Central olfaction:
The two images on the left (click for larger size) are of mouse olfactory bulbs imaged for different neuron types.  The output neurons, also known as mitral cells, are expressing a genetically encoded yellow fluorescent protein (green/yellow).  Immunolabeling for brain derived neurotrophic factor (BDNF; red) indicates localization of BDNF to interneurons (red) of the external plexiform layer, as well as to the mitral cell layer (red plus green = yellow).  All nuclei are stained with DAPI (blue).  

The difference between the two olfactory bulbs is the amount of olfactory information, ie the sensory input to the olfactory bulb from the nose.  The top image is from a bulb with unchanged input, while the bottom bulb received reduced sensory input as compared to the first.  Note that in the lower image the size of the red 'stripe' is smaller indicating BDNF immunolabeling in lost in the external plexiform layer (interneuron neurites).

In summary, these images indicate that in the olfactory bulb, neurogenesis and/ or neurite growth is regulated by both the amount of stimulus and the amount of BDNF. 

Sensory deprivation induces cellular neurite loss from the olfactory bulb external plexiform layer.

Please see our article in Neuroscience Letters for more information.

In follow-up experiments we found that the neurite loss seen above (well, above left) can be mimicked by in vivo application of proBDNF (unprocessed BDNF).  We also found that neurite loss occurred in concert with dopamine loss.

Check out our article in PloS One for the details

Current olfactory questions: what role does the neurite loss play in sensory processing?  what role does the dopamine loss play in sensory processing?What other signalling molecules--if any--are regulating neurite loss and growth?

Peripheral Taste:
Previously we investigated how peripheral taste neurons responded to stimuli.  Just two neuron types could distinguish among complex mixtures of sodium salts and acids.  For more information check out the Plos One  paper.

Current taste questions: Does the peripheral taste system change with physiological stress or learning?
  To address this question we are looking at the effects of thirst on the taste system.