Sensory neurobiology, the process by which selective sensory modalities -for example light, sound and smell- are transduced and coded by the nervous system, may seem an unlikely candidate for non-invasive electrochemical analysis. Sensory cells are frequently small and deeply embedded in organs and tissues. However, advances in our development of ltramicro-electrochemical sensors have allowed us to examine cells and structures down to approximately 10 µm diameter. This now includes rod and horizontal cells from the eye,^1,10 as well as auditory hair cells,⁷ epithelial structures and, at a totally different scale, ion loss from the lymph in the olfactory sensilla of crustaceans.^5,6

Vision research has had a long-standing history at the MBL, particularly with the use of the skate as a model. Collaborators with the BRC have used the self-referencing ion-selective technologies (SERIS), combined with single cell imaging, to address a controversial area in the field with regards to the role of proton concentration in the bulk media acting as a feedback modulator of horizontal cell function.¹ Metabolic information has also been obtained from these cells, most recently as part of an ongoing study to assess the metabolic cost of signal processing (unpublished).