Frontal-striatal tract integrity and depression in older adults with and without multiple sclerosis.

OBJECTIVE: Lower white matter integrity of frontal-subcortical circuitry has been associated with late-life depression in normally aging older adults and with the presence of multiple sclerosis (MS). Frontal-striatal white matter tracts involved in executive, cognitive, emotion, and motor function may underlie depression in older adults with MS. The present study examined the association between depression score and frontal-striatal white matter integrity in older adults with MS and controls. METHODS: Older adults with MS (OAMS) (n = 67, mean age = 64.55 ± 3.89) and controls (n = 74, mean age = 69.04 ± 6.32) underwent brain MRI, cognitive assessment, psychological, and motoric testing. Depression was assessed through the 30-item Geriatric Depression Scale. Fractional anisotropy (FA) was extracted from two bilateral tracts: dorsolateral prefrontal cortex to putamen nucleus (DLPFC-pn) and dorsolateral prefrontal cortex to caudate nucleus (DLPFC-cn). RESULTS: OAMS reported significantly worse (i.e., higher) depression symptoms (ß = .357, p < .001) compared to healthy controls. Adjusted moderation analyses revealed, via group by FA interactions, significantly stronger associations between FA of the left DLPFC-pn tract and total depression (B = - 61.70, p = .011) among OAMS compared to controls. Conditional effects revealed that lower FA of the left DLPFC-pn was significantly associated with worse (i.e., higher) depression symptoms (b = - 38.0, p = .028) only among OAMS. The other three tracts were not significant in moderation models. CONCLUSIONS: We provided first evidence that lower white matter integrity of the left DLPFC-pn tract was related to worse depression in older adults with MS.

Caudate volume and symptoms of apathy in older adults with multiple sclerosis.

BACKGROUND: Apathy is common in multiple sclerosis (MS) and neurological disease, but its presence and underlying brain mechanisms in older adults with MS (OAMS) have not been evaluated. OBJECTIVE: Examine apathy and its association with caudate nuclei volume in OAMS and controls. We hypothesized that compared to controls, OAMS would demonstrate: a) greater apathy; b) stronger associations between apathy and caudate nuclei volumes. METHODS: OAMS (n = 67, mean age = 64.55 ± 3.89) and controls (n = 74, mean age = 69.04 ± 6.32) underwent brain MRI, cognitive assessment, psychological, and motoric testing. Apathy was assessed through the apathy subscale of the 30-item Geriatric Depression Scale. RESULTS: OAMS reported greater apathy compared to controls (ß = 0.281, p = 0.004). Adjusted moderation analyses revealed a significantly stronger association between caudate volume and apathy (left: B = -1.156, p = 0.039, right: B = -1.163, p = 0.040) among OAMS compared to controls. Conditional effects revealed that in adjusted models, lower volume of both the left (b = -0.882, p = 0.037) and right (b = -0.891, p = 0.038) caudate nuclei was significantly associated with greater apathy only among OAMS. CONCLUSION: Caudate nuclei, which are susceptible to adverse MS effects and implicated in mediating cognitive and motor function, may influence the presence and severity of apathy in OAMS.

Targeting Cognitive Control Deficits With Neuroplasticity-Based Computerized Cognitive Remediation in Patients With Geriatric Major Depression: A Randomized, Double-Blind, Controlled Trial.

Late life major depression (LLD) is often accompanied by cognitive deficits. When patients have specific deficits in cognitive control functions (CCD), they are not only distressing and debilitating, they often predict poor clinical outcomes such as reduced response to SSRI/SNRI antidepressants, increased disability, suicide and all-cause mortality. We recently reported that in an open label trial, our treatment designed to target these specific CCD with neuroplasticity-based computerized cognitive remediation (nCCR) improved depression and CCD in patients who failed to remit with conventional antidepressant treatment. This study tested the hypothesis that in patients with LLD who have failed at least one trial of an SSRI/SNRI antidepressant at an adequate dose for at least 8 weeks, nCCR will improve both depressive symptoms and the CCD associated with poor antidepressant response (i.e. semantic strategy, inhibition of prepotent responses) more than an active control group. Participants were randomized (1:1) to receive either 30 hours/ 4 weeks of neuroplasticity based computerized cognitive remediation (nCCR) designed to target CCD, or the active control condition matched for duration, engagement, reward, computer presentation, and contact with study staff. All participants and raters were blinded. Mixed effects model analysis the time effect (week) (F(1,71.22)=25.2, p<0.0001) and treatment group X time interaction (F(1,61.8)=11.37, p=.002) reached significance indicating that the slope of decline in MADRS was steeper in the nCCR-GD group. Further, the nCCR group improved their semantic clustering strategy(t(28)=9.5; p=.006), as well as performance on the Stroop interference condition, and cognitive flexibility (Trails B). Further, results transferred to memory performance, which was not a function trained by nCCR. clinicaltrials.gov.

Dysregulated protocadherin-pathway activity as an intrinsic defect in induced pluripotent stem cell-derived cortical interneurons from subjects with schizophrenia.

We generated cortical interneurons (cINs) from induced pluripotent stem cells derived from 14 healthy controls and 14 subjects with schizophrenia. Both healthy control cINs and schizophrenia cINs were authentic, fired spontaneously, received functional excitatory inputs from host neurons, and induced GABA-mediated inhibition in host neurons in vivo. However, schizophrenia cINs had dysregulated expression of protocadherin genes, which lie within documented schizophrenia loci. Mice lacking protocadherin-α showed defective arborization and synaptic density of prefrontal cortex cINs and behavioral abnormalities. Schizophrenia cINs similarly showed defects in synaptic density and arborization that were reversed by inhibitors of protein kinase C, a downstream kinase in the protocadherin pathway. These findings reveal an intrinsic abnormality in schizophrenia cINs in the absence of any circuit-driven pathology. They also demonstrate the utility of homogenous and functional populations of a relevant neuronal subtype for probing pathogenesis mechanisms during development.