Short-term plasticity of visuo-haptic object recognition

Abstract

Functional magnetic resonance imaging (fMRI) studies have provided ample evidence for the involvement of the lateral occipital cortex (LO), fusiform gyrus (FG), and intraparietal sulcus (IPS) in visuo-haptic object integration. Here we applied 30 min of sham (non-effective) or real offline 1 Hz repetitive transcranial magnetic stimulation (rTMS) to perturb neural processing in left LO immediately before subjects performed a visuo-haptic delayed-match-to-sample task during fMRI. In this task, subjects had to match sample (S1) and target (S2) objects presented sequentially within or across vision and/or haptics in both directions (visual-haptic or haptic-visual) and decide whether or not S1 and S2 were the same objects. Real rTMS transiently decreased activity at the site of stimulation and remote regions such as the right LO and bilateral FG during haptic S1 processing. Without affecting behavior, the same stimulation gave rise to relative increases in activation during S2 processing in the right LO, left FG, bilateral IPS, and other regions previously associated with object recognition. Critically, the modality of S2 determined which regions were recruited after rTMS. Relative to sham rTMS, real rTMS induced increased activations during crossmodal congruent matching in the left FG for haptic S2 and the temporal pole for visual S2. In addition, we found stronger activations for incongruent than congruent matching in the right anterior parahippocampus and middle frontal gyrus for crossmodal matching of haptic S2 and in the left FG and bilateral IPS for unimodal matching of visual S2, only after real but not sham rTMS. The results imply that a focal perturbation of the left LO triggers modality-specific interactions between the stimulated left LO and other key regions of object processing possibly to maintain unimpaired object recognition. This suggests that visual and haptic processing engage partially distinct brain networks during visuo-haptic object matching.

Functional and Structural Neuroplasticity Induced by Short-Term Tactile Training Based on Braille Reading

“…The increase in activity within the fusiform gyrus (Figure 3 , Table 1 ) is congruent with previously reported involvement of the lateral occipital cortex/fusiform gyrus in tactile object recognition in both blind and sighted subjects (Sadato et al, 2002 ; Amedi et al, 2003 ; Striem-Amit et al, 2012 ) or multisensory object perception (Kassuba et al, 2011 , 2014 ; Schlaffke et al, 2015 ). Alternatively, it could reflect the emergence of tactile Braille recognition mechanisms similar to those found in the VWFA (Price and Devlin, 2001 ; Cohen et al, 2002 ; Dehaene and Cohen, 2011 ), recently found in sighted whole-word tactile Braille readers (Siuda-Krzywicka et al, 2016 ).…”

Are critical periods reversible in the adult brain? Insights on cortical specializations based on sensory deprivation studies

“…This raised the intriguing hypothesis that LOC specialization might be related to the processing of sensory-independent 3D geometric shapes rendering, rather than related solely to visual object recognition (this was later corroborated by many studies, e.g. see (Kassuba et al, 2014;Kim and Zatorre, 2011;Kim and James, 2010;Reed et al, 2004;Stilla and Sathian, 2008;Tal and Amedi, 2009;Zhang et al, 2004). This hypothesis was further strengthen by results demonstrating LOC activations for tactile or auditory objects recognition in congenitally blind adults, namely people who did not experience any visual inputs during CPs (Amedi et al, 2010;Dormal et al, 2018;Peelen et al, 2014;Pietrini et al, 2004) (Fig.…”

Massive cortical reorganization in sighted Braille readers

“…It is also known that regions higher up in the sensory processing hierarchy, notably the antero-medial parts of the ventral temporal cortex (MNI y>-40), can host multisensory, abstract object representations (e.g. Fairhall and Caramazza, 2013 ; Kassuba et al, 2014 ). The left fusiform gyrus in particular is suggested to process object-specific crossmodal interactions ( Kassuba et al, 2011 ).…”