Musical deficits and cortical thickness in people with schizophrenia

Music rhythm perception and production relate to treatment response in schizophrenia

Accumulating evidence indicates that pathophysiology of schizophrenia involves abnormalities in the dopamine and glutamatergic neuronal systems. Antipsychotic medications are currently used to normalize dopaminergic function for schizophrenia. However, approximately 30 % of the patients have no response to antipsychotic medications, which is classified as treatment-resistant schizophrenia (TRS). Furthermore, dopamine and glutamate levels in the neural basis have been reported to differ between TRS and non-TRS. In this study, we assumed that these differences may affect music rhythm perception and production abilities between the two groups. We examined fifty-seven schizophrenia (26 TRS, 31 non-TRS) and thirty-one healthy controls (HCs) by using the Harvard Beat Assessment Test (H-BAT). As a result, we found that rhythm production was worse in patients with TRS compared to patients with non-TRS and HCs, while no difference was observed between patients with non-TRS and HCs. In addition, rhythm perception and production abilities were impaired in the whole patient group compared with HCs. Furthermore, in the patient group, the deficits were correlated with cognitive impairments. Collectively, these results suggest that patients with schizophrenia may have rhythm processing deficits, with particular a rhythm production problem in the TRS group.

Music and neuro-cognitive deficits in depression

Background

Cognitive deficits are one of the core features of major depressive disorder (MDD) that play crucial role in functional recovery. Studies have explored cognitive deficits in MDD, however, given inconsistent results, especially in mild-moderate MDD. Recently, studies have explored music as cognitive ability in various clinical conditions. In MDD, large focus has been on evaluating emotion deficits and just a handful on music cognition. With growing evidence on use of music based intervention to target cognitive deficits, it is imperative to explore nature of music cognitive ability in MDD.

Aim

To examine musical and neuro-cognitive deficits in patients with mild-moderate MDD.

Methods

Patients diagnosed with mild or moderate MDD (n = 19) and matched healthy controls (HC) (n = 18) were evaluated on selected tests from NIMHANS Neuropsychological test battery and Montreal battery for evaluation of amusia (MBEA).

Results

MDD group performed significantly lower than HC on working memory (p = 0.007), verbal learning (p = 0.02) and retention (p = 0.03). Three indices were computed for a comprehensive evaluation. Groups did not differ significantly in any of the indices- focused attention, executive function, learning and memory as well as on music cognition. Focused attention and memory index predicted music cognition in HC and the combined group (MDD + HC) (p < 0.01). Attention alone contributed to 62.1% of variance in music cognition. Similarly, music cognition significantly predicted focused attention (p < 0.01).

Conclusion

Individuals with mild-moderate MDD show significant deficits in working memory, verbal learning and memory, however, not in music cognition. There exists a significant relationship between music cognition and attention, which could be implicated in use of music interventions to ameliorate cognitive deficits. Limitations of study include small sample size and heterogeneity. Future studies on larger cohort examining musical emotion perception and neurocognition is imperative to have deeper understanding of this debilitating condition.

Individual differences in the experience of body ownership are related to cortical thickness

The widely used rubber hand illusion (RHI) paradigm provides insight into how the brain manages conflicting multisensory information regarding bodily self-consciousness. Previous functional neuroimaging studies have revealed that the feeling of body ownership is linked to activity in the premotor cortex, the intraparietal areas, the occipitotemporal cortex, and the insula. The current study investigated whether the individual differences in the sensation of body ownership over a rubber hand, as measured by subjective report and the proprioceptive drift, are associated with structural brain differences in terms of cortical thickness in 67 healthy young adults. We found that individual differences measured by the subjective report of body ownership are associated with the cortical thickness in the somatosensory regions, the temporo-parietal junction, the intraparietal areas, and the occipitotemporal cortex, while the proprioceptive drift is linked to the premotor area and the anterior cingulate cortex. These results are in line with functional neuroimaging studies indicating that these areas are indeed involved in processes such as cognitive-affective perspective taking, visual processing of the body, and the experience of body ownership and bodily awareness. Consequently, these individual differences in the sensation of body ownership are pronounced in both functional and structural differences.

Gray matter hypertrophy in primary insomnia: a surface-based morphometric study

Studies have explored brain structural abnormalities in patients with primary insomnia (PI). However, most of them are based on volumetric measures, in a specific region of interest, and have small sample sizes. Here, we investigated changes in cortical morphology (thickness and volume) in PI using an advanced surface-based morphometric method. Sixty-seven patients with PI and 55 matched healthy controls were recruited for this study and underwent a structural magnetic resonance imaging scan. The reconstructed cortical surface was processed by Freesurfer 6.0. A general linear model was used to explore group differences in surface-based morphometric features. Furthermore, the association between these cortical features and clinical characteristics were assessed in the PI group. Compared to controls, PI patients showed cortical thickening in the left orbital frontal cortex (OFC), right rostral anterior cingulate cortex (rACC), left middle cingulate cortex (MCC), bilateral insula, left superior parietal lobule (SPL), and right fusiform area (FFA), and showed increased cortical volume in the left OFC, right rACC, bilateral rostral middle frontal gyrus, and right FFA. Cortical thickness in the right OFC and FFA was positively correlated with the severity of insomnia in the PI group, suggesting a right-lateralized relationship. This study was the first to explore multiple-scale cortical morphometric changes in a relatively large sample of PI patients. Our results suggest that hypertrophic cortical morphology may underlie the neuropathology of primary insomnia.

Altered cortical morphology in major depression disorder patients with suicidality

Background

Major depressive disorder (MDD) is associated with high risk of suicide, but the biological underpinnings of suicidality in MDD patients are far from conclusive. Previous neuroimaging studies using voxel-based morphometry (VBM) demonstrated that depressed individuals with suicidal thoughts or behaviors exhibit specific cortical structure alterations. To complement VBM findings, surface-based morphometry (SBM) can provide more details into gray matter structure, including the cortical complexity, cortical thickness and sulcal depth for brain images.

Objective

This study aims to use SBM to investigate cortical morphology alterations to obtain evidence for neuroanatomical alterations in depressed patients with suicidality.

Methods

Here, 3D T1-weighted MR images of brain from 39 healthy controls, 40 depressed patients without suicidality (patient controls), and 39 with suicidality (suicidal groups) were analyzed based on SBM to estimate the fractal dimension, gyrification index, sulcal depth, and cortical thickness using the Computational Anatomy Toolbox. Correlation analyses were performed between clinical data and cortical surface measurements from patients.

Results

Surface-based morphometry showed decreased sulcal depth in the parietal, frontal, limbic, occipital and temporal regions and decreased fractal dimension in the frontal regions in depressed patients with suicidality compared to both healthy and patient controls. Additionally, in patients with depression, the sulcal depth of the left caudal anterior cingulate cortex was negatively correlated with Hamilton Depression Rating Scale scores.

Conclusions

Depressed patients with suicidality had abnormal cortical morphology in some brain regions within the default mode network, frontolimbic circuitry and temporal regions. These structural deficits may be associated with the dysfunction of emotional processing and impulsivity control. This study provides insights into the underlying neurobiology of the suicidal brain.