The human brain modulates sniffs according to fine-grained perceptual features of odours.

Sensorimotor feedback is a fundamental mechanism of active sensing. In olfaction, the primary motor behaviour is the sniff. Thus, in active olfactory sensing, we would expect the dynamics of the sniff to change according to detailed odour characteristics. Furthermore, percept-related modulations of sniffing behaviour should correspond to neural activity in participating brain regions. Here we analysed a high-precision functional MRI dataset including more than 4,300 sniffs per participant taken of 160 odours during ~18 hours of scanning, to probe the relationship between odour-induced sniff modulations and perceptual features at a high level of granularity. We found that fine-grained perceptual odour information-and even odour identity-can be decoded from sniffing dynamics, and that olfactory brain regions, particularly the amygdala, are involved in percept-driven modulation of sniffing behaviour. Thus, olfactory cortical areas participate in real-time modulations of sniffs according to perceptual properties of the odour at a high level of granularity.