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MidFrontal Cortex Theta Oscillations: Causes and Consequences

Periodic Reporting for period 4 - MidFrontalTheta2.0 (MidFrontal Cortex Theta Oscillations: Causes and Consequences)

Reporting period: 2020-01-01 to 2020-06-30

While reading this text, pat your head and rub your stomach (if someone sees you, tell them it's OK; you're doing science). Right now you are engaging in an action that must be actively monitored and quickly
adjusted to avoid making mistakes. Over the past five years, my collaborators and I discovered that there is a specific pattern of brain electrical activity that occurs during response conflict—competition between
multiple conflicting actions when a mistake could be made. This brain activity is observed over the midfrontal cortex (MFC) and is characterized by oscillations at around 6 cycles per second (the theta band).
MFC theta is a highly statistically robust marker of the neural networks involved in action monitoring and behavior adjustments, correlates with single-trial reaction time, and predicts how well people learn from
mistakes. Despite these robust findings linking MFC theta to action monitoring, the significance of MFC theta for how neural microcircuits actually implement action monitoring and adjustments is unknown. In the
ERC research we will use computer simulations and rodent models to understand how different types of neurons in different cortical layers might use action potentials and oscillations to implement action
monitoring. The results will help us understand how the brain monitors behavior and avoids mistakes, and will also give insight into neural microcircuit organization as it relates to higher cognitive function. While
developing these computer simulations and rodent models, we will also take our human research to the next level by asking: If action monitoring in the MFC is supported by theta oscillations, does this mean that our
actions, and our ability to monitor and adjust them, occur with theta rhythmicity? To answer this question, we will develop new tasks combining keyboard typing and EEG to test how the timing of human sequenced
actions during keyboard typing (typists type in “theta”) corresponds to temporal dynamics of MFC theta.
"This ERC project is now just under half-way through the project period of 5 years. The first two years involved developing and building a next-generation data acquisition system that will provide an unprecedented detailed view of large-scale networks in the brain operating on multiple spatial scales, from individual brain cells (a fraction of a millimeter) to brain circuits (a millimeter) to large-scale networks (centimeter). In the winter of 2017-2018 the lab was completed and piloting/testing is nearly finished. The rest of the ERC project will involve collecting and analyzing the data to understand the role of MFC theta in neural network coordination and cognition.

Simultaneously with developing the lab, we have also been working on (1) computer simulations of MFC theta circuitry and (2) non-invasive electrical brain recordings in humans. The computer simulations provide a level of detail and manipulations that are not possible in real biology, and thus are a crucial way to understand the circuitry under investigation. With the simulations, we can assess the importance of different sizes of neurons, different patterns of neural inter-connectivity, and so on.

The projects with humans involve having volunteers type words and sentences while we record their brain activity using EEG. We have found that people type rhythmically in the ""theta band"" -- approximately 6-8 keystrokes each second. One of the important hypotheses we will examine is whether synchronization between the brain and the finger movements decreases before making a typo. Such a finding would allow us to predict when someone is about to make a mistake. We are still in the early stages of data processing and analysis, so the key results will be presented in the final project summary."
As mentioned above, most of the work thus far has been building, testing, developing, and preparing. The final two years of the project will be when most of the data are collected and analyzed. Upon publication of the scientific reports, we will make all of our data and data analysis code freely available for others in the scientific community to extend and continue working with.