Cacciamani Laura, Likova Lora T
The Smith-Kettlewell Eye Research Institute, San Francisco CA, USA.
Front Hum Neurosci. 2016 Apr 12;10:92. doi: 10.3389/fnhum.2016.00092. eCollection 2016.
This study is the first to investigate the neural underpinnings of tactile object familiarity in the blind during both perception and memory. In the sighted, the perirhinal cortex (PRC) has been implicated in the assessment of visual object familiarity-a crucial everyday task-as evidenced by reduced activation when an object becomes familiar. Here, to examine the PRC's role in tactile object familiarity in the absence of vision, we trained blind participants on a unique memory-guided drawing technique and measured brain activity while they perceptually explored raised-line drawings, drew them from tactile memory, and scribbled (control). Functional magnetic resonance imaging (fMRI) before and after a week of training revealed a significant decrease in PRC activation from pre- to post-training (i.e., from unfamiliar to familiar) during perceptual exploration as well as memory-guided drawing, but not scribbling. This familiarity-based reduction is the first evidence that the PRC represents tactile object familiarity in the blind. Furthermore, the finding of this effect during both tactile perception and tactile memory provides the critical link in establishing the PRC as a structure whose representations are supramodal for both perception and memory.
本研究首次探究了盲人在触觉物体熟悉度的感知和记忆过程中的神经基础。在有视力的人群中，鼻周皮质（PRC）参与视觉物体熟悉度的评估——这是一项至关重要的日常任务——当物体变得熟悉时，其激活程度降低就证明了这一点。在此，为了研究在没有视觉的情况下PRC在触觉物体熟悉度中的作用，我们对盲人参与者进行了一种独特的记忆引导绘图技术训练，并在他们通过触觉探索凸起线条图、根据触觉记忆绘制这些图以及随意涂鸦（对照）时测量大脑活动。在一周的训练前后进行的功能磁共振成像（fMRI）显示，在感知探索以及记忆引导绘图过程中，从训练前到训练后（即从不熟悉到熟悉），PRC的激活显著减少，但在随意涂鸦时没有减少。这种基于熟悉度的减少是PRC在盲人中代表触觉物体熟悉度的首个证据。此外，在触觉感知和触觉记忆过程中都发现了这种效应，这为将PRC确立为一种其表征在感知和记忆方面都是超模态的结构提供了关键联系。
