Figure 3.

Changes in neuronal activity during olfactory learning under anesthesia. (A) Neuronal activity was sampled from neurons across a 6 × 4 array of tungsten microelectrodes (tip separation 350 µ) advanced into the olfactory bulb from the dorsal surface. Spikes from individual neurons were sorted from multineuronal activity at multiple channels across the array. The averaged waveform is shown for spikes generated by a single neuron at the position highlighted on the array. Odors were presented for 10 s, by switching the normal anesthetic gas supply with one carrying an odor. (B) The times of occurrence of spikes generated by the neuron depicted in (A) are shown during presentations of the coriander food odor. The histogram shows the average response across 10 presentations of this odor. (C) Each odor was presented 10 times before training, and 10 times after training. Training comprised 10 presentations of the ginger food odor combined with CS₂. The response during training was elevated relative to the response to ginger alone before training. This enhanced response achieved significance after training when ginger was presented in the absence of CS₂. The response to coriander fell from pre- to post-training. (D) In the pilot behavioral simulation of social transfer of odor preference, mice were anesthetized and presented with odors carried in the anesthetic gas; ginger, CS₂, or ginger and CS₂ combined. When tested for preference between coriander and ginger flavored foods, mice which had been exposed to the ginger odor or CS₂ separately preferred coriander over ginger. In those exposed to ginger and CS₂ combined, this preference was overcome, and the mice consumed similar amounts of both foods.