Phase-locking in behavioral reports

Tuesday 6 June 2023, 2:30 pm
PhD student
T. Tosato MSc.
prof. dr. P. Fries
dr. G. Rohenkohl

Rhythmic modulations of cognitive processes, such as perception, attention, decision-making, and movement, have been a subject of intense research. These rhythms are believed to reflect the dynamics of neural processing and to coordinate sensory and motor functions. 
This thesis primarily focuses on the analysis methods and statistical testing used in this field of research. To compare the performance of different methods, datasets are simulated based on a plausible model, which produces data resembling actual psychophysical experiments. The sensitivity, specificity, and D-prime of each method are quantified, enabling direct method comparison. The importance of correctly interpreting the spectrum for inferring periodicity and distinguishing between periodic and aperiodic modulations is highlighted. Additionally, the potential for certain preprocessing steps to introduce distortions in the spectra is discussed. 
The thesis also presents empirical data resulting from a psychophysical experiment testing for modulations of visual detection accuracy phase-locked to a button press. The results reveal a significant 17 Hz modulation in specific subsets of trials and participants, suggesting that the button press resets a 17 Hz brain rhythm that only transpires in behavior during specific internal states of the participants (characterized, for example, by lower attentional engagement or a more conservative decision criterion). 
In conclusion, this thesis provides insights into the detection and characterization of phase-locked modulations in behavioral reports and emphasizes the importance of proper methodology for advancing our understanding. 

Tommaso Tosato was born on March 13th 1990 in Padua, Italy. He earned a bachelor degree in molecular biology at the University of Padua and a master degree in cellular and molecular biology at the University of Pisa with a concurrent diploma from the Scuola Normale Superiore di Pisa. In November 2015 he joined the Lab of Prof. Pascal Fries at the Ernst Strüngmann Institute (ESI) for Neuroscience in Frankfurt. In addition, starting from 2016, he has been involved in interdisciplinary projects opening a dialog between neuroscience and contemporary dance, collaborating with choreographers such as Meg Stuart, Laurent Chétouane, Ildikó Tóth and Fabrice Mazliah. In 2018 he co-organized the scientific conference ESI-Sync. In 2020, 2021, and 2022 he participated to ESRI (European Summer Research Institute, organized by Mind & Life Europe).