Abnormal dynamic brain activity and functional connectivity of primary motor cortex in blepharospasm

Abstract

Background and purpose: Accumulating evidence indicates that dynamic amplitude of low-frequency fluctuations (dALFF) or dynamic functional connectivity (dFC) can provide complementary information, distinct from static amplitude of low-frequency fluctuations (sALFF) or static functional connectivity (sFC), in detecting brain functional abnormalities in brain diseases. We aimed to examine whether dALFF and dFC can offer valuable information for the detection of functional brain abnormalities in patients with blepharospasm. Methods:We collected resting-state functional magnetic resonance imaging data from 46 patients each of blepharospasm, hemifacial spasm (HFS), and healthy controls (HCs).We examined intergroup differences in sALFF and dALFF to investigate abnormal regional brain activity in patients with blepharospasm. Based on the dALFF results, we conducted seed-based sFC and dFC analyses to identify static and dynamic connectivity changes in brain networks centered on areas showing abnormal temporal variability of local brain activity in patients with blepharospasm.Results: Compared with HCs, patients with blepharospasm displayed different brain functional change patterns characterized by increased sALFF in the left primary motor cortex (PMC) but increased dALFF variance in the right PMC. However, differences were not found between patients with HFS and HCs. Additionally, patients with blepharospasm exhibited decreased dFC strength, but no change in sFC, between right PMC and ipsilateral cerebellum compared with HCs; these findings were replicated when patients with blepharospasm were compared to those with HFS. Conclusions:Our findings highlight that dALFF and dFC are complementary to sALFF and sFC and can provide valuable information for detecting brain functional abnormalities in blepharospasm. Blepharospasm may be a network disorder involving the cortico-pontocerebello-thalamo-cortical circuit.

Amplitude of low-frequency fluctuation after a single-trigger pain in patients with classical trigeminal neuralgia

“…It is a novel metric reflecting the changes in ALFF over time. dALFF describes the temporal fluctuation in energy expenditure based on the oxygen level and reflects the plasticity and flexibility of spontaneous brain activity [27,28]. DALFF likely captures useful information missed in sALFF, and can therefore provide complementary information [27].…”

“…dALFF describes the temporal fluctuation in energy expenditure based on the oxygen level and reflects the plasticity and flexibility of spontaneous brain activity [27,28]. DALFF likely captures useful information missed in sALFF, and can therefore provide complementary information [27]. Chen et al [29] found that the dALFF values of the bilateral anterior insula, bilateral orbitofrontal cortex, bilateral medial prefrontal cortex, bilateral anterior cingulate cortex (ACC), and left middle frontal gyrus cortex were significantly lower in patients with migraine without aura compared with HC.…”

“…Also, the dALFF values of the ACC negatively correlated with pain intensity. Luo et al [27] showed that patients with blepharospasm had increased sALFF values in the left primary motor cortex (PMC) compared with the HC, while increased dALFF variance was seen in the right PMC.…”

Cerebellar gray matter alterations predict deep brain stimulation outcomes in Meige syndrome

“…All these three functions are impaired in MS patients since the eyelids spasm or apraxia of eyelids opening can interfere with their visuospatial ability and attention, and then influence the motor comprehension and motor planning. Moreover, Luo et al (2022) found lower dynamic FC between the lobule VIII and the primary motor cortex in blepharospasm patients compared to HCs and hemifacial spasm patients, and from this, they claimed that lobule VIII might play a crucial role in triggering the development of blepharospasm. All the evidence verifies the motor role of lobule VIII in MS.…”

Brain White Matter Structural Alteration in Hemifacial Spasm: A Diffusion Tensor Imaging Study

“…The ponto-cerebello-thalamo-cortical motor circuit plays a crucial role in controlling the blink reflex and coordinating eyelid movements. Earlier fMRI studies have shown that focal dystonia is closely related to the ponto-cerebello-thalamo-cortical circuit dysfunction 35. Alterations in the thalamus have been a hot issue in HFS, and several studies have shown structural, functional, and metabolic abnormalities in the thalamus of HFS patients 6,16,19,36.…”