What differs in visual recognition of handwritten vs. printed letters? An fMRI study

Abstract

In models of letter recognition, handwritten letters are considered as a particular font exemplar, not qualitatively different in their processing from printed letters. Yet, some data suggest that recognizing handwritten letters might rely on distinct processes, possibly related to motor knowledge. We applied functional magnetic resonance imaging to compare the neural correlates of perceiving handwritten letters vs. standard printed letters. Statistical analysis circumscribed to frontal brain regions involved in hand-movement triggering and execution showed that processing of handwritten letters is supported by a stronger activation of the left primary motor cortex and the supplementary motor area. At the whole-brain level, additional differences between handwritten and printed letters were observed in the right superior frontal, middle occipital, and parahippocampal gyri, and in the left inferior precentral and the fusiform gyri. The results are suggested to indicate embodiment of the visual perception of handwritten letters.

Brain responses to handwritten and printed letters differentially depend on the activation state of the primary motor cortex

“…At 300-350 ms, the effect was restricted to the right posterior region, consistent with several recent studies showing a stronger involvement of right hemispheric occipital regions for the processing of handwritten letters (Barton et al, 2010b;Heckmann et al, 2001;Hellige and Adamson, 2007;Longcamp et al, 2011;Qiao et al, 2010). This rightsided effect has been hypothesized to be related to the processing of shape properties that are necessary for script style identification (Barton et al, 2010b).…”

“…Finally, the possible lateralization of the effects is of interest: it is now well established that the difference in processing handwritten and printed letters or words relies on a stronger involvement of visual regions of the right hemisphere (Barton et al, 2010a(Barton et al, , 2010bHellige and Adamson, 2007;Longcamp et al, 2011;Qiao et al, 2010). This right-hemispheric involvement has been related to the handling of visual complexity that is inherent to handwritten traces (Hellige and Adamson, 2007) and to the analysis of script style (Barton et al, 2010a).…”

Writing's Shadow: Corticospinal Activation during Letter Observation

“…Previous studies using oscillatory MEG signals or fMRI showed the involvement of the left M1 activation for the handwritten letter observation (Longcamp et al, 2006(Longcamp et al, , 2011. For the MEG study, in which the oscillatory activity in the ∼20-Hz frequency band was shown to be suppressed from 0 to 1500 msec.…”

Distinct role of spatial frequency in dissociative reading of ideograms and phonograms: An fMRI study

“…It is possible that visual complexity itself rather than HSF-Kanji preferentially activated the left IT. By using fMRI, Longcamp et al (2011) demonstrated that the left IT is significantly more activated by handwritten letters, which are more complex compared to printed letters in terms of their intrinsic production-related information and the continuity of their lines (font). Vogel et al (2012) reported that the left IT was more strongly activated by more complicated words, which they defined as words composed of a greater number of strokes.…”