Neurobiology and free will: a dialogue between Mariano Artigas and John Eccles

In this article, I discuss the importance of multidisciplinary research to tackle the questions that empirical sciences, and in particular neuroscience, ultimately encounter. The last decades have witnessed an enormous progress in brain research, mainly because of the improvement of neuroimaging techniques and neurogenetics, and the development of optogenetics. Furthermore, the US Government and European Union have launched the BRAIN Initiative and Human Brain Project, respectively, to promote a better understanding of brain functioning and its disorders. Unfortunately, their gates appear sealed for disciplines that pursue a deep knowledge of the mind, such as philosophy or psychology. The most probable outcome of this situation is “promissory materialism”, as Sir John Eccles warned several decades ago. I review the multidisciplinary approach of Eccles to the study of the brain and mind, especially through his relationship with Mariano Artigas. Finally, I propose that interdisciplinary research may be improved by a more solid understanding of the discipline one wants to dialogue with, and a multidisciplinary training from the beginning of the research career

Hubs of belief networks across sociodemographic and ideological groups

Beliefs are essential components of the human mind, as they define personal identity, integration and adaptation to social groups. Most theoretical studies suggest that beliefs are organized as structured networks: the so-called belief system. According to these studies and their empirical implementation using graph-theoretical approaches, a belief is any proposition considered as true by the respondent. In a recent contribution, we introduced a novel operationalization: a proposition is a belief if (1) it is taken to be true; and (2) the subject declares to be willing to hold it even if irrefutable evidence were hypothetically argued against it. Here, we implement this operationalization using a graph theory approach to investigate the network organization of the belief system in a sample of 108 participants, as well as the differences between key ideological (left- vs. right-wingers) and sociodemographic features (younger vs. older, female vs. male). We identified a well-coordinated network of interlocked spiritual, prosocial and nature-related beliefs, which displays a dense core of 10 hub nodes. Moreover, we observed how specific social liberalist beliefs and transcendental or individualistic/prosocial viewpoints are articulated within left- and right-wingers networks or younger and older participants. Interestingly, we observed that females tend to engage in denser belief networks than male respondents. In conclusion, our research expands tangible scientific evidence of the belief system of humans through the network study of belief reports, which in turn opens innovative ways to study belief systems in social and clinical samples

Visualización de modelos digitales tridimensionales en la enseñanza de anatomía: principales recursos y una experiencia docente en neuroanatomía

La conformación de las estructuras anatómicas es compleja en los 3 planos del espacio. Históricamente, la enseñanza de la anatomía se ha hecho a partir de representaciones bidimensionales, de modelos físicos tridimensionales o de cuerpos reales. Solo recientemente ha sido factible crear modelos anatómicos digitales tridimensionales, que pueden ser explorados en línea a través de Internet. El objetivo del presente trabajo es analizar 2 de las herramientas en línea más conocidas para la visualización anatómica (Anatomography® y BioDigital® Human), y presentar una experiencia docente de uso en el área de neurociencias. Se crearon imágenes de estructuras cerebrales animadas que se usaron en clase posteriormente, y se preguntó a los alumnos sobre su interés y utilidad. Los resultados indicaron que la utilización de este tipo de recursos es interesante por su flexibilidad, atractivo y coste.The conformation of anatomical structures is complex in the 3 spatial planes. Historically, anatomy teaching has been carried out using 2-dimensional representation, 3-dimensional physical models, or real bodies. Only recently has it been possible to create digital 3-dimensional anatomical models that can be explored online or downloaded. The aim of this work is to critically describe two of the best-known online tools for anatomical visualisation (Anatomography® and BioDigital® Human), and to present a teaching experience in the neuroscience domain. Animated images of brain structures were created and later used in class, and students were asked about their interest and usefulness. Results indicated that the use of this kind of resource is interesting, due to its flexibility, attractiveness and cost

A conceptual framework to safeguard the neuroright to personal autonomy

In this article, we propose a philosophical exploration on the main problems involved in two neurorights that concern autonomous action, namely free will and cognitive liberty, and sketch a possible solution to these problems by resourcing to a holistic interpretation of human actions. First, we expose the main conceptual and practical issues arising from the neuroright to free will, which are far from minor: the term itself is denied by some trends participating in the neurorights debate, the related concept of ultimate control is also disputed, the understanding of free will depends on cultural context, and the exercise of being free to act in several domains may be covered by other regulations. Second, we analyze the historical origin of cognitive liberty, its current status, and its relation with free will. Third, we criticize the concept of decision in mainstream action theory and propose to conceive action as a unified process constituted by three explanatory, non-sequential dimensions: intention, decision, and action realization. Fourth, we discuss two possible cases involving neurotechnologies and suggest ways to interpret them according to a unified framework in which free will and cognitive liberty fall under a single neuroright to personal autonomy. Finally, we outline a recommendation to introduce freedom of thought and personal autonomy as complementary neurorights to protect both the internal and external dimensions of thought and action

Distribution of GABAergic Interneurons and Dopaminergic Cells in the Functional Territories of the Human Striatum

BACKGROUND: The afferent projections of the striatum (caudate nucleus and putamen) are segregated in three territories: associative, sensorimotor and limbic. Striatal interneurons are in part responsible for the integration of these different types of information. Among them, GABAergic interneurons are the most abundant, and can be sorted in three populations according to their content in the calcium binding proteins calretinin (CR), parvalbumin (PV) and calbindin (CB). Conversely, striatal dopaminergic cells (whose role as interneurons is still unclear) are scarce. This study aims to analyze the interneuron distribution in the striatal functional territories, as well as their organization regarding to the striosomal compartment. METHODOLOGY/PRINCIPAL FINDINGS: We used immunohistochemical methods to visualize CR, PV, CB and tyrosine hydroxylase (TH) positive striatal neurons. The interneuronal distribution was assessed by stereological methods applied to every striatal functional territory. Considering the four cell groups altogether, their density was higher in the associative (2120±91 cells/mm(3)) than in the sensorimotor (959±47 cells/mm(3)) or limbic (633±119 cells/mm(3)) territories. CB- and TH-immunoreactive(-ir) cells were distributed rather homogeneously in the three striatal territories. However, the density of CR and PV interneurons were more abundant in the associative and sensorimotor striatum, respectively. Regarding to their compartmental organization, CR-ir interneurons were frequently found in the border between compartments in the associative and sensorimotor territories, and CB-ir interneurons abounded at the striosome/matrix border in the sensorimotor domain. CONCLUSIONS/SIGNIFICANCE: The present study demonstrates that the architecture of the human striatum in terms of its interneuron composition varies in its three functional territories. Furthermore, our data highlight the importance of CR-ir striatal interneurons in the integration of associative information, and the selective role of PV-ir interneurons in the motor territory. On the other hand, the low density of dopaminergic cells casts doubts about their role in the normal human striatum

Cholinergic Interneurons Are Differentially Distributed in the Human Striatum

BACKGROUND: The striatum (caudate nucleus, CN, and putamen, Put) is a group of subcortical nuclei involved in planning and executing voluntary movements as well as in cognitive processes. Its neuronal composition includes projection neurons, which connect the striatum with other structures, and interneurons, whose main roles are maintaining the striatal organization and the regulation of the projection neurons. The unique electrophysiological and functional properties of the cholinergic interneurons give them a crucial modulating function on the overall striatal response. METHODOLOGY/PRINCIPLE FINDINGS: This study was carried out using stereological methods to examine the volume and density (cells/mm(3)) of these interneurons, as visualized by choline acetyltransferase (ChAT) immunoreactivity, in the following territories of the CN and Put of nine normal human brains: 1) precommissural head; 2) postcommissural head; 3) body; 4) gyrus and 5) tail of the CN; 6) precommissural and 7) postcommissural Put. The distribution of ChAT interneurons was analyzed with respect to the topographical, functional and chemical territories of the dorsal striatum. The CN was more densely populated by cholinergic neurons than the Put, and their density increased along the anteroposterior axis of the striatum with the CN body having the highest neuronal density. The associative territory of the dorsal striatum was by far the most densely populated. The striosomes of the CN precommissural head and the postcommissural Put contained the greatest number of ChAT-ir interneurons. The intrastriosomal ChAT-ir neurons were abundant on the periphery of the striosomes throughout the striatum. CONCLUSIONS/SIGNIFICANCE: All these data reveal that cholinergic interneurons are differentially distributed in the distinct topographical and functional territories of the human dorsal striatum, as well as in its chemical compartments. This heterogeneity may indicate that the posterior aspects of the CN require a special integration of information by interneurons. Interestingly, these striatal regions have been very much left out in functional studies