Final Activity Report Summary - CISA (Cortical interactions underlying the selection of actions)
The goal of this scientific project was to investigate the way in which different brain regions interact to produce behaviour. Current understanding of the brain stresses the fact that, in order to understand how the brain works, we must not just focus on the role of single brain regions by themselves, but we must focus instead on how different brain regions work together in a network.
In this project we further developed and applied a technique, called paired-pulse transcranial magnetic stimulation (ppTMS), to probe how brain regions interacted while people were deciding which response was appropriate during a computer task. We showed the importance of two regions, the pre-supplementary motor area (pre-SMA) and the right inferior frontal gyrus (rIFG), in selecting appropriate actions. When people planned to make a certain movement, but then had to change their plan and execute a different movement instead, the pre-SMA and rIFG influenced the motor cortex which was responsible for the actual movement execution. The pre-SMA helped the motor cortex select and execute the correct movement, while the rIFG helped the motor cortex to inhibit the inappropriately planned movement. This was the first time that people were able to look at the interaction of such specific brain regions at the millisecond time-scale in which our brains make adjustments to the decisions we make.
We further looked at two additional techniques to help us understand these interactions. The first technique was electroencephalography (EEG), which allowed us to look at brain activity at a high temporal resolution. Using a new way of analysing EEG data, we were able to better quantify the computations that the brain was performing. Utilisation of this technique helped us identify some of the processes that helped the brain to efficiently select our actions and determine when a planned action was inappropriate and needed to be adjusted. The second technique, diffusion-weighted imaging, allowed us to investigate the anatomical connections between brain areas. Understanding these connections helped us to build hypotheses about which brain regions might interact with one another, a knowledge we could then use to probe the network with the abovementioned techniques.
In this project we further developed and applied a technique, called paired-pulse transcranial magnetic stimulation (ppTMS), to probe how brain regions interacted while people were deciding which response was appropriate during a computer task. We showed the importance of two regions, the pre-supplementary motor area (pre-SMA) and the right inferior frontal gyrus (rIFG), in selecting appropriate actions. When people planned to make a certain movement, but then had to change their plan and execute a different movement instead, the pre-SMA and rIFG influenced the motor cortex which was responsible for the actual movement execution. The pre-SMA helped the motor cortex select and execute the correct movement, while the rIFG helped the motor cortex to inhibit the inappropriately planned movement. This was the first time that people were able to look at the interaction of such specific brain regions at the millisecond time-scale in which our brains make adjustments to the decisions we make.
We further looked at two additional techniques to help us understand these interactions. The first technique was electroencephalography (EEG), which allowed us to look at brain activity at a high temporal resolution. Using a new way of analysing EEG data, we were able to better quantify the computations that the brain was performing. Utilisation of this technique helped us identify some of the processes that helped the brain to efficiently select our actions and determine when a planned action was inappropriate and needed to be adjusted. The second technique, diffusion-weighted imaging, allowed us to investigate the anatomical connections between brain areas. Understanding these connections helped us to build hypotheses about which brain regions might interact with one another, a knowledge we could then use to probe the network with the abovementioned techniques.