We are not static! The brain is wired for learning.

Published! is a series of chats with women in science highlighting their publications as leading authors. If you know someone who has recently published a scientific manuscript who would like to chat with me, you can get in touch via Twitter @laurenpoppi or email <lauren.poppi@rutgers.edu>.

Taehyeon Kim is a PhD Candidate from the University of Pittsburgh Center for Neuroscience who studies motor learning in Dr. Bryan (Mac) Hooks’ laboratory. Taehyeon, together with Dr. Bryan Hooks and Dr. Claire E.J. Cheetham, recently published a textbook chapter in Neural Circuit and Cognitive Development titled “Circuit development in somatosensory cortex”. You can find the chapter here on ScienceDirect. Taehyeon came to the USA from Korea almost 15 years ago as an international student, and has since become a neuroscientist who uses cutting-edge techniques to study development and motor learning. We chatted about Taehyeon’s research journey, the excitement of seeing neurons communicate in real time, and how important it is for young researchers to look after themselves both mentally and physically.

 

What motivated you to write this textbook chapter?

I was always interested in development. When I was applying for labs, my PI’s (Principal Investigator; Dr. Bryan (Mac) Hooks) PhD work was in development – in the visual system – but then he was working on motor systems. I wanted to study development, that has always been my interest. After finishing my rotation, I think it was around the summer, he got in contact with me because he knows my background. I was working in somatosensory cortex. He asked, “I’ve got this textbook chapter, do you want to write it with me?” I thought it would be a great opportunity for me to learn more about development, because there are a lot of aspects that I don’t fully understand. I’m a physiologist - I don’t really know about all the different aspects of development like molecular/cellular pathways in somatosensory cortex. I thought this would be a really good opportunity for me to deep dive and learn more about this brain area, and that’s how it all started. It took a while, and it took a while to publish, but yay! It’s out! I’m really excited.

 

How is the process of putting a textbook chapter together – it’s a bit different than writing a manuscript for a journal. Was the writing and editing process what you expected?

This was my first time actively involved in writing for scientific publication. We put a lot of effort into the figures, because that is what easily grabs people’s attention. Somebody will open the chapter, and the figures are the first thing they will look at. We wanted to make it easy to follow, and we didn’t want to omit any information. This process of ‘what is relevant for the chapter versus what is not’ was hard, but making the figures to represent that information was actually… I found it very hard. Even the colours! (laughs) We went back and forth about the colour scheme. That was what I least expected about this writing process.

 

The figures are beautiful, by the way. Tell us a bit about the techniques that you use in the lab to study the neocortex.

We use electrophysiology as our major technique, everyone records in our lab. We use optogenetics and transgenic techniques to target specific cell types, and we do motor learning behavior. Everyone in my lab patches¹. It takes patience. I’m a rising fourth year, but I feel like I’m still learning. I feel like I’m not at ‘that level’ yet. Every time, I think “Oh. I can do better.”

 

Don’t worry, I have been patching since 2012, and I still feel like a novice.

(laughs) I still get stressed the day before! I’m starting back my recording and behavior now, and I think “OK… it’s been a hot second”…. and you KNOW the first day never goes right!!

 

I really like asking people this question. What first got you interested in studying the cortex, and what made you decide to focus your PhD work on it?

My parents back in Korea are psychologists and they specialize in [treating] children with autism. For as long as I can remember, I’ve always interacted with children with autism, and some who cannot commute to my parents’ clinic stay with us in the house. So even though I am the only child, I was never really the only child. There was always someone staying with us. As a child…. [I thought] you know, there is no cure for autism. My parents would take them to see a doctor, and they might get anaesthesia if they are going through a dental procedure. Whatever the normal dose was - proportional to body weight - wouldn’t work. I always thought, “why are they different, and why do they behave the way they do? What is the cause of it?”.

I then moved to the States by myself, as an international student. When I was a kid watching my parents, [I knew] that being a psychologist was not an easy job. It’s 24/7. I told them that I would never be a psychologist. But… I majored in psychology as an undergrad, oh no! It wasn’t until I took a class in neuroscience, one of the faculty, Dr. Juraska, was teaching a class on the neuroendocrine² system. Basically, hormones in the brain have activating and organizational effects. I was really interested in that. I thought, there are sex differences in autism, so I wondered “do hormones have a role in it that leads to long-term effects on behavior?”. Hormones have a profound role in how the male versus the female brain develops. I wanted to know more, so I joined the Juraska lab, and that’s how I got started working in neuroscience. We were looking at the the neuroanatomical differences in male and female rats during development and aging under normal conditions, as well as the impact of neuroendocrine disruptors or bionutrients during these periods. That’s basically how I got into neuroscience and I still am interested. I wanted to do physiology because you can see what is happening in front of you. It’s really exciting when you break in³ and see the brain active. Yes, now we have GCaMP⁴, but I’m still excited [about electrophysiology].

 
 

All of the work you have just talked about has led to what you are doing now, so tell us a little bit about your PhD and the kind of questions you’re working on answering at the moment.

Right now, we are interested in two populations of inhibitory neurons, parvalbumin- and somatostatin-positive interneurons. They’re about 2/3 of the entire inhibitory neuron population, and they have been implicated in critical period and motor learning. We want to know what are the synaptic changes are being mediated by these interneurons when we acquire a motor task. So that’s what we are interested in, and obviously this has been difficult. The project is basic science, but hopefully this will give us a better understanding of disorders like autism, or even things like stroke.

 

When most people think about plasticity and learning, they’re probably imagining someone doing a puzzle, or learning a new task or behavior. You are able to study plasticity in vitro. Tell us a bit about how that works in a practical sense, and how your work relates to improving our understanding of neurodevelopmental disorders like autism?

An analogy I have is, imagine barrel running on the lake. You have to balance, and as the barrel starts going faster, you have to learn to go faster. This is a motor learning paradigm. So, after acquiring this task, we want to know how synaptic connections change. We use transgenic models that have optogenetic activators in specific cell types. We can ask, ok, what happens to these cells and their partner cells? How much inhibition do they receive? We also use this technique to label specific cells that become active when engaged in the motor learning task. So then, we can ask is there a difference between how much inhibition they receive with cells that are active in the task versus not active? Is there a difference between parvalbumin- versus somatostatin-positive neurons in terms of how they mediate this inhibition?

 

What is the coolest thing about being an electrophysiologist?

Seeing a cell spike⁵ in front of you. That’s how I got hooked on being a physiologist. Even now, I get really excited when doing optogenetics I shine the light and get an immediate response.  I think, “Yes! There it is!”. It is still exciting. There is something about seeing the cells in front of you. It’s something different to just looking at images. You can watch them communicate. I’m still hooked and still trying to be a better physiologist.

 

Do you have any little-known facts about the brain that you’d like to share?

This isn’t related to what I do, but it’s fascinating to me. It’s called Dehnel’s phenomenon. In certain species, like the shrew, their skull and brain mass shrink during the winter, and in the spring it regains back some of the mass. Not completely, I think in winter it shrinks 10-15% and in the spring it regains 8-10%.

So, the brain and skull shrink during the winter, and re-expand back out in the spring?!

Yes.

That is wild!

Whenever I think about this, it motivates me. There’s that saying, you know - “you can’t teach an old dog a new trick”. There’s this idea that once you’re an adult everything is static and you can’t change. But look at these kind of changes that happen in nature [in the shrew]. We know the brain is plastic. We are not static, we can learn new things. What is causing that volume change? Are the connections reacquired? Physiologists – we care about that. When I got back from SfN (Society for Neuroscience – a major conference). They asked me, “what is the most fascinating thing you learned?”. Yes, there were tons of posters on motor learning, and yes, they were amazing. But this was the first thing. I was like “did you know there is a species out there that can shrink their brain size!?”.

 

What would be your advice to a younger student considering doing a PhD?

We are all really hard working, motivated people. Sometimes we just forget to take care of ourselves. We overlook ourselves. I think it is important to take a second, both mentally and physically. Do something that will make you happy that is not science. Even just take a step away for a second - that actually helps rejuvenate you. A lot of people suffer from burnout during their PhD. It is a LONG run. I mean, PhD… post-doc. Everyone says it’s a marathon, right? To prevent yourself from getting burned out, getting exhausted – it’s important to take a second, take a look at yourself, and take care of yourself. I mean, I think it’s hard to do, because we want to do science. But I think it’s important.

That’s a really important message, because we tend not to be greatest at recognizing when we need to take a step back. Often it takes someone else to say “Hey, are you ok? You need to chill a bit.”

This I actually didn’t come across until I was talking to a guest lecturer. He said, “just take a walk! When I was a PhD student, I just took an hour walk when things were not happening. You want to be happy and excited to go into work every day.” I think sometimes we lose that excitement because we get so overwhelmed with what we do. Sometimes it’s easy to forget that we actually love what we do. Taking a rest will help us to gain back that insight and allow us to appreciate it.

 

What are some of your goals for the future, in your PhD and beyond?

Obviously, the immediate goal is – get a PhD, get the publication. That’s my immediate goal, but if someone asked me a few years ago, “what is your long term goal?”, I would have said, “I want to get a PhD, I want to get a postdoc, I want be on tenure track faculty.” But now, especially in this pandemic, I’ve got to think more about non-traditional, non-academic options that I can explore as a career. You know, what are the set of skills that I get from a PhD, that are maybe not scientific method, but can be applied? Maybe by the time I graduate I’ll have options for my career. Honestly right now, I don’t have the exact answer for what I want to do. I am still looking. But at the end of the day, hopefully in ten years and forward, I am doing something that I am passionate about and I feel self-fulfilled. Whether that be in academia or not in academia. Short answer – I don’t know!

 

I have a list somewhere of all the transferable skills that you get from doing a PhD. For example, you learn project management from your PhD because you had to manage three different projects at different stages and see them through to completion. This really helped me at the end of my PhD, because it helped me to realize that I can do other things. I can choose to stay in academia, but there are so many other things that we can do. Even as a PhD student, there are so many different skills that you don’t even realize that you have.

 

I’ve told this to my PI – I feel like all I can do is recording and even then, I feel like I am not good enough. I think we get stuck and define ourselves based on the approach that we use. At least the pandemic gave me time to think, “Ok – let’s try to think of the bigger picture”. I’ve seen a lot of friends and colleagues who are more ahead of my year applying for non-academic jobs. There is a bigger world than what I limit myself to thinking about, other than just scientist.

 

We as scientists are guilty of putting the blinders on and seeing nothing else except the tenure-track. Even if it becomes less and less attainable, that’s all we can see. People at our stage, especially at this time in society, we are forced to start thinking “ok, what are the other options? What can we do?”.

 

How do you hope to see the scientific landscape change for women in the future?

I want to see a better representation of women from different backgrounds, from BIPOC. Coming from a different background gives you a different perspective – ways of looking at the problem and arriving with a different approach to solve the problem. We always want to have inputs from lots of different people because it opens our minds. After all, we are scientists trying to answer a question and we cannot limit ourselves to one way of doing things. It’s always great to have people that can bring different ideas.

 It’s always surprised me, even as a female scientist, the fact that people have to be reminded that we need to have an equal ratio of male and female scientists in a given panel or lecture series. We shouldn’t have to be reminded! GWIS fosters women scientists and has fellowships for women in science. I wish there was also more institution-based support for women in science. Especially with marriage and childbirth, often times, the responsibility falls onto women. Here at Pitt, I have seen multiple faculty members with very supportive partners, but I wish more programs would be more actively involved in supporting us, especially graduate students and postdocs. When we look at this career pipeline in academia, I want to see more women scientists becoming PIs. This came up in a forum recently, where there were two male PIs and two female PIs. When somebody asked, “how do you survive as a young female scientist in this field?”, it was a male PI who picked up the mic and answered. What?! No. This question was specifically directed towards the women on the panel. We are moving forward… but we are not there yet. This isn’t going to happen in the next five years, but I know we are making a very conscious effort. I wish that in the future – we don’t have to be reminded – it just naturally happens.

 

Is there anything else you would like to add (e.g. acknowledgements)?

I would like to thank my PI. He has been very supportive, and my undergraduate advisors. I was very lucky to have such supportive mentors, who care about individual students. I’d like to thank my fellow lab members and my family… especially my dogs because I wouldn’t know how to deal without them! I look at their pictures and I feel better!

¹ technique in neurobiology – patch clamp electrophysiology

²refers to the action of hormones in the nervous system

³refers to rupturing the cell membrane of a neuron and thereby gaining high-resolution electrical access, such that the neuron’s activity can be measured.

⁴an indicator that can be used to optically report neuron activity

⁵refers to firing an action potential