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Research activities

We study cerebellar function using realistic models of neurons and neural networks combined with electrophysiological and functional imaging studies in rats. We also develop neural simulation software.

View here our research activities.
Just click on a name and find out what this person does in our lab.

Experimental research:

Quinten Robberechts
Koen Tahon
Ken Veys
RamaKrishnan.K.B.

Theoretical research:

Reinoud Maex
Sergio Solinas
Stefan Wils
Werner Van Geit
Pablo Achard

Quinten Robberechts

PhD student Biomedical Sciences (Master in Medicine)
Quintenattnb.ua.ac.be

My research focuses on the synaptic plasticity of the excitatory synaptic input of the parallel fibers in the molecular layer on the Golgi cell, the largest interneuron of the cerebellar cortex. Whether these synapses are actually plastic has as yet not been shown. The induction of long-term depression or long-term potentiation of these synapses must have far-reaching effects on the functioning of the cerebellar cortical network, not only considering the transmission of activity from the mossy fibers via the granule cells to the Purkinje cells, but also considering the reverse synaptic plasticity of the parallel fiber Purkinje cell synapse. An important additional aspect will be to study the effect of blocking or activating metabotropic glutamate receptors (mGluRs), and more specifically in the case of the Golgi cell the effect of mGluR2 on the synaptic plasticity of these synapses.

Koen Tahon

PhD student Biomedical Sciences (Master in biomedical science)
Koenattnb.ua.ac.be

I'm interested in the role of different brain structures in the process of sensorimotor integration. Brain areas of interest are the cerebellum, motor and sensory cortices and other areas involved in the integration of sensory and motor information. To study this I’ll use trained awake rats in which I’ll implant several arrays of electrodes so I can look at a lot of neural signals at the same time. The rats will be trained to perform a sensorimotor task in which motor control is dependent on sensory information. After this, the rats will have to rely merely onto their brain signals to control the learned task by use of a brain-computer interface. By doing all this we hope to unravel some of the mystery of the brain’s function in this interesting and important topic.

Reinoud Maex

MD, PhD Medicine
Reinoudattnb.ua.ac.be

By constructing detailed models of the cerebellar cortex, I try to predict the dynamics of the underlying neuronal circuit (1).
From this, I hope to design new, more directed experiments, and to offer the resulting electrophysiological data a more substantiated explanation (2, 3).
In addition, I try to derive general relationships between structure and dynamics that are applicable to other brain areas (4,5).

  1. Maex & De Schutter, 1998, J Neurophysiol (Synchronization of Golgi and ...)
  2. Maex, Vos & De Schutter, 2000, J Physiol (Weak common parallel fiber synapses explain ...)
  3. Volny-Luraghi, Maex, Vos & De Schutter, 2002, Neuroscience (Peripheral stimuli excite coronal beams of Golgi cells in rat cerebellar cortex)
  4. Maex & De Schutter, 1998, ICANN98 (The critical synaptic number for rhythmogenesis and ...)
  5. Maex & De Schutter, 1999, ICANN99 (An optimal connection radius for ...)

Sergio Solinas

PhD student Biomedical Sciences (Master in Physics)
Sergioattnb.ua.ac.be

Morphological studies show that neurons with a large dendrite arborization in the molecular layer of the cerebellar cortex, Purkinje (PC) and Golgi cells (Goc), share a large part of their excitatory input. Nearby PCs can share up to 50% of their parallel fibers (PF) afferents [R. J. Harvey and R. M. Napper, Prog. Neurobiol. 36:437-63, 1991]. Synchrony of Goc pairs along the PF axis was predicted [R. Maex and E.De Schutter, J Neurophysiol. 80:2521-37, 1998] and subsequently observed [BP Vos R Maex A Volny-Luraghi E De Schutter, J Neurosci. 19(11):RC6, 1999], while PC pairs did not show synchronous firing [JR. Bloedel TJ Ebner, J Neurophysiol. 45:948-61, 1981]. Why do PC pairs not synchronize? This project aim to predict the minimal distance between model PC pairs needed to achieve synchronous firing based on morphological data and computer simulations. The model PCs are placed in a realistic model of the cerebellar molecular layer. Our simulations are based on the high detailed PC model with 4550 compartments described previously by De Schutter and Bower.

Stefan Wils

PhD student Biomedical Sciences (Master in Computer Science)
Stefanattnb.ua.ac.be

Many neural processes, such as learning and synaptic transmission, are thought to be mediated by chemical signaling pathways inside and in between nerve cells. My main aim in our lab is the development of simulation algorithms that can simulate the kinetics of these pathways. Since many of these reactions involve only small numbers of molecules, we describe them as discrete stochastic processes. In addition, our algorithms can take into account spatial distributions of molecules, diffusion and various boundary conditions such as plasma membranes and membrane-associated receptors and channels. I'm also the author of a software implementation of these algorithms. This software is currently being developed for a study of various aspects of the plasticity induction pathways in the cerebellar parallel fiber-Purkinje cell synapses, but will eventually be released as a general computational tool for stochastic simulation of 3-dimensional reaction-diffusion systems in biology.

Werner Van Geit

PhD student Biomedical Sciences (Master in Computer Science)
Wernerattnb.ua.ac.be

The main subject of my research is the coding that takes place inside Purkinje cells. The best way to study this, is by looking at the spike trains that are generated by these cells. In a lot of studies the assumption is made that in spike trains, there is no correlation between two or more consecutive interspike intervals or, in short, these spike trains are looked at as resulting from renewal processes. As seen in data from recordings of Purkinje cells, this is not always the right assumption. If an interspike interval is small, the next interval has a higher chance of also being small. This kind of correlation could be explained by different kinds of mechanisms, including interactions between inhibitory neurons and intrinsically spiking Purkinje cells, or it could also originate from correlations in the input. My research focuses on modelling these possible mechanisms and seeing which of them is fitting most with experimental results.

Ken Veys

PhD student Biomedical Sciences (Master in Molecular biology)
Kenattnb.ua.ac.be

My research will focus on the A-currents in Purkinje cells in the cerebellum. The size of the currents will be correlated with the expression profile of a single cell by combining electrophysiology with single cell real-time PCR. For this the aRNA protocol of Ginsberg 2004 will be modified for single cell level. In a later stage I will look at the influence of the A current on LTP/Ltd of the parallel fibre - Purkinje synapse.

Pablo Achard

PhD Physics
Pabloattnb.ua.ac.be

My present goal is to build a new detailed model of the Purkinje neuron, integrating as much as possible of the new data. To do so, I search the best way to automatically tune the parameters of the model, which brings me in the field of evolutionary algorithms and, more specifically, evolutions strategies. The landscape of solutions obtained allows us to study the compensatory effects of the different ionic currents. Long term plans include the integration of subcellular dynamics into the cell model (see the work of Stefan) or the automatic generation of realistic Purkinje cell models.

RamaKrishnan.K.B.

PhD student Biomedical Sciences (Master in Biotechnology)
Ramkiattnb.ua.ac.be

One of the exciting and interesting topics in coding studies is the synchronization of neuronal activity. Particularly in the cerebellum arises the question why only Purkinje cells which are located very closely are synchronized in firing. Synchronization between the simple spikes (SSs) of two adjacent Purkinje cells (PC) has been observed before (Ebner and Bloedel, 1981). Simple spikes of PC pairs separated by less than 100μm are synchronized in firing. Similar studies in our lab (Shin and De Schutter, 2006) confirmed synchronous patterns between pairs of very close Purkinje cells. The cause of this synchronized activity remains unresolved. In this project, I investigate whether inhibition, most likely from stellate or basket cells, contributes to this property.
I am also interested in how this mechanism influences the final output neurons of the cerebellum, the deep cerebellar nuclei (DCN) neurons. The interplay of the inhibitory (Purkinje cell) and excitatory (mossy and climbing fibers) inputs to the deep nuclei determines their output signal to the other parts of the brain. Since the DCN neurons are the final output structure of the cerebellum, it is important to understand how excitatory and inhibitory inputs are integrated at this level.
To address these questions I use extracellular single unit recording in anesthetized rats during rest and after stimulation, multi-electrode recording of pairs of PCs and DCN neurons, and local pharmacological manipulation of the different types of synapses.