Gastl Mareike, Brünner Yvonne F, Wiesmann Martin, Freiherr Jessica
Diagnostic and Interventional Neuroradiology, RWTH Aachen University, Aachen, Germany.
Hum Brain Mapp. 2014 Sep;35(9):4751-66. doi: 10.1002/hbm.22509. Epub 2014 Mar 21.
The nose is important not only for breathing, filtering air, and perceiving olfactory stimuli. Although the face and hands have been mapped, the representation of the internal and external surface of the nose on the primary somatosensory cortex (SI) is still poorly understood. To fill this gap functional magnetic resonance imaging (fMRI) was used to localize the nose and the nasal mucosa in the Brodman areas (BAs) 3b, 1, and 2 of the human postcentral gyrus (PG). Tactile stimulation during fMRI was applied via a customized pneumatically driven device to six stimulation sites: the alar wing of the nose, the lateral nasal mucosa, and the hand (serving as a reference area) on the left and right side of the body. Individual representations could be discriminated for the left and right hand, for the left nasal mucosa and left alar wing of the nose in BA 3b and BA 1 by comparing mean activation maxima and Euclidean distances. Right-sided nasal conditions and conditions in BA 2 could further be separated by different Euclidean distances. Regarding the alar wing of the nose, the results concurred with the classic sensory homunculus proposed by Penfield and colleagues. The nasal mucosa was not only determined an individual and bilateral representation, its position on the somatosensory cortex is also situated closer to the caudal end of the PG compared to that of the alar wing of the nose and the hand. As SI is commonly activated during the perception of odors, these findings underscore the importance of the knowledge of the representation of the nasal mucosa on the primary somatosensory cortex, especially for interpretation of results of functional imaging studies about the sense of smell.
鼻子不仅对于呼吸、过滤空气以及感知嗅觉刺激很重要。尽管面部和手部的图谱已经绘制出来，但鼻子的内、外表面在初级体感皮层（SI）上的表征仍知之甚少。为了填补这一空白，功能磁共振成像（fMRI）被用于在人类中央后回（PG）的Brodmann区（BAs）3b、1和2中定位鼻子和鼻黏膜。在fMRI期间，通过定制的气动驱动装置对六个刺激部位施加触觉刺激：鼻子的鼻翼、鼻外侧黏膜以及身体左右两侧的手部（作为参考区域）。通过比较平均激活最大值和欧几里得距离，可以区分出左手和右手、左侧鼻黏膜以及BA 3b和BA 1中鼻子的左鼻翼的个体表征。右侧鼻腔状况和BA 2中的状况可以通过不同的欧几里得距离进一步区分。关于鼻子的鼻翼，结果与Penfield及其同事提出的经典感觉小人图一致。鼻黏膜不仅确定了个体和双侧表征，与鼻子的鼻翼和手部相比，其在体感皮层上的位置也更靠近PG的尾端。由于在嗅觉感知过程中SI通常会被激活，这些发现强调了了解鼻黏膜在初级体感皮层上的表征的重要性，特别是对于解释有关嗅觉的功能成像研究结果。
