A groundbreaking study explores the interplay of neural dynamics
By Lyn Markey
Are cognitive processes, such as planning an errand or trying to recall a name, separable from related muscle movements, like blinking rapidly or scratching one’s chin? In a groundbreaking study published as the cover story in Nature Neuroscience, a BU team has begun to disentangle cognitive and motor processes, with implications in the near term for the research community and in the long term for people with neurological conditions.
The team, led by Assistant Professor Michael Economo (BME) and including colleagues in BME and the BU Neurophotonics Center, has developed a way to both determine when correlated processes and movements are separable and, when they are, how to isolate them. “This capacity strikes at the heart of a conceptual question that is central to how neural data are interpreted in a broad sense,” says Economo, and it has wide-ranging implications for both future and past research.
The neural underpinnings
Systems neuroscientists have long sought to understand the neural underpinnings of cognitive processes that are highly correlated with specific, subtle movements. Like a poker player’s “tell,” says Economo, these movements may include changes in posture, facial expressions, or “fidgets” that are closely associated with processes like perceptual decisions, working memory, contextual encoding, reward prediction, and action planning. These subtle movements are, in turn, associated with strong neural activation across the brain.
The association between these cognitive processes and movements creates a distinct challenge for neuroscientists, since they cannot know whether the patterns of neural activation they observe are related to the particular process they wish to study or to the movements that just happen to be related to those processes.
“If you want to treat a disease, you really want to understand the mechanisms involved,” says BME doctoral student and study co–first author Munib Hasnain. “And to understand the mechanisms involved, you want to make sure that the neural activity or the neural correlates that you’re picking up on are actually related to that disease, and not related to some correlated movements that a person is making when you’re studying some behavior.”
Rethinking results
As one example, the team re-examined seminal findings about the neural processes responsible for action planning. “We demonstrated that neural signatures long thought to be associated with the urgency of actions are, in fact, not related to urgency at all,” says Economo. “In contrast, we demonstrated that other neural signals, for example those encoding perceptual decisions, do exist and are separable from related movements, but they have been misidentified in past work.”
Neural signatures that have long been associated with the urgency of actions, are not related to urgency at all.”
Michael Economo
“It highlights within the field the importance of considering this relationship between cognitive processes and movement,” says doctoral student and study co–first author Jaclyn Birnbaum. “It’s kind of prescriptive advice for people who are thinking about behavior. Other researchers might want to consider this going forward when interpreting their data.”
By demonstrating how the separability of cognitive and motor processes can be assessed, and, when separable, how the neural dynamics associated with each component can be isolated, the study holds great promise for the field. “I expect that it will have a high impact for years to come,” says Economo. Understanding how the brain’s neural mechanisms function and control cognitive processes in a healthy state has implications for future research, and in the longer term, for the development of potential treatments for neurological disease conditions or disabilities.
James Cooney contributed to this story.