Olfactory tract

The olfactory tract describes the neuroanatomical path of odor perception from the odor sensors in the nose, more precisely the olfactory mucosa , to the olfactory cortex of the endbrain . The olfactory tract consists of three nerve cells (neurons) connected in series.

1. Neuron

Cross-section through the human nasal cavity with the olfactory threads

There are bipolar olfactory cells (primary sensory cells ) in the olfactory mucous membrane ( regio olfactoria ) of the upper nasal concha . Its peripheral process ( dendrite ) pulls towards the surface of the mucous membrane, the central axon reaches the olfactory bulb ( bulb olfactorius ) through the sieve plate ( lamina cribrosa ) of the ethmoid bone in the form of olfactory threads ( fila olfactoria ). The totality of the olfactory threads is called the first cranial nerve ( Nervus olfactorius ) , although it is not neuroanatomically exact .

2. Neuron

In the olfactory bulb, the first switch to the mitral cells takes place , the axons of which pass via the olfactory tract to the medial and lateral olfactory stria .

3. Neuron

The third neuron runs from the medial olfactory stria to the olfactory mound ( tuberculum olfactorium ) and from there to the septal nuclei and the parahippocampal gyrus and thus reaches the limbic system . This is where the unconscious olfactory perception takes place.

From the lateral olfactory stria the third neuron extends to the area periamygdalaris / praepiriformis the frontal lobe . In this way, the conscious odor perception takes place.