Category Archives: Neuroscience

Neuroscience, We Are Brandeis Science

We are Brandeis science: Madelen Díaz

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There is no rule that says scientists have to look or act a certain way. Scientists can be funny and outgoing, athletic and artistic. They come from all different backgrounds and have all different interests. At Brandeis, our scientists are as diverse as the groundbreaking research they engage in. This on-going series is inspired by This is What a Scientist Looks Like. 

This post was written by Madelen Díaz, PhD student in professor Michael Rosbash’s lab. 

The music of the mind

Madelen Diaz
Madelen Diaz

Where are you from?

I was born and raised in Miami, Fla. after my parents emigrated from Cuba.

What do you research?

I currently research the neuronal circuitry responsible for circadian rhythm in the fruit fly (Drosophila melanogaster). Why do we use the fruit fly to study circadian rhythm? Fruit flies sleep at night and even sleep the siesta during the afternoon. Several of the molecular proteins responsible for these behavioral oscillations are conserved across species. We use complex genetic tools, behavioral assays, and several imaging techniques to see how these circadian neurons coordinate with each other to produce their active/sleep cycle throughout the day.

What is your biggest passion outside of science? 

My passion outside of science has always been classical piano. I’ve been playing since I was 6 years old. There is something incredibly relaxing about immersing yourself into the music that you forget that ever-growing “to-do” list.

How do you define discovery, and how does it make you feel?

I would term discovery as obtaining an unexpected or controversial result. It’s very exciting thinking of the possibilities of a new discovery and how this can potentially contribute to the “big picture.” It can also be nerve-wracking because of the uncertainty of not knowing what to do next or where to look. The most difficult part of graduate school is to continue working through all of the uncertainty.

What do you do to unwind, after a long day at the lab?

After a long day in the lab, I most commonly relax by baking desserts or playing piano. On weekends, I like to go out salsa dancing or traveling New England.

Neuroscience, Research

Researchers identify potential cause of schizophrenic symptoms

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Imagine a waking nightmare.

That’s how Elyn Saks, law professor and mental health advocate, describes the delusions, hallucinations, memory loss and mental fragmentation that schizophrenia causes.

The mental disorder affects millions of people worldwide but the cause of its wide-ranging symptoms remains largely unknown.

At Brandeis University, researchers believe they have discovered an abnormality in the schizophrenic brain that could be responsible for many of the disease’s symptoms and could provide a drug target for therapeutic treatments.

John Lisman photo/Mike Lovett
John Lisman photo/Mike Lovett

Led by John Lisman, the Zalman Abraham Kekst Chair in Neuroscience and professor of biology, and Matthew Wilson of MIT, the research team published their findings in a recent issue of the Journal of Biological Psychiatry. The paper was co-authored by Aranda Duan, Carmen Varela, Yuchun Zhang, Yinghua Shen, Lealia Xiong, and Matthew Wilson.

Unusual neural oscillations — brain waves — have long been associated with schizophrenia. The oscillations, called delta waves, are similar to slow oscillations seen in normal brains during sleep, but in schizophrenic brains, they occur during wakefulness. The connection between these oscillations and schizophrenic symptoms, particularly cognitive deficits such as memory impairment, has long been unclear.

Lisman and his team set out to understand that connection by artificially producing delta waves in mammalian brains using a new technique called optogenetics, which activates brain signals using light.

When the delta frequency light was turned on, Lisman observed disruption in the working memory of rats. When it was turned off, the rodents were once again able to perform working memory tasks. More important, Lisman and his team were able activate the abnormal oscillations only in a tiny subpart of the thalamus, a region of the brain that has long been a focus of schizophrenia research.

An information hub and relay center, the thalamus is central to working memory, sleep, consciousness and sensory-information processing.

“The oscillations produce an artificial signal that jams normal communication,” Lisman says. “The part of the thalamus that is supposed to carry information about working memory couldn’t do the task at all with these sleep-like delta waves. We suspect the abnormal delta oscillations seen in patients with schizophrenia are producing a similar jamming of normal signals.”

The green axons of thalamic neurons can be seen as they innervate the hippocampus. It is these axons, when stimulated by light, that jam communication. Courtesy/Lisman Lab
The green axons of thalamic neurons can be seen as they innervate the hippocampus. It is these axons, when stimulated by light, that jam communication. Courtesy/Lisman Lab

Delta waves require a specific type of ion channel called a T-type Ca channel. These channels are of particular interest because they are one of the few types of ion channel implicated in schizophrenia by genetic studies. The next step, Lisman says, is to figure out what kind of agents could be used to block these channels.

“If you could block these channels, you could block these bad oscillations,” he says. “That may have therapeutic value in patients.”

Neuroscience, Psychology, Research

The Science of Stressing People Out

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Ever had that dream where you’re about to take a test or perform in a play or go to a job interview and you are completely, woefully unprepared?

Many of us have that classic nightmare when we’re stressed out. But, for the scientists who study the effect of stress on the body, recreating those unnerving situations in real life is an important part of their research, however sadistic it may sound.

Psychology professor Nicolas Rohleder and his team of graduate and undergraduate researchers use so-called stress tests to study interleukin-6 (IL-6), an inflammatory agent linked to stress and a known contributor to heart disease, diabetes and cancer.

The science of stressing people out has, thankfully, evolved over the years from early tests in which participants were asked to stick their hands in buckets of ice or forced to watch videos of bloody surgeries, to more humane procedures today.

Although stress and its impact on the body have been studied since Austrian-Canadian endocrinologist Hans Selye’s experiments in the 1930s, stress tests weren’t standardized until the 1990s, when Clemens Kirschbaum of the Technische Universität in Germany came up with the Trier Social Stress Test (TSST).

Instead of using ghoulish or physically shocking methods to measure stress response, the TSST is designed to trigger a stress response to a social threat.

Considered the gold standard of stress tests, it has been used around the world in thousands of studies. Rohleder’s lab alone has put more than 1,200 people through the test. Though Rohleder can’t reveal everything in the TSST — it would ruin the stress for participants — he can share the basics.

First, researchers invite participants to sit in a comfy chair in a quiet room to draw blood to establish a baseline. Of course, needles themselves are stressors for some, so researchers attempt to make the experience as relaxing as possible.

Next, participants are introduced to a team of researchers and asked to perform two different kinds of tasks. The first requires interacting with the researchers and the second requires solving a problem. Two researchers observe and time participants performing the tasks.

Credit: John Coetzee
Credit: John Coetzee

I know problem-solving tasks can be stressful — math certainly stresses me out. But what’s so scary about a social interaction, you might ask. Think about a time you went on a first date, or to a party where you didn’t know many people. Think about your first day of orientation at Brandeis. How did you feel? Were your palms sweaty? Was your heart beating a little faster?

As social creatures, humans need social interactions to survive, says Rohleder. But people who perform poorly in social situations risk being isolated or cast out of the group. Evolutionarily speaking, their genetic longevity may be in danger (though there are exceptions to the rule).

Obviously, researchers can’t expose subjects to life-threatening stressors, but luckily, social stressors provide the next best measure. The risk of social isolation triggers many of the same biological responses as physical threats, and the sympathetic nervous system kicks into gear, cortisol levels spike, and secondary stress systems, such as the inflammatory agent IL-6, activate.

Most of the time, by the end of the TSST, participants’ heart rates are up,  they might be sweating; their adrenalin might be pumping. The test usually stresses researchers out, too, Rohleder says, since they are also in a difficult social situation.

After the test, researchers take another blood sample to measure the biochemical changes in the body caused by stress. Participants can then leave — probably to calm down over a stiff drink.

Future stress test might include social media stressors, like Twitter trolls or nasty Facebook posts but we likely won’t see that in the lab until more people start seeing it in their dreams.

To read about Rohleder’s current research, check out our story on BrandeisNow.

Alumni, Biology, Neuroscience

Musicians rock at audiovisual integration

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In a noisy restaurant, isn’t it a lot easier to hear someone if you can see their lips moving? That’s because our brain’s audio and visual centers are deeply connected, allowing for multisensory integration.

As a senior at Brandeis University, Avi Aizenman ’13 wanted to know if musicians were better at exploiting that connection than non-musicians. Aizenman, a long-time flautist, thought they might be. Turns out — she was right.

Aizenman turned that idea into her senior thesis, which she presented at the 2013 meeting of theVision Sciences Society, and is now submitting to a scientific journal. If the paper gets accepted, it will be her third published paper in two years. Not bad for a student who didn’t want to study high-level brain processing a few years ago.

When Aizenman transferred to Brandeis as a sophomore, she was interested in social psychology, how thoughts and behaviors are influenced by the presence of other people. This changed when there was an opening in professor Robert Sekuler’s vision lab, an opportunity too good for Aizenman to pass up.

As the only undergraduate in the lab, Aizenman spent her time working directly with graduate students and postdoctoral fellows.

“At first, it was intimidating,” Aizenman recalls.  “But it was amazing how quickly I caught on. It gave me so much self-respect and confidence to be able to present my work with people who had so much more experience.”

Aizenman became entranced by how the brain processes audio and visual stimulation and memory, especially as someone who spent so much time playing music. It’s been long established that people with musical training are better at remembering and identifying different auditory stimulation — but could they also be better at identifying different visual and audiovisual stimulations?

To answer this question, Aizenman needed to recruit groups of student musicians and non-musicians, which turned out to be harder than she anticipated.

“Brandeis is so full of over achievers in the best possible way, it was hard to find someone who didn’t play an instrument,” Aizenman laughs.

Eventually, she found 14 non-musicians and 14 musicians, with at least six years of musical experience. She gave each group a test measuring their ability to identify which fast moving visual, audio and audiovisual sequences repeated identically.

She found that not only were musicians significantly better at remembering and identifying repeating and non-repeating auditory sequences but they were also better at visual and audiovisual sequences.

“It’s pretty amazing,” Aizenman says. “Music unifies the brain in a way that almost nothing else does.”

Of course, Aizenman notes, correlation doesn’t imply causation, so more research needs to be done to better determine if and how studying music shapes the brain’s relationship between audio and visual stimulation. It may be that someone begins playing an instrument and sticks with it partly because they are good at processing rapid sequences naturally.

Aizenman, who works as a research assistant at Brigham and Women’s Hospital Visual Attention Lab in Cambridge, hopes to pursue that question and others when she goes to graduate school in a couple years.

Be sure to look for her name in the journals.