Microcircuit Mechanisms Involved in Paired Associative Stimulation-Induced Depression of Corticospinal Excitability.
Microcircuit mechanisms involved in paired associative stimulation-induced depression of corticospinal excitability.
J Physiol. 2013 Jul 15;
Weise DT, Mann JJ, Ridding MC, Eskandar K, Huss M, Rumpf JJ, Di Lazzaro V, Mazzone P, Ranieri F, Classen J
Synaptic weight changes induced by temporal correlations between the spikes of pre- and postsynaptic neurons are referred to as spike-timing dependent plasticity (STDP). Transcranial magnetic stimulation (TMS) induces long-lasting effects on corticospinal excitability, if it is repetitively paired with stimulation of afferents from a corresponding contralateral hand region at short intervals (paired associative stimulation, PAS). PAS-induced plasticity has been linked with synaptic STDP. We aimed to investigate which elements of the cortical microcircuitry sustain and govern PAS-induced depression of corticospinal excitability in the target muscle representation (and enhancement of excitability in its functional surround). We show that the time window during which the interaction between both stimulus-induced cortical events leads to immediate post-interventional depression is short (<4.5 ms). The depressant PAS-effects at the target representation were completely blocked by applying a subthreshold magnetic pulse 3 ms before the principal TMS-pulse, even when the strength of the latter was adjusted to generate a motor evoked potential of similar amplitude as with unconditioned magnetic pulse. Epidural recordings from the cervical cord of a patient showed that under this condition late TMS-evoked I-waves remain suppressed. When the intensity of the TMS component during PAS was lowered - sufficient to allow activation of inhibitory neurons, but insufficient to activate corticospinal neurons - excitability of short-latency intracortical inhibition remained unchanged. PAS-induced facilitation in the functional surround followed the same pattern as the centre-depressant effects. Findings may suggest that excitability depressant PAS-induced effects are due to weakening of excitatory synapses between upper cortical layer principal neurons, but not those located on CSN, or inhibitory synapses. Inhibitory interneurons involved in short-latency intracortical inhibition are gate-keepers to producing centre-depressant / surround-facilitatory PAS effects. Based on these findings and those by Elahi et al. (Journal of Neurophysiology, 2012) we propose a model specifying the composition and laminar location of the involved microcircuit of PAS-induced plasticity that may enhance its utility as a model of STDP in humans. HubMed – depression
Communication and Trust in the Care Provided to a Dying Parent: A Nationwide Study of Cancer-Bereaved Youths.
J Clin Oncol. 2013 Jul 15;
Grenklo TB, Kreicbergs UC, Valdimarsdóttir UA, Nyberg T, Steineck G, Fürst CJ
PURPOSETo assess children’s trust in the care provided to a dying parent during the final week of life in relation to end-of-life medical information about disease, treatment, and death. METHODSThis nationwide population-based survey included 622 (73%) of 851 youths who, 6 to 9 years earlier, at age 13 to 16 years, lost a parent to cancer. We asked about the children’s reception of end-of-life professional information and trust in the care provided. We also asked about depression and several potential risk factors of distrust in the care provided.ResultsA majority (82%) reported moderate/very much trust in the care provided. Compared with children who received end-of-life medical information before their loss, the risk of distrust in the care provided was higher in those who received no information (risk ratio [RR], 2.5; 95% CI, 1.5 to 4.1), in those who only received information afterward (RR, 3.2; 95% CI, 1.7 to 5.9), and in those who did not know or remember if end-of-life medical information was provided (RR, 1.7; 95% CI, 1.1 to 2.5). Those reporting distrust in the care provided had an RR of 2.3 (95% CI, 1.5 to 3.5) for depression. Furthermore, the risk of distrust in the care provided was higher among children reporting poor efforts to cure (RR, 5.1; 95% CI, 3.6 to 7.3), and/or a poor relationship with the surviving parent (RR, 2.9; 95% CI, 2.0 to 4.1). CONCLUSIONOur study suggests that children’s trust in the care provided to a dying parent was highest when they received end-of-life medical information before their loss. HubMed – depression
Efficacy of Williams LifeSkills training for improving psychological health: A pilot comparison study of Chinese medical students.
Asia Pac Psychiatry. 2013 May 21;
Li C, Chu F, Wang H, Wang XP
High stress levels and mental health problems are common among medical students. Behavioral interventions aimed at preventing mental health problems among medical students have been recommended in managing stress during their study period. The aim of the study was to evaluate the efficacy of Williams LifeSkills training (WLST) for improving psychological health of Chinese medical students.Sixty medical students were chosen as the study group (n?=?30) and the control group (n?=?30). The study group completed the 8-week WLST, while the controls did not take any training course. All subjects were assessed before and after the 8-week training period using the Self-Rating Anxiety Scale (SAS), Self-Rating Depression Scale (SDS), Trait Coping Style Questionnaire (TCSQ), Interpersonal Support Evaluation List (ISEL) and Self-Esteem Scale (SES). The data of 29 students in the study group and 26 students in the control group were qualified for statistical analysis in the current study.Group-time interactions were significant for the ISEL total (P?=?0.008), ISEL appraisal (P?=?0.002), SES (P?=?0.002), SAS (P?=?0.005) and SDS (P?=?0.032). Post-hoc paired Student’s t-tests showed that all these measures improved significantly (P?HubMed – depression