By Nils Muhlert
Professor Leah Somerville is an associate professor of psychology and director of the Affective Neuroscience and Development lab at Harvard university. She was recently awarded the Early Career award by the Social & Affective Neuroscience Society. Here we find out more about her academic career path, and what we can expect from her keynote speech at OHBM2018 in Singapore.
Nils Muhlert (NM): First, can you tell us about your career path – how did you get into neuroimaging?
Leah Somerville (LS): I started working on brain imaging research as an undergraduate at the university of Wisconsin. I was working in a couple of different brain imaging labs, right when the first research dedicated scanners arrived at the university. I was one of the first people to have the opportunity to run experiments on it – along with a team, of course, of other researchers in the labs I was working in.
I got that little thrill moment of seeing a person’s brain image pop up on the screen. Maybe others have had a similar experience. I still have that feeling every once in a while, it hasn’t completely gone away! I find neuroimaging so fascinating and powerful. From there I tried to orient my training towards continuing my brain imaging research, and in particular, fMRI-based research. I’ve studied emotion and anxiety-related processes. I’ve also studied motivation and cognitive control. Now in my lab we’re focused on understanding how those processes change with ongoing brain development through adolescence.
NM: What would you say is so special about adolescence in the context of human development?
LS: There’s a lot I could say here - I’ll try to keep it short! Adolescence is a time of life that on the surface level is associated with a number of important challenges, that individuals are facing sometimes for the very first time.
Adolescents are people who are faced with independent choices about how to act, who to affiliate with, what kind of goals they like to hold for themselves. At the same time there’s increasing demands on their self-control. They’re becoming more and more self-guided in the way that they’re interacting with the world. We can sometimes think of them as novice independent people who are still developing the toolkit that can support mature independent actions.
We find that ongoing brain development facilitates a number of great achievements at this time of life. But it also places a number of constraints on the way in which adolescents might optimize their behavior in certain situations. We’re very interested in understanding the interplay in that – thinking about adolescence as a very adaptive and useful time of life but also one that differs from adults in a number of important ways.
One insight that has fascinated me is looking at brain development measures and asking “when does a person become fully mature?” It may seem like an easy question or one that could be measured using a single modality. In fact, the answer you get really differs when it comes to brain structure or function or network properties. It’s especially surprising that on certain measures – including measures of white matter – the developmental changes continue to play out throughout the twenties and perhaps even through the thirties. So one thing that’s interesting, as an extension of that, is thinking about how we decide when a person is mature from a societal standpoint.
NM: In your work you also discuss socioaffective circuitry – how do changes in that circuit map on to the behaviors we see in adolescence? And what have you found out about that over the last decade?
LS: In our lab we tackle this from different angles – so I’ll let you know about one in particular that I’ll be talking about in OHBM.
We’re very interested in the intersection between motivation and cognitive control. That is, the degree to which motivational cues in the environment – potential rewards and punishments for example – can shape the way in which a person is able to optimize their cognitive control in a given context.
We’re interested in the shift across development, in which individuals across the ages can recognize situations that hold different motivational values. They might want to perform better in certain conditions than in others – either to avoid punishment or to obtain rewards. All of the detection and assignment of values seems to be very consistent in early development. But the degree to which we can take that information and use it to guide our goal-directed actions in the moment, seems to be continuing to develop well throughout adolescence.
One arm of our work is in trying to understand how the dynamic interactions in cortico-striatal circuitry (including the dorsal and ventral striatum and lateral prefrontal cortex) coordinate and give rise to motivation-guided cognition. This is something that we’ve seen play out and continue to change and refine well throughout adolescence and into early adulthood. This is one area of work that we’re excited about.
Another area we’re interested in is adolescent attunement to their social environment. This is a time of life that’s associated with dramatic changes in daily life; individuals are forging new independent relationships for the first time and there’s a lot of volatility in adolescent relationships. They are falling out of favour with one another more frequently than adults would be, giving them lots of opportunities to get feedback about how they’re doing socially. Another arm of our work is therefore to understand how adolescents learn from feedback and use positive and negative social feedback as learning cues to inform how they should feel about themselves in a given situation and how they should feel about other people.
We’ve seen in a couple of studies that when adolescents are on the receiving end of negative social feedback they tend to take that as a very strong cue to influence how they feel about themselves. This would result, for example, in a reduction in the momentary feelings of self-worth or self-esteem. Adults actually show a bias in the opposite direction. They have different strategies in place that allow them to offload or buffer themselves from negative feedback and maintain a positive self-concept, even in the face of very opposite social information. We’re really interested in understanding how learning processes – again subserved by striatal-based systems – might be biased towards learning from negative or positive information in the social domain at different points of life.
NM: And how does this system seem to change from early to late teenage years, or even people's early twenties?
LS: Well we carried out a study of individuals from age 10 to 25, and found that there is a period from early to mid-adolescence, perhaps from 12 to 15, that negative feedback had a strong negative impact on their self views. Whereas individuals of college age seem to have a lot of strategies in place already to buffer themselves from negative feedback. So this is one time period when a few years of age makes a large difference in terms of how these cues are incorporated into learning about themselves and other people.
NM: Thinking about how social media might tap into this, and perhaps exacerbate the concerns that adolescents have: as social media has become a more integral part of their everyday lives, has this had negative and positive consequences?
LS: Great question and one that I don’t have a scientific answer for but I’m happy to speculate!
This is a very hot issue now – thinking about how developmental stage might manifest the influences of these kinds of media processes differently. It’s only in very recent generations where people have taken up a lot of social interactions online. This is something that has not been subjected yet to empirical study.
There is a lot of speculation that perhaps social media is detrimental to adolescent development. Adolescents themselves are quite happy at having the option to socialize over the phone and over the internet. They say it helps them maintain strong social bonds, it gives them lots of information. They can stay attuned to the goings on of all of their friends more easily.
There is also the potential for social media to have certain negative and perhaps unintended consequences. One that has been suggested by our work is that social media has been almost designed to elicit and deliver feedback to people – by getting friended, getting thumbs-up or the absence of a like or lack of response from somebody. This can be interpreted as negative by someone or by people on social media.
The way we see it is that there can be very positive interaction on social media but there’s also the potential for a higher frequency of negative feedback, or the absence of positive feedback being interpreted as negative feedback. We’ve shown that negative feedback has a very potent influence on adolescent self-views, so that very high frequency of receiving negative feedback online could have a more detrimental effect during adolescence than other ages.
Developmental scientists have often had concerns about the effects of new technology influencing self-views. When I was a kid this would have come up with video games – suddenly people would have a Nintendo in their house, there was a wave of concern about that. At this point we just don’t know enough to have a definitive evidence-based account about whether social media is a good or bad thing for adolescence.
NM: Turning to your other work, what would you say are the scientific achievements that you’re most proud of during your career?
LS: I’m not sure if I’d call this a scientific achievement but I’m most proud of having had the opportunity to run my own lab.
I never thought I’d be a PI. It has been one of the most challenging and rewarding things I have ever done. I feel proud and gain a lot of reward from it, particularly when I interact with my trainees. They conduct great work, are great people and are becoming great mentors in their own right! It makes science very fun to do in our group. Fostering an atmosphere that makes science fun and exciting and collaborative is something I’m very proud of, and is down to the efforts of my whole lab.
NM: And to reflect the quality of your mentoring you were awarded the Everett Mendelsohn excellence in mentoring award. When you look back at your own career, which people could you point to that offered you good advice during your career, and how has that affected how you interact with your own trainees?
LS: I’ve been very fortunate to have had a number of wonderful mentors throughout my training. They’ve helped me bridge gaps into the next steps of my career – giving me advice, and sometimes tough love when I needed it! This includes my graduate mentor and my postdoctoral mentor, BJ Casey. I would point out BJ in particular – she was a big part of me discovering this very strong interest in developmental neuroscience, particularly after trialling out a number of different topics of study. That one fit for me in very large part because of the support in mentoring from her.
It’s important to mention that at first I didn’t realize that every trainee needs something different from a mentor. You need a lot of flexible thinking when you’re mentoring to understand what each person needs at different points in time. This of course evolves at different points of training. They might start by needing more hands-on help and more topically-focussed advising. But watching a person beginning to strive for independence and allowing for independence is something that I work hard to detect and accommodate.
When I became a PI I didn’t realize that I would still benefit from mentoring myself. I still have mentors who guide me and I don’t think anyone is ever quite finished in needing mentoring, advice and guidance. I have a number of colleagues – both peer-age going through similar career stages, as well as more senior mentors – who are still helping to guide me. I am very appreciative of that.
NM: And finally, your OHBM 2018 talk – can you give us a sneak preview? Which gems from your research career have you decided to focus on?
LS: Well I’m very excited about being invited to speak at OHBM and having the chance to go to Singapore. I’ll be talking about two main themes: adolescence as a phase of the lifetime associated with ongoing and dynamic brain development, in particular in development of functional brain connectivity.
I’ll also specifically focus on understanding the interactions between motivations and cognition as a test bed to think about how ongoing brain development would lead to important shifts in behavior. In doing that I’ll present some specialized studies that were conducted in my lab in Harvard, as well as some broader projects that we’re currently working on.
Most notably we’re one of the groups completing the human connectome project on development – a large scale ‘big data’ style project - that will ultimately collect brain imaging data on over 1,300 5-21 year olds. This is an ongoing study that we are about half-way through collecting data for. It’s partly longitudinal and partly cross-sectional, and it’s designed to help us really understand both fundamental patterns of brain connectivity that are changing at the basic neuroscience level as well as the implications of those connectivity changes for behaviours including motivated behavior and cognitive control.
So I’ll be discussing how we approach these problems from a broad, big-data standpoint and how this can complement the more specialized work that we’re doing.
NM: We’re definitely looking forward to that – many thanks for taking the time to speak to us and we’re looking forward to your talk in Singapore.