revised (BVMT-R) in a randomized clinical trial. Total and delayed recall scores were assessed from baseline data, and a learning ratio calculation was applied to participants' scores. Average CON, FPCN, and DMN connectivity values were obtained with CONN Toolbox. Hierarchical regressions controlled for sex, race, ethnicity, years of education, and scanner site, as this was a multi-site study. Greater within-network CON connectivity was associated with better verbal learning (HVLT-R Total Recall, Learning Ratio), visuospatial learning (BVMT-R Total Recall), and visuospatial memory (BVMT-R Delayed Recall). Greater FPCN connectivity was associated with better visuospatial learning (BVMT-R Learning Ratio) but did not survive multiple comparison correction. DMN connectivity was not associated with these measures of learning and memory. CON may make small but unique contributions to learning and memory across domains, making it a valuable target in future longitudinal studies and interventions to attenuate memory decline. Further research is necessary to understand the role of FPCN in learning and memory.


Asunto(s)
Encéfalo , Imagen por Resonancia Magnética , Humanos , Anciano , Anciano de 80 o más Años , Encéfalo/diagnóstico por imagen , Memoria , Aprendizaje , Recuerdo Mental
11.
Res Sq ; 2023 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-37609235

RESUMEN

Repetitive transcranial magnetic stimulation (rTMS) is an effective treatment for depression and has been shown to modulate resting-state functional connectivity (RSFC) of depression-relevant neural circuits. To date, however, few studies have investigated whether individual treatment-related symptom changes are predictable from pretreatment RSFC. We use machine learning to predict dimensional changes in depressive symptoms using pretreatment patterns of RSFC. We hypothesized that changes in dimensional depressive symptoms would be predicted more accurately than scale total scores. Patients with depression (n=26) underwent pretreatment RSFC MRI. Depressive symptoms were assessed with the 17-item Hamilton Depression Rating Scale (HDRS-17). Random forest regression (RFR) models were trained and tested to predict treatment-related symptom changes captured by the HDRS-17, HDRS-6 and three previously identified HDRS subscales: core mood/anhedonia (CMA), somatic disturbances, and insomnia. Changes along the CMA, HDRS-17, and HDRS-6 were predicted significantly above chance, with 9%, 2%, and 2% of out-of-sample outcome variance explained, respectively (all p<0.01). CMA changes were predicted more accurately than the HDRS-17 (p<0.05). Higher baseline global connectivity (GC) of default mode network (DMN) subregions and the somatomotor network (SMN) predicted poorer symptom reduction, while higher GC of the right dorsal attention (DAN) frontoparietal control (FPCN), and visual networks (VN) predicted reduced CMA symptoms. HDRS-17 and HDRS-6 changes were predicted with similar GC patterns. These results suggest that RSFC spanning the DMN, SMN, DAN, FPCN, and VN subregions predict dimensional changes with greater accuracy than syndromal changes following rTMS. These findings highlight the need to assess more granular clinical dimensions in therapeutic studies, particularly device neuromodulation studies, and echo earlier studies supporting that dimensional outcomes improve model accuracy.

12.
Cortex ; 166: 154-171, 2023 09.
Artículo en Inglés | MEDLINE | ID: mdl-37385005

RESUMEN

Psychological refractory period (PRP) effect refers to the delay in responding to the second of two tasks occurring in rapid succession. While all the major models of PRP highlight the importance of the frontoparietal control network (FPCN) in prioritizing the neural processing of the first task, the fate of the second task remains poorly understood. Here, we provide novel neural evidence on how the functional connectivity between sensory systems and the default-mode network (DMN) suspends the neural processing of the second task to ensure the efficient completion of the first task in dual-task situation. In a cross-modal PRP paradigm, a visual task could either precede or follow an auditory task. The DMN was generally deactivated during task performance and selectively coupled with the sensory system underlying the second task subjected to the PRP effect. Specifically, the DMN showed neural coupling with the auditory system when the auditory task came after the visual task, and with the visual system vice versa. More critically, the strength of the DMN-Sensory coupling correlated negatively with the size of the PRP effect: the stronger the coupling, the shorter the PRP. Therefore, rather than being detrimental to the dual-task performance, temporary suspension of the second task, via the DMN-Sensory coupling, surprisingly guaranteed the efficient completion of the first task by reducing the interference from the second task. Accordingly, the entry and processing of the second stimuli in the central executive system were speeded up as well.


Asunto(s)
Red en Modo Predeterminado , Análisis y Desempeño de Tareas , Humanos , Órganos de los Sentidos , Imagen por Resonancia Magnética , Mapeo Encefálico , Encéfalo , Vías Nerviosas , Red Nerviosa
13.
J Hazard Mater ; 457: 131826, 2023 Sep 05.
Artículo en Inglés | MEDLINE | ID: mdl-37320904

RESUMEN

Membrane separation techniques are promising methods for effectively treating hazardous emulsified oily wastewater, but membrane fouling remains a serious challenge because the high viscosity and complex composition of crude oil make it easy to adhere to membranes and difficult to be removed by conventional physical or chemical cleaning means. Herein, a two-stage solar-driven (photo-Fenton degradation/evaporation) strategy was proposed to realize the self-cleaning of membranes fouled by viscous crude oil (>60,000 mPa s), wherein the photo-Fenton process helped to degrade the heavy components into light components, and all light components removed during the solar-driven evaporation process. A 1D/2D heterostructure membrane with photo-Fenton activity and anti-crude-oil-fouling performance was prepared via a facile self-assembly vacuum-assist method. The addition of rod-like g-C3N4 (RCN) increased the interlayer distance of α-FeOOH/porous g-C3N4 (FPCN) nanosheets, resulting in a high permeation flux. The FPCN-RCN membrane exhibited both high permeation flux of 779 ± 19 L m-2h-1bar-1 and a separation efficiency of 99.4% for highly viscous crude oil-in-water emulsion. Importantly, the viscous crude oil fouled on the membrane was completely removed by the photo-Fenton degradation/solar-driven evaporation strategy, and the flux recovery rate of the membrane was ∼100%. Therefore, the FPCN-RCN membrane combined with the novel self-cleaning strategy exhibits great potential for practical emulsified oily wastewater treatment.

14.
Schizophr Bull ; 48(6): 1344-1353, 2022 11 18.
Artículo en Inglés | MEDLINE | ID: mdl-35869578

RESUMEN

BACKGROUND: The deficit syndrome is a clinical subtype of schizophrenia that is characterized by enduring negative symptoms. Several lines of evidence point to frontoparietal involvement, but the frontoparietal control network (FPCN) and its subsystems (FPCNA and FPCNB) proposed by Yeo et al. have not been systematically characterized at rest in patients with the deficit syndrome. METHODS: We used resting-state fMRI to investigate the FPCN and its subnetworks in 72 healthy controls and 65 antipsychotic medication-naive, first-episode psychosis patients (22 displayed deficit syndrome features, 43 did not). To assess whole-brain FPCN connectivity, we used the right posterior parietal cortex as the seed region. We then performed region of interest analyses in FPCN subsystems. RESULTS: We found that patterns of FPCN dysconnectivity to the whole brain differed in patients who displayed deficit syndrome features compared with those who did not. Examining the FPCN on a more granular level revealed reduced within-FPCN(A) connectivity only in patients displaying deficit features. FPCNB connectivity did not differ between patient groups. DISCUSSION: Here, we describe a neurobiological signature of aberrant FPCN connectivity in antipsychotic-naive, first-episode patients who display clinical features of the deficit syndrome. Importantly, frontoparietal subnetwork connectivity differentiated subgroups, where the FPCNA is selectively involved in patients with deficit features. Our findings add to the growing body of literature supporting a neurobiological distinction between two clinical subtypes of schizophrenia, which has the potential to be leveraged for patient stratification in clinical trials and the development of novel treatments.


Asunto(s)
Antipsicóticos , Trastornos Psicóticos , Humanos , Antipsicóticos/farmacología , Trastornos Psicóticos/diagnóstico por imagen , Trastornos Psicóticos/tratamiento farmacológico , Mapeo Encefálico , Encéfalo , Imagen por Resonancia Magnética , Red Nerviosa/diagnóstico por imagen
15.
Sci Rep ; 12(1): 12260, 2022 07 18.
Artículo en Inglés | MEDLINE | ID: mdl-35851275

RESUMEN

This meta-analysis sought to expand upon neurobiological models of mindfulness through investigation of inherent brain network connectivity outcomes, indexed via resting state functional connectivity (rsFC). We conducted a systematic review and meta-analysis of rsFC as an outcome of mindfulness training (MT) relative to control, with the hypothesis that MT would increase cross-network connectivity between nodes of the Default Mode Network (DMN), Salience Network (SN), and Frontoparietal Control Network (FPCN) as a mechanism of internally-oriented attentional control. Texts were identified from the databases: MEDLINE/PubMed, ERIC, PSYCINFO, ProQuest, Scopus, and Web of Sciences; and were screened for inclusion based on experimental/quasi-experimental trial design and use of mindfulness-based training interventions. RsFC effects were extracted from twelve studies (mindfulness n = 226; control n = 204). Voxel-based meta-analysis revealed significantly greater rsFC (MT > control) between the left middle cingulate (Hedge's g = .234, p = 0.0288, I2 = 15.87), located within the SN, and the posterior cingulate cortex, a focal hub of the DMN. Egger's test for publication bias was nonsignificant, bias = 2.17, p = 0.162. In support of our hypothesis, results suggest that MT targets internetwork (SN-DMN) connectivity implicated in the flexible control of internally-oriented attention.


Asunto(s)
Atención Plena , Encéfalo/diagnóstico por imagen , Mapeo Encefálico/métodos , Red en Modo Predeterminado , Imagen por Resonancia Magnética/métodos , Atención Plena/métodos
16.
Transl Psychiatry ; 12(1): 262, 2022 06 27.
Artículo en Inglés | MEDLINE | ID: mdl-35760805

RESUMEN

Previous work identified a cognitive subtype of PTSD with impaired executive function (i.e., impaired EF-PTSD subtype) and aberrant resting-state functional connectivity between frontal parietal control (FPCN) and limbic (LN) networks. To better characterize this cognitive subtype of PTSD, this study investigated (1) alterations in specific FPCN and LN subnetworks and (2) chronicity of PTSD symptoms. In a post-9/11 veteran sample (N = 368, 89% male), we identified EF subgroups using a standardized neuropsychological battery and a priori cutoffs for impaired, average, and above-average EF performance. Functional connectivity between two subnetworks of the FPCN and three subnetworks of the LN was assessed using resting-state fMRI (n = 314). PTSD chronicity over a 1-2-year period was assessed using a reliable change index (n = 175). The impaired EF-PTSD subtype had significantly reduced negative functional connectivity between the FPCN subnetwork involved in top-down control of emotion and two LN subnetworks involved in learning/memory and social/emotional processing. This impaired EF-PTSD subtype had relatively chronic PTSD, while those with above-average EF and PTSD displayed greater symptom reduction. Lastly, FPCN-LN subnetworks partially mediated the relationship between EF and PTSD chronicity (n = 121). This study reveals (1) that an impaired EF-PTSD subtype has a specific pattern of FPCN-LN subnetwork connectivity, (2) a novel above-average EF-PTSD subtype displays reduced PTSD chronicity, and (3) both cognitive and neural functioning predict PTSD chronicity. The results indicate a need to investigate how individuals with this impaired EF-PTSD subtype respond to treatment, and how they might benefit from personalized and novel approaches that target these neurocognitive systems.


Asunto(s)
Mapeo Encefálico , Trastornos por Estrés Postraumático , Función Ejecutiva , Femenino , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Vías Nerviosas/diagnóstico por imagen
17.
Neurobiol Aging ; 117: 151-164, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35759984

RESUMEN

Cognitive Reserve (CR) is considered a protective factor during the aging process. However, although CR is a multifactorial construct, it has been operationalized in a unitary way (years of formal education or IQ). In the present study, a validated measure to categorize CR holistically (Cognitive Reserve Index Questionnaire) was used to evaluate the resting-state functional connectivity in 77 cognitively unimpaired participants aged 50 years and over with high and low CR, and matched brain global atrophy levels. The connectivity of networks linked to attentional (Dorsal Attention Network -DAN-) and executive (Frontal-Parietal Control Network -FPCN-) processes were evaluated by the combination of Independent Component Analysis and seed-based approaches, since these networks have been proposed as candidates to underlie the protective effect of CR in the aging context. Participants with high CR showed an increase of the connectivity in the FPCN and a decrease in the DAN with respect to the low CR group, correlating with neuropsychological scores and supporting that high CR is related to a better neurocognitive preservation during aging.


Asunto(s)
Reserva Cognitiva , Anciano , Envejecimiento , Atrofia , Encéfalo/diagnóstico por imagen , Mapeo Encefálico , Humanos , Imagen por Resonancia Magnética , Persona de Mediana Edad , Vías Nerviosas , Pruebas Neuropsicológicas
18.
Brain Struct Funct ; 227(7): 2243-2260, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35751677

RESUMEN

The frontoparietal control network (FPCN) plays a central role in tuning connectivity between brain networks to achieve integrated cognitive processes. It has been proposed that two subnetworks within the FPCN separately regulate two antagonistic networks: the FPCNa is connected to the default network (DN) that deals with internally oriented introspective processes, whereas the FPCNb is connected to the dorsal attention network (DAN) that deals with externally oriented perceptual attention. However, cooperation between the DN and DAN induced by distinct task demands has not been well-studied. Here, we characterized the dynamic cooperation among the DN, DAN, and two FPCN subnetworks in a task in which internally oriented self-referential processing could facilitate externally oriented visual working memory. Functional connectivity analysis showed enhanced coupling of a circuit from the DN to the FPCNa, then to the FPCNb, and finally to the DAN when the self-referential processing improved memory recognition in high self-referential conditions. The direct connection between the DN and DAN was not enhanced. This circuit could be reflected by an increased chain-mediating effect of the FPCNa and the FPCNb between the DN and DAN in high self-referential conditions. Graph analysis revealed that high self-referential conditions were accompanied by increased global and local efficiencies, and the increases were mainly driven by the increased efficiency of FPCN nodes. Together, our findings extend prior observations and indicate that the coupling between the two FPCN subnetworks serves as a bridge between the DN and DAN, supporting the interaction between internally oriented and externally oriented processes.


Asunto(s)
Mapeo Encefálico , Red Nerviosa , Encéfalo , Imagen por Resonancia Magnética
19.
Front Aging Neurosci ; 14: 858405, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35527739

RESUMEN

Previous research suggests a marked impact of aging on structural and functional connectivity within the frontoparietal control network (FPCN) and default mode network (DMN). As aging is also associated with reductions in cardiovascular fitness, age-related network connectivity differences reported by past studies could be partially due to age-related declines in fitness. Here, we use data collected as part of a 16-week exercise intervention to explore relationships between fitness and functional connectivity. Young and older adults completed baseline assessments including cardiovascular fitness, health and functioning measures, and an fMRI session. Scan data were acquired on a Siemens 3T MRI scanner with a 32-channel head coil. Results from regression analyses indicated that average connectivity did not differ between young and older adults. However, individual ROI-to-ROI connectivity analyses indicated weaker functional correlations for older adults between specific regions in the FPCN and DMN and, critically, many of these differences were attenuated when fitness was accounted for. Taken together, findings suggest that fitness exerts regional rather than global effects on network connectivity.

20.
Ultrason Sonochem ; 86: 106006, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35462135

RESUMEN

Crocin (saffron bioactive) loaded protein nanoparticles were prepared from three underutilised cereal varieties viz., sorghum (SPCN), foxtail millet (FPCN) and pearl millet (PPCN) using ultrasonication technique. The particle size of crocin loaded protein complex was attained in the nano range with reduced polydispersity index and negative zeta potential. The encapsulation efficiency of crocin in protein nanoparticles was found to be 83.78% (FPCN), 78.74 % (SPCN) and 70.01% (PPCN). The topographical images of crocin loaded protein nano complex was revealed using field emission-scanning electron microscopy (FE-SEM). The attenuated total reflectance fourier transform infra-spectroscopy (ATR-FTIR) analysis showed the characteristic peaks of crocin at 956, 1700 and 3350 cm-1 in protein-crocin nanocomplex as a confirmatory test for nanoencapsulation. The antimicrobial activity of crocin loaded protein nanocomplex against three strains (Escherichia coli, Staphylococcus aureus and Fusarium oxysporium) were also evaluated. In vitro release studies showed higher content of crocin released in simulated intestinal conditions ensuring its controlled release at target site. Bioactivity (anti-cancerous and anti-hypertensive) of crocin upon in-vitro digestion were well retained indicating that protein nanoparticles can act as an effective wall material. Our results suggest that protein nanoparticles prepared in this study can act as an effective oral delivery vehicle for crocin that could be used for development of functional foods.


Asunto(s)
Mijos , Nanopartículas , Grano Comestible , Nanopartículas/química , Tamaño de la Partícula , Staphylococcus aureus
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...