Volume and shape of subcortical grey matter structures related to headache: A cross-sectional population-based imaging study in the Nord-Trøndelag Health Study

Brain structural and functional abnormalities in patients with tension-type headache: A systematic review of magnetic resonance imaging studies

Tension-type headache (TTH) stands as the most prevalent form of headache, yet an adequate understanding of its underlying mechanisms remains elusive. This article endeavors to comprehensively review structural and functional magnetic resonance imaging (MRI) studies investigating TTH patients, to gain valuable insights into the pathophysiology of TTH, and to explore new avenues for enhanced treatment strategies. We conducted a systematic search to identify relevant articles examining brain MRI disparities between TTH individuals and headache-free controls (HFC). Fourteen studies, encompassing 312 diagnosed TTH patients, were selected for inclusion. Among these, eight studies utilized conventional MRI, one employed diffusion tensor imaging, and five implemented various functional MRI modalities. Consistent findings across these studies revealed a notable increase in white matter hyperintensity (WMH) in TTH patients. Furthermore, the potential involvement of the specific brain areas recognized to be involved in different dimensions of pain perception including cortical regions (anterior and posterior cingulate cortex, prefrontal cortex, anterior and posterior insular cortex), subcortical regions (thalamus, caudate, putamen, and parahippocampus), cerebellum in TTH pathogenesis was identified. However, no significant association was established between TTH and intracranial abnormalities or total intracranial volume. In conclusion, these findings support the hypotheses regarding the role of central mechanisms in TTH pathophysiology and offer probable brain regions implicated in these mechanisms. Due to the scarce data on the precise role of these regions in the TTH, further preclinical and clinical investigations should be done to advance our knowledge and enhance targeted therapeutic options of TTH.

Aberrant hippocampal shape development in young adults with heavy cannabis use: Evidence from a longitudinal study

Cannabis is one of the most commonly used illicit drugs globally. Mounting evidence indicates that cannabis use, particularly consumption during young adulthood, is related to adverse mental and behavioral outcomes and an increased risk of the onset and relapse of psychosis. However, the neuromechanism underpinnings of heavy cannabis use (HCU) in young adults remain largely unknown, and no study has yet investigated the development of hippocampal shape in young adults with HCU. Twenty young adults with HCU and 22 matched non-cannabis-use healthy controls (HCs) were enrolled. Neuroimaging scanning and clinical assessments for all participants were performed at baseline (BL) and 3-year follow-up (FU). The vertex-wise shape analysis was conducted to investigate aberrant hippocampal shape development in young adults with HCU. Aberrant shape development pattern of the hippocampus was observed in young adults with HCU. There was no significant difference in hippocampal shape between the groups at BL, but young adults with HCU at FU exhibited significant shape atrophy of the right dorsal anterior hippocampus related to HCs. In addition, there was a significantly lower growth rate of the right hippocampal shape. Furthermore, there were significant associations of heavy cannabis use, as indicated by the age at onset first and frequent cannabis use, with the growth rate of hippocampal shape in young adults with HCU. The aberrant hippocampal shape development may reflect the effect of heavy cannabis use on young adults and it may be a potential target for heavy cannabis use treatment for young adults.

Restoration of aberrant shape of caudate sub-regions associated with cognitive function improvement in mild traumatic brain injury

Mild traumatic brain injury (mTBI) is an important but less recognized public health concern. Research shows that altered subcortical structures mediate cognitive impairment in patients with mTBI. This has been performed mostly using voxel-based morphometry methods and traditional volume measurement methods, which have certain limitations. In this study, we conducted a vertex-wise shape analysis to understand the aberrant patterns of caudate sub-regions and recovery from mTBI. The study involved 36 mTBI patients and 34 matched healthy controls (HCs) observed at seven-days (acute phase) and followed-up for one-month (subacute phase) post-injury. Different aberrant shapes of the caudate sub-regions were observed at acute phase, which revealed atrophy in the bilateral dorsal medial caudate, and increase in the size of the right ventral anterior caudate in mTBI patients related to HCs. Moreover, specific and significant shape restoration of right dorsal medial caudate in mTBI was observed at subacute phase, which significantly associated with the cognitive function improvement of the patients. These findings suggest that the restoration of the aberrant shape atrophy of right dorsal medial caudate plays a vital role in the improvement of cognitive function of mTBI patients, providing an alternative clinical target for these patients.

Hippocampus shape deformation: a potential diagnostic biomarker for chronic back pain in women

ABSTRACT

Sex differences in the quality and prevalence of chronic pain are manifold, with women generally presenting higher incidence and severity. Uncovering chronic pain-related sex differences inform neural mechanisms and may lead to novel treatment routes. In a multicenter morphological study (total n = 374), we investigated whether the shape of subcortical regions would reflect sex differences in back pain. Given the hormone-dependent functions of the hippocampus, and its role in the transition to chronic pain, this region constituted our primary candidate. We found that the anterior part of the left hippocampus (alHP) presented outer deformation in women with chronic back pain (CBP), identified in CBP in the United States (n = 77 women vs n = 78 men) and validated in a Chinese data set (n = 29 women vs n = 58 men with CBP, in contrast to n = 53 female and n = 43 male healthy controls). Next, we examined this region in subacute back pain who persisted with back pain a year later (SBPp; n = 18 women vs n = 18 men) and in a subgroup with persistent back pain for 3 years. Weeks after onset of back pain, there was no deformation within alHP, but at 1 and 3 years women exhibited a trend for outer deformation. The alHP partly overlapped with the subiculum and entorhinal cortex, whose functional connectivity, in healthy subjects, was associated with emotional and episodic memory related terms (Neurosynth, reverse inference). These findings suggest that in women the alHP undergoes anatomical changes with pain persistence, highlighting sexually dimorphic involvement of emotional and episodic memory-related circuitry with chronic pain.

The Instant Effects of Continuous Transcutaneous Auricular Vagus Nerve Stimulation at Acupoints on the Functional Connectivity of Amygdala in Migraine without Aura: A Preliminary Study

Background

A growing body of evidence suggests that both auricular acupuncture and transcutaneous auricular vagus nerve stimulation (taVNS) can induce antinociception and relieve symptoms of migraine. However, their instant effects and central treatment mechanism remain unclear. Many studies proved that the amygdalae play a vital role not only in emotion modulation but also in pain processing. In this study, we investigated the modulation effects of continuous taVNS at acupoints on the FC of the bilateral amygdalae in MwoA.

Methods

Thirty episodic migraineurs were recruited for the single-blind, crossover functional magnetic resonance imaging (fMRI) study. Each participant attended two kinds of eight-minute stimulations, taVNS and sham-taVNS (staVNS), separated by seven days in random order. Finally, 27 of them were included in the analysis of seed-to-voxel FC with the left/right amygdala as seeds.

Results

Compared with staVNS, the FC decreased during taVNS between the left amygdala and left middle frontal gyrus (MFG), left dorsolateral superior frontal gyrus, right supplementary motor area (SMA), bilateral paracentral lobules, bilateral postcingulum gyrus, and right frontal superior medial gyrus, so did the FC of the right amygdala and left MFG. A significant positive correlation was observed between the FC of the left amygdala and right SMA and the frequency/total time of migraine attacks during the preceding four weeks.

Conclusion

Continuous taVNS at acupoints can modulate the FC between the bilateral amygdalae and pain-related brain regions in MwoA, involving the limbic system, default mode network, and pain matrix, with obvious differences between the left amygdala and the right amygdala. The taVNS may produce treatment effects by modulating the abnormal FC of the amygdala and pain networks, possibly having the same central mechanism as auricular acupuncture.

Migraine with aura in women is not associated with structural thalamic abnormalities

Migraine with aura is a highly prevalent disorder involving transient neurological disturbances associated with migraine headache. While the pathophysiology is incompletely understood, findings from clinical and basic science studies indicate a potential key role of the thalamus in the mechanisms underlying migraine with and without aura. Two recent, clinic-based MRI studies investigated the volumes of individual thalamic nuclei in migraine patients with and without aura using two different data analysis methods. Both studies found differences of thalamic nuclei volumes between patients and healthy controls, but the results of the studies were not consistent. Here, we investigated whether migraine with aura is associated with changes in thalamic volume by analysing MRI data obtained from a large, cross-sectional population-based study which specifically included women with migraine with aura (N = 156), unrelated migraine-free matched controls (N = 126), and migraine aura-free co-twins (N = 29) identified from the Danish Twin Registry. We used two advanced, validated analysis methods to assess the volume of the thalamus and its nuclei; the MAGeT Brain Algorithm and a recently developed FreeSurfer-based method based on a probabilistic atlas of the thalamic nuclei combining ex vivo MRI and histology. These approaches were very similar to the methods used in each of the two previous studies. Between-group comparisons were corrected for potential effects of age, educational level, BMI, smoking, alcohol, and hypertension using a linear mixed model. Further, we used linear mixed models and visual inspection of data to assess relations between migraine aura frequency and thalamic nuclei volumes in patients. In addition, we performed paired t-tests to compare volumes of twin pairs (N = 29) discordant for migraine with aura. None of our analyses showed any between-group differences in volume of the thalamus or of individual thalamic nuclei. Our results indicate that the pathophysiology of migraine with aura does not involve alteration of thalamic volume.

Subcortical Brain Abnormalities and Clinical Relevance in Patients With Hemifacial Spasm

Purpose: Hemifacial spasm (HFS), a rare neuromuscular movement disorder, is characterized by unilateral, irregular, and paroxysmal facial muscle contractions. To explore the central neural mechanisms of HFS, we conducted vertex-wise shape analyses to investigate volume and shape alterations of subcortical structures, which could help to better understand the abnormality in distinct subcortical regions and determine alternative biomarkers of HFS.

Methods: Thirty patients with HFS and 30 age- and sex-matched healthy controls provided written informed consent. T1-weighted structural magnetic resonance imaging (MRI) data were collected from all participants. Vertex-wise shape analyses were performed to assess the volume and shape alterations of subcortical structures following HFS. Post hoc correlations with spasm severity and measures of mood dysfunction were applied to characterize subcortical brain alterations.

Results: Compared with healthy controls, patients with HFS showed increased volume in the right caudate specifically. Furthermore, patients exhibited significant shape atrophy in the anterior medial aspect of left pallidum, together with shape expansion in the anterior ventrolateral aspect of right caudate head. In addition, shape alteration in right caudate was positively correlated with both anxiety and depression severity in patients with HFS.

Conclusions: This is the first study to employ vertex-wise shape analysis to investigate subcortical brain abnormalities in patients with HFS. Our findings provide compelling evidence for subcortical brain alterations specific to HFS, and further may shed light on the pathophysiology of HFS and apply to the translational medicine.

Alterations of individual thalamic nuclei volumes in patients with migraine

Background

The aim of this study is to investigate the alterations of thalamic nuclei volumes and the intrinsic thalamic network in patients with migraine.

Methods

We enrolled 35 patients with migraine without aura and 40 healthy controls. All subjects underwent three-dimensional T1-weighted imaging. The thalamic nuclei were segmented using the FreeSurfer program. We investigated volume changes of individual thalamic nuclei and analyzed the alterations of the intrinsic thalamic network based on volumes in the patients with migraine.

Results

Right and left thalamic volumes as a whole were not different between the patients with migraine and healthy controls. However, we found that right anteroventral and right and left medial geniculate nuclei volumes were significantly increased (0.00985% vs. 0.00864%, p = 0.0002; 0.00929% vs. 0.00823%, p = 0.0005; 0.00939% vs. 0.00769%, p < 0.0001; respectively) whereas right and left parafascicular nuclei volumes were decreased in the patients with migraine (0.00359% vs. 0.00435%, p < 0.0001; 0.00360% vs. 0.00438%, p < 0.0001; respectively) compared with healthy controls. The network measures of the intrinsic thalamic network were not different between the groups.

Conclusions

We found significant alterations of thalamic nuclei volumes in patients with migraine compared with healthy controls. These findings might contribute to the underlying pathogenesis of the migraine.

Trial registration

None.

Hypoechogenicity of brainstem raphe correlates with depression in migraine patients

Background

Brainstem raphe (BR) hypoechogenicity in transcranial sonography (TCS) has been depicted in patients with major depression (MD) and in depressed patients with different neurodegenerative diseases. But, up to date, the association of BR alterations in TCS with depression in migraineurs has never been reported. This study was to investigate the possible role of BR examination via TCS in migraineurs with depression.

Methods

Forty two migraine without aura (MwoA) patients and 40 healthy controls were recruited. Echogenicity of lentiform nuclei (LN), caudate nuclei (CN), substantia nigra (SN) and brainstem raphe (BR) and width of the frontal horns of the lateral ventricles and the third ventricle were assessed with TCS. The diagnosis of depression was based on the criteria of the Diagnostic and Statistical Manual of Mental Disorders IV (DSM –IV), and the severity of depression was measured by Hamilton Rating Scale for Depression (HAM-D) and Hospital Anxiety and Depression Scale depression subscale (HADS-D).

Results

There were no significant differences between migraineurs and controls in the width of frontal horn of the lateral ventricle (p = 0.955), width of third ventricle (p = 0.129) as well as in the echogenicity of SN (p = 0.942), CN (p = 0.053), LN (p = 0.052) and BR (p = 0.677). Here, it seems that more migraineurs were detected with increased echogenecity of CN and LN compared with controls (33.3% versus 15.0% for CN, 19.0% versus 5.0% for LN) though they had no statistical significance. Patients with hypoechogenic BR had significantly higher HAM-D and HADS-D scores than those with normal BR signal (p = 0.000 for both HAM-D and HADS-D), and most (83.33%) migraineurs with depression exhibited hypoechogenic raphe but none (0.00%) of the migraineurs without depression exhibited hypoechogenic raphe (p = 0.000).

Conlusions

TCS signal alteration of BR can be a biomarker for depression in migraine but it is not associated with migraine headache itself. LN and CN alterations in TCS may reflect a potential role of them in the pathogenesis of migraine, which needs to be further elucidated.

Subcortical Volume Changes in Migraine with Aura

Background and Purpose

Various features of the cerebral cortex and white matter have been extensively investigated in migraine with aura (MwA), but the morphological characteristics of subcortical structures have been largely neglected. The aim of this study was to identify possible differences in subcortical structures between MwA patients and healthy subjects (HS), and also to determine the correlations between the characteristics of migraine aura and the volumes of subcortical structures.

Methods

Thirty-two MwA patients and 32 HS matched by sex and age were analyzed in this study. Regional subcortical brain volumes were automatically calculated using the FSL/FMRIB Image Registration and Segmentation Tool software (https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/Glossary). A general linear model analysis was used to investigate differences in the volume of subcortical structures between the MwA patients and HS. A partial correlation test was used to assess correlations between the volume of subcortical structures and characteristics of MwA.

Results

The volumes of the right globus pallidus, left globus pallidus, and left putamen were significantly smaller in MwA patients than in HS (mean±SD): 1,427±135 mm³ vs. 1,557±136 mm³ (p<0.001), 1,436±126 mm³ vs. 1,550±139 mm³ (p=0.001), and 4,235±437 mm³ vs. 4,522±412 mm³ (p=0.006), respectively. There were no significant relationships between subcortical structures and clinical parameters.

Conclusions

These findings suggest that both the globus pallidi and left putamen play significant roles in the pathophysiology of the MwA. Future studies should determine the cause-and-effect relationships, since these could not be discriminated in this study due to its cross-sectional design.