The last several decades have seen a large increase in knowledge of the underlying biological mechanisms that serve learning and memory. The insights gleaned from neurobiological and cognitive neuroscientific experimentation in humans and in animal models have identified many of the processes at the molecular, cellular, and systems levels that occur during learning and the formation, storage, and recall of memories. Moreover, with the advent of noninvasive technologies to monitor patterns of neural activity during various forms of human cognition, the efficacy of different strategies for effective teaching can be compared. Considerable insight has also been developed as to how to most effectively engage these processes to facilitate learning, retention, recall, and effective use and application of the learned information. However, this knowledge has not systematically found its way into the medical education process. Thus, there are considerable opportunities for the integration of current knowledge about the biology of learning with educational strategies and curricular design. By teaching medical students in ways that use this knowledge, there is an opportunity to make medical education easier and more effective. The authors present 10 key aspects of learning that they believe can be incorporated into effective teaching paradigms in multiple ways. They also present recommendations for applying the current knowledge of the neurobiology of learning throughout the medical education continuum.

Background Interindividual variability in postoperative pain presents a clinical challenge. Preoperative quantitative sensory testing is useful but time consuming in predicting postoperative pain intensity. The current study was conducted to develop and validate a predictive model of acute postcesarean pain using a simple three-item preoperative questionnaire. Methods A total of 200 women scheduled for elective cesarean delivery under subarachnoid anesthesia were enrolled (192 subjects analyzed). Patients were asked to rate the intensity of loudness of audio tones, their level of anxiety and anticipated pain, and analgesic need from surgery. Postoperatively, patients reported the intensity of evoked pain. Regression analysis was performed to generate a predictive model for pain from these measures. A validation cohort of 151 women was enrolled to test the reliability of the model (131 subjects analyzed). Results Responses from each of the three preoperative questions correlated moderately with 24-h evoked pain intensity (r = 0.24-0.33, P < 0.001). Audio tone rating added uniquely, but minimally, to the model and was not included in the predictive model. The multiple regression analysis yielded a statistically significant model (R2 = 0.20, P < 0.001), whereas the validation cohort showed reliably a very similar regression line (R2 = 0.18). In predicting the upper 20th percentile of evoked pain scores, the optimal cut point was 46.9 (z =0.24) such that sensitivity of 0.68 and specificity of 0.67 were as balanced as possible. Conclusions This simple three-item questionnaire is useful to help predict postcesarean evoked pain intensity, and could be applied to further research and clinical application to tailor analgesic therapy to those who need it most.

The degree of stenosis predictive of a clinically significant pressure gradient (30-35%) in the venous sinuses is considerably lower than the arterial stenosis at which pathologic hemodynamic alterations occur. While highly predictive of a venous pressure gradient when a stenosis is identified, non-invasive imaging does not appear to be a suitable diagnostic evaluation for the purpose of ruling out clinically significant cerebral VSS.

BackgroundThe toll of burnout on healthcare is significant and associated with physician depression and medical errors.ObjectiveTo assess the prevalence and risk factors for burnout among neurointerventionalists.MethodsA 39-question online survey containing questions about neurointerventional practice and the Maslach Burnout Inventory-Human Services Survey for medical personnel was distributed to members of major US neurointerventional physician societies.Results320 responses were received. Median (interquartile range) composite scores for emotional exhaustion were 25 (16–35), depersonalization 7 (4–12), and personal accomplishment 39 (35–44). 164/293 respondents (56%) met established criteria for burnout. There was no significant relationship between training background, practice setting, call frequency, or presence of a senior partner on burnout prevalence. Multiple logistic regression analysis showed that feeling underappreciated by hospital leadership (OR=3.71; p<0.001) and covering more than one hospital on call (OR=1.96; p=0.01) were strongly associated with burnout. Receiving additional compensation for a call was independently protective against burnout (OR= 0.70; p=0.005).ConclusionsThis survey of United States neurointerventional physicians demonstrated a self-reported burnout prevalence of 56%, which is similar to the national average among physicians across other specialties. Additional compensation for a call was a significant protective factor against burnout. In addition, feeling underappreciated by departmental or hospital leadership and covering more than one hospital while on call were associated with greater odds of burnout.

Boada MD, Gutierrez S, Aschenbrenner CA, Houle TT, Hayashida K, Ririe DG, Eisenach JC. Nerve injury induces a new profile of tactile and mechanical nociceptor input from undamaged peripheral afferents. J Neurophysiol 113: 100 -109, 2015. First published October 1, 2014 doi:10.1152/jn.00506.2014.-Chronic pain after nerve injury is often accompanied by hypersensitivity to mechanical stimuli, yet whether this reflects altered input, altered processing, or both remains unclear. Spinal nerve ligation or transection results in hypersensitivity to mechanical stimuli in skin innervated by adjacent dorsal root ganglia, but no previous study has quantified the changes in receptive field properties of these neurons in vivo. To address this, we recorded intracellularly from L 4 dorsal root ganglion neurons of anesthetized young adult rats, 1 wk after L 5 partial spinal nerve ligation (pSNL) or sham surgery. One week after pSNL, hindpaw mechanical withdrawal threshold in awake, freely behaving animals was decreased in the L 4 distribution on the nerve-injured side compared with sham controls. Electrophysiology revealed that highthreshold mechanoreceptive cells of A-fiber conduction velocity in L 4 were sensitized, with a seven-fold reduction in mechanical threshold, a seven-fold increase in receptive field area, and doubling of maximum instantaneous frequency in response to peripheral stimuli, accompanied by reductions in after-hyperpolarization amplitude and duration. Only a reduction in mechanical threshold (minimum von Frey hair producing neuronal activity) was observed in C-fiber conduction velocity high-threshold mechanoreceptive cells. In contrast, low-threshold mechanoreceptive cells were desensitized, with a 13-fold increase in mechanical threshold, a 60% reduction in receptive field area, and a 40% reduction in instantaneous frequency to stimulation. No spontaneous activity was observed in L 4 ganglia, and the likelihood of recording from neurons without a mechanical receptive field was increased after pSNL. These data suggest massively altered input from undamaged sensory afferents innervating areas of hypersensitivity after nerve injury, with reduced tactile and increased nociceptive afferent response. These findings differ importantly from previous preclinical studies, but are consistent with clinical findings in most patients with chronic neuropathic pain. chronic pain model; in vivo electrophysiology; sensory neurons; spinal nerve ligation IN HUMANS, NEUROPATHIC PAIN includes both spontaneous and evoked pain, often accompanied by hypersensitivity to normal nociceptive stimuli (hyperalgesia) and normally nonnociceptive stimuli (allodynia). This pathological condition is also sometimes accompanied by dysesthesias and paresthesias (von Hehn et al. 2012), suggesting that both tactile and nociceptive information channels and/or processing are disrupted.

Background Chronic post-surgical pain (CPSP), a significant public health problem, occurs in 10-50% of patients undergoing major surgery. Acute pain induces endogenous analgesia termed conditioned pain modulation (CPM), and the strength of CPM preoperatively predicts the likelihood of CPSP. The relationship between CPM and recovery from surgery has not been examined in preclinical models. Methods CPM was assessed in individual rats and correlated with each animal’s time course of recovery of hypersensitivity following partial spinal nerve ligation (pSNL). The role of descending noradrenergic pathways in the spinal cord to mechanisms of CPM and recovery was tested using idazoxan to block noradrenergic receptors or antidopamine β hydroxylase conjugated saporin (DβH-saporin) to ablate these pathways. Behavioral hypersensitivity, static weight bearing and spinal glial activation were measured after pSNL. Results The strength of CPM varied over two-fold between individuals and was directly correlated with the slope of recovery from hypersensitivity after surgery (P < 0.0001, r = 0.660). CPM induced release of norepinephrine in the spinal cord and was partially blocked by intrathecal idazoxan or DβH-saporin. DβH-saporin also slowed recovery and enhanced spinal glial activation following pSNL surgery. Ongoing activation of these pathways was critical to sustained recovery, since intrathecal DβH-saporin given 7 weeks after recovery reinstituted hypersensitivity, while having no effect in animals without previous surgery. Conclusions Collectively, these studies provide a clear back-translation from clinical observations of CPM and CPSP and suggest that the ability to engage ongoing descending endogenous noradrenergic signaling may be critical in determining time course of recovery from hypersensitivity after surgery.

We know little about the individual pain experience of patients recovering from surgery in the first weeks after hospital discharge. Here, we examine individual differences in the day-to-day experience after 2 major surgeries: lower limb total major joint arthroplasty (TJA) and cesarean delivery (CD). Fifty-five TJA patients and 157 CD patients were recruited to complete questionnaires and record their daily pain experiences after surgery. After hospital discharge, patients recorded their pain intensity once daily for 60 days (CD) or twice daily for 2 weeks, once daily for 2 weeks, weekly for 8 weeks, and monthly for 3 months (TJA). Pain scores were modeled using growth curve and Bayesian change-point models. Individual differences in the model fits were examined for evidence of day-to-day differences in pain. A log time model was the simplest model that fit the data, but examination of the residuals revealed high autocorrelation representing misspecification. A change-point model fit the data better and revealed that the form of recovery fundamentally changed between days 10 and 21 after surgery. These data add meaningfully to our understanding of recovery from pain after surgery by extending the period of frequent observations a few days after surgery to a 2-month period. These high time resolution data suggest that there is a typical experience of pain resolution after surgery, but that meaningful subpopulations of experience may exist. They also indicate that a transition occurs within 1 month after surgery from 1 pattern of change in pain over time to another.

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