Abstract
Tourette syndrome (TS) is a childhood-onset chronic disorder characterized by the presence of multiple motor and vocal tics. This study investigated spontaneous low-frequency fluctuations in TS patients during resting-state functional magnetic resonance imaging (rs-fMRI) scans. We obtained rs-fMRI scans from 17 drug-naïve TS children and 15 demographically matched healthy children. We computed the amplitude of low-frequency fluctuation (ALFF) and fractional ALFF (fALFF) of rs-fMRI data to measure spontaneous brain activity, and assessed the between-group differences in ALFF/fALFF and the relationship between ALFF/fALFF and tic severity scores. Our results showed that the children with TS exhibited significantly decreased ALFF in the posterior cingulate gyrus/precuneus and bilateral parietal gyrus. fALFF was decreased in TS children in the anterior cingulated cortex, bilateral middle and superior frontal cortices and superior parietal lobule, and increased in the left putamen and bilateral thalamus. Moreover, we found significantly positive correlations between fALFF and tic severity scores in the right thalamus. Our study provides empirical evidence for abnormal spontaneous neuronal activity in TS patients, which may implicate the underlying neurophysiological mechanism in TS and demonstrate the possibility of applying ALFF/fALFF for clinical TS studies.
Highlights
Tourette syndrome (TS) is a childhood-onset chronic disorder characterized by the presence of involuntary, multiple movements and vocalizations called “tics” which last for more than one year
Our results showed that the children with TS exhibited significantly decreased amplitude of low-frequency fluctuation (ALFF) in the posterior cingulate gyrus/precuneus and bilateral parietal gyrus. fractional ALFF (fALFF) was decreased inTS children in the anterior cingulated cortex, bilateral middle and superior frontal cortices and superior parietal lobule, and increased in the left putamen and bilateral thalamus
Functional imaging studies have revealed increased activity in the supplementary motor area (SMA) prior to tics (Bohlhalter et al, 2006; Hampson et al, 2009), which has been suggested as reflecting the premonitory urge that precedes tics, and might give rise to the aberrant striatal activity, which has been demonstrated in positron emission tomography (PET) and single photon emission tomography (SPET) studies to be increasing along with blood flow in TS subjects during tic release (Lerner et al, 2007)
Summary
Tourette syndrome (TS) is a childhood-onset chronic disorder characterized by the presence of involuntary, multiple movements and vocalizations called “tics” which last for more than one year. Mink (2001) proposed a model of dysfunction of the corticostriatal-thalamo-cortical (CSTC) circuit in TS, hypothesizing that aberrant activity in the striatum will release the thalamus from inhibition, and the thalamus will excite the cortex to the execution of unwanted movements (tics). Evidence for abnormalities in subcortical and cortical regions within the CSTC circuits has been derived from structural and functional neuroimaging studies in TS (for a review, see Martino and Leckman, 2013). Structural imaging studies have revealed consistent findings of reduced volume in children and adults with TS in striatal areas, the caudate nucleus (Peterson et al, 1993, 2003; Hyde et al, 1995; Makki et al, 2008), with a smaller caudate volume in childhood would lead to higher symptom severity later in life (Bloch et al., 2005). A previous study has found aberrant activity in regions within the cognitive control network (Church et al, 2009), expanding the functional anatomy of putative abnormalities in TS from the CSTC circuit to other cortical networks that support cognitive functions
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
