Joseph LeDoux “Rethinking the Emotional Brain”

Neuron, Volume 73, Issue 4, 653-676, 23 February 2012
Copyright © 2012 Elsevier Inc. All rights reserved.
10.1016/j.neuron.2012.02.004

 Joseph LeDouxsend emailSee Affiliations

I propose a reconceptualization of key phenomena important in the study of emotion—those phenomena that reflect functions and circuits related to survival, and that are shared by humans and other animals. The approach shifts the focus from questions about whether emotions that humans consciously feel are also present in other animals, and toward questions about the extent to which circuits and corresponding functions that are present in other animals (survival circuits and functions) are also present in humans. Survival circuit functions are not causally related to emotional feelings but obviously contribute to these, at least indirectly. The survival circuit concept integrates ideas about emotion, motivation, reinforcement, and arousal in the effort to understand how organisms survive and thrive by detecting and responding to challenges and opportunities in daily life.

Can the “connectome” save psychiatry?

An individual’s “connectome” (Sporns, Tonino, & Klötter, 2005; Hagmann, 2005) is in essence a mathematical object that describes all the neural connections in a nervous system. The word was coined by Olaf Sporns et al. in their 2005 paper and independently by Patric Hagmann in his doctoral dissertation. Sporns describes the 2005 paper as a “manifesto” outlining an ambitious research program in support of a model linking structure and function that the authors felt would have a profound impact on how we understand the brain. (The following excerpts are from Sporns’ 2010 talk at the Allen institute; the full video is embedded in references.)

We had no information until just a few years ago about similar data [about brain networks]  from the human brain. That was a big gap in our understanding of the human brain because we had no good structural model for it. We had a lot of imaging data . . . But it’s very difficult to interpret imaging data if you have no structural model by which it is generated. (Allen Institute, 2010)

Since 2005, data-driven research on the connectome (some of which is under the auspices of the NIH Human Connectome Project) is now being conducted at multiple scales: micro (“single neurons and synapses”), meso (“brain regions and pathways”), and macro (“neuronal populations and their interconnecting circuitry”) using different imaging technologies.

Implications for Psychiatry

What is particularly attractive about the concept of a connectome vis-a-vis psychiatry is that it “naturally fits within a larger theoretical framework and thus links neuroscience to modern developments in network science and complex systems” (Sporns, 2011). In other words, it grounds a longstanding intuition that the brain in general and psychiatric disorders in particular reflect continuous interactions of biological and sociocultural systems (Kirmayer, 2012).

In the network science field, in other contexts – internet, social networks, epidemiology  – perturbations of networks are very important to study because people want to know what happens when we lesion the network, what happens when we disrupt its functionality in terms of the global outcomes that result. I think we have a similar question on the horizon here for these neurological, psychiatric conditions. What is it about the brain that has changed in terms of its network architecture that brings about – or is involved or at least associated with – the function that is being perturbed. (Allen Institute, 2010)

A second factor is its ability to account for plasticity (and individual differences). This is because while, on the one hand, the connectome constrains neural activity – Sebastian Seung (2012) likens it to a streambed that organizes the flow of water [1]  (and Sporns calls it a “structural skeleton”), on the other neural activity (thoughts, feelings, and perceptions) over time can change the connectome.

If we have a structural model of the human brain we can actually damage it in the computer. And we can ask questions about how impactful are certain lesions that we make inside this computational model. We make these lesions by deleting a number of nodes and their connections. And we then observe how the dynamics – in a forward computing sense – of the human brain changes as a result of making these lesions.  We can then compare  our empirical data to data that is obtained from people with stroke and we can ask questions about recovery. What is it about the metrics of global brain connectivity, functional interactions that changes in a good outcome scenario and is there anything we can do on an interventional level with therapeutic or other interventional means that can guide brain repair and recovery in a good direction. The brain really is a complex network. If we make a lesion in our model in any particular spot, it’s not just that that spot is lost, and the rest of the brain just goes on doing what it’s doing, all relationships across all other nodes in the brain change, and that’s because the brain responds as a whole. This is something that becomes very plastic and very graspable if you do computational modeling and it really opens up new horizons . . . for understanding the functional impact of lesions and perhaps other disease states as well. (Allen Institute, 2010)

Notes

[1] Computational neuroscientist Sebastion Seung (MIT), who is studying the connectome from the neuron’s eye view, gave an exuberant talk on the connectome at one of the Ted conferences, and now he’s written an exuberant book on the subject that is, seriously, a page turner that concludes with a section on cryonics and “the ultimate cyber-fantasy” of uploading your brain and “living happily ever after as a computer simluation” (2012, xxi).

 References

Hagmann, P. (2005) From diffusion MRI to brain connectomics (Doctoral dissertation). École Polytechnique Fédérale de Lausanne (EPFL), Lausanne.

Seung, S. (2012). The connectome: How the brain’s wiring makes us who we are. New York: Houghton Mifflin Harcourt.

Allen Institute (2010). Olaf Sporns: 2010  Allen Institute for Brain Science Symposium. Retrieved 21 February 2012 from http://www.youtube.com/watch?v=oikjPdV7LbU

Sporns, O. (2011). The human connectome: A complex network. Annals of the New York Academy of Sciences, 1224, 109–125.

Sporns, O., Tononi, G., & Kötter, R. (2005). The human connectome: A structural description of the human brain. PLoS Computational Biology, 1(4), e42. doi:10.1371/journal.pcbi.0010042

CMB 2012 hot topic: “Functional and Clinical Neuroanatomy of Morality”

Alberto Priori of Università degli Studi di Milano, has just sent me an advanced copy of his co-authored review on morality for Brain.  (This was in response to our email blast about the FPR-UCLA 2012 conference, “Culture, Mind, and Brain: Emerging Concepts, Methods, and Applications.”)  Unfortunately, we don’t have the space to give morality its full due in the conference program, but I’m posting the abstract and link since this is sure to be a “hot topic” for discussion and debate at the conference.

Brain. 2012 Feb 13. [Epub ahead of print]

Functional and clinical neuroanatomy of morality.

Source

Dipartimento di Scienze Neurologiche, Università degli Studi di Milano, Fondazione IRCCS Ca’ Granda, Ospedale Maggiore Policlinico, 20122 Milano, Italy.

Abstract

Morality is among the most sophisticated features of human judgement, behaviour and, ultimately, mind. An individual who behaves immorally may violate ethical rules and civil rights, and may threaten others’ individual liberty, sometimes becoming violent and aggressive. In recent years, neuroscience has shown a growing interest in human morality, and has advanced our understanding of the cognitive and emotional processes involved in moral decisions, their anatomical substrates and the neurology of abnormal moral behaviour. In this article, we review research findings that have provided a key insight into the functional and clinical neuroanatomy of the brain areas involved in normal and abnormal moral behaviour. The ‘moral brain’ consists of a large functional network including both cortical and subcortical anatomical structures. Because morality is a complex process, some of these brain structures share their neural circuits with those controlling other behavioural processes, such as emotions and theory of mind. Among the anatomical structures implicated in morality are the frontal, temporal and cingulate cortices. The prefrontal cortex regulates activity in subcortical emotional centres, planning and supervising moral decisions, and when its functionality is altered may lead to impulsive aggression. The temporal lobe is involved in theory of mind and its dysfunction is often implicated in violent psychopathy. The cingulate cortex mediates the conflict between the emotional and the rational components of moral reasoning. Other important structures contributing to moral behaviour include the subcortical nuclei such as the amygdala, hippocampus and basal ganglia. Brain areas participating in moral processing can be influenced also by genetic, endocrine and environmental factors. Hormones can modulate moral behaviour through their effects on the brain. Finally, genetic polymorphisms can predispose to aggressivity and violence, arguing for a genetic-based predisposition to morality. Because abnormal moral behaviour can arise from both functional and structural brain abnormalities that should be diagnosed and treated, the neurology of moral behaviour has potential implications for clinical practice and raises ethical concerns. Last, since research has developed several neuromodulation techniques to improve brain dysfunction (deep brain stimulation, transcranial magnetic stimulation and transcranial direct current stimulation), knowing more about the ‘moral brain’ might help to develop novel therapeutic strategies for neurologically based abnormal moral behaviour.

Call for Proposals: Cross-Disciplinary Conversations Around the Neurosciences

From NeuroSelves to NeuroSocieties:
Cross-disciplinary Conversations around the Neurosciences

June 11th & 12th, 2012
An interdisciplinary conference hosted by Hampshire College, Amherst MA and the Foundation for Psychocultural Research-Hampshire College
Program in Culture, Brain & Development

Call for Proposals

Our understandings of self and society are being transformed by the neurosciences. At the same time neuroscience is shaped and driven by social structures such as law, media and education, and informed by fields such as sociology, anthropology, philosophy and evolutionary biology. The emerging fields of neuroethics, neurolaw and neuroeconomics are a testament to the desire to apply a better understanding of the brain to moral and social issues, but also point to a need to understand the myriad ethical, legal and cultural implications of the science itself.

This conference offers an opportunity for cross-disciplinary communication among scholars from many disciplines around how the neurosciences shape – and are shaped by – diverse social forces and cultural ideas.

We invite proposals from faculty and graduate students from a wide range of disciplines and perspectives.

Please submit a proposal that describes your background, interest, and proposed presentation topic.  Participants will be expected to give a short presentation of how their work engages with – or could shed light on – issues at the intersections of law, philosophy, economics, ethics, or some other aspect of the cultural/social/political sphere and the neurosciences. Participants will receive a $500 stipend. Some assistance is available to help with travel costs; applicants are invited to apply for travel funding.

The conference program features two keynote speakers: Dr. Adina Roskies, Associate Professor of Philosophy at Dartmouth College, and Dr. Peter Reiner, Professor, National Core for Neuroethics and the Kinsman Laboratory of Neurological Research, Department of Psychiatry and Brain Research Center, University of British Columbia.

Presentations and panels will be structured around participant interests and proposals. For illustrative purposes only, possible topics might include (but are not limited to): changing conceptions of moral, personal or economic decision-making; diagnosis, treatment and conceptions of mental illness; ethical challenges posed by neuroscience research; art and neuroscience of creativity; social and ethical implications of neuropharmacological interventions; interactions between educational policies, practices, and the neurosciences; questions of free will and human agency; neuroscience of empathy, trust, and sociality; brain imagery and popular media; neuroscientific recasting of social problems such as addiction and violence.

Please go to http://www.hampshire.edu/cbd/22808.htm for more information about the conference and submitting a proposal. The deadline to submit proposals is February 15th, 2012.  Please send proposals and questions to Ryan McLaughlin, CBD coordinator, rmclaughlin@hampshire.edu .