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1.
Cortex ; 176: 113-128, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38772050

ABSTRACT

Selective attention is a cognitive function that helps filter out unwanted information. Theories such as the biased competition model (Desimone & Duncan, 1995) explain how attentional templates bias processing towards targets in contexts where multiple stimuli compete for resources. However, it is unclear how the anticipation of different levels of competition influences the nature of attentional templates, in a proactive fashion. In this study, we used electroencephalography (EEG) to investigate how the anticipated demands of attentional selection (either high or low stimuli competition contexts) modulate target-specific preparatory brain activity and its relationship with task performance. To do so, participants performed a sex/gender judgment task in a cue-target paradigm where, depending on the block, target and distractor stimuli appeared simultaneously (high competition) or sequentially (low competition). Multivariate Pattern Analysis (MVPA) showed that, in both competition contexts, there was a preactivation of the target category to select, with a ramping-up profile at the end of the preparatory interval. However, cross-classification showed no generalization across competition conditions, suggesting different preparatory formats. Notably, time-frequency analyses showed differences between anticipated competition demands, with higher theta band power for high than low competition, which mediated the impact of subsequent stimuli competition on behavioral performance. Overall, our results show that, whereas preactivation of the internal templates associated with the category to select are engaged in advance in high and low competition contexts, their underlying neural patterns differ. In addition, these codes could not be associated with theta power, suggesting that they reflect different preparatory processes. The implications of these findings are crucial to increase our understanding of the nature of top-down processes across different contexts.


Subject(s)
Attention , Electroencephalography , Reaction Time , Humans , Male , Female , Attention/physiology , Young Adult , Adult , Reaction Time/physiology , Brain/physiology , Cues , Psychomotor Performance/physiology , Judgment/physiology
2.
Pediatrics ; 153(3)2024 Mar 01.
Article in English | MEDLINE | ID: mdl-38356410

ABSTRACT

CONTEXT: Health care settings have increasingly adopted universal suicide risk screening tools into nonpsychiatric pediatric care; however, a systematic review examining the accuracy of these tools does not yet exist. OBJECTIVE: Identify and review research on the test accuracy of suicide risk screening tools for pediatric patients in nonpsychiatric medical settings. DATA SOURCES: PubMed and PsycINFO were searched to identify peer-reviewed articles published before March 23, 2023. STUDY SELECTION: Articles that quantified the accuracy of a suicide risk screening tool (eg, sensitivity, specificity) in a nonpsychiatric medical setting (eg, primary care, specialty care, inpatient or surgical units, or the emergency department) were included. DATA EXTRACTION: A total of 13 studies were included in this review. Screening tool psychometric properties and study risk of bias were evaluated. RESULTS: Sensitivity among individual studies ranged from 50% to 100%, and specificity ranged from 58.8% to 96%. Methodological quality was relatively varied, and applicability concerns were low. When stratifying results by screening tool, the Ask Suicide-Screening Questions and Computerized Adaptive Screen for Suicidal Youth had the most robust evidence base. LIMITATIONS: Because of considerable study heterogeneity, a meta-analytic approach was deemed inappropriate. This prevented us from statistically testing for differences between identified screening tools. CONCLUSIONS: The Ask Suicide-Screening Questions and Computerized Adaptive Screen for Suicidal Youth exhibit satisfactory test accuracy and appear promising for integration into clinical practice. Although initial findings are promising, additional research targeted at examining the accuracy of screening tools among diverse populations is needed to ensure the equity of screening efforts.


Subject(s)
Medicine , Suicide , Adolescent , Humans , Child , Suicidal Ideation , Emergency Service, Hospital , Inpatients
3.
Neuroimage ; 271: 119960, 2023 05 01.
Article in English | MEDLINE | ID: mdl-36854351

ABSTRACT

Proactive cognition brain models are mainstream nowadays. Within these, preparation is understood as an endogenous, top-down function that takes place prior to the actual perception of a stimulus and improves subsequent behavior. Neuroimaging has shown the existence of such preparatory activity separately in different cognitive domains, however no research to date has sought to uncover their potential similarities and differences. Two of these, often confounded in the literature, are Selective Attention (information relevance) and Perceptual Expectation (information probability). We used EEG to characterize the mechanisms that pre-activate specific contents in Attention and Expectation. In different blocks, participants were cued to the relevance or to the probability of target categories, faces vs. names, in a gender discrimination task. Multivariate Pattern (MVPA) and Representational Similarity Analyses (RSA) during the preparation window showed that both manipulations led to a significant, ramping-up prediction of the relevant or expected target category. However, classifiers trained with data from one condition did not generalize to the other, indicating the existence of unique anticipatory neural patterns. In addition, a Canonical Template Tracking procedure showed that there was stronger anticipatory perceptual reinstatement for relevance than for expectation blocks. Overall, the results indicate that preparation during attention and expectation acts through distinguishable neural mechanisms. These findings have important implications for current models of brain functioning, as they are a first step towards characterizing and dissociating the neural mechanisms involved in top-down anticipatory processing.


Subject(s)
Brain Mapping , Motivation , Humans , Attention/physiology , Cognition , Cues
4.
Materials (Basel) ; 16(2)2023 Jan 04.
Article in English | MEDLINE | ID: mdl-36676208

ABSTRACT

Formic acid has recently been revealed to be an excellent hydrogen carrier, and interest in the development of efficient and selective catalysts towards its dehydrogenation has grown. This reaction has been widely explored using homogeneous catalysts; however, from a practical and scalable point of view, heterogeneous catalysts are usually preferred in industry. In this work, formic acid dehydrogenation reactions in both liquid- and vapor-phase conditions have been investigated using heterogeneous catalysts based on mono- or bimetallic Pd/Ru. In all of the explored conditions, the catalysts showed good catalytic activity and selectivity towards the dehydrogenation reaction, avoiding the formation of undesired CO.

5.
BMC Pediatr ; 22(1): 492, 2022 08 19.
Article in English | MEDLINE | ID: mdl-35986266

ABSTRACT

BACKGROUND: Achondroplasia is the most common bone dysplasia associated with disproportionate short stature, and other comorbidities, such as foramen magnum stenosis, thoracolumbar kyphosis, lumbar hyperlordosis, genu varum and spinal compression. Additionally, patients affected with this condition have higher frequency of sleep disorders, ear infections, hearing loss and slowed development milestones. Considering these clinical features, we aimed to summarize the regional experts' recommendations for the multidisciplinary management of patients with achondroplasia in Latin America, a vast geographic territory with multicultural characteristics and with socio-economical differences of developing countries. METHODS: Latin American experts (from Argentina, Brazil, Chile and Colombia) particiáted of an Advisory Board meeting (October 2019), and had a structured discussion how patients with achondroplasia are followed in their healthcare centers and punctuated gaps and opportunities for regional improvement in the management of achondroplasia. RESULTS: Practical recommendations have been established for genetic counselling, prenatal diagnosis and planning of delivery in patients with achondroplasia. An outline of strategies was added as follow-up guidelines to specialists according to patient developmental phases, amongst them neurologic, orthopedic, otorhinolaryngologic, nutritional and anthropometric aspects, and related to development milestones. Additionally, the role of physical therapy, physical activity, phonoaudiology and other care related to the quality of life of patients and their families were discussed. Preoperative recommendations to patients with achondroplasia were also included. CONCLUSIONS: This study summarized the main expert recommendations for the health care professionals management of achondroplasia in Latin America, reinforcing that achondroplasia-associated comorbidities are not limited to orthopedic concerns.


Subject(s)
Achondroplasia , Kyphosis , Achondroplasia/diagnosis , Achondroplasia/genetics , Achondroplasia/therapy , Child , Female , Genetic Counseling , Humans , Latin America/epidemiology , Quality of Life
6.
Cortex ; 149: 59-72, 2022 04.
Article in English | MEDLINE | ID: mdl-35184015

ABSTRACT

Verbal instructions allow fast and optimal implementation of novel behaviors. Previous research has shown that different control-related variables structure neural activity in frontoparietal regions during the encoding of novel instructed tasks. However, it is uncertain whether different task goals modulate the organizing effect of these variables. In this study, we investigated whether the neural encoding of three task-relevant variables (dimension integration, response set complexity and target category) is modulated by implementation and memorization demands. To do so, we combined functional Magnetic Resonance Imaging (fMRI), an instruction-following paradigm and multivariate analyses. We addressed how and where distributed activity patterns encoded the instructions' variables and the impact of the implementation and memorization demands on the fidelity of these representations. We further explored the nature of the neural code underpinning this process. Our results reveal, first, that the content of to-be-implemented and to-be-memorized instructions is represented in overlapping brain regions, flexibly using a common neural code across tasks. Importantly, they also suggest that preparing to implement the instructions increases the decodability of task-relevant information in frontoparietal areas, in comparison with memorization demands. Overall, our work emphasizes both similarities and differences in task coding under the two contextual demands. These findings qualify the previous understanding of novel instruction processing, suggesting that representing task attributes in a generalizable code, together with the increase in encoding fidelity induced by the implementation goals, could be key mechanisms for proactive control in novel scenarios.


Subject(s)
Frontal Lobe , Psychomotor Performance , Brain/diagnostic imaging , Brain/physiology , Brain Mapping , Frontal Lobe/physiology , Humans , Magnetic Resonance Imaging/methods , Parietal Lobe/diagnostic imaging , Parietal Lobe/physiology , Psychomotor Performance/physiology
7.
Comput Methods Programs Biomed ; 214: 106549, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34910975

ABSTRACT

BACKGROUND AND OBJECTIVE: The study of brain function has recently expanded from classical univariate to multivariate analyses. These multivariate, machine learning-based algorithms afford neuroscientists extracting more detailed and richer information from the data. However, the implementation of these procedures is usually challenging, especially for researchers with no coding experience. To address this problem, we have developed MVPAlab, a MATLAB-based, flexible decoding toolbox for multidimensional electroencephalography and magnetoencephalography data. METHODS: The MVPAlab Toolbox implements several machine learning algorithms to compute multivariate pattern analyses, cross-classification, temporal generalization matrices and feature and frequency contribution analyses. It also provides access to an extensive set of preprocessing routines for, among others, data normalization, data smoothing, dimensionality reduction and supertrial generation. To draw statistical inferences at the group level, MVPAlab includes a non-parametric cluster-based permutation approach. RESULTS: A sample electroencephalography dataset was compiled to test all the MVPAlab main functionalities. Significant clusters (p<0.01) were found for the proposed decoding analyses and different configurations, proving the software capability for discriminating between different experimental conditions. CONCLUSIONS: This toolbox has been designed to include an easy-to-use and intuitive graphic user interface and data representation software, which makes MVPAlab a very convenient tool for users with few or no previous coding experience. In addition, MVPAlab is not for beginners only, as it implements several high and low-level routines allowing more experienced users to design their own projects in a highly flexible manner.


Subject(s)
Electroencephalography , Magnetoencephalography , Algorithms , Brain , Machine Learning , Software
8.
Neurobiol Lang (Camb) ; 2(4): 586-604, 2021.
Article in English | MEDLINE | ID: mdl-37214627

ABSTRACT

The benefits of bilingualism in executive functions are highly debated. Even so, in switching tasks, these effects seem robust, although smaller than initially thought (Gunnerud et al., 2020; Ware et al., 2020). By handling two languages throughout their lifespan, bilinguals appear to train their executive functions and show benefits in nonlinguistic switching tasks compared to monolinguals. Nevertheless, because bilinguals need to control for the interference of another language, they may show a disadvantage when dealing with task-switching paradigms requiring language control, particularly when those are performed in their less dominant language. The present work explored this issue by studying bilingualism's effects on task switching within the visual and language domains. On the one hand, our results show that bilinguals were overall faster and presented reduced switch costs compared to monolinguals when performing perceptual geometric judgments with no time for task preparation. On the other hand, no bilingual advantage was found when a new sample of comparable bilinguals and monolinguals completed a within-language switching task. Our results provide clear evidence favoring the bilingual advantage, yet only when the task imposes greater executive demands and does not involve language control.

9.
Psychol Res ; 85(3): 1016-1028, 2021 Apr.
Article in English | MEDLINE | ID: mdl-32036442

ABSTRACT

Recent research reveals that when faced with alternative lines of action, humans tend to choose the less cognitively demanding one, suggesting that cognitive control is intrinsically registered as costly. This idea is further supported by studies showing that the exertion of cognitive control evokes negative affective states. Despite extensive evidence for mood-induced modulations on control abilities, the impact of affective states on the avoidance of cognitive demand is still unknown. Across two well-powered experiments, we tested the hypothesis that negative affective states would increase the avoidance of cognitively demanding tasks. Contrary to our expectations, induced affective states did not modulate the avoidance of demand, despite having an effect on task performance and subjective experience. Altogether, our results indicate that there are limits to the effect of affective signals on cognitive control and that such interaction might depend on specific affective and control settings.


Subject(s)
Avoidance Learning/physiology , Cognition/physiology , Emotions/physiology , Mood Disorders/physiopathology , Task Performance and Analysis , Adolescent , Adult , Female , Humans , Male , Spain , Young Adult
10.
Neuropsychologia ; 147: 107584, 2020 10.
Article in English | MEDLINE | ID: mdl-32783954

ABSTRACT

Prior personal information is highly relevant during social interactions. Such knowledge aids in the prediction of others, and it affects choices even when it is unrelated to actual behaviour. In this investigation, we aimed to study the neural representation of positive and negative personal expectations, how these impact subsequent choices, and the effect of mismatches between expectations and encountered behaviour. We employed functional Magnetic Resonance Imaging in combination with a version of the Ultimatum Game (UG) where participants were provided with information about their partners' moral traits previous to receiving their fair or unfair offers. Univariate and multivariate analyses revealed the implication of the supplementary motor area (SMA) and inferior frontal gyrus (IFG) in the representation of expectations about the partners in the game. Further, these regions also represented the valence of these expectations, together with the ventromedial prefrontal cortex (vmPFC). Importantly, the performance of multivariate classifiers in these clusters correlated with a behavioural choice bias to accept more offers following positive descriptions, highlighting the impact of the valence of the expectations on participants' economic decisions. Altogether, our results suggest that expectations based on social information guide future interpersonal decisions and that the neural representation of such expectations in the vmPFC is related to their influence on behaviour.


Subject(s)
Decision Making , Prefrontal Cortex , Games, Experimental , Humans , Interpersonal Relations , Magnetic Resonance Imaging , Morals , Prefrontal Cortex/diagnostic imaging
11.
Int J Neural Syst ; 30(7): 2050024, 2020 Jul.
Article in English | MEDLINE | ID: mdl-32496140

ABSTRACT

A central challenge in cognitive neuroscience is to understand the neural mechanisms that underlie the capacity to control our behavior according to internal goals. Flanker tasks, which require responding to stimuli surrounded by distracters that trigger incompatible action tendencies, are frequently used to measure this conflict. Even though the interference generated in these situations has been broadly studied, multivariate analysis techniques can shed new light into the underlying neural mechanisms. The current study is an initial approximation to adapt an interference Flanker paradigm embedded in a Demand-Selection Task (DST) to a format that allows measuring concurrent high-density electroencephalography (EEG). We used multivariate pattern analysis (MVPA) to decode conflict-related electrophysiological markers associated with congruent or incongruent target events in a time-frequency resolved way. Our results replicate findings obtained with other analysis approaches and offer new information regarding the dynamics of the underlying mechanisms, which show signs of reinstantiation. Our findings, some of which could not have been obtained with classic analytical strategies, open novel avenues of research.


Subject(s)
Attention/physiology , Cerebral Cortex/physiology , Conflict, Psychological , Electroencephalography/methods , Pattern Recognition, Automated/methods , Psychomotor Performance/physiology , Adult , Female , Humans , Male , Multivariate Analysis , Young Adult
12.
Tog (A Coruña) ; 17(1): 46-54, mayo 2020. graf, tab
Article in Spanish | IBECS | ID: ibc-196304

ABSTRACT

OBJETIVOS: analizar si los jugadores de un equipo de fútbol a través de un entrenamiento cognitivo desde Terapia Ocupacional incrementan sus habilidades cognitivas y rendimiento deportivo. MÉTODOS: estudio experimental no aleatorio que sigue las consideraciones éticas pertinentes, realizado a 16 jugadores de 14-15 años de un equipo de fútbol, mediante la recogida de datos a través de 4 escalas ad hoc y 1 estandarizada. Se realizan 30 sesiones con periodicidad semanal de 30 min de duración. RESULTADOS: extraemos una mejora de los aspectos cognitivos trabajados, destacando los resultados obtenidos en la prueba TrailMaking Test, con un 22% de mejora en la parte A y un 26% en la parte B (P-value<0.01) y la escala ad hoc de Espacio Semiótico con una mejora global del 76%. CONCLUSIONES: la Terapia Ocupacional podría aportar sus conocimientos y herramientas en el ámbito deportivo para trabajar aspectos cognitivos y de cohesión grupal, repercutiendo en el desempeño e identidad ocupacional de los jugadores


OBJECTIVE: The aim is to analyze if the players of a soccer team increase their cognitive abilities and sports performancethrough cognitive training from Occupational Therapy. METHODS: Non-randomized experimental study that follows the pertinent ethical considerations was carried out on sixteen 14-15 year-old players from a soccer team, by collecting data through 4 ad hoc and 1 standardized scales. 30 sessions are held with a weekly duration of 30 min. RESULTS: We extract an improvement in the cognitive aspects worked on, highlighting the results obtained in Trail Making Test, with a 22% improvement in part A and 26% in part B (P-value <0.01) and in the ad hoc Semiotic Space scale with an overall improvement of 76%. CONCLUSIONS: Occupational Therapy could contribute with its knowledge and tools in the sports field to work on cognitive and group cohesion aspects, impacting on the performance and occupational identity of the players


Subject(s)
Humans , Male , Adolescent , 28573 , Occupational Therapy/methods , Soccer/physiology , Athletic Performance/physiology , Cognitive Behavioral Therapy , Decision Making , Exercise/physiology , Orientation, Spatial/physiology , Trail Making Test
13.
Chronobiol Int ; 37(4): 520-541, 2020 04.
Article in English | MEDLINE | ID: mdl-32000532

ABSTRACT

Since emotions and regulatory control are relevant for decision-making, their circadian fluctuation should influence the outcome of such decisions, but this question has been rarely addressed. A review of the literature suggests that the evidence regarding circadian synchrony effects (better performance at optimal vs. non-optimal times of day according to chronotype) on decision-making is mixed, likely due to the use of different approaches to estimate chronotype. The current experiment studied economic decision-making as a function of both chronotype and the time of day when decisions are made. The influence of chronotype (Morning-type: N = 28 vs. Evening-type: N = 30) and time of day (8 am vs. 10 pm) on decision-making was measured by the acceptance rate of unfair and fair offers in the Ultimatum Game, and the event-related potentials time-locked to such offers. Subjective affect (PANAS), and appraisal of emotional images (IAPS) were also measured. Chronotype was estimated through questionnaires (MEQ, rMEQ, MCTQ) and the circadian rhythm of wrist temperature. Synchrony effects were found for both wrist temperature and subjective affect, but not for behavioral performance. Morning-types showed earlier phases of circadian rhythms in temperature, reported better sleep quality, more positive affective balance, accepted more unfair offers, and their frontal P200 potential was attenuated as compared to Evening-types in the Ultimatum Game. Acceptance rate of unfair offers correlated with the chronotype measured by questionnaires (positive correlation with rMEQ and MEQ scores, and negative correlation with Midsleep time in workdays -MSWsc from MCTQ) but not with midsleep time estimated through wrist temperature. Finally, participants who accepted more unfair offers later judged positive IAPS stimuli as more pleasant. We did not observe a synchrony effect in the Ultimatum Game, but morningness was related to rational decision-making as indexed by increased acceptance of unfair offers. Since morning-types show higher emotional regulation and positive mood than evening-types, it is possible that unfair offers did not elicit negative emotions as intense in morning-types as in evening-types, making it easier for them to accept.Abbreviations: ACC: anterior cingulate cortex; ANOVA: analysis of variance; BART: Balloon Analogue Risk Task; DLPFC: dorsolateral prefrontal cortex; EEG: electroencephalography; IAPS: International Affective Picture System; ICA: Independent component analysis; KSS: Karolinska Sleepiness Scale; LPP: Late Positive Potential; M: mean; MCTQ: Munich Chronotype Questionnaire; MEQ: Morningness Eveningness Questionnaire; MFN: Medial Frontal Negativity; MSWsc: midsleep time for working days corrected for sleep debt; MSFsc: midsleep time for free days corrected for sleep debt; N: number of participants; PANAS: Positive and Negative Affect Schedule; PSQI: Pittsburgh Sleep Quality Index; PVT: Psychomotor Vigilance Task; rMEQ: reduced Morningness Eveningness Questionnaire; RNA: Ribonucleic acid; RT: reaction time; SAM: Self-Assessment Manikin; SD: standard deviation; UG: Ultimatum Game.


Subject(s)
Circadian Rhythm , Sleep , Electroencephalography , Humans , Surveys and Questionnaires , Wakefulness
14.
Neuroimage ; 204: 116219, 2020 01 01.
Article in English | MEDLINE | ID: mdl-31546049

ABSTRACT

Engaging in a demanding activity while holding in mind another task to be performed in the near future requires the maintenance of information about both the currently-active task set and the intended one. However, little is known about how the human brain implements such action plans. While some previous studies have examined the neural representation of current task sets and others have investigated delayed intentions, to date none has examined the representation of current and intended task sets within a single experimental paradigm. In this fMRI study, we examined the neural representation of current and intended task sets, employing sequential classification tasks on human faces. Multivariate decoding analyses showed that current task sets were represented in the orbitofrontal cortex (OFC) and fusiform gyrus (FG), while intended tasks could be decoded from lateral prefrontal cortex (lPFC). Importantly, a ventromedial region in PFC/OFC contained information about both current and delayed tasks, although cross-classification between the two types of information was not possible. These results help delineate the neural representations of current and intended task sets, and highlight the importance of ventromedial PFC/OFC for maintaining task-relevant information regardless of when it is needed.


Subject(s)
Brain Mapping , Executive Function/physiology , Facial Recognition/physiology , Intention , Memory, Short-Term/physiology , Prefrontal Cortex/physiology , Psychomotor Performance/physiology , Temporal Lobe/physiology , Adult , Female , Humans , Judgment/physiology , Magnetic Resonance Imaging , Male , Prefrontal Cortex/diagnostic imaging , Temporal Lobe/diagnostic imaging , Young Adult
15.
Neuroinformatics ; 18(2): 219-236, 2020 04.
Article in English | MEDLINE | ID: mdl-31402435

ABSTRACT

Multi-voxel pattern analysis (MVPA) has been successfully applied to neuroimaging data due to its larger sensitivity compared to univariate traditional techniques. Searchlight is the most widely employed approach to assign functional value to different regions of the brain. However, its performance depends on the size of the sphere, which can overestimate the region of activation when a large sphere size is employed. In the current study, we examined the validity of two different alternatives to Searchlight: an atlas-based local averaging method (ABLA, Schrouff et al. Neuroinformatics 16, 117-143, 2013a) and a Multi-Kernel Learning (MKL, Rakotomamonjy et al. Journal of Machine Learning 9, 2491-2521, 2008) approach, in a scenario where the goal is to find the informative brain regions that support certain mental operations. These methods employ weights to measure the informativeness of a brain region and highly reduce the large computational cost that Searchlight entails. We evaluated their performance in two different scenarios where the differential BOLD activation between experimental conditions was large vs. small, and employed nine different atlases to assess the influence of diverse brain parcellations. Results show that both methods were able to localize informative regions when differences between conditions were large, demonstrating a large sensitivity and stability in the identification of regions across atlases. Moreover, the sign of the weights reported by these methods provided the directionality of univariate approaches. However, when differences were small, only ABLA localized informative regions. Thus, our results show that atlas-based methods are useful alternatives to Searchlight, but that the nature of the classification to perform should be taken into account when choosing the specific method to implement.


Subject(s)
Brain/physiology , Machine Learning , Neuroimaging/methods , Pattern Recognition, Automated/methods , Humans , Magnetic Resonance Imaging/methods
16.
J Neurosci ; 39(42): 8386-8397, 2019 10 16.
Article in English | MEDLINE | ID: mdl-31427394

ABSTRACT

Recent multivariate analyses of brain data have boosted our understanding of the organizational principles that shape neural coding. However, most of this progress has focused on perceptual visual regions (Connolly et al., 2012), whereas far less is known about the organization of more abstract, action-oriented representations. In this study, we focused on humans' remarkable ability to turn novel instructions into actions. While previous research shows that instruction encoding is tightly linked to proactive activations in frontoparietal brain regions, little is known about the structure that orchestrates such anticipatory representation. We collected fMRI data while participants (both males and females) followed novel complex verbal rules that varied across control-related variables (integrating within/across stimuli dimensions, response complexity, target category) and reward expectations. Using representational similarity analysis (Kriegeskorte et al., 2008), we explored where in the brain these variables explained the organization of novel task encoding, and whether motivation modulated these representational spaces. Instruction representations in the lateral PFC were structured by the three control-related variables, whereas intraparietal sulcus encoded response complexity and the fusiform gyrus and precuneus organized its activity according to the relevant stimulus category. Reward exerted a general effect, increasing the representational similarity among different instructions, which was robustly correlated with behavioral improvements. Overall, our results highlight the flexibility of proactive task encoding, governed by distinct representational organizations in specific brain regions. They also stress the variability of motivation-control interactions, which appear to be highly dependent on task attributes, such as complexity or novelty.SIGNIFICANCE STATEMENT In comparison with other primates, humans display a remarkable success in novel task contexts thanks to our ability to transform instructions into effective actions. This skill is associated with proactive task-set reconfigurations in frontoparietal cortices. It remains yet unknown, however, how the brain encodes in anticipation the flexible, rich repertoire of novel tasks that we can achieve. Here we explored cognitive control and motivation-related variables that might orchestrate the representational space for novel instructions. Our results showed that different dimensions become relevant for task prospective encoding, depending on the brain region, and that the lateral PFC simultaneously organized task representations following different control-related variables. Motivation exerted a general modulation upon this process, diminishing rather than increasing distances among instruction representations.


Subject(s)
Frontal Lobe/diagnostic imaging , Motivation/physiology , Parietal Lobe/diagnostic imaging , Psychomotor Performance/physiology , Adult , Brain Mapping , Female , Humans , Magnetic Resonance Imaging , Male , Photic Stimulation , Young Adult
17.
Neuron ; 101(5): 977-987.e3, 2019 03 06.
Article in English | MEDLINE | ID: mdl-30683546

ABSTRACT

Humans and other animals make decisions in order to satisfy their goals. However, it remains unknown how neural circuits compute which of multiple possible goals should be pursued (e.g., when balancing hunger and thirst) and how to combine these signals with estimates of available reward alternatives. Here, humans undergoing fMRI accumulated two distinct assets over a sequence of trials. Financial outcomes depended on the minimum cumulate of either asset, creating a need to maintain "value equilibrium" by redressing any imbalance among the assets. Blood-oxygen-level-dependent (BOLD) signals in the rostral anterior cingulate cortex (rACC) tracked the level of imbalance among goals, whereas the ventromedial prefrontal cortex (vmPFC) signaled the level of redress incurred by a choice rather than the overall amount received. These results suggest that a network of medial frontal brain regions compute a value signal that maintains value equilibrium among internal goals.


Subject(s)
Brain Mapping , Choice Behavior , Prefrontal Cortex/physiology , Female , Goals , Humans , Male , Prefrontal Cortex/diagnostic imaging , Young Adult
18.
Cereb Cortex ; 29(9): 3948-3960, 2019 08 14.
Article in English | MEDLINE | ID: mdl-30364950

ABSTRACT

The success of humans in novel environments is partially supported by our ability to implement new task procedures via instructions. This complex skill has been associated with the activity of control-related brain areas. Current models link fronto-parietal and cingulo-opercular networks with transient and sustained modes of cognitive control, based on observations during repetitive task settings or rest. The current study extends this dual model to novel instructed tasks. We employed a mixed design and an instruction-following task to extract phasic and tonic brain signals associated with the encoding and implementation of novel verbal rules. We also performed a representation similarity analysis to capture consistency in task-set encoding within trial epochs. Our findings show that both networks are involved while following novel instructions: transiently, during the implementation of the instruction, and in a sustained fashion, across novel trials blocks. Moreover, the multivariate results showed that task representations in the cingulo-opercular network were more stable than in the fronto-parietal one. Our data extend the dual model of cognitive control to novel demanding situations, highlighting the high flexibility of control-related regions in adopting different temporal profiles.


Subject(s)
Brain/physiology , Psychomotor Performance/physiology , Adult , Brain Mapping , Female , Humans , Magnetic Resonance Imaging , Male , Neural Pathways/physiology , Practice, Psychological , Young Adult
19.
J Neurosci Methods ; 308: 248-260, 2018 10 01.
Article in English | MEDLINE | ID: mdl-30352691

ABSTRACT

The use of Multi-Voxel Pattern Analysis (MVPA) has increased considerably in recent functional magnetic resonance imaging (fMRI) studies. A crucial step consists in the choice of a method for the estimation of responses. However, a systematic comparison of the different estimation alternatives and their adequacy to predominant experimental design is missing. In the current study we compared three pattern estimation methods: Least-Squares Unitary (LSU), based on run-wise estimation, Least-Squares All (LSA) and Least-Squares Separate (LSS), which rely on trial-wise estimation. We compared the efficiency of these methods in an experiment where sustained activity needed to be isolated from zero-duration events as well as in a block-design approach and in a event-related design. We evaluated the sensitivity of the t-test in comparison with two non-parametric methods based on permutation testing: one proposed in Stelzer et al. (2013), equivalent to performing a permutation in each voxel separately and the Threshold-Free Cluster Enhancement. LSS resulted the most accurate approach to address the large overlap of signal among close events in the event-related designs. We found a larger sensitivity of Stelzer's method in all settings, especially in the event-related designs, where voxels close to surpass the statistical threshold with the other approaches were now marked as informative regions. Our results provide evidence that LSS is the most accurate approach for unmixing events with different duration and large overlap of signal. This is consistent with previous studies showing that LSS handles large collinearity better than other methods. Moreover, Stelzer's potentiates this better estimation with its large sensitivity.


Subject(s)
Brain Mapping/methods , Brain/physiology , Magnetic Resonance Imaging , Adult , Female , Humans , Image Processing, Computer-Assisted/methods , Least-Squares Analysis , Male , Models, Neurological , Models, Statistical , Young Adult
20.
Psicológica (Valencia, Ed. impr.) ; 39(1): 41-63, ene. 2018. tab, graf
Article in English | IBECS | ID: ibc-175101

ABSTRACT

Previous research suggests that utilitarian decisions to moral dilemmas often stem from analytic, controlled cognitive processes. Furthermore, processing disfluency can trigger analytic thinking and improve performance on tasks that require logic and cognitive reflection. In the present study we investigated how processing fluency affects the readiness with which people give utilitarian responses to both personal and impersonal dilemmas. Participants were presented in two different experimental blocks with dilemmas written in both easy- (fluent) and hard-to-read (disfluent) fonts. We expected that dilemmas written in a disfluent font would be associated with more utilitarian responses. Results supported this prediction, albeit only when the disfluent dilemmas appeared first, showing that participants endorsed more utilitarian actions in the disfluent condition than in the fluent condition across dilemma types. These data suggest that increasing processing disfluency by manipulating the font affects decisions in the moral domain


Investigaciones previas sugieren que las decisiones utilitarias a dilemas morales a menudo tienen origen en procesos cognitivos controlados y analíticos. Se sabe además que el procesamiento disfluente puede inducir pensamiento analítico y mejorar la ejecución en tareas que requieren lógica y reflexión cognitiva. En este estudio se investigó cómo la fluencia de procesamiento afecta a la disponibilidad con la que se dan repuestas utilitarias a dilemas morales personales e impersonales. Se presentaron a los participantes dilemas escritos tanto en una letra fácil (fluent) como difícil de leer (disfluent) en dos bloques experimentales diferentes. Se esperaba encontrar una asociación entre este último tipo de dilemas y respuestas más utilitarias. Los resultados apoyaron esta predicción cuando los dilemas disfluent se presentaron en primer lugar, mostrando que los participantes subscribían más acciones utilitarias en la condición disfluent que en la fluent, tanto para dilemas personales como impersonales. Estos datos sugieren que incrementar la disfluencia de procesamiento manipulando el tipo de letra utilizado afecta a las decisiones en el ámbito moral


Subject(s)
Humans , Male , Female , Adolescent , Young Adult , Adult , Morals , Decision Making/ethics , Executive Function , Choice Behavior , Students/psychology , Psychological Tests/statistics & numerical data , Task Performance and Analysis , Problem Solving
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