Research Group Staiger

Department of Neuroanatomy

[Translate to Englisch:] Schematische Darstellung der whisker-to-barrel-pathway bei Nagern — Figure: The left part shows schematically the whisker-to-barrel pathway in rodents. The whiskers (vibrissae) discretely perceive parts of the external world using the mechanoreceptors located in their follicles. This tactile information is carried via trigeminal afferents to modules in trigeminal brainstem nuclei (PrV and SpV; barrelettes). From there it reaches the thalamus via the lemniscal and paralemniscal pathway (VPM with barreloids; POm without) and is finally directed to the primary somatosensory cortex (barrels) for conscious perception. The location information (i.e. which vibrissae was activated with its receptors) is largely preserved, which is also called somatotopy. The right part shows that there are modules in the cortex that preferentially code for the information of the isotopic vibrissae. In the cortex, an integration of the information received by the different vibrissae takes place in the circuits of the different layers (L1-L6) of a barrel-associated column. In this way, a uniform perception (e.g. walnut) can emerge from the original partial information. This requires a large number of different excitatory (black) and inhibitory (red, orange, blue) neurons to work together. From: Staiger and Petersen, Physiological Reviews 2021.

Columnar modules can be considered the basic unit for cortical information processing. We are interested in the processing of tactile information in primary somatosensory cortex, where barrel-associated columns are particularly well identified in rodents. Because of the marked heterogeneity of neurons in a cortical column, the approach of studying the functional and structural connectivity of single, molecularly defined neurons in vitro and in vivo seems particularly promising for identifying the fundamental principles of columnar information processing.

Using mouse barrel cortex as a model system (see Figure), we are working on multiple questions concerning the connectivity of excitatory and inhibitory neurons in order to decipher the blueprint of cortical microcircuits.

Our present research uses transgenic mouse models to get access to genetically labeled neurons, which allows us to specifically study pre-identified subpopulations of GABAergic neurons. Since previous transcriptomic studies have suggested more than 40 types of GABAergic neurons, we now also use intersectional mouse genetics to get an ever more specific access to these neurons. Basically, we want to “decode” neuronal identity and function by multimodal characterization of their (i) transcriptome, (ii) morphology, (iii) electrophysiology and (iv) connectivity. The methods of choice are transgenic mice, Patch-seq and paired recordings, in combination with 3D reconstructions of biocytin-filled cells.

This powerfully array of methods has recently been applied to primate material as well. By implementing marmoset and macaque monkeys into our line of research, we are in position to directly compare cell types between primate and non-primate species.

For a deeper inspection of our research, please check our publications.

Research Group Staiger

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