Phonological repetition-suppression in bilateral superior temporal sulci

Abstract

Evidence has accumulated that posterior superior temporal sulcus (STS) is critically involved in phonological processing during speech perception, although there are conflicting accounts regarding the degree of lateralization. The current fMRI experiment aimed to identify phonological processing during speech perception through repetition-suppression effects. Repetition-suppression occurs when brain activity decreases from repetitive presentation of stimulus characteristics, in regions of cortex that process those characteristics. We manipulated the degree of phonological repetition among words in short lists to obtain systematic decreases in brain response, indicative of phonological processing. The fMRI experiment presented seventeen participants with recorded wordlists, of low, medium, or high phonological repetition, defined by how many phonemes were shared among words. Bilaterally, middle STS demonstrated activity differences consistent with our prediction of repetition-suppression, as responses decreased systematically with each increase in phonological repetition. Phonological repetition-suppression in bilateral STS converges with neuroimaging evidence for phonological processing, and word deafness resulting from bilateral superior temporal lesions.

Brain network dynamics in the human articulatory loop

“…Relatively reduced neural activation to repetition of a similar sound (also known as repetition suppression) in the posterior STG has been reported in a number of studies using fMRI, scalp EEG, MEG, and ECoG (Bergerbest et al, 2004; Garrido et al, 2009; Vaden et al, 2010; Boutros et al, 2011; Todorovic et al, 2011). Repetition suppression is an automatic process initiated at the level of low-order sensory cortex, resulting from habituation induced by the first stimulus, neural fatigue associated with the first response, or top-down perceptual expectation to the second stimulus (Grill-Spector et al, 2006; Todorovic et al, 2011; Matsuzaki et al, 2012).…”

Phonological processing in first‐degree relatives of individuals with autism: An fMRI study

“…The STG and SMG are both regions known to be involved in phonetic and prelexical phonological processing (e.g., Booth et al, 2002; Hickok and Poeppel, 2007; Jobard et al, 2003; Turkeltaub and Coslett, 2010; Vaden et al, 2010). While there is clear evidence for the involvement of bilateral STG and SMG in language processing (e.g., Benson et al, 2001; Booth et al, 2002; Lee et al, 2007; Vaden et al, 2010), the left hemisphere of the brain is generally accepted to be functionally specialized for linguistic processing in approximately 95% of right-handed individuals (Knecht et al, 2000a; Knecht et al, 2000b; Pujol et al, 1999; Szaflarski et al, 2002). Numerous studies have provided evidence for atypical language lateralization in individuals with ASD (Bigler et al, 2007; Flagg et al, 2005; Herbert et al, 2002; Jou et al, 2010; Kleinhans et al, 2008; Knaus et al, 2010; Knaus et al, 2008; Redcay and Courchesne, 2008; Rojas et al, 2002).…”

“…Therefore, we conducted a functional magnetic resonance imaging (fMRI) study in parents of children with ASD utilizing a priming task that we developed in order to investigate the automatic, implicit stages of phonological processing. Behaviorally, priming refers to an increased sensitivity to a stimulus following prior experience with that or a related stimulus and has been used in conjunction with fMRI as a tool to identify brain regions associated with the processing of linguistic stimuli and more specifically phonological processing (Chou et al, 2006; Graves et al, 2008; Haist et al, 2001; Kouider et al, 2010; Kouider et al, 2007; Vaden et al, 2010; Wilson et al, 2011). In order to investigate phonological processing, the task in the present study consisted of prime-target word pairs differing in terms of their phonological relatedness including both word-word homophone (e.g., PAUSE-paws) and pseudoword-word pseudohomophone (e.g., JURM-germ) pairs.…”

Inferior frontal sensitivity to common speech sounds is amplified by increasing word intelligibility

“…Global mean signal fluctuations were detrended from the preprocessed functional images using voxel-level Linear Model of the Global Signal (Macey et al, 2004). Next, we applied an algorithm described in Vaden, Muftuler, Hickok (2010) to identify extreme intensity fluctuations that occurred during each run. Cutoff values were all set to 2.5 standard deviations from the mean, identifying extreme noise in 4.65% of the functional images.…”