Maastricht

Within the University of Maastricht I have various research collaborations. On the one hand other researchers need my expertise in behavioral analysis of animals (rats and mice). Since I have no biochemical training I have to consult other researcher to help me with biological assays. Within the department of Psychiatry and Neuropsychology (section Cellular Neuroscience [home page]) I collaborate with Dr. Jos Prickaerts with whom I have worked for a long time, although we were both for some time working in a pharmaceutical company. Our colloboration involves the neurobiology of learning & memory and affective disorders. I am also very grateful to Dr. Jan de Vente (who has retired unfortunately) who enabled me to study the biochemical aspects of cGMP and cAMP in brain tissue. This research is related to the role of these cyclic nucleotides in learning and memory by using selective phosphodiesterase inhibitors.

The interest to develop a method to decrease peripheral TRP concentrations was based on human studies that were conducted by Prof. Wim Riedel [home page] and Dr. Jeroen Schmitt [Nestle Research] using the acute TRP depletion model. In this collaboration we try to link the findings of human and animal studies. A first advantage of our joint effort is that we use the same method which allows to make very direct comparisons between the behavioral effects and the effects of TRP depletion on bio/neurochemical changes in the brain.

A further collaboration is with Dr. Monique Mulder in which we are interested in the pathological and behavioural assessment genetically modified mice. In our joined projects our focus lies in the genetics of lipid metabolism in the central nervous system. These may be relevant as prediposing factors for dementia of the Alzheimer type. Related to this studies we recently showed that apoE plays an important role in maintaining the integrity of the blood brain barrrier [PubMed]. This finding might point towards a possible mechanism underlying apoE as an at-risk factor for Alzheimer's disease.

The reaction time task has also been used in Parkinson's disease related studies. In the Academic Hospital of Maastricht (AZM), the department of Neurosurgery operates on patients with advanced Parkinson's disease by implanting electrostimulating electrodes in the subthalamic nucleus. Together with Dr. Yasin Temel, MD and Dr. Visser-vanderWalle we study the effects of stimulation in rats. In addition, we do neuropsychological testing in Parkinson patients in which the sensomotoric- and cognitive functions are dissociated.

Netherlands

In the curriculum of the Faculty of Psychology students have to do perform an experiment. This is done in course 2.5a 'Research Practical'. In one of these course I did a study in which the phenomenon Hysteresis was studied. It appears that previous stimuli affect the processing of new stimuli (of the same dimension). We unexpectedly observed an 'enhanced contrast' effect. In collaboration with Prof. Han van der Maas [home page] we are going to study this feature in more detail.

Our psychopharmacological studies that try to unravel the biological mechanisms underlying learning and memory are based on certain assumptions of neurotransmitters are involved in memory performance. This line of research has also a more cognitive approach, in which memory models are constructed on basis of biological circuits in the brain. We are collaborating with Martijn Meeter [home page] who has developed a model that predicts the effects of cholinergic and serotonergic drugs.

Rest of World

Dr. Iain McGregor (University of Sydney, Australia) [home page]: 5-HT and behavior

Dr. Rudy Schreiber (Sepracor, USA): Translational psychopharmacology

Prof. H. Schröder (University of Cologne, Germany): Phenotyping of genetic modified mice.

Prof. M. Hasselmo (University of Boston, USA) [home page]: EEG and memory