Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 71
Filtrar
Más filtros

Banco de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Clin Gastroenterol Hepatol ; 22(7): 1518-1527.e7, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38325601

RESUMEN

BACKGROUND: Post-fecal immunochemical test (FIT) colonoscopy represents a setting with an enriched prevalence of advanced adenomas. Due to an expected higher risk of colorectal cancer (CRC), postpolypectomy surveillance is recommended, generating a substantially increased load on endoscopy services. The aim of our study was to investigate postpolypectomy CRC risk in a screening population of FIT+ subjects after resection of low-risk adenomas (LRAs) or high-risk adenomas (HRAs). METHODS: We retrieved data from a cohort of patients undergoing postpolypectomy surveillance within a FIT-based CRC screening program in Italy between 2002 and 2017 and followed-up to December 2021. Main outcomes were postpolypectomy CRC incidence and mortality risks according to type of adenoma (LRA/HRA) removed at colonoscopy as well as morphology, size, dysplasia, and location of the index lesion. We adopted as comparators FIT+/colonoscopy-negative and FIT- patients. The absolute risk was calculated as the number of incident CRCs per 100,000 person-years of follow-up. We used Cox multivariable regression models to identify associations between CRC risks and patient- and polyp-related variables. RESULTS: Overall, we included 87,248 post-FIT+ colonoscopies (133 endoscopists). Of these, 42,899 (49.2%) were negative, 21,650 (24.8%) had an LRA, and 22,709 (26.0%) an HRA. After a median follow-up of 7.25 years, a total of 635 CRCs were observed. For patients with LRAs, CRC incidence (hazard ratio [HR], 1.18; 95% confidence interval [CI], 0.92-1.53) was not increased compared with the FIT+/colonoscopy-negative group, while for HRAs a significant increase in CRC incidence (HR, 1.53; 95% CI, 1.14-2.04) was found. The presence of 1 or more risk factors among proximal location, nonpedunculated morphology, and high-grade dysplasia explained most of this excess CRC risk in the HRA group (HR, 1.85; 95% CI, 1.36-2.52). Patients with only distal pedunculated polyps without high-grade dysplasia, representing 39.2% of HRA, did not have increased risk compared with the FIT- group (HR, 0.87; 95% CI, 0.59-1.28). CONCLUSIONS: CRC incidence is significantly higher in patients with HRAs diagnosed at colonoscopy. However, such excess risk does not appear to apply to patients with only distal pedunculated polyps without high-grade dysplasia, an observation that could potentially reduce the burden of surveillance in FIT programs.


Asunto(s)
Pólipos del Colon , Colonoscopía , Neoplasias Colorrectales , Humanos , Masculino , Femenino , Neoplasias Colorrectales/cirugía , Neoplasias Colorrectales/epidemiología , Neoplasias Colorrectales/patología , Persona de Mediana Edad , Anciano , Italia/epidemiología , Pólipos del Colon/cirugía , Pólipos del Colon/patología , Pólipos del Colon/epidemiología , Incidencia , Adenoma/cirugía , Adenoma/epidemiología , Adenoma/patología , Medición de Riesgo , Detección Precoz del Cáncer/métodos , Factores de Riesgo , Estudios Retrospectivos
2.
Ann Intern Med ; 176(3): 303-310, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36802754

RESUMEN

BACKGROUND: Colorectal cancer (CRC) screening programs based on fecal immunochemical tests (FITs) represent the standard of care for population-based interventions. Their benefit depends on the identification of neoplasia at colonoscopy after FIT positivity. Colonoscopy quality measured by adenoma detection rate (ADR) may affect screening program effectiveness. OBJECTIVE: To examine the association between ADR and postcolonoscopy CRC (PCCRC) risk in a FIT-based screening program. DESIGN: Retrospective population-based cohort study. SETTING: Fecal immunochemical test-based CRC screening program between 2003 and 2021 in northeastern Italy. PATIENTS: All patients with a positive FIT result who had a colonoscopy were included. MEASUREMENTS: The regional cancer registry supplied information on any PCCRC diagnosed between 6 months and 10 years after colonoscopy. Endoscopists' ADR was categorized into 5 groups (20% to 39.9%, 40% to 44.9%, 45% to 49.9%, 50% to 54.9%, and 55% to 70%). To examine the association of ADR with PCCRC incidence risk, Cox regression models were fitted to estimate hazard ratios (HRs) and 95% CIs. RESULTS: Of the 110 109 initial colonoscopies, 49 626 colonoscopies done by 113 endoscopists between 2012 and 2017 were included. After 328 778 person-years follow-up, 277 cases of PCCRC were diagnosed. Mean ADR was 48.3% (range, 23% and 70%). Incidence rates of PCCRC from lowest to highest ADR group were 13.13, 10.61, 7.60, 6.01, and 5.78 per 10 000 person-years. There was a significant inverse association between ADR and PCCRC incidence risk, with a 2.35-fold risk increase (95% CI, 1.63 to 3.38) in the lowest group compared with the highest. The adjusted HR for PCCRC associated with 1% increase in ADR was 0.96 (CI, 0.95 to 0.98). LIMITATION: Adenoma detection rate is partly determined by FIT positivity cutoff; exact values may vary in different settings. CONCLUSION: In a FIT-based screening program, ADR is inversely associated with PCCRC incidence risk, mandating appropriate colonoscopy quality monitoring in this setting. Increasing endoscopists' ADR may significantly reduce PCCRC risk. PRIMARY FUNDING SOURCE: None.


Asunto(s)
Adenoma , Neoplasias Colorrectales , Humanos , Estudios de Cohortes , Estudios Retrospectivos , Detección Precoz del Cáncer , Neoplasias Colorrectales/diagnóstico , Neoplasias Colorrectales/epidemiología , Colonoscopía , Adenoma/diagnóstico , Adenoma/epidemiología , Convulsiones , Tamizaje Masivo
3.
PLoS Comput Biol ; 16(12): e1007579, 2020 12.
Artículo en Inglés | MEDLINE | ID: mdl-33290414

RESUMEN

In mammals, goal-directed and planning processes support flexible behaviour used to face new situations that cannot be tackled through more efficient but rigid habitual behaviours. Within the Bayesian modelling approach of brain and behaviour, models have been proposed to perform planning as probabilistic inference but this approach encounters a crucial problem: explaining how such inference might be implemented in brain spiking networks. Recently, the literature has proposed some models that face this problem through recurrent spiking neural networks able to internally simulate state trajectories, the core function at the basis of planning. However, the proposed models have relevant limitations that make them biologically implausible, namely their world model is trained 'off-line' before solving the target tasks, and they are trained with supervised learning procedures that are biologically and ecologically not plausible. Here we propose two novel hypotheses on how brain might overcome these problems, and operationalise them in a novel architecture pivoting on a spiking recurrent neural network. The first hypothesis allows the architecture to learn the world model in parallel with its use for planning: to this purpose, a new arbitration mechanism decides when to explore, for learning the world model, or when to exploit it, for planning, based on the entropy of the world model itself. The second hypothesis allows the architecture to use an unsupervised learning process to learn the world model by observing the effects of actions. The architecture is validated by reproducing and accounting for the learning profiles and reaction times of human participants learning to solve a visuomotor learning task that is new for them. Overall, the architecture represents the first instance of a model bridging probabilistic planning and spiking-processes that has a degree of autonomy analogous to the one of real organisms.


Asunto(s)
Potenciales de Acción , Objetivos , Redes Neurales de la Computación , Algoritmos , Teorema de Bayes , Encéfalo/fisiología , Humanos
4.
PLoS Comput Biol ; 14(8): e1006227, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-30153263

RESUMEN

Learning in biologically relevant neural-network models usually relies on Hebb learning rules. The typical implementations of these rules change the synaptic strength on the basis of the co-occurrence of the neural events taking place at a certain time in the pre- and post-synaptic neurons. Differential Hebbian learning (DHL) rules, instead, are able to update the synapse by taking into account the temporal relation, captured with derivatives, between the neural events happening in the recent past. The few DHL rules proposed so far can update the synaptic weights only in few ways: this is a limitation for the study of dynamical neurons and neural-network models. Moreover, empirical evidence on brain spike-timing-dependent plasticity (STDP) shows that different neurons express a surprisingly rich repertoire of different learning processes going far beyond existing DHL rules. This opens up a second problem of how capturing such processes with DHL rules. Here we propose a general DHL (G-DHL) rule generating the existing rules and many others. The rule has a high expressiveness as it combines in different ways the pre- and post-synaptic neuron signals and derivatives. The rule flexibility is shown by applying it to various signals of artificial neurons and by fitting several different STDP experimental data sets. To these purposes, we propose techniques to pre-process the neural signals and capture the temporal relations between the neural events of interest. We also propose a procedure to automatically identify the rule components and parameters that best fit different STDP data sets, and show how the identified components might be used to heuristically guide the search of the biophysical mechanisms underlying STDP. Overall, the results show that the G-DHL rule represents a useful means to study time-sensitive learning processes in both artificial neural networks and brain.


Asunto(s)
Aprendizaje/fisiología , Red Nerviosa/fisiología , Plasticidad Neuronal/fisiología , Potenciales de Acción/fisiología , Fenómenos Biofísicos , Encéfalo/fisiología , Simulación por Computador , Humanos , Modelos Teóricos , Red Nerviosa/metabolismo , Redes Neurales de la Computación , Neuronas/fisiología , Sinapsis/fisiología
5.
PLoS Comput Biol ; 13(3): e1005395, 2017 03.
Artículo en Inglés | MEDLINE | ID: mdl-28358814

RESUMEN

Motor tics are a cardinal feature of Tourette syndrome and are traditionally associated with an excess of striatal dopamine in the basal ganglia. Recent evidence increasingly supports a more articulated view where cerebellum and cortex, working closely in concert with basal ganglia, are also involved in tic production. Building on such evidence, this article proposes a computational model of the basal ganglia-cerebellar-thalamo-cortical system to study how motor tics are generated in Tourette syndrome. In particular, the model: (i) reproduces the main results of recent experiments about the involvement of the basal ganglia-cerebellar-thalamo-cortical system in tic generation; (ii) suggests an explanation of the system-level mechanisms underlying motor tic production: in this respect, the model predicts that the interplay between dopaminergic signal and cortical activity contributes to triggering the tic event and that the recently discovered basal ganglia-cerebellar anatomical pathway may support the involvement of the cerebellum in tic production; (iii) furnishes predictions on the amount of tics generated when striatal dopamine increases and when the cortex is externally stimulated. These predictions could be important in identifying new brain target areas for future therapies. Finally, the model represents the first computational attempt to study the role of the recently discovered basal ganglia-cerebellar anatomical links. Studying this non-cortex-mediated basal ganglia-cerebellar interaction could radically change our perspective about how these areas interact with each other and with the cortex. Overall, the model also shows the utility of casting Tourette syndrome within a system-level perspective rather than viewing it as related to the dysfunction of a single brain area.


Asunto(s)
Ganglios Basales/fisiopatología , Cerebelo/fisiopatología , Modelos Neurológicos , Corteza Motora/fisiopatología , Tálamo/fisiopatología , Tics/fisiopatología , Síndrome de Tourette/fisiopatología , Simulación por Computador , Humanos , Red Nerviosa/fisiopatología
6.
Dig Dis ; 36(4): 264-268, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29669354

RESUMEN

BACKGROUND: Our aims were to assess the real life effectiveness and safety of the new bismuth-containing quadruple therapy in a large population of patients infected by Helicobacter pylori. METHODS: Consecutive dyspeptic H. pylori-positive patients were enrolled, both naïve for treatment and already unsuccessfully treated. Patients were treated with Pylera® 3 capsules 4 times/daily plus omeprazole 20 mg or esomeprazole 40 mg 2 times/daily for 10 days. Eradication was confirmed using a urea-breath test (at least 30 days after the end of the treatment). Efficacy and safety were assessed. RESULTS: A total of 349 patients were treated. H. pylori eradication was achieved in 316 (90.5%, 95% CIs 80.8-1.0) patients in the intention-to-treat population, and in 93.5% (95% CIs 83.5-1.0) in the per-protocol population. No difference in the eradication rate was found between naïve and previously treated patients (91.3 vs. 90.0%, p = 0.901). Adverse events occurred in 55 patients (15.8%, 95% CIs 11.9-20.1). Five patients discontinued treatment: 2 patients suffered from severe abdominal pain, one patient from headache, one patient from diarrhea, and one patient from diffuse urticarial rush. CONCLUSIONS: Pylera® achieved a remarkable eradication rate in real life both as first treatment and as a rescue therapy, with a good safety profile.


Asunto(s)
Antibacterianos/efectos adversos , Antibacterianos/uso terapéutico , Infecciones por Helicobacter/tratamiento farmacológico , Infecciones por Helicobacter/microbiología , Helicobacter pylori/fisiología , Bismuto/uso terapéutico , Demografía , Quimioterapia Combinada , Endoscopía , Femenino , Humanos , Masculino , Metronidazol/uso terapéutico , Persona de Mediana Edad , Compuestos Organometálicos/uso terapéutico , Estudios Retrospectivos , Tetraciclina/uso terapéutico , Resultado del Tratamiento
7.
Cerebellum ; 16(1): 203-229, 2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-26873754

RESUMEN

Despite increasing evidence suggesting the cerebellum works in concert with the cortex and basal ganglia, the nature of the reciprocal interactions between these three brain regions remains unclear. This consensus paper gathers diverse recent views on a variety of important roles played by the cerebellum within the cerebello-basal ganglia-thalamo-cortical system across a range of motor and cognitive functions. The paper includes theoretical and empirical contributions, which cover the following topics: recent evidence supporting the dynamical interplay between cerebellum, basal ganglia, and cortical areas in humans and other animals; theoretical neuroscience perspectives and empirical evidence on the reciprocal influences between cerebellum, basal ganglia, and cortex in learning and control processes; and data suggesting possible roles of the cerebellum in basal ganglia movement disorders. Although starting from different backgrounds and dealing with different topics, all the contributors agree that viewing the cerebellum, basal ganglia, and cortex as an integrated system enables us to understand the function of these areas in radically different ways. In addition, there is unanimous consensus between the authors that future experimental and computational work is needed to understand the function of cerebellar-basal ganglia circuitry in both motor and non-motor functions. The paper reports the most advanced perspectives on the role of the cerebellum within the cerebello-basal ganglia-thalamo-cortical system and illustrates other elements of consensus as well as disagreements and open questions in the field.


Asunto(s)
Ganglios Basales/fisiología , Ganglios Basales/fisiopatología , Cerebelo/fisiología , Cerebelo/fisiopatología , Corteza Cerebral/fisiología , Corteza Cerebral/fisiopatología , Animales , Consenso , Humanos , Vías Nerviosas/fisiología , Vías Nerviosas/fisiopatología
8.
Helicobacter ; 22(3)2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28125857

RESUMEN

BACKGROUND: Rising antibiotic resistance requires the evaluation of new and effective therapies. AIMS: To test the efficacy and safety of the new bismuth-containing quadruple therapy in patients infected with Helicobacter pylori. MATERIAL AND METHODS: Consecutive H. pylori-positive dyspeptic patients were enrolled, either naïve or with previous failure treatment. Patients were treated with Pylera® (three-in-one capsules containing bismuth subcitrate potassium 140 mg, metronidazole 125 mg, and tetracycline 125 mg) three capsules q.i.d. plus omeprazole 20 mg or esomeprazole 40 mg b.i.d. for 10 days. Eradication was confirmed using an urea breath test (at least 30 days after the end of treatment). Efficacy was assessed by UBT and safety by means of treatment-emergent adverse events. RESULTS: One hundred and thirty-one patients were included in the study: 42% of patients were naïve, and 58%, with previous failure treatment. H. pylori eradication was achieved in 124 patients (94.7%, 95% confidence intervals (CIs) 89.3-97.8) in ITT population. In the PP population, the percentage was 97.6% (95%, CIs 93.3-99.2). No difference in eradication rate was found either between naïve and previously treated patients (92.7% vs 96.0%, P=.383), or smoking and nonsmoking ones, or in patients taking omeprazole or esomeprazole. Treatment-emergent adverse events occurred in 35 patients (26.7%, 95% CIs 19.9-34.9). They were mild in all cases except in four, who discontinued the study due to diarrhea (three patients) and diffuse urticarial rush (one patient). CONCLUSIONS: Pylera® achieved a remarkable eradication rate in clinical practice, irrespective if it was used as first treatment or as a rescue therapy. Treatment-emergent adverse events were uncommon generally mild.


Asunto(s)
Antibacterianos/uso terapéutico , Bismuto/uso terapéutico , Infecciones por Helicobacter/tratamiento farmacológico , Helicobacter pylori/aislamiento & purificación , Inhibidores de la Bomba de Protones/uso terapéutico , Antibacterianos/efectos adversos , Bismuto/efectos adversos , Pruebas Respiratorias , Quimioterapia Combinada/efectos adversos , Quimioterapia Combinada/métodos , Femenino , Humanos , Italia , Masculino , Metronidazol/efectos adversos , Metronidazol/uso terapéutico , Persona de Mediana Edad , Estudios Prospectivos , Inhibidores de la Bomba de Protones/efectos adversos , Tetraciclina/efectos adversos , Tetraciclina/uso terapéutico , Resultado del Tratamiento , Urea/análisis
9.
Behav Brain Sci ; 40: e254, 2017 01.
Artículo en Inglés | MEDLINE | ID: mdl-29342684

RESUMEN

In this commentary, we highlight a crucial challenge posed by the proposal of Lake et al. to introduce key elements of human cognition into deep neural networks and future artificial-intelligence systems: the need to design effective sophisticated architectures. We propose that looking at the brain is an important means of facing this great challenge.


Asunto(s)
Encéfalo , Aprendizaje , Inteligencia Artificial , Humanos , Inteligencia , Redes Neurales de la Computación
10.
Endoscopy ; 48(3): 223-31, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26760605

RESUMEN

BACKGROUND AND STUDY AIMS: The high volume and poor palatability of 4 L of polyethylene glycol (PEG)-based bowel cleansing preparation required before a colonoscopy represent a major obstacle for patients. The aim of this study was to compare two low volume PEG-based preparations with standard 4 L PEG in individuals with a positive fecal immunochemical test (FIT) within organized screening programs in Italy. PATIENTS AND METHODS: A total of 3660 patients with a positive FIT result were randomized to receive, in a split-dose regimen, 4 L PEG or 2 L PEG plus ascorbate (PEG-A) or 2 L PEG with citrate and simethicone plus bisacodyl (PEG-CS). The noninferiority of the low volume preparations vs. 4 L PEG was tested through the difference in proportions of adequate cleansing. RESULTS: A total of 2802 patients were included in the study. Adequate bowel cleansing was achieved in 868 of 926 cases (93.7 %) in the 4 L PEG group, in 872 out of 911 cases in the PEG-A group (95.7 %, difference in proportions  + 1.9 %, 95 % confidence interval [CI]  - 0.1 to 3.9), and in 862 out of 921 cases in the PEG-CS group (93.6 %, difference in proportions  - 0.2 %, 95 %CI  - 2.4 to 2.0). Bowel cleansing was adequate in 95.5 % of cases when the preparation-to-colonoscopy interval was between 120 and 239 minutes, whereas it dropped to 83.3 % with longer intervals. Better cleansing was observed in patients with regular bowel movements (95.6 %) compared with those with diarrhea (92.4 %) or constipation (90.8 %). CONCLUSION: Low volume PEG-based preparations administered in a split-dose regimen guarantee noninferior bowel cleansing compared with 4 L PEG. Constipated patients require a personalized preparation. TRIAL REGISTRATION: EudraCT 2012 - 003958 - 82.


Asunto(s)
Catárticos/administración & dosificación , Colonoscopía , Adulto , Anciano , Ácido Ascórbico/administración & dosificación , Bisacodilo/administración & dosificación , Ácido Cítrico/administración & dosificación , Relación Dosis-Respuesta a Droga , Esquema de Medicación , Quimioterapia Combinada , Femenino , Humanos , Italia , Masculino , Persona de Mediana Edad , Evaluación de Resultado en la Atención de Salud , Polietilenglicoles/administración & dosificación , Simeticona/administración & dosificación
11.
Biol Cybern ; 109(6): 575-95, 2015 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-26537483

RESUMEN

The basal ganglia and cortex are strongly implicated in the control of motor preparation and execution. Re-entrant loops between these two brain areas are thought to determine the selection of motor repertoires for instrumental action. The nature of neural encoding and processing in the motor cortex as well as the way in which selection by the basal ganglia acts on them is currently debated. The classic view of the motor cortex implementing a direct mapping of information from perception to muscular responses is challenged by proposals viewing it as a set of dynamical systems controlling muscles. Consequently, the common idea that a competition between relatively segregated cortico-striato-nigro-thalamo-cortical channels selects patterns of activity in the motor cortex is no more sufficient to explain how action selection works. Here, we contribute to develop the dynamical view of the basal ganglia-cortical system by proposing a computational model in which a thalamo-cortical dynamical neural reservoir is modulated by disinhibitory selection of the basal ganglia guided by top-down information, so that it responds with different dynamics to the same bottom-up input. The model shows how different motor trajectories can so be produced by controlling the same set of joint actuators. Furthermore, the model shows how the basal ganglia might modulate cortical dynamics by preserving coarse-grained spatiotemporal information throughout cortico-cortical pathways.


Asunto(s)
Ganglios Basales/fisiología , Corteza Cerebral/fisiología , Actividad Motora , Mapeo Encefálico , Humanos
12.
Anim Cogn ; 17(5): 1081-8, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-24638875

RESUMEN

Animals have a strong propensity to explore the environment. Spontaneous exploration has a great biological significance since it allows animals to discover and learn the relation between specific behaviours and their consequences. The role of the contingency between action and outcome for learning has been mainly investigated in instrumental learning settings and much less in free exploration contexts. We tested 16 capuchin monkeys (Sapajus spp.) with a mechatronic platform that allowed complex modules to be manipulated and to produce different outcomes. Experimental subjects could manipulate the modules and discover the contingencies between their own specific actions and the outcomes produced (i.e., the opening and lighting of a box). By contrast, Control subjects could operate on the modules, but the outcomes experienced were those performed by their paired Experimental subjects ("yoked-control" paradigm). In the exploration phase, in which no food reward was present, Experimental subjects spent more time on the board and manipulated the modules more than Yoked subjects. Experimental subjects outperformed Yoked subjects in the following test phase, where success required recalling the effective action so to open the box, now baited with food. These findings demonstrate that the opportunity to experience action-outcome contingencies in the absence of extrinsic rewards promotes capuchins' exploration and facilitates learning processes. Thus, this intrinsically motivated learning represents a powerful mechanism allowing the acquisition of skills and cognitive competence that the individual can later exploit for adaptive purposes.


Asunto(s)
Cebus/psicología , Conducta Exploratoria , Aprendizaje , Animales , Femenino , Masculino , Motivación , Recompensa
13.
Exp Brain Res ; 232(7): 2167-77, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24691755

RESUMEN

Action selection is extremely important, particularly when the accomplishment of competitive tasks may require access to limited motor resources. The spontaneous exploration of the world plays a fundamental role in the development of this capacity, providing subjects with an increasingly diverse set of opportunities to acquire, practice and refine the understanding of action-outcome connection. The computational modeling literature proposed a number of specific mechanisms for autonomous agents to discover and target interesting outcomes: intrinsic motivations hold a central importance among those mechanisms. Unfortunately, the study of the acquisition of action-outcome relation was mostly carried out with experiments involving extrinsic tasks, either based on rewards or on predefined task goals. This work presents a new experimental paradigm to study the effect of intrinsic motivation on action-outcome relation learning and action selection during free exploration of the world. Three- and four-year-old children were observed during the free exploration of a new toy: half of them were allowed to develop the knowledge concerning its functioning; the other half were not allowed to learn anything. The knowledge acquired during the free exploration of the toy was subsequently assessed and compared.


Asunto(s)
Desarrollo Infantil/fisiología , Conducta de Elección/fisiología , Conducta Exploratoria , Objetivos , Motivación , Factores de Edad , Niño , Preescolar , Femenino , Humanos , Aprendizaje , Masculino , Juego e Implementos de Juego , Desempeño Psicomotor , Factores de Tiempo
14.
Neural Netw ; 176: 106292, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38657422

RESUMEN

Goal-directed manipulation of internal representations is a key element of human flexible behaviour, while consciousness is commonly associated with higher-order cognition and human flexibility. Current perspectives have only partially linked these processes, thus preventing a clear understanding of how they jointly generate flexible cognition and behaviour. Moreover, these limitations prevent an effective exploitation of this knowledge for technological scopes. We propose a new theoretical perspective that extends our 'three-component theory of flexible cognition' toward higher-order cognition and consciousness, based on the systematic integration of key concepts from Cognitive Neuroscience and AI/Robotics. The theory proposes that the function of conscious processes is to support the alignment of representations with multi-level goals. This higher alignment leads to more flexible and effective behaviours. We analyse here our previous model of goal-directed flexible cognition (validated with more than 20 human populations) as a starting GARIM-inspired model. By bridging the main theories of consciousness and goal-directed behaviour, the theory has relevant implications for scientific and technological fields. In particular, it contributes to developing new experimental tasks and interpreting clinical evidence. Finally, it indicates directions for improving machine learning and robotics systems and for informing real-world applications (e.g., in digital-twin healthcare and roboethics).


Asunto(s)
Cognición , Estado de Conciencia , Objetivos , Humanos , Estado de Conciencia/fisiología , Cognición/fisiología , Inteligencia Artificial , Robótica , Aprendizaje Automático
15.
Psychol Res ; 77(1): 7-19, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-22327121

RESUMEN

Seeing an object activates both visual and action codes in the brain. Crucial evidence supporting this view is the observation of object to response compatibility effects: perception of an object can facilitate or interfere with the execution of an action (e.g., grasping) even when the viewer has no intention of interacting with the object. TRoPICALS is a computational model that proposes some general principles about the brain mechanisms underlying compatibility effects, in particular the idea that top-down bias from prefrontal cortex, and whether it conflicts or not with the actions afforded by an object, plays a key role in such phenomena. Experiments on compatibility effects using a target and a distractor object show the usual positive compatibility effect of the target, but also an interesting negative compatibility effect of the distractor: responding with a grip compatible with the distractor size produces slower reaction times than the incompatible case. Here, we present an enhanced version of TRoPICALS that reproduces and explains these new results. This explanation is based on the idea that the prefrontal cortex plays a double role in its top-down guidance of action selection producing: (a) a positive bias in favour of the action requested by the experimental task; (b) a negative bias directed to inhibiting the action evoked by the distractor. The model also provides testable predictions on the possible consequences of damage to volitional circuits such as in Parkinsonian patients.


Asunto(s)
Simulación por Computador , Modelos Teóricos , Desempeño Psicomotor/fisiología , Corteza Visual/fisiología , Percepción Visual/fisiología , Fuerza de la Mano/fisiología , Humanos , Intención , Aprendizaje/fisiología , Movimiento/fisiología , Tiempo de Reacción/fisiología
16.
J Integr Neurosci ; 11(1): 87-101, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22744785

RESUMEN

In this work we present a new mechatronic platform for measuring behavior of nonhuman primates, allowing high reprogrammability and providing several possibilities of interactions. The platform is the result of a multidisciplinary design process, which has involved bio-engineers, developmental neuroscientists, primatologists, and roboticians to identify its main requirements and specifications. Although such a platform has been designed for the behavioral analysis of capuchin monkeys (Cebus apella), it can be used for behavioral studies on other nonhuman primates and children. First, a state-of-the-art principal approach used in nonhuman primate behavioral studies is reported. Second, the main advantages of the mechatronic approach are presented. In this section, the platform is described in all its parts and the possibility to use it for studies on learning mechanism based on intrinsic motivation discussed. Third, a pilot study on capuchin monkeys is provided and preliminary data are presented and discussed.


Asunto(s)
Terapia Conductista/instrumentación , Conducta Animal/fisiología , Ciencias de la Conducta/instrumentación , Animales , Terapia Conductista/métodos , Cebus
17.
Sci Rep ; 12(1): 14198, 2022 08 20.
Artículo en Inglés | MEDLINE | ID: mdl-35987942

RESUMEN

Experimental and computational studies propose that inner speech boosts categorisation skills and executive functions, making human behaviour more focused and flexible. In addition, many clinical studies highlight a relationship between poor inner-speech and an executive impairment in autism spectrum condition (ASC), but contrasting findings are reported. Here we directly investigate the latter issue through a previously implemented and validated computational model of the Wisconsin Cards Sorting Tests. In particular, the model was applied to explore potential individual differences in cognitive flexibility and inner speech contribution in autistic and neurotypical participants. Our model predicts that the use of inner-speech could increase along the life-span of neurotypical participants but would be reduced in autistic ones. Although we found more attentional failures (i.e., wrong behavioural rule switches) in autistic children/teenagers and more perseverative behaviours in autistic young/older adults, only autistic children and older adults exhibited a lower performance (i.e., fewer consecutive correct rule switches) than matched control groups. Overall, our results corroborate the idea that the reduced use of inner speech could represent a disadvantage for autistic children and autistic older adults. Moreover, the results suggest that cognitive-behavioural therapies should focus on developing inner speech skills in autistic children as this could provide cognitive support throughout their whole life span.


Asunto(s)
Trastorno del Espectro Autista , Trastorno Autístico , Adolescente , Anciano , Trastorno del Espectro Autista/psicología , Trastorno del Espectro Autista/terapia , Niño , Objetivos , Humanos , Habla , Trastornos del Habla
18.
Front Comput Neurosci ; 16: 954847, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36157843

RESUMEN

The human brain has a remarkable lifelong learning capability to acquire new experiences while retaining previously acquired information. Several hypotheses have been proposed to explain this capability, but the underlying mechanisms are still unclear. Here, we propose a neuro-inspired firing-rate computational model involving the hippocampus and surrounding areas, that encompasses two key mechanisms possibly underlying this capability. The first is based on signals encoded by the neuromodulator dopamine, which is released by novel stimuli and enhances plasticity only when needed. The second is based on a homeostatic plasticity mechanism that involves the lateral inhibitory connections of the pyramidal neurons of the hippocampus. These mechanisms tend to protect neurons that have already been heavily employed in encoding previous experiences. The model was tested with images from the MNIST machine learning dataset, and with more naturalistic images, for its ability to mitigate catastrophic interference in lifelong learning. The results show that the proposed biologically grounded mechanisms can effectively enhance the learning of new stimuli while protecting previously acquired knowledge. The proposed mechanisms could be investigated in future empirical animal experiments and inspire machine learning models.

19.
Front Psychol ; 13: 701714, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35756268

RESUMEN

Traditionally, research on affordances and emotions follows two separate routes. For the first time, this article explicitly links the two phenomena by investigating whether, in a discrimination task (artifact vs. natural object), the motivational states induced by emotional images can modulate affordances-related motor response elicited by dangerous and neutral graspable objects. The results show faster RTs: (i) for both neutral and dangerous objects with neutral images; (ii) for dangerous objects with pleasant images; (iii) for neutral objects with unpleasant images. Overall, these data support a significant effect of emotions on affordances. The article also proposes a brain neural network underlying emotions and affordance interplay.

20.
Front Syst Neurosci ; 16: 841085, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35350477

RESUMEN

Social avoidance in rodents arises from a complex interplay between the prefrontal cortex and subcortical structures, such as the ventromedial hypothalamus and the dorsal periaqueductal gray matter. Experimental studies are revealing the contribution of these areas, but an integrative view and model of how they interact to produce adaptive behavior are still lacking. Here, we present a computational model of social avoidance, proposing a set of integrated hypotheses on the possible macro organization of the brain system underlying this phenomenon. The model is validated by accounting for several different empirical findings and produces predictions to be tested in future experiments.

SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA