- 1 - 1 2 The coding of odor stimulus features among secondary olfactory 3 structures 4 5 6

32 Sensory systems must represent stimuli in manners dependent upon a 33 wealth of factors, including stimulus intensity and duration. One way the brain 34 might handle these complex functions is to assign the tasks throughout 35 distributed nodes, each contributing to information processing. We sought to 36 explore this important aspect of sensory network function in the mammalian 37 olfactory system, wherein the intensity and duration of odor exposure are critical 38 contributors to odor perception. This is a quintessential model for exploring 39 processing schemes given the distribution of odor information by olfactory bulb 40 mitral and tufted cells into several anatomically-distinct secondary processing 41 stages, including the piriform cortex (PCX) and olfactory tubercle (OT), whose 42 unique contributions to odor coding are unresolved. We explored the coding of 43 PCX and OT neuron responses to odor intensity and duration. We found that 44 both structures similarly partake in representing descending intensities of odors 45 by reduced recruitment and modulation of neurons. Additionally, while neurons in 46 the OT adapt to odor exposure, they display reduced capacity to adapt to either 47 repeated presentations of odor or a single prolonged odor presentation in 48 comparison to neurons in the PCX. These results provide insights into manners 49 whereby secondary olfactory structures may, at least in some cases, uniquely 50 represent stimulus features. 51 52