Main Research Fields

Main Research Fields (effective 2012)

Supported by DFG, special issue "olfaction", 2009-2012

Project „Characterization of the genetic basis of human olfactory variance”, in cooperation with Prof. Dr. Hanns Hatt and Dr. Günter Gisselmann

Summary: The ability to detect individual odors is highly variable between individuals. For many chemicals, a high percentage of the human population is specifically anosmic. On an individual basis all humans are expected to have some of such specific anosmias. The reason underlying this individual variance is largely unknown.

In the last years, research on human genomics intensively focused on genetic variations between individuals. One of the main reasons for individuality is the occurrence of millions of single nucleotide polymorphisms (SNPs) making each genome unique. Recently, it was shown that SNPs in odorant receptor genes may be one of the general principles for partial anosmias.

In the proposed project, we plan to characterize the genetic basis of human variation in odor perception by analyzing SNP variations or copy number variations related to several well defined and frequent occurring anosmic phenotypes. The ultimate goal is to identify corresponding genes and the SNP patterns responsible for 'smeller' and 'non-smeller' alleles and use this information also for deorphanization receptors. Our knowledge about the genetic variation within the human population is still fragmentary, and present SNP databases cover naturally occurring SNPs only partially. Therefore, we additionally intend to analyze genetic variations of several selected odor receptor genes to gain profound insights into differences within the main worldwide human populations.

The proposed project will elucidate the genetic basis of variations in human odor perception and moreover enhance or understanding about the mechanisms creating an individual 'unique smeller' in terms of odor sensitivity and rating.

Supported by Roland-Ernst foundation: 2010-2012

Plasticity of the olfactory bulb

Plasticity in the adult brain has for years been among the most thrilling and controversial issues in medicine. Apparently, growth of the brain is not restricted to early age. Rather, synaptic links still enable some plasticity to occur in the adult brain. Recently, increased density/volume of grey matter has even been observed in the hippocampal region of adults, indicating new cell growth, or reoragnization of the hippocampal regulatory circuit - which would have been inconceivable 20 years ago. This plasticity effects in regeneration, particularly after cerebral injuries or insults. While plasticity research has so far mainly focused on the hippocampus as a "structure of memory", we intend to address this topic for the first time in the olfactory bulb (OB), the primary central interface of olfaction. Thus, we want to explore brain plasticity in a structure of high sensory significance.

With respect to plasticity, the OB seems of particular interest - it receives information through synaptic links with olfactory receptor neurons in the nasal mucosa. As these cells regenerate roughly every couple of months, the olfactory system represents one among few structures to exhibit regular cell differentiation in the adult brain. Olfaction is a very old (in terms of evolution) and a rather significant system, in terms of food intake, procreation and communication, with smell loss often resulting in social impairment, or even depressive symptoms.

Due to regular regeneration of the olfactory epithelium, recoveries from olfactory disorders occur relatively frequently, as compared to other sensory systems. However, it has so far been unclear whether, along with the remission of symptoms, any morphological changes of the OB - that is, plasticity - may be observed. The aim of the study is to investigate OB plasticity during and after smell disorders.

Trigeminal function in anosmia

Loss of smell is accompanied by a decrease of trigeminal sensitivity, probably due to impaired interactions between the chemosensory channels.

Therapy of smell disorders

Approximately 5% of the general population are anosmic, mainly because of injuries, acute infections or chronic inflammations. As hardly any established therapies are available, we perform studies to investigate several approaches to treat smell disorders (e.g. trials with Pentoxifyllin, or olfactory training).

Olfaction in Parkinson's disease (PD)

Impaired olfactory function is an early symptom in PD.

in addition:

Investigations of human olfactory performance

by means of tests using the so called "Sniffin' Sticks", or recording of olfactory event related potentials (oERP), or recording of peripheral signals from the olfactory epithelium.