Line scanning: a bridge between invasive electrophysiological experiments in animals and non-invasive fMRI in humans
Direct visual input is mainly processed in the middle layers of the brain, and contextual input in the upper and deepest layers. Jurjen Heij discovered how different layers of the brain work together and used a new kind of MRI technique for this.
"Our brain processes information by combining signals from the senses and from the environment," says Heij. "This happens at different levels in the cerebral cortex: from individual brain cells to large brain areas that work together. But how exactly was still unclear. Traditional MRI methods provide insight into brain activity, but lack details about how signals move within brain layers. For this research, I therefore used a new MRI technique, line-scanning fMRI, which maps brain activity with unprecedented precision.
"By using targeted visual stimuli, I investigated how the visual cortex processes and combines sensory and contextual information. The results show that direct visual input is mainly processed in the middle layers, while contextual information is visible in both the upper and deepest layers. This insight helps to better understand how the brain organizes perception.
“In my dissertation, I describe methods to refine this technique and apply it to different brain areas. This will allow us to better understand brain processes and possibly improve diagnostics and treatments in the future. The technique can also contribute to research into brain disorders such as depression, in which subtle changes in the brain play a role."
Narrowing the gap with invasive animal research
"This research builds on previous animal studies that used invasive methods to investigate the role of different brain layers in visual processing. Our method makes it possible to test these insights in humans in a non-invasive way – and in this case confirm them – bridging the gap between animal models and human neuroimaging.
“If we can narrow the gap between invasive animal experiments and human fMRI studies, we can better translate findings from animal models to humans. This opens the door to new applications in neuroscientific and clinical research, and, for example, a better understanding of brain disorders in which sensory processing is disrupted, such as schizophrenia or autism."
More information on the thesis
