Berkeley Neuroscience researchers are trying to understand how the brain uses incoming sensory information to decide how to act. Though linked to sensory inputs, which can be controlled, and behavioral outputs, which can be observed and measured, the cognitive processes of perception and decision making are internal and difficult to study.
For example, the Wallis Lab has used a decoding approach to identify and track the neural representations of two options being evaluated for a decision in primates [see “Decoding hidden mental processes: Decision making”]. The Adesnik Lab has created new optical tools to observe patterns of neural activity in the mouse cortex during controlled sensory experiences and resulting behaviors, and then to stimulate the same neurons in the same pattern to see if the same behavior can be elicited [see “Mind-control MICROSCOPE changes the behaviour of mice in an instant,” Daily Mail].
And they are not the only Berkeley Neuroscience faculty asking this major open question in neuroscience. Martin Banks, George Bentley, Kristofer Bouchard, Silvia Bunge, Anne Collins, Mark D’Esposito, Yang Dan, Michael DeWeese, Dan Feldman, David Foster, Ming Hsu, Richard Ivry, Lucia Jacobs, Robert Knight, Stephan Lammel, Kristin Scott, Kevin Weiner, Linda Wilbrecht, and Michael Yartsev are each using their unique approach to contribute pieces of the answer to this fundamental question.
In a paper published in Nature Human Behavior in January 2018, the Knight Lab approached this question by recording neural activity from the human cortex while individuals were engaged in a series of cognitive tests that required behavioral responses. They found that the prefrontal cortex is the central hub of a distributed cortical network that becomes active during the time between stimulus presentation and behavioral response.
For a simple word repetition task, the brain received (yellow), interpreted (red) and responded (blue) within a second, during which time the prefrontal cortex (red) coordinated all areas of the brain involved. Video by Avgusta Shestyuk, UC Berkeley.
First author and PhD Program alum (2010-2016) Matar Haller helps us understand the importance of this research discovery.
Georgeann Sack: What do you think was the most interesting outcome of this study?
Matar Haller: The paper is a dense one with all sorts of interesting insights. For me, the big take away was the heterogenity of activity, even within clearly defined functional regions. We also found that increases in neural activity were due to increased recruitment of neuronal populations, and not due to the same populations firing more, which sheds some light on fMRI findings.
GS: What was the most difficult aspect of this study?
MH: Patience! This study was drawn from data collected over a span of almost a decade from patients in hospitals around the country. We did a lot of data exploration since in some aspects our analysis was in an entirely new space, and sometimes it felt like we were chasing a moving target.
GS: What previous research inspired your own?
MH: I was inspired by research on neurological patients – the elegance of the double dissociations found in prefrontal lesion studies. While my ECoG [electrocorticography] research is nowhere near as elegant as those classic studies, I hope that by working with patients, I have also contributed my small share.
GS: How will this research advance our knowledge of how the brain works, and why is that important?
MH: In this paper we defined a new analysis technique that enabled us to group neuronal populations across cortex in an objective, data-driven manner. We found robust functional heterogeneity across cortex that was more strongly correlated with behavior than activity derived from classical regions of interest. This finding can inform standard analysis techniques that test hypotheses based primarily on predefined regions of interest.
GS: Are there any open questions from your research that you would like someone with a different expertise to address?
MH: As always, there is the question of causality. If someone can solve that, we’re good.
- Read the research article in Nature Human Behavior, “Persistent neuronal activity in human prefrontal cortex links perception and action,” by Matar Haller, John Case, Nathan E. Crone, Edward F. Chang, David King-Stephens, Kenneth D. Laxer, Peter B. Weber, Josef Parvizi, Robert T. Knight & Avgusta Y. Shestyuk.
- Read the press release in Berkeley News, “Recording a thought’s fleeting trip through the brain,” by Robert Sanders.
- Learn more about recording neural activity from the surface of the human brain from the Neurofriends Podcast on Decoding, produced by PhD Program alum Sarah Hillenbrand and featuring alum Chris Holdgraf.
- Since receiving her PhD in 2016, Matar Haller was an Insight Data Science Fellow then worked for Winton Capital in San Francisco. She is currently a Senior Data Scientist and Researcher at SparkBeyond.
- Senior author Avgusta Y. Shestyuk is a Berkeley Neuroscience Senior Research Scientist in the Knight Lab and VP of Neuroscience, R&D at Nielsen Consumer Neuroscience.
- Knight Lab website