The cerebellum plays an important role in depression. Cerebro-cerebellar circuits have been found to show aberrance in bipolar disorder (BD) and major depressive disorder (MDD). However, whether the cerebro-cerebellar connectivity contributes equally to the pathologic mechanisms of BD and MDD remains unknown. We recruited 33 patients with MDD, 32 patients with BD, and 43 healthy controls (HC). We selected six seed regions (three per hemisphere) in the cerebrum, corresponding to the affective, cognitive control, and default mode networks, to establish cerebro-cerebellar functional connectivity maps. Relative to the HC, both the BD and MDD patients exhibited weaker negative connectivity between the right subgenual anterior cingulate cortex and the cerebellar vermis IV_V (p = 0.03, p = 0.001) and weaker positive connectivity between the left precuneus and the left cerebellar lobule IX (p = 0.043, p = 0.000). Moreover, the MDD patients showed weaker positive connectivity in the left precuneus-left cerebellar lobule IX circuit than the BD patients (p = 0.049). In addition, the BD patients showed weaker positive connectivity in the right dorsolateral prefrontal cortex-left cerebellar lobule Crus Ι circuit compared to the HC (p = 0.002) or the MDD patients (p = 0.013). Receiver operating characteristic curves analyses showed that the altered cerebro-cerebellar connectivities could be used to distinguish the patients from the HC with relatively high accuracy. Our findings suggested that differences in connectivity of cerebro-cerebellar circuits, which are involved in affective or cognitive functioning, significantly contributed to BD and MDD.
Propofol is a rapid-acting sedative-hypnotic medication that has been widely used for the induction and maintenance of anesthesia; it has specific actions on different areas of the brain, such as sensory information transmission in the somatosensory cortex. However, the effects of propofol on the properties of sensory stimulation-evoked responses in cerebellar Purkinje cells (PCs) are currently unclear. In the present study, we studied the effects of propofol on facial stimulation-evoked responses in cerebellar PCs and molecular level interneurons (MLIs) in urethane-anesthetized mice using electrophysiological and pharmacological methods. Our results showed that cerebellar surface perfusion with propofol induced a decrease in the amplitude of the gamma-aminobutyric acid (GABA)-ergic component (P1) in a dose-dependent manner, but induced a significant increase in the amplitude of the excitatory response (N1). The IC50 of propofol-induced inhibition of P1 was 217.3 μM. In contrast, propofol (100 μM) depressed the spontaneous activity and tactile-evoked responses in MLIs. In addition, blocking GABA(A) receptor activity abolished the propofol (300 μM)-induced inhibition of the tactile-evoked inhibitory response and the increase in the sensory stimulation-evoked spike firing rate of PCs. These results indicated that propofol depressed the tactile stimulation-evoked spike firing of MLIs, resulting in a decrease in the amplitude of the tactile-evoked inhibitory response and an increase in the amplitude of the excitatory response in the cerebellar PCs of mice. Our results suggest that propofol modulates sensory information processing in cerebellar cortical PCs and MLIs through the activation of GABA(A) receptors.
Current treatment of apnea attributable to acute tonsillar herniation often is inadequate. This study was undertaken to verify the clinical usefulness of normal saline injection via lumbar puncture for the treatment of apnea secondary to acute tonsillar herniation. Between 1969 and 2009, 45 patients who had not regained spontaneous respiratory function after external ventricular drainage or removal of a supratentorial lesion via open craniotomy received an injection of normal saline via lumbar puncture. Patient data were retrospectively analyzed. Eleven of the 45 patients regained spontaneous breathing and recovered fully (24.4%). Sixteen patients regained spontaneous breathing but died later (35.6%), and 18 patients did not regain spontaneous respiration (40.0%). The overall rate of effectiveness of injected normal saline was therefore 60.0%. For patients with tonsillar hernia who did not regain spontaneous respiration after external ventricular drainage or removal of a supratentorial lesion, an aggressive approach may be considered. Injection of normal saline via lumbar puncture could improve outcome in some of these patients.
Long-term intensive gymnastic training can induce brain structural and functional reorganization. Previous studies have identified structural and functional network differences between world class gymnasts (WCGs) and non-athletes at the whole-brain level. However, it is still unclear how interactions within and between functional networks are affected by long-term intensive gymnastic training. We examined both intra- and inter-network functional connectivity of gymnasts relative to non-athletes using resting-state fMRI (R-fMRI). R-fMRI data were acquired from 13 WCGs and 14 non-athlete controls. Group-independent component analysis (ICA) was adopted to decompose the R-fMRI data into spatial independent components and associated time courses. An automatic component identification method was used to identify components of interest associated with resting-state networks (RSNs). We identified nine RSNs, the basal ganglia network (BG), sensorimotor network (SMN), cerebellum (CB), anterior and posterior default mode networks (aDMN/pDMN), left and right fronto-parietal networks (lFPN/rFPN), primary visual network (PVN), and extrastriate visual network (EVN). Statistical analyses revealed that the intra-network functional connectivity was significantly decreased within the BG, aDMN, lFPN, and rFPN, but increased within the EVN in the WCGs compared to the controls. In addition, the WCGs showed uniformly decreased inter-network functional connectivity between SMN and BG, CB, and PVN, BG and PVN, and pDMN and rFPN compared to the controls. We interpret this generally weaker intra- and inter-network functional connectivity in WCGs during the resting state as a result of greater efficiency in the WCGs' brain associated with long-term motor skill training.