Reviewed by Kate Anderton, B.Sc. (Editor) Jan 14 2020
He calls it his "chocolate and peanut butter moment."
A University at Buffalo neuroimaging researcher has developed a computer model of the human brain that more realistically simulates actual patterns of brain impairment than existing methods. The novel advancement represents the union of two established approaches to create a digital simulation environment that could help stroke victims and patients with other brain injuries by serving as a testing ground for hypotheses about specific neurological damage.
This model is tied accurately to the functional connectivity of the brain and is able to demonstrate realistic patterns of cognitive impairment. Since the model reflects how the brain is connected, we can manipulate it in ways that provide insights, for example, into the areas of a patient's brain that might be damaged.
This recent work doesn't prove that we have a digital facsimile of the human brain, but the findings indicate that the model is performing in a way that is consistent with how the brain performs, and that at least suggests that the model is taking on properties that are moving in the direction of possibly one day creating a facsimile." Christopher McNorgan, assistant professor of psychology in UB's College of Arts and Sciences
The findings provide a powerful means of identifying and understanding brain networks and how they function, which could lead to what once were unrealized possibilities for discovery and understanding.
Details on the model and the results of its testing appear in the journal NeuroImage .
Explaining McNorgan's model starts with a look at the two fundamental components of its design: functional connectivity and multivariate pattern analyses (MVPA).
For many years, traditional brain-based models have relied on a general linear approach. This method looks at every spot in the brain and how those areas respond to stimuli. This approach is used in traditional studies of functional connectivity, which rely on functional magnetic resonance imaging (fMRI) to explore how the brain is wired. A linear model assumes a direct relationship between two things, such as the visual region of the brain becoming more or less active when a light flickers on or off.
While linear models excel at identifying which areas are active under certain conditions, they often fail to detect complicated relationships potentially existing among multiple areas. That's the domain of more recent advances, like MVPA, a "teachable" machine-learning technique that operates on a more holistic level to evaluate how activity is patterned across brain regions.
MVPA is non-linear. Assume for instance that there's a set of neurons dedicated to recognizing the meaning of a stop sign. These neurons are not active when we see something red or something octagonal because there's not a one-to-one linear mapping between being red and being a stop sign (an apple isn't a stop sign), nor between being octagonal and being a stop sign (a board room table isn't a stop sign).
"A non-linear response ensures that they do light up when we see an object that is both red and octagonal," explains McNorgan. "For this reason, non-linear methods like MVPA have been at the core of so-called 'Deep Learning' approaches behind technologies, such as the computer vision software required for self-driving cars." Related Stories
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