Rebound Discharge in Deep Cerebellar Nuclear Neurons In Vitro

Neurons of the deep cerebellar nuclei (DCN) play a critical role in defining the output of cerebellum in the course of encoding Purkinje cell inhibitory inputs. The earliest work performed with in vitro preparations established that DCN cells have the capacity to translate membrane hyperpolarizations into a rebound increase in firing frequency. The primary means of distinguishing between DCN neurons has been according to cell size and transmitter phenotype, but in some cases, differences in the firing properties of DCN cells maintained in vitro have been reported. In particular, it was shown that large diameter cells in the rat DCN exhibit two phenotypes of rebound discharge in vitro that may eventually help define their functional roles in cerebellar output. A transient burst and weak burst phenotype can be distinguished based on the frequency and pattern of rebound discharge immediately following a hyperpolarizing stimulus. Work to date indicates that the difference in excitability arises from at least the degree of activation of T-type Ca2+ current during the immediate phase of rebound firing and Ca2+-dependent K+ channels that underlie afterhyperpolarizations. Both phenotypes can be detected following stimulation of Purkinje cell inhibitory inputs under conditions that preserve resting membrane potential and natural ionic gradients. In this paper, we review the evidence supporting the existence of different rebound phenotypes in DCN cells and the ion channel expression patterns that underlie their generation

Changes in mental disorder prevalence among conflict-affected populations: a prospective study in Sri Lanka (COMRAID-R).

BACKGROUND: Longitudinal data are lacking on mental health trajectories following conflict resolution and return migration. COMRAID-R is a follow-up study of Muslims displaced by conflict from Northern Sri Lanka 20 years ago who are now beginning to return. METHODS: Of 450 participants in displacement interviewed in 2011, 338 (75.1%) were re-interviewed a year later, and a supplementary random sample (n = 228) was drawn from return migrants with a comparable displacement history. Common mental disorder (CMD; Patient Health Questionnaire) and post-traumatic stress disorder (CIDI-subscale) were measured. RESULTS: A CMD prevalence of 18.8% (95%CI 15.2-22.5) at baseline had reduced to 8.6% (5.6-11.7) at follow-up in those remaining in displacement, and was 10.3% (6.5-14.1) in return migrants. PTSD prevalences were 2.4%, 0.3% and 1.6% respectively. CONCLUSIONS: We observed a substantial decrease in CMD prevalence in this population over a short period, which may reflect the prospect of return migration and associated optimism following conflict resolution