Intensity modulation of olfactory acuity.

Acuity is fundamental to sensory systems, establishing the foundation for detectable differences in stimulus quality and consequently shaping animals' sensory capacities. In the olfactory system, which samples intrinsically high-dimensional chemical information, acuity for odor quality is measurable by means of ad hoc dimensions based on behaviorally confirmed sets of sequentially similar odorants. The authors measure olfactory acuity in mice using a rewarded forced-choice odor generalization task and show that mice exhibit greater olfactory acuity in response to higher concentration (1,0 Pa) odorants than to lower concentration (0.01 Pa) odorants. Results suggest that the dynamic modulation of sensory acuity--not necessarily its maximization--is an important component of olfactory processing and reflects the salience of odorant stimuli. (c) 2003 APA