CSHC - Center for the Study of Human Cognition

PhD student

I am working in a research group led by Professor Svein Magnussen, and Associate Professor Tor Endestad. Our main tool of investigation is functional magnetic resonance imaging (fMRI), and inspired by the psychophysical research tradition (and unlike most fMRI studies), we prioritize experimental control over large samples of participants. This gives us the opportunity to investigate not only which brain areas that are active during a given cognitive or perceptual task, but also how computations are performed within and between the individual areas. 

These are some of the projects I am involved in:

Low-level memory mechanisms in vision

Early visual areas in the brain are sensitive to differences in basic stimulus features such as orientation, size (spatial frequency), and motion; so-called low-level features. The low-level feature coding neurons are highly active during the analysis of incoming perceptual information, and normally, when the stimulus disappears, their activity goes back to a pre-stimulus level. In a visual working memory task, however, the information about the low-level features of the stimulus to be remembered is probably retained and retrieved through activity in some of the areas of their encoding. Thus, under certain task-related demands the sensory role of the visual system can be utilized by and extended into other, often characterized as higher-level, cognitive domains. Using fMRI in combination with psychophysical paradigms, we investigate how the early visual system in the human cortex is recruited during memory for low-level visual features.

Collaborators: Svein Magnussen (UiO), Tor Endestad (UiO), Dag Alnæs (UiO), Mark W. Greenlee (University of Regensburg), Gianluca Campana (University of Padova).

Neural mechanisms of filling-in

Some regions of the visual field are blind as a consequence of the normal organization of the visual system, e.g. the blind spot which is caused by the lack of photoreceptors at the point where the optic nerve leaves the retina. Such constantly blind regions of the visual field are normally not noticed because of filling-in processes; one perceive the brightness, color, and texture of the adjacent areas as if they were genuine visual inputs to the blind area. Again, using a combination of fMRI and psychophysics, we try to elucidate the mechanisms behind such filling-in processes.

Collaborators: Dag Alnæs (UiO), Svein Magnussen (UiO), Tor Endestad (UiO), Lothar Spillmann (University of Freiburg), John S. Werner (University of California)

Individual differences in attentional mechanisms

Using the Multiple Object Tracking (MOT) paradigm, we test how participants perform under different levels of attentional load. Individual differences in performance, as measured behaviorally, are then compared with information about genetic variations in the sample, and further investigated using methods for probing brain activity (fMRI, pupillometry).

Collaborators: Thomas Espeseth (UiO), Bruno Laeng (UiO)