Navigation Links
Deciphering hidden code reveals brain activity
Date:3/28/2011

PHILADELPHIA By combining sophisticated mathematical techniques more commonly used by spies instead of scientists with the power and versatility of functional magnetic resonance imaging (fMRI), a Penn neurologist has developed a new approach for studying the inner workings of the brain. A hidden pattern is encoded in the seemingly random order of things presented to a human subject, which the brain reveals when observed with fMRI. The research is published in the journal NeuroImage.

Geoffrey K. Aguirre, MD, Assistant Professor of Neurology at the University of Pennsylvania School of Medicine, says "the same math that could break into your car can be used to crack the brain's codes." It's called a de Bruijn sequence, which is a set or "alphabet" of things (letters, pictures, sounds) in a cyclic order such that every possible "word" or combination of things occurs only once. De Bruijn sequences are what mathematicians call "pseudo-random" because they appear to be a confused jumble but actually contain an underlying structure. To break into a car protected by an electronic lock with a five-digit numerical keycode, for example, a thief could try every possible combination. However, such a brute-force technique is time-consuming because it involves a great deal of repetition. But a de Bruijn sequence uses "every possible combination squeezed together," explains Aguirre. The overlapping combinations encode a pattern scientists can observe in brain activity using fMRI, revealing how nerve cells work to represent the world.

Breaking Codes in Brain Studies

This approach measures how the order of things changes brain responses. Do you see a photo of your brother differently when it follows a picture of your sister? Aguirre says, "Many neuroscience experiments use the context and order of sights, sounds, words, and feelings to reveal how the nervous system is organized."

Previous experiments have presented information to study participants in more or less completely random order. This can be inefficient and inaccurate, making it difficult to discern important patterns and correlations between stimuli and neural responses. "We use the de Bruijn sequence to design the experiment," Aguirre says. "It tells us how to present things to the subject. By presenting a series of faces in different combinations and orders, as dictated by the de Bruijn sequence, it's possible to measure the brain response to each face individually."

Beating the Blood Flow Problem

Aguirre's new algorithm for creating de Bruijn sequences also helps correct an important limitation of fMRI, which works by measuring changes in brain blood flow. "It takes a little while for the blood flow changes to catch up with the brain response," Aguirre says. "By creating these sequences in a special way that accounts for the slower blood flow response, experiments are many times more powerful than before."

"The amazing thing is the person in the experiment just sees random pictures," Aguirre notes. "But in fact, we're hiding in this seemingly random sequence a signal that's invisible to the person but can be decoded by the MRI scanner. We can measure the nerve cells' response to that hidden pattern and then use that to understand how the brain is representing information."

Aguirre's unique marriage of advanced mathematics with the latest neuroimaging techniques promises to both open up new areas of research and improve current experimental designs in the study of the brain. The next step is to apply the new algorithm to actual fMRI studies in one of Aguirre's special research areas, visual perception and representation in the brain.


'/>"/>

Contact: Kim Menard
kim.menard@uphs.upenn.edu
215-662-6183
University of Pennsylvania School of Medicine
Source:Eurekalert

Related medicine news :

1. America's Hidden Pandemic: 100 Million Suffer From Sleep Problems
2. Thyroid Disease: The Hidden Epidemic
3. MRIs May Detect Hidden Tumors in Breast Cancer Patients
4. Health Care Reform's Hidden Racket Exposed
5. Hidden Pond Productions Announces a Unique One-Stop Shop of Music/Talent Supervisions, IP Licensing and Original Custom Music
6. Brainstem, spinal cord images hidden in Michelangelos Sistine Chapel fresco
7. Global media campaign finds hidden children with rare, fatal aging disorder
8. Sickle Cell May Be Hidden Danger to Young Athletes
9. Mini-strokes leave hidden brain damage: Vancouver Coastal Health and UBC Research
10. Self-Drawings May Reveal Hidden Eating Disorders
11. Am I safe here?: How people with HIV/AIDS perceive hidden prejudices in their communities
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/5/2016)... ... May 05, 2016 , ... United Benefit Advisors (UBA), ... as the latest addition to its family of Partner Firms. Headquartered in Mount ... wellness, human resources, and health care consumerism specialists. , “Partnering with UBA will ...
(Date:5/5/2016)... ... 05, 2016 , ... Michael Lanteri Agency in Fort Collins, ... the people of their local community. The agency pledges to select a new ... hope is to bring awareness to important local causes with fundraising and other ...
(Date:5/5/2016)... , ... May 05, 2016 , ... ... ongoing community enrichment program serving families of greater Dubuque, IA. The current campaign ... reserve and honorably discharged veterans. Donations to Veteran’s Freedom Center may now be ...
(Date:5/5/2016)... ... , ... TIME for Kids and The ZAC Foundation – a national leader ... nearly 1 million children with important water safety messages before summer break begins. ... accidental death in children one to 6 years of age. TIME for Kids ...
(Date:5/5/2016)... ... May 05, 2016 , ... The 2016 Nike Soccer Camp will be directed ... university coaching staff. Together they bring their winning Vandals coaching philosophy to young athletes. ... ages 5-13, and high school players. Session dates are as follows: , Youth Day ...
Breaking Medicine News(10 mins):
(Date:5/3/2016)... May 4, 2016 Global ... pages, profiling 09 key companies and supported with ... and in-depth study on the current state of ... of the industry including definitions, classifications, applications and ... is provided for the international market including development ...
(Date:5/3/2016)... , May 3, 2016  As a teenager, ... contracted rheumatic fever, which damaged his heart. He continued ... But by June 2013, Shepherd,s heart was giving out ... death. On June 20, 2013, the Mesa, ... Artificial Heart (TAH-t). Like a heart transplant, the SynCardia ...
(Date:5/3/2016)... , May 3, 2016   BIOTRONIK ... of extending care beyond the implant at the Heart ... 4-7 in San Francisco . ... delivering the highest quality of patient care and satisfaction ... cared for each and every tomorrow," said Marlou ...
Breaking Medicine Technology: