Tactile Object Familiarity in the Blind Brain Reveals the Supramodal Perceptual-Mnemonic Nature of the Perirhinal Cortex

• Published in: Frontiers in human neuroscience Vol. 10; p. 92
• Main Authors: Cacciamani, Laura, Likova, Lora T.
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Research Foundation 12.04.2016; Frontiers Media S.A
• Subjects: Blindness; Brain mapping; Brain research; Cortex (perirhinal); Exploration; Familiarity; Functional magnetic resonance imaging; Investigations; Medical imaging; Memory; Neuroscience; perirhinal cortex; tactile memory; Tactile perception; Visual cortex; Visual perception; tactile perception; familiarity; tactile memory; blindness; perirhinal cortex
• ISSN: 1662-5161; 1662-5161
• DOI: 10.3389/fnhum.2016.00092

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.