同じ匂いでも言葉によって感じ方が異なる
https://gyazo.com/ec428018c9dbb194cf025bbb1d9a4939
超高磁場の機能的磁気共鳴画像法(Functional Magnetic Resonance Imaging: fMRI)を用いて匂いを嗅いでいる際の脳活動を高解像度で計測し、匂いと共に呈示された言葉が嗅覚野の活動に与える影響を明らかにしました。 同じ匂いを嗅いでも、同時に見ている言葉(言葉ラベル)が異なると、匂いの感じ方、および一次嗅覚野の脳活動が変化することが示されました。 本研究成果は、ヒトにおける匂いの脳内情報処理を包括的に理解するための足がかりとなるとともに、産業面では香料のもたらす印象を予測する技術への応用が期待されます
匂いの感じ方は言葉ラベルによって影響を受けることが以前から知られていた
どのような情報処理かがあまりわかっていなかった
匂いの脳内情報伝達経路の中でも上流に位置する一次嗅覚野に言葉ラベルの影響があったことは、ヒトにおける匂いの脳内情報処理機構を包括的に理解するための足がかりとなることが期待されます title:Semantic context-dependent neural representations of odors in the human piriform cortex revealed by 7T MRI
First published: 24 April 2024
abstract
Olfactory perception depends not only on olfactory inputs but also on semantic context. Although multi-voxel activity patterns of the piriform cortex, a part of the primary olfactory cortex, have been shown to represent odor perception, it remains unclear whether semantic contexts modulate odor representation in this region. Here, we investigated whether multi-voxel activity patterns in the piriform cortex change when semantic context modulates odor perception and, if so, whether the modulated areas communicate with brain regions involved in semantic and memory processing beyond the piriform cortex. We also explored regional differences within the piriform cortex, which are influenced by olfactory input and semantic context. We used 2 × 2 combinations of word labels and odorants that were perceived as congruent and measured piriform activity with a 1-mm isotropic resolution using 7T MRI. We found that identical odorants labeled with different words were perceived differently. This labeling effect was observed in multi-voxel activity patterns in the piriform cortex, as the searchlight decoding analysis distinguished identical odors with different labels for half of the examined stimulus pairs. Significant functional connectivity was observed between parts of the piriform cortex that were modulated by labels and regions associated with semantic and memory processing. While the piriform multi-voxel patterns evoked by different olfactory inputs were also distinguishable, the decoding accuracy was significant for only one stimulus pair, preventing definitive conclusions regarding the locational differences between areas influenced by word labels and olfactory inputs. These results suggest that multi-voxel patterns of piriform activity can be modulated by semantic context, possibly due to communication between the piriform cortex and the semantic and memory regions.