Recognition memory for vibrotactile rhythms: An fMRI study in blind and sighted individuals

Abstract

Calcarine sulcal cortex possibly contributes to semantic recognition memory in early blind (EB). We assessed a recognition memory role using vibrotactile rhythms and a retrieval success paradigm involving learned "old" and "new" rhythms in EB and sighted. EB showed no activation differences in occipital cortex indicating retrieval success but replicated findings of somatosensory processing. Both groups showed retrieval success in primary somatosensory, precuneus, and orbitofrontal cortex. The S1 activity might indicate generic sensory memory processes.

Repetition learning of vibrotactile temporal sequences: An fMRI study in blind and sighted individuals

“…Long delays were not previously observed with single presentations of a vibrotactile stimulus (Burton et al, 2004; Burton et al, 2008b; Burton et al, 2010; Sinclair et al, 2011). The current study required assessment of two vibrotactile sequences in a trial.…”

“…Participants pressed one of two optical response keys with left hand fingers to indicate discrimination choices. In addition to the same-different task, participants had to memorize the vibrotactile temporal sequences for identification in an immediately following recognition test, the results of which appear elsewhere (Sinclair et al, 2011). Participants received task training and practice trials prior to entering the scanner and again while in the scanner.…”

“…Extracted signals were percent MR signal change per voxel relative to baseline. The predefined ROI in occipital cortex included areas previously activated in blind participants with a variety of somatosensory tasks (Amedi et al, 2010; Bonino et al, 2008; Burton et al, 2002; Burton et al, 2004; Burton et al, 2006; Burton et al, 2010; Hötting and Röder, 2009; Melzer et al, 2001; Merabet et al, 2007; Sadato et al, 1996; Sadato et al, 1998; Sadato et al, 2004; Sathian, 2005; Sathian and Stilla, 2010; Sinclair et al, 2011). These occipital cortex ROI in sighted were within lower and upper tier retinotopic visual areas (Grill-Spector and Malach, 2004) from the calcarine sulcus to superior occipital dorsally, lateral occipital anteriorly, and fusiform gyrus ventrally.…”

“…In occipital cortex, blind would probably show effects throughout occipital cortex based on prior reports of activation with tactile stimulation in early blind (Amedi et al, 2010; Burton et al, 2004; Burton et al, 2006; Gizewski et al, 2003; Kujala et al, 1995a; Merabet et al, 2004; Pascual-Leone and Hamilton, 2001; Ptito et al, 2005; Sadato et al, 1996; Sinclair et al, 2011; Uhl et al, 1991). In sighted, we expected effects to be limited to parts of occipital cortex activated by tactile stimulation: primary visual (Burton et al, 2004; Burton et al, 2006; Burton et al, 2010; Sinclair et al, 2011), lateral occipital (Amedi et al, 2002; Amedi et al, 2010; James et al, 2002; Pietrini et al, 2004), and middle temporal (Hagen et al, 2002). Finding the probable implicit memory effects of practice only in primary visual cortex (V1) of blind participants would bolster the idea of a role for V1 in memory processes (Amedi et al, 2003; Azulay et al, 2009; Raz et al, 2005).…”

“…In the present study, participants learned to associate one of two button push responses with matched or unmatched vibrotactile sequences. A secondary task prompted by instruction involved deep encoding of sequences for later recognition (Sinclair et al, 2011). However, the overt pair-comparison task involved implicit learning of sequences.…”