Altered Functional Segregated Sensorimotor, Associative, and Limbic Cortical-Striatal Connections in Parkinson's Disease: An fMRI Investigation.

Multiple studies have identified segregated functional territories in the basal ganglia for the control of goal-directed and habitual actions. It has been suggested that in PD, preferential loss of dopamine in the posterior putamen may cause a major deficit in habitual control (mediated by the sensorimotor cortical-striatal loop), and the patients may therefore be forced into a progressive reliance on the goal-directed behavior (regulated by the associative cortical-striatal loop). Functional evidence supporting this point is scarce at present. This study aims to verify the functional connectivity changes within the sensorimotor, associative, and limbic cortical-striatal loops in PD. Resting-state fMRI of 70 PD patients and 30 controls were collected. Bilateral tripartite functional territories of basal ganglia and their associated cortical structures were chosen as regions of interest, including ventral striatum and ventromedial prefrontal cortex for limbic loop; dorsomedial striatum and dorsolateral prefrontal cortex for associative loop; dorsolateral striatum and sensorimotor cortex for sensorimotor loop. Pearson's correlation coefficients for each seed pair were calculated to obtain the functional connectivity. The relationships between functional connectivity and disease severity were further investigated. Functional connectivity between dorsolateral striatum and sensorimotor cortex is decreased in PD patients, and negatively correlated with disease duration; whereas functional connectivity between dorsomedial striatum and dorsolateral prefrontal cortex is also decreased but postitively correlated with disease duration. The functional connectivity within the sensorimotor loop is pathologically decreased in PD, while the altered connectivity within the associative loop may indicate a failed attempt to compensate for the loss of connectivity within the sensorimotor loop.

Ganoderma lucidum extract ameliorates MPTP-induced parkinsonism and protects dopaminergic neurons from oxidative stress via regulating mitochondrial function, autophagy, and apoptosis.

Neuroprotection targeting mitochondrial dysfunction has been proposed as an important therapeutic strategy for Parkinson's disease. Ganoderma lucidum (GL) has emerged as a novel agent that protects neurons from oxidative stress. However, the detailed mechanisms underlying GL-induced neuroprotection have not been documented. In this study, we investigated the neuroprotective effects of GL extract (GLE) and the underlying mechanisms in the classic MPTP(1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-induced mouse model of PD. Mice were injected with MPTP to induce parkinsonism. Then the mice were administered GLE (400 mg kg-1 d-1, ig) for 4 weeks. We observed that GLE administration significantly improved locomotor performance and increased tyrosine hydroxylase expression in the substantia nigra pars compact (SNpc) of MPTP-treated mice. In in vitro study, treatment of neuroblastoma neuro-2a cells with 1-methyl-4-phenylpyridinium (MPP+, 1 mmol/L) caused mitochondrial membrane potential collapse, radical oxygen species accumulation, and ATP depletion. Application of GLE (800 µg/mL) protected neuroblastoma neuro-2a cells against MPP+ insult. Application of GLE also improved mitochondrial movement dysfunction in cultured primary mesencephalic neurons. In addition, GLE counteracted the decline in NIX (also called BNIP3L) expression and increase in the LC3-II/LC3-I ratio evoked by MPP+. Moreover, GLE reactivated MPP+-inhibited AMPK, mTOR, and ULK1. Similarly, GLE was sufficient to counteract MPP+-induced inhibition of PINK1 and Parkin expression. GLE suppressed MPP+-induced cytochrome C release and activation of caspase-3 and caspase-9. In summary, our results provide evidence that GLE ameliorates parkinsonism pathology via regulating mitochondrial function, autophagy, and apoptosis, which may involve the activation of both the AMPK/mTOR and PINK1/Parkin signaling pathway.

Neural regeneration: role of traditional Chinese medicine in neurological diseases treatment.

The effects of a single compound and a mixture of traditional Chinese medicine (TCM) on promoting proliferation, differentiation, and migration of neural stem cells and regulating their microenvironment have been observed by Chinese scholars in recent years. These results showed good prospects in improving neural regeneration and repair of neurological disorders such as ischemic brain injury, Alzheimer's disease, Parkinson's disease, and depression. According to the TCM theory, the relationship between life of an individual and the disease was regarded as an entirety, and the theory emphasized the treatment based on syndrome differentiation since ancient times. In this paper, we attempted to introduce these medicines, which belong to natural products and have already been proved to possess clear therapeutic action on human bodies in the clinical setting. We summarized their effects promoting brain neurogenesis and repairing brain injuries in animal models and some mechanisms at the cellular and molecular levels.