Multimodal Imaging

In-vivo Functional Analysis of Brain Plasticity.

Both temporal and spatial reorganization (plasticity) of brain functions occurs after brain damage, during development and with training. While functional magnetic resonance imaging (fMRI) can resolve details of spatial reorganization, event-related potentials (ERPs) can measure fast temporal reorganization, i.e. changes in latency of cognitive processes.

• The goal of this project was to track non-invasively developmental and training induced plasticity of different brain functions (visual, language, motor) using multi-modal imaging (fMRI / ERP). In this study:
• Long-term plasticity was investigated in healthy children, adolescents and adults. The goal was to clarify whether and what plastic changes in distribution (fMRI) and latency (ERP) occur during development. Evidences from developmental plasticity could contribute to an understanding of plastic changes taking place during learning and training.
• Fast plastic changes (short-term plasticity) due to visual and motor learning was investigated in adults.
• The measurement of simultaneous ERP and fMRI recordings was established. Fully concurrent measurements have some advantages over interleaved or sequential measurements, being more efficient and indispensable when investigating fast plastic changes.

Subproject: Maturation of luminance- and motion-defined form perception

The main goal of this study was to examine the development of visual pathways for dynamic form perception and to clarify how age-related changes in brain function are linked to the maturation of perceptual and cognitive abilities. Brain activity was measured with ERP and fMRI in healthy children, adolescents and adults during a visual form discrimination task. Forms were defined by luminance or motion.

The fMRI activation patterns were very similar in all three groups. This indicates that the neuronal networks for the processing of luminance- and motion-defined shapes get established early in childhood.

The latencies of the ERP responses decreased with age, reflecting a further specialization and fine tuning of visual functions. Furthermore, the children’s ERP responses were correlated with form detection and reading performance, indicating that maturation of timing in visual processes is most relevant for improvements in perceptual and cognitive skills during development.

Figure. Children, adolescents and adults activate similar neuronal networks (fMRI: left). The processing speed becomes faster in during the development (ERP: right).

Collaborations

PD. Dr. Daniel Brandeis, Zentrum für Kinder- und Jugendpsychiatrie, Universität Zürich

PD. Dr. Spyros Kollias, Institut für Neuroradiologie, Universitätsklinik Zürich

Prof. Thomas Dierks, Psychiatrische Neurophysiologie, Universitätsklinik für Klinische Psychiatrie Bern

PD. Dr. Roberto D. Pascual-Marqui, The KEY-Institute, Psychiatrische Universitätsklinik Zürich

Contact

Prof. Ernst Martin
ernst.martinkispi.uzh.ch

Former collaborators

Dr. Kerstin Bucher   

Funding Source

NCCR on Neural Plasticity and Repair

Project duration

2001-2005

Publications

Halder P, Brem S, Bucher K, Boujraf S, Summers P, Dietrich T, Kollias S, Martin E, Brandeis D (2007). Electrophysiological and hemodynamic evidence for late maturation of hand power grip and force control under visual feedback. Hum Brain Mapp, 28(1): 69-84.

Brem S, Bucher K, Halder P, Summers P, Dietrich T, Martin E, Brandeis D (2006). Evidence for developmental changes in the visual word processing network beyond adolescence. Neuroimage, 29(3): 822-837.

Bucher K, Dietrich T, Marcar VL, Brem S, Halder P, Boujraf S, Summers P, Brandeis D, Martin E, Loenneker T (2006). Maturation of luminance- and motion-defined form perception beyond adolescence: a combined ERP and fMRI study. Neuroimage, 31(4): 1625-1636.

Halder P, Curt A, Brem S, Lang-Dullenkopf A, Bucher K, Kollias S, Brandeis D (2006). Preserved aspects of cortical foot control in paraplegia. Neuroimage, 31(2): 692-698.

Brem S, Lang-Dullenkopf A, Maurer U, Halder P, Bucher K, Brandeis D (2005). Neurophysiological signs of rapidly emerging visual expertise for symbol strings. Neuroreport, 16(1): 45-48.

Halder P, Sterr A, Brem S, Bucher K, Kollias S, Brandeis D (2005). Electrophysiological evidence for cortical plasticity with movement repetition. Eur J Neurosci, 21(8): 2271-2277.

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