Neural Dynamics of Visual Cognition Group
I joined the lab in February 2017 as a PhD student. Before that I did a B.Sc. in Psychology at the University of Amsterdam with a specialization in neuropsychology and a M.Sc. in Social, Cognitive and Affective Neuroscience at Freie Universität Berlin.
In my free time I enjoy bouldering, rope climbing and jazz music.
My research interest is focused around the question how invariant object representations are constructed in the human brain. Here I focus on visual representations of the object’s location and somatosensory representations of Braille letters in congenitally blind individuals. I study how these representations are encoded using a combination of machine learning, deep learning, electroencephalography and neuroimaging. I also collaborated on the Algonauts challenge 2021, a computer vision challenge to advance collaborations between empirical neuroscientific and machine intelligence researchers.
My PhD research is currently funded by an Emmy Noether grant by the DFG. The project runs until March 2023.
I have two finished and one ongoing research projects, each consisting of an EEG and an fMRI experiment.
Project 1 The spatiotemporal neural dynamics of object location representations in the human brain
To efficiently interact with cluttered environments in every day life, it is crucial that we not only quickly recognize objects but also localize them. In this project we characterized the spatiotemporal neural dynamics of object location representations in the human brain, comparing location representations when object are presented on blank vs. on cluttered backgrounds to approximate the complexity of real-world vision in an experimentally controlled setting. Using fMRI, EEG, deep neural networks and pattern classifiers, our results show that location representations emerge along the ventral visual stream, peaking in region LOC during a late processing stage in time, involving recurrent processing. You can find the published article here.
Project 2 Independent spatiotemporal effects of spatial attention and background clutter on human object location representations
Spatial attention is a fundamental cognitive function that helps us to focus our attentional resources on relevant portions of the visual field when environments are cluttered. However, previous research yielded heterogenous results concerning the neural processing stage during which attention modulates object location representations. Taking the role of background clutter into account, in this project we investigated at which processing stage object location representations are modulated by attention in the human brain. We characterized attentional modulation in time in an EEG experiment and across the ventral stream in an fMRI experiment. Our results show that attention modulates location representations during late processing stages both in time and along the ventral stream, independent of whether the background is cluttered or not. You can find the preprint on bioRxiv.
Project 3 Invariant Braille letter representations in the brain of congenitally blind individuals
Numerous studies have shown that the category-selective topography of human high-level ventral visual cortex is preserved even in the absence of visual stimulation. However, thus far it is unclear whether those high-level regions of congenitally blind individuals also host invariant representations, as is known for example for representations in LOC or the VWFA in sighted individuals. Furthermore, as opposed to the ventral visual processing stream in the sighted, the sensory pathways building high-level object representations are not well characterized in congenitally blind individuals. Therefore, here we conducted and EEG and an fMRI experiment to characterize the neural processing pathways of invariant Braille letter representations in neural processing time and across the cortex. In this project, we classify single Braille letters that depend on or are independent of the stimulated hand.
I currently do not have a project for an internship/master thesis. However, feel free to contact me if you are interested in my research and have any questions.
Graumann, M., Ciuffi, C., Dwivedi, K., Roig, G., & Cichy, R. M. (2022). The spatiotemporal neural dynamics of object location representations in the human brain. Nature Human Behaviour, 1-16.
Graumann, M., Wallenwein, L. A., & Cichy, R. M. (2022). Independent spatiotemporal effects of spatial attention and background clutter on human object location representations. bioRxiv.
Cichy, R. M., Dwivedi, K., Lahner, B., Lascelles, A., Iamshchinina, P., Graumann, M., ... & Oliva, A. (2021). The Algonauts Project 2021 Challenge: How the Human Brain Makes Sense of a World in Motion. arXiv preprint arXiv:2104.13714.