The perineuronal nets of the extracellular matrix surround many neurons in the brain. They are formed during maturation of the nervous system. These nets envelop and insulate neuronal somata and synaptic contact sites (Fig 1) . The neural proteoglycans brevican and neurocan are components of perineuronal nets. Brevican/neurocan deficiency in knock out animals has several consequences for plastic properties of the mouse brain, however, the mode of action of extracellular matrix components on synaptic transmission and plasticity is still hypothetical (Fig. 2).

Figure 1 : Caught in the net: Brevican-containing perineuronal nets (green) surround Bassoon-positive synaptic contacts (red).

Figure 2 : Matrix matters: perisynaptic proteoglycan nets can influence synaptic function in different ways (G, perisynaptic glia producing proteoglycans; GF, growth factors).

Our group studies proteoglycan-interacting molecules, the development of perineuronal nets in neural culture systems, the proteoglycan deficiency phenotype in knock out mice and cognitive consequences of polymorphisms in the human proteoglycan genes.

Collaborators in the project:

The Brevicanos: Nora John, Björn Schott, Constanze Seidenbecher, Renato Frischknecht (from left to right; sculpture by Volker Kiehn).

External collaborations:

• DFG Special Program 1172 "Glia-Synapse"
• Reinhard Fässler, Martinsried
• Michael Frotscher, Freiburg
• Rolf Mentlein, Kiel
• Thomas Seidenbecher, Münster
• Anne Zurn, Lausanne
• Detlef Balschun, Project Group Neuropharmacology
• Special Lab Molecular Biological Techniques
• Special Lab Electron and Laserscanning Microscopy
• Special Lab Non-invasive Imaging
• Special Lab Behavioral Pharmacology

Selected publications: