Nav: Home

Shining lasers on mouse brains sheds light on cells central to Alzheimer's, schizophrenia

April 09, 2019

TUCSON, Ariz. - Alzheimer's disease and schizophrenia are some of the most common brain disorders and have been associated with problems in cells that contain a type of protein, called parvalbumin. These parvalbumin-containing cells account for almost one-tenth of the cells in your brain, however, relatively little is known about what parvalbumin cells do. By stimulating mouse brains with lasers, researchers have started to make surprising findings about how they work.

Researchers in the lab of Dr. Adam Q. Bauer, at Washington University in St. Louis, U.S.A., have found surprising changes in blood volume and flow when parvalbumin-containing cells are stimulated. The technique they used relies on specially bred mice whose brains can be stimulated with laser pulses. They will present their findings at the OSA Biophotonics Congress: Optics in the Life Sciences meeting in Tucson, Ariz., U.S.A., 14-17 April 2019.

One of the main types of the brain's inhibitory cells, parvalbumin-expressing cells have been found to be responsible for keeping the endless signals of the brain in sync. Since proper nervous system development relies on nerves repeatedly firing in concert with one another over time, conducting this neural symphony has been found to be an important part of regulating the connections between brain cells that allow them to develop normally.

The technique of stimulating the brain with light signals, called optogenetics, has produced great leaps in our understanding of how the brain works, including how our brains process fear and our sense of smell, or what causes us to become addicted to drugs.

"Optogenetics is convenient, less invasive and repeatable," Joonhyuk Lee, one of the Bauer group researchers said. "And it's more straightforward. You don't have to stick any probes into mouse brains or anything."

First, the researchers bred mice that expressed a special, light-sensitive protein called channelrhodopsin throughout the brain. Channelrhodopsin was originally found in algae, but scientists can use it to pick which parts of a mouse brain to turn on. Hit that area of the mouse brain with the right colored laser and you can activate a desired neural circuit.

The team bred mice that had channelrhodopsin stuck to parvalbumin-expressing neurons and mice with channelrhodopsin on excitatory Thy1-expressing cells, for comparison. With each group, they were able to stimulate the mouse brains with lasers and compare the results.

When most neurons are stimulated, Lee said, the brain provides them with more blood and oxygen. This occurred with the excitatory Thy 1 cells, but the lab's findings regarding blood flow and volume revealed the opposite response when parvalbumin-expressing cells were stimulated.

"How activity in specific neural populations is coupled to local changes in blood flow is fundamental to understanding how the brain regulates its blood supply," said Lee.

The scientists concluded that parvalbumin-expressing cells have a way of pulling back and fine-tuning the blood supply in areas where they are activated.

Researchers measured the blood and oxygen levels by shining a separate laser system, called laser speckle contrasting imaging, on the brain. When the mice whiskers were touched, Lee and his colleagues first found that parvalbumin cells could scale down nearby available blood and oxygen when excited. The group then measured different areas of the brain and discovered that parvalbumin cells could help relay messages to faraway corners of the brain to change their hemodynamics, or blood flow, as well.

"We really weren't expecting that activation of parvalbumin-expressing neurons would result in a reduction of local blood flow and volume," Lee said. "Even more so, although it could be an indirect cause, the fact that we saw similar hemodynamic activity in more distant areas of the brain was very surprising."

Eventually, Lee said, he hopes the findings and techniques will help lead to a better understanding of parvalbumin's role in neurovascular coupling and provide another piece of the puzzle on how it influences brain development or formation of neurological disorders.
-end-
Registration Information

Media and analysts who wish to cover OSA Biophotonics Congress: Optics in the Life Sciences should send registration requests to: mediarelations@osa.org.

About The Optical Society

Founded in 1916, The Optical Society (OSA) is the leading professional organization for scientists, engineers, students and business leaders who fuel discoveries, shape real-life applications and accelerate achievements in the science of light. Through world-renowned publications, meetings and membership initiatives, OSA provides quality research, inspired interactions and dedicated resources for its extensive global network of optics and photonics experts. For more information, visit osa.org.

Media Contacts: mediarelations@osa.org

Authors: Joonhyuk Lee, Annie R. Bice, Zachary P. Rosenthal, Jin-Moo Lee and Adam Q. Bauer
Author Affiliations: Washington University in St. Louis School of Medicine
Contact: joonhyuk.lee@wustl.edu

The Optical Society

Related Schizophrenia Articles:

Schizophrenia: When the thalamus misleads the ear
Scientists at the University of Geneva (UNIGE) and the Synapsy National Centre of Competence in Research (NCCR) have succeeded in linking the onset of auditory hallucinations - one of the most common symptoms of schizophrenia - with the abnormal development of certain substructures of a region deep in the brain called the thalamus.
Unlocking schizophrenia
New research, led by Prof. LIU Bing and Prof. JIANG Tianzi from the Institute of Automation of the Chinese Academy of Sciences and their collaborators have recently developed a novel imaging marker that may help in the personalized medicine of psychiatric disorders.
Researchers discover second type of schizophrenia
In a study of more than 300 patients from three continents, over one third had brains that looked similar to healthy people.
New clues into the genetic origins of schizophrenia
The first genetic analysis of schizophrenia in an ancestral African population, the South African Xhosa, appears in the Jan.
Dietary supplement may help with schizophrenia
A dietary supplement, sarcosine, may help with schizophrenia as part of a holistic approach complementing antipsychotic medication, according to a UCL researcher.
Schizophrenia: Adolescence is the game-changer
Schizophrenia may be related to the deletion syndrome. However, not everyone who has the syndrome necessarily develops psychotic symptoms.
Study suggests overdiagnosis of schizophrenia
In a small study of patients referred to the Johns Hopkins Early Psychosis Intervention Clinic (EPIC), Johns Hopkins Medicine researchers report that about half the people referred to the clinic with a schizophrenia diagnosis didn't actually have schizophrenia.
The ways of wisdom in schizophrenia
Researchers at UC San Diego School of Medicine report that persons with schizophrenia scored lower on a wisdom assessment than non-psychiatric comparison participants, but that there was considerable variability in levels of wisdom, and those with higher scores displayed fewer psychotic symptoms.
Recognizing the uniqueness of different individuals with schizophrenia
Individuals diagnosed with schizophrenia differ greatly from one another. Researchers from Radboud university medical center, along with colleagues from England and Norway, have demonstrated that very few identical brain differences are shared amongst different patients.
Resynchronizing neurons to erase schizophrenia
Today, a decisive step in understanding schizophrenia has been taken.
More Schizophrenia News and Schizophrenia Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Meditations on Loneliness
Original broadcast date: April 24, 2020. We're a social species now living in isolation. But loneliness was a problem well before this era of social distancing. This hour, TED speakers explore how we can live and make peace with loneliness. Guests on the show include author and illustrator Jonny Sun, psychologist Susan Pinker, architect Grace Kim, and writer Suleika Jaouad.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.