Periodic Reporting for period 1 - EXPAT (How EXPectation and ATtention shape visual information processing in the human brain)
Periodo di rendicontazione: 2023-02-01 al 2025-07-31
Visual perception always happens in the context of our knowledge about what we are observing. However, the neural mechanisms by which our brain leverages this knowledge to enhance visual perception remain largely unknown. Therefore, as part of our ERC program EXPAT, we are investigating how expectation and attention alter the way our brain processes images. Specifically, our aim is to reveal how these two top-down processes affect the speed and efficiency of visual information processing and how they influence the flow of image information between brain areas.
To realize our objectives, we have completed two EEG studies, and we are currently initiating one psychophysical study and two fMRI studies. The insights obtained so far from the two EEG studies are as follows: (1) our brain preferentially processes expected image components early on, while unexpected components are processed preferentially at a later stage, and (2) expectation and attention have independent and opposite effects on overall image identity information encoding during separate temporal stages of visual information processing. Moreover, we have developed a novel psychophysical method that allows us to determine which features of images are most and least important for image recognition. This method will be key for our future fMRI experiment, which will test whether expectation increases the efficiency of visual information processing in the human brain.
Our results so far go beyond the state of the art by providing the first direct evidence of Bayesian and prediction error coding occurring during distinct time periods, and by showing that expectation and attention have independent and opposite effects on image information encoding in EEG response patterns.