If, unlike me, half of your Facebook friends are not predominantly neuroscientist, you might have missed one of the most important events happening this month.
It is not about Sergio Ramos announcing that he is leaving the Real Madrid to start a new life in Manchester (Ramos in exchange for de Gea? What’s wrong with you, Man United?). It is not about Tim Hunt articulating the ‘mea culpa’ for his unfortunate comments about women in science. It is not about Kim Kardashian and her upcoming talk about female objectivation (can somebody explain to me why TED hasn’t invited her yet as a speaker?). It is about the 2015 conference of the Organization for the Human Brain Mapping!! (#OHBM2015) (yay!!).
I love going to conferences. This year, OHBM had the additional incentive of taking place just nearby the paradise, in Honolulu. So it was just great to sneak out of the conference center and to go to the beach or around the city every time the title of the talk contained the words ‘Bayesian’ or ‘multivariate algorithm’ or, every time the presentation included more than three equations. But please, don’t judge me for that! This blog is actually called ArousedBrain for a reason. Otherwise, it would be called VectorizedBrain, ComplexBrain, or ComputationalBrain.
Going to conferences might offer you a great opportunity for meeting inspiring people and old friends working somewhere else. Additionally, it might be useful to ckeck if other groups that are working in your field are performing the same type of studies that you are carrying out. This can be an issue sometimes.
While I was in my first year of my PhD in Barcelona, I was working hard to apply independent component analysis (ICA) to evaluate resting-state connectivity in obesity. ICA allows the evaluation of networks in the brain, which are formed by regions that tend to activate in a synchronized way. So, I had a cool result comparing participants with obesity and participants with a normal-weight, and I was getting very excited about it.
Sometimes, I feel that science is like being on a roller coaster. There are times in which you feel like being in a ‘maniac periods’, and you feel that your result will lead you to international recognition, and (using some words from ‘Gladiator’) will echo in eternity. Conversely, other times you enter ‘depressive periods’, in which you just feel like the most incompetent person in the world.
Back to the point, I was in a maniac phase with my results in resting-state and obesity. Relative to control individuals, I had discovered that participants with obesity exhibited an increased functional connectivity in the salience network. The salience network is formed by the co-activation of the anterior insula, anterior cingulate, and other limbic and striatal areas, and it has been associated with the integration of sensory and homeostatic information (1). So, I was really excited preparing my results for publication and dreaming with winning a Nobel Prize. And then, another paper on resting-state in obesity came out.
In this ‘other paper’, Kullmann et al. reported an obesity-related increased functional connectivity strength in the precuneus, inside the default mode network (2). At that time, I thought that my career as a neuroscientist was finished. I would never be the first person in the world to investigate resting state fMRI in obesity!! Such a big deal! My group in Barcelona saw me going through a depressive phase after this. I think I even told my hairdresser too much about how terrible my life was. Well… first world problems, right?
Luckily, my wise supervisors considered that our study on the salience network still provided new and relevant information to the field. So we decided to keep on working on it and we eventually submit it to a journal. After some effort, it was successfully published (3) and I sill remember being in shock when I saw our study accessible in PubMed (finally! I had published my first ‘real’ study!!!!).
After the euphoria of getting my first paper accepted, I decided to continue applying ICA-based analysis in obesity. But this time, I wanted to study differences in an fMRI task acquisition. We had an fMRI sequence available, in which the same participants from the first study were presented with a food reward paradigm. So, I wanted to analyze differences in functional networks according to the different experimental conditions (food reward, other non-food reward and neutral stimuli). I obtained a cool result, in which participants with obesity and individuals with normal-weight differed in the connectivity strength of a network containing activation in visual and lateral prefrontal areas and deactivation in the posterior part of the default mode network.
So, again, I entered a second maniac phase imagining myself being hired by a pharmaceutical company and signing multimillionaire contracts. But then, another paper was published and brought me again back to reality. Somehow similar to what I was trying to write down, the same group of Kullmann and collaborators published an elegant study in which they applied ICA-based analysis to investigate food reward processing in obesity (4). Seriously, their study is still today one of the coolest papers published in the field!! This time, my previous experience prevented me from entering in a self-pitying and depressive phase for not being the first person in the world applying ICA to study reward processing in obesity. Instead of that, I worked hard to highlight the novelty of our study, we submitted it, and after some time, we also got it accepted (5).
So, as I said before, conferences are useful because they allow you to meet inspiring people. Last year, also during the OHBM congress, I met some of the authors from the Kullmann et al. studies. In my mind, I was imagining them as scientist with dark powers and with the ability to read minds from thousands of kilometers in the distance and being able to perform better and faster studies. It turned out that they are a very friendly and nice people. It was just a pleasure to talk and exchange ideas with them.
Results in ICA-based analysis –like the ones in Kullmann et al. studies (2,4) or the ones in my previous studies (3,5) – could be associated with the principle of modularity or segregation in functional connectivity. This principle refers to the organization of a system (i.e., the brain) into a set of modules (i.e., networks) containing highly inter-correlated components (6). Imagine that you are in a party, and you are trying to identify sub-groups of people based on the pattern of social inter-relations that they present. You look around and you see a group of cool people happily drunk talking with each other and dancing, romantic couples on the corners kissing like there’s no tomorrow, and a group of women wearing pink ballet skirts and diadems with bunny ears that just came from a bachelorette party. If you think about the people in the party in this manner, you are segregating the different components of the system into subgroups or modules.
Another perspective would be to assess how the system as a whole becomes interconnected and how the information can be distributed through the different components. This has been referred to as the principle of integration (6). Again, taking the example of the party, you could be interested in investigating the way in which relevant information (e.g., the club is running out of gin tonic) is transmitted to the rest of the members in the party. Here, you will be especially interested in identifying those members with the highest accessibility to the other members. It is likely that waiters and some of the most popular guests in the party will be the ones spreading information to the other members.
In our most recent study in obesity, we aimed to examine functional brain differences between participants with obesity and normal-weight individuals by examining functional brain integration. We found that participants with obesity exhibited a diminished functional integration (that is, less information exchange) of the middle prefrontal gyrus and the lateral occipital cortex with the entire brain network (7). Since the middle prefrontal gyrus is a structure associated with inhibitory control processes (8) we speculated that the obesity-related differences observed could be associated with difficulties in impulse-control processes. However, this needs to be further investigated with proper fMRI tasks.
So, enough writing for today, it is time for me to procrastinate and to look at my pictures from Hawaii. Mahalo for your time reading my blog!!
- Seeley W, Menon V. Dissociable intrinsic connectivity networks for salience processing and executive control. J Neurosci, 2007, 27: 2349–56.
- Kullmann S, Heni M, Veit R, Ketterer C, Schick F, Häring H-U, et al. The obese brain: Association of body mass index and insulin sensitivity with resting state network functional connectivity. Hum Brain Mapp, 2011, 33: 11052–61.
- García-García I, Jurado MÁ, Garolera M, Segura B, Sala-Llonch R, Marqués-Iturria I, et al. Alterations of the salience network in obesity: a resting-state fMRI study. Hum Brain Mapp, 2013, 34: 2786–97.
- Kullmann S, Pape A-AA, Heni M, Ketterer C, Schick F, Häring H-U, et al. Functional Network Connectivity Underlying Food Processing: Disturbed Salience and Visual Processing in Overweight and Obese Adults. Cereb Cortex, 2013, 23:1247–56.
- García-García I, Jurado MA, Garolera M, Segura B, Marqués-Iturria I, Pueyo R, et al. Functional connectivity in obesity during reward processing. Neuroimage, 2013, 66C: 232–9.
- Sporns O. Network attributes for segregation and integration in the human brain. Curr Opin Neurobiol, 2013,
- García-García I, Jurado MÁ, Garolera M, Marqués-Iturria I, Horstmann A, Segura B, et al. Functional network centrality in obesity: A resting-state and task fMRI study. Psychiatry Res Neuroimaging, 2015, (in press).
- Hare TA, Camerer CF, Rangel A. Self-control in decision-making involves modulation of the vmPFC valuation system. Science. 2009, 324: 646–8.