Experimental neurology
-
Experimental neurology · Jun 2009
Expression of the repulsive guidance molecule RGM and its receptor neogenin after spinal cord injury in sea lamprey.
The sea lamprey recovers normal-appearing locomotion after spinal cord transection and its spinal axons regenerate selectively in their correct paths. However, among identified reticulospinal neurons some are consistently bad regenerators and only about 50% of severed reticulospinal axons regenerate through the site of injury. We previously suggested (Shifman, M. ⋯ Following spinal cord transection, RGM message was downregulated in neurons close (within 10 mm) to the transection at 2 and 4 weeks, although it was upregulated in reactive microglia at 2 weeks post-transection. Neogenin mRNA expression was unchanged in the brainstem after spinal cord transection, and among the identified reticulospinal neurons, was detected only in "bad regenerators", neurons that are known to regenerate well never expressed neogenin. The downregulation of RGM expression in neurons near the transection may increase the probability that regenerating axons will regenerate through the site of injury and entered caudal spinal cord.
-
Experimental neurology · Jun 2009
Functional MRI study of the primary somatosensory cortex in comatose survivors of cardiac arrest.
It is difficult to assess cerebral function in comatose patients. Because earlier functional neuroimaging studies demonstrate associations between cerebral metabolism and levels of consciousness, fMRI in comatose survivors of cardiac arrest could provide further insight into cerebral function during coma. Using fMRI, cerebral activation to somatosensory stimulation to the palm of the hand was measured in 19 comatose survivors of cardiac arrest and in 10 healthy control subjects and was compared to somatosensory-evoked potential (SSEP) testing of the median nerve. ⋯ Greater BOLD was also seen in S1 of patients who retained their SSEP N20 waveforms. There were also positive correlations between BOLD in S1 with both levels of consciousness and measures of outcome at 3 months. In summary, this study demonstrates that BOLD in the S1 contralateral to somatosensory stimulation of the hand varies with clinical measures of the level of consciousness during coma.
-
Experimental neurology · May 2009
Therapeutic window for cinnamophilin following oxygen-glucose deprivation and transient focal cerebral ischemia.
Cinnamophilin (CINN, (8R, 8'S)-4, 4'-dihydroxy-3, 3'-dimethoxy-7-oxo-8, 8'-neolignan) protects against ischemic stroke in mice. While some anti-oxidative effects of CINN have been characterized, its therapeutic window and molecular basis for neuroprotection remain unclear. We evaluated antioxidant and anti-inflammatory properties and therapeutic window of CINN against brain ischemia using a panel of in vitro and in vivo assays. ⋯ Relative to controls, CINN, administrated at 80 mg/kg, 2, 4, or 6 h postinsult, but not 12 h, significantly reduced brain infarction by 34-43% (P<0.05) and improved neurobehavioral outcome (P<0.05) following transient focal cerebral ischemia in rats. CINN (10-30 microM) also significantly reduced oxygen-glucose deprivation-induced neuronal damage (P<0.05) in rat organotypic hippocampal slices, even when it was administrated 2, 4, or 6 h postinsult. Together, CINN protects against ischemic brain damage with a therapeutic window up to 6 h in vivo and in vitro, which may, at least in part, be attributed by its direct antioxidant and anti-inflammatory effects.
-
Experimental neurology · May 2009
Changes of resting state brain networks in amyotrophic lateral sclerosis.
The defining feature of amyotrophic lateral sclerosis is degeneration of upper and lower motor neurons but extramotor involvement, evidenced for example by executive dysfunction, has also been demonstrated. Here we employed a novel functional imaging approach, the analysis of resting state activity, followed by the definition of functionally connected brain networks by independent component analysis (ICA) to assess differences between ALS patients (n=20) and healthy controls (n=20). ICA analysis revealed 5 typical brain networks among which the so-called default mode network and the sensori-motor network showed distinct differences between patients and controls. ⋯ The sensori-motor network showed group differences in the premotor cortex. We propose that resting state analysis affords a new and simple means to assess disease-related neurofunctional alterations in widespread brain networks. A decisive advantage is that no task is demanded from the subjects and, thus, the problem of differential task difficulty and effort between groups is circumvented.
-
Experimental neurology · May 2009
Longitudinal microPET imaging of brain glucose metabolism in rat lithium-pilocarpine model of epilepsy.
The lithium-pilocarpine model of epilepsy in rat has been used extensively to investigate basic mechanisms of epilepsy and mimics human temporal lobe epilepsy. Our aim was to investigate longitudinal alterations in metabolism after lithium-pilocarpine induced status epilepticus (SE) using [(18)F]FDG microPET. Twenty-eight Wistar rats received lithium chloride followed by pilocarpine (n=19) or saline (n=9) IP. ⋯ There were no significant differences between SS and no SS animals in CR condition. Pilocarpine-induced SE causes a severe, but transient reduction in overall metabolism on D3 in rat brain. Metabolic differences on D3 between SS and no SS animals need further study to investigate potential use as an early marker of epileptogenesis.