Continuing with the American psychologist, “denying to express a passion is to die”. Would emotion be possible without interoceptive, visceral or sensory sensations? How can the mind be understood leaving out of the formula a body and the surrounding environment? These questions are the starting point of a philosophical posture which was born in the context of cognitive sciences called “The embodied mind”. In the context of an embodied mind, the absence of bodily sensations would reduce emotions to a mere intellectual thought. “To deny to express a passion is to die”, as James emphasized even more.
From the 1950’s, in the field of psychology, the role of body language has started to be studied, establishing that the mind uses the body to give sense to abstract notions. Bases of non-verbal communication were established, codes of facial expression were studied, and the same with hand movements to speak and body posture. The mind uses the body to support its arguments. However, the relation mind-body was a bi-directional arrow: the mind influences the body and the body influences the mind. Today we wonder if these two entities are different or are to be treated as a problem of language.
One of the clearest and most beautiful examples of this idea is that of the hypothesis of facial feedback. In 1998 Fritz Strack and his team carried out an experiment where they saw that the participants enjoyed humour clips more when they kept a pen between their teeth, therefore simulating a smile without realising it. However, when the pen was kept between the lips their gesture appeared more like being angry and they enjoyed the joke less.
“When you smile, the world smiles back to you” as the popular saying goes, an affirmation in line with the investigation developed by the psychologist Paula Niedenthal (Neidenthal,2007), among others. More recently, in 2009, investigators from the University of Munich studied the reach of botox injections on the forehead, an operation that paralysed or attenuates the ability to frown. This is one of the most basic expressions of emotions. Their experiments showed that the blocking of this facial muscle interrupted the neuron circuits necessary to activate the amygdala, a cerebral area highly involved in emotions and therefore, the people not able to express unhappiness (see revision in Finzi,2013).
In order to understand our feelings, opinions and actions, we do not only focus on thinking, but also in our body and the surroundings: the mind goes together with the interaction of all those things.
The embodied mind
The relation between the body and the mind has been a subject of great interest in the philosophy of the mind, although historically it has been treated in a more theoretical way than related with the physical body. Nevertheless, the advances in knowledge of biological mechanisms, the sophistication of techniques in estimating the visceral activity and the concern for a new form of conceiving it are reigniting a fire which was thought extinguished: body and mind are inseparable.
Although little, evidence exists of the embodied mind. We start with the experiments of Kelly and Kravitz in 1989, which showed the reaction of an alarm in brain activity when a person heard a phrase which bore no relation to the gesture accompanying it. These studies showed that we interpret body language at the same time as speaking: gestures and words are processed together.
Until now it was a fact, especially in the world of psychology, that the brain requires the body to interpret the world. The brain modulates gestures or body posture, and the body modulates the cerebral processes. This is already an advance but let’s go a step further: let’s imagine that cognition not only requires cerebral activity as the last stop. Very recent studies have demonstrated that the perception of pain from a simple visual stimulus or racial prejudice depends on the interaction between heart and brain (see article in the same blog “The heart of the mind”).
Not only is the heart recovering its role as part of the cognitive system. The group of Catherine Tallon-Baudry, which showed one of the first pieces of evidence of the interaction heart-brain, has demonstrated that the electrical fields in the stomach and intestine are coupled with cerebral rhythms. And additionally, that this interaction leaves the stomach and arrives at the brain: the stomach modulates the cerebral rhythms. Another great recent discovery is the influence of bacteria that inhabit our intestine in the development of the brain and our mood state (Smith,2016) and that is revolutionising the investigation in treatment of autism.
There was a revolution in neuroscience when it was decided to change from the idea of the brain as a group of specialised areas where each carried out its own function independently to others (localizationism) to a vision where cerebral connectivity is the process that accompanies cognition. Now cognitive sciences must take a step further and include the relation between the brain and the different organs as internal and external sources that are still unknown.
A complex network
A change in paradigm which omits considering the brain as the source or integrator of cognition to a mark where the reach of possible influences is today unknown must be accompanied with the development or implementation of an equally complex methodology. Until now, the investigation has been focused on measuring the brain activity under different conditions and to compare statistically the areas cerebral areas one by one in both states.
The process used and proposed by mathematician Bonferroni that was called “correction by multiple comparisons”, is until now the only consideration that a variable can be seen as influenced by other variables. (cerebral areas in this case). Besides, it does not take into account how the activity in the rest of the cerebral areas was, and if between them there was some relation, they would be considered isolated. The pie chart is only divided among the total number of areas.
The new methods of analysis should include the total group and its interactions. It is not the same to compare A with B if they are isolated than to compare A with B given that C exists and they can interact between them. We should go from comparing magnitudes to compare interactions. A suitable candidate for this is the theory of networks, developed with the aim to study the global structure of a system of various components, and the interaction between specialisation and the integration of information in a system.
The word Internet comes from the English expression Interconnected Networks interlinked networks or networks of networks, being Internet the union of all networks and compatible computers of the world. Everyone knows how it works, the capacity to transmit information and the potential to communicate. Perhaps it is one of the most efficient networks that exist because it is a decentralised combination of interconnected communication networks. However, an example which makes the theory of networks or theory of graphs more understandable and intuitive is the network of world airports.
In this example, cities with airports are called “nodes” of the network, which in neuroscience are the equivalent of the brain areas. The routes of the aeroplanes or communication between neuronal regions would be the connections of the network. The nodes and the pattern of connections give raise to a network or graph. The interesting thing comes from the study of the topological characteristics of the said network. The first measure would be the strength of the link of the network connections: how many cities are connected with each city, and the same for cerebral areas. The role of each node as an intermediary: to be able to calculate which nodes are the most important in the network has infinite applications depending on the environment.
Let us imagine that London airport cancels all of its aeroplanes and for many hours. World chaos is assured. London airport is known as a central connection or hub, which centralises many connections that are made all around the world. To go from any European city to another part of the world it is almost sure that a transfer is needed in London. And it is like this for the high-level coupling in the network. To determine the cerebral hubs is one of the great landmarks of neuroscience and specifically the project “Human Connector”, which now allows us to study the possible cerebral hierarchy and the most important areas of therapies or pharmacological treatments.
Two of the key parameters are: clustering, or in other words how good friends are my friends with each other, and path length or how many transfers should be made to go from one city to another. These two parameters are perhaps the most important ones because they are strongly related with the efficiency of the transmission of information inside the network and with the cost (it will be economical in one case or energetic/metabolic in another).
Depending on the value of these parameters different types of networks will be defined. On the one hand we have a completely ordered network where all the nodes are connected to all (maximum clustering, minimal length of route). It is obviously an inefficient network in terms of optimising costs. On the other extreme we have a network where the connections between nodes have been established randomly. It is also a poorly optimised network.
The most efficient architecture
In the 1960s, the psychologist Stanley Milgram carried out an experiment at Harvard University to study how the network was formed by the inhabitants of the United States. Surprisingly, he saw that any pair of people were connected to at least another 6. This phenomenon was called “six degrees of separation” and has inspired many things, from films to sociological studies.
In this network it is essential the presence of hubs, or particularly connected nodes, like for example the president or a celebrity. We all know someone who knows someone who knows the president. In 1998 Duncan Watts and Steven Strogatz discovered an interesting type of network, which was called the “small world network” and these are the networks whose architecture has two characteristics: they had a small route length and a high clustering. This network architecture has been proved as the most efficient and it is used in nature.
There are many parameters to study networks which contain information around its structure in communities, modularity, diversity, capacity transition, overlapping topology, fluidity coefficient or identification of central networks inside a network and its surroundings.
According to Jackson (2008), the application of the theory of networks is indispensable to understand the working of our social and economic life. His project is one of the examples of greater relevance of the application of the theory of networks in sociological studies. In organisational surroundings, the application of the theory of networks accelerate changes in behaviour, improve efficiency of organisations, social change and carry out important contributions in the design of diffusion strategies. As Cournot discovered, the economy system is actually a whole whose parts are connected and react to each other, an inter-dependency which is not fixed, but that organisations, individuals and nations can change according to the thread of history.
The application of the theory of networks in neuroscience has opened a study that goes from the characterisation of areas of greater relevance of the execution of a cognitive task, or the seed for degeneration to the simulation of the propagation of chemicals and strategies for cerebral plasticity (Bullmore and Sporns, 2009). It is always present that the nodes are inside a network and all of them are important.
To consider the brain as a network has meant such a big change in perspective that the number of lines of investigation in neuroscience has multiplied in the last decades. We are facing a new challenge: to consider the mind as a connected holograph of interactions between the brain, main organs and other parts of the body and in order to do this we must incorporate ways of analysis and interpretation that can grasp this complexity.
Los principios de la psicologia, William James.
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