Deep learning in a bilateral brain with hemispheric specialization

The brains of all bilaterally symmetric animals on Earth are are divided into left and right hemispheres. The anatomy and functionality of the hemispheres have a large degree of overlap, but they specialize to possess different attributes. The left hemisphere is believed to specialize in specificity and routine, the right in generalities and novelty. In this study, we propose an artificial neural network that imitates that bilateral architecture using two convolutional neural networks with different training objectives and test it on an image classification task. The bilateral architecture outperforms architectures of similar representational capacity that don't exploit differential specialization. It demonstrates the efficacy of bilateralism and constitutes a new principle that could be incorporated into other computational neuroscientific models and used as an inductive bias when designing new ML systems. An analysis of the model can help us to understand the human brain.Comment: 11 pages, 10 figure

New insights into the human brain’s cognitive organization : Views from the top, from the bottom, from the left and, particularly, from the right

The view that the left cerebral hemisphere in humans “dominates” over the “subdominant” right hemisphere has been so deeply entrenched in neuropsychology that no amount of evidence seems able to overcome it. In this article, we examine inhibitory cause-and-effect connectivity among human brain structures related to different parts of the triune evolutionary stratification —archicortex, paleocortex and neocortex— in relation to early and late phases of a prolonged resting-state functional magnetic resonance imaging (fMRI) experiment. With respect to the evolutionarily youngest parts of the human cortex, the left and right frontopolar regions, we also provide data on the asymmetries in underlying molecular mechanisms, namely on the differential expression of the protein-coding genes and regulatory microRNA sequences. In both domains of research, our results contradict the established view by demonstrating a pronounced right-to-left vector of causation in the hemispheric interaction at multiple levels of brain organization. There may be several not mutually exclusive explanations for the evolutionary significance of this pattern of lateralization. One of the explanations emphasizes the computational advantage of separating the neural substrates for processing novel information ("exploration") mediated predominantly by the right hemisphere, and processing with reliance on established cognitive routines and representations ("exploitation") mediated predominantly by the left hemisphere.publishedVersio

Agent-Centered Decision Making in Normal and Abnormal Cognition

La Toma de Decisiones Centrada en el Agente en la Cognición Normal y Anormal: Gran parte de la cognición humana está "centrada en el agente", es subjetiva, y en ese sentido, está dirigida a decidir: "¿Qué es lo mejor para mí?". Esta es una perspectiva muy diferente a la de la cognición "verídica", que está más dirigida a encontrar una solución objetivamente correcta, inherente a la tarea, e independiente del agente. Los lóbulos frontales, en particular, son fundamentales para la toma de decisiones "centrada en el agente". Sin embargo, existen pocos paradigmas cognitivos en el marco de la neurociencia cognitiva y de la neuropsicología clínica, que se hayan diseñado para evaluar la toma de decisiones "centrada en el agente". Los paradigmas actuales y las pruebas utilizadas para medir la toma de decisiones clínica y experimentalmente son "verídicos" en su naturaleza y, por lo mismo, no son adecuados para la evaluación de la cognición "centrada en el agente". La escasez de paradigmas "centrados en el agente" limita severamente nuestra capacidad de entender plenamente la función y la disfunción de los lóbulos frontales. Al respecto, la Tarea de Sesgo Cognitivo (o Cognitive Bias Task, CBT) es un paradigma "centrado en el agente" diseñado para llenar este vacío. La CBT se ha utilizado como una tarea de activación cognitiva en estudios de IRMf, SPECT y EEG, así como en estudios del desarrollo normal, adicciones, demencia, lesiones focales, y esquizofrenia. Consecuentemente, se han obtenido hallazgos que evitan algunas de las limitaciones de los paradigmas más tradiciones, "verídicos", y que se revisan en este artículo.Much of human cognition is �agent-centered,� subjective, and in that sense relative, directed at deciding, �What is best for me�. This is very different from �veridical� cognition, directed at finding an objectively correct solution inherent in the task and independent of the agent. The frontal lobes in particular are central to agent-centered decision making. Yet very little is available in the arsenal of cognitive paradigms used in the cognitive neuroscience research and in clinical neuropsychology test design to examine �agent-centered� decision making. Current paradigms and tests used to measure decision making clinically and experimentally are veridical in nature and as such miss the essence of �agent-centered� cognition. The dearth of �agent-centered� cognitive paradigms severely limits our ability to understand fully the function and dysfunction of the frontal lobes. The Cognitive Bias Task (CBT) is an agent-centered paradigm designed to fill this gap. CBT has been used as a cognitive activation task in fMRI, SPECT, and EEG, as well as in studies of normal development, addiction, dementia, focal lesions, and schizophrenia. This resulted in a range of findings that eluded more traditional �veridical� paradigms and are reviewed here

Altered adaptive but not veridical decision-making in substance dependent individuals.

Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't;Drug addiction is associated with impaired judgment in unstructured situations in which success depends on self-regulation of behavior according to internal goals (adaptive decision-making). However most executive measures are aimed at assessing decision-making in structured scenarios, in which success is determined by external criteria inherent to the situation (veridical decision-making). The aim of this study was to examine the performance of Substance Abusers (SA, n = 97) and Healthy Comparison participants (HC, n = 81) in two behavioral tasks that mimic the uncertainty inherent in real-life decision-making: the Cognitive Bias Task (CB) and the Iowa Gambling Task (IGT) (administered only to SA). A related goal was to study the interdependence between performances on both tasks. We conducted univariate analyses of variance (ANOVAs) to contrast the decision-making performance of both groups; and used correlation analyses to study the relationship between both tasks. SA showed a marked context-independent decision-making strategy on the CB's adaptive condition, but no differences were found on the veridical conditions in a subsample of SA (n = 34) and HC (n = 22). A high percentage of SA (75%) also showed impaired performance on the IGT. Both tasks were only correlated when no impaired participants were selected. Results indicate that SA show abnormal decision-making performance in unstructured situations, but not in veridical situations.This study has been supported by grant BSO2003-07169 from the Spanish Ministry of Science and Technology, whose principal researcher is Dr. Miguel Pérez GarcíaYe

New insights into the human brain’s cognitive organization : Views from the top, from the bottom, from the left and, particularly, from the right

The view that the left cerebral hemisphere in humans “dominates” over the “subdominant” right hemisphere has been so deeply entrenched in neuropsychology that no amount of evidence seems able to overcome it. In this article, we examine inhibitory cause-and-effect connectivity among human brain structures related to different parts of the triune evolutionary stratification —archicortex, paleocortex and neocortex— in relation to early and late phases of a prolonged resting-state functional magnetic resonance imaging (fMRI) experiment. With respect to the evolutionarily youngest parts of the human cortex, the left and right frontopolar regions, we also provide data on the asymmetries in underlying molecular mechanisms, namely on the differential expression of the protein-coding genes and regulatory microRNA sequences. In both domains of research, our results contradict the established view by demonstrating a pronounced right-to-left vector of causation in the hemispheric interaction at multiple levels of brain organization. There may be several not mutually exclusive explanations for the evolutionary significance of this pattern of lateralization. One of the explanations emphasizes the computational advantage of separating the neural substrates for processing novel information ("exploration") mediated predominantly by the right hemisphere, and processing with reliance on established cognitive routines and representations ("exploitation") mediated predominantly by the left hemisphere