MRC Cognition and Brain Sciences Unit, Cambridge
Finding meaning in the brain
To what degree is semantic information processing dependent on classical language areas or semantic hubs, and to what degree on distributed brain systems including sensory-motor areas? We addressed these questions in EEG/MEG studies using visual word recognition paradigms: 1) A semantic hub should activate at the earliest stages of semantic information retrieval. 2) If sensory-motor areas play a role in semantics, their activation levels should affect language performance. With respect to issue 1), we only found effects of lexico-semantic variables before 250 ms in ATL, but not in AG and IFG. We conclude that the ATL serves as a semantic hub, linking word forms to distributed brain networks representing semantic information. With respect to issue 2), we used a novel movement priming paradigm to investigate the effect of pre-activation of motor cortex on spatio-temporal brain dynamics and behaviour. Pre-activation by means of hand and foot movements reduced activation in posterior superior temporal cortex for hand- and foot-related words, respectively. However, we did not observe priming effects in our behavioural data. Our data support ATL’s role as a semantic hub. However, characterising the contribution of sensorimotor areas to semantics, and especially establishing their behavioural relevance, remains a challenge.
I started EEG/MEG research as a physics student at the University of Münster, where I received my master’s in physics for work on the EEG/MEG inverse problem in 1996. I continued methodological as well as experimental EEG/MEG work at the University of Konstanz, to obtain my PhD in 2000. I then moved to the MRC Cognition and Brain Sciences Unit, Cambridge, where I worked with Prof. Friedemann Pulvermüller in multi-modal imaging projects on reading and embodied semantics. I am continuing my research at the Cognition and Brain Sciences Unit as a Senior Investigator Scientist, and in the role of Head of Methods and Head of MEG. My methods research focusses on the development and evaluation of methods for source estimation and single-trial analysis of EEG/MEG data. I apply neuroimaging methods to problems in the cognitive neuroscience of language, especially visual word recognition and reading, as well as arithmetic problem solving.