The superficial dorsal horn of the spinal cord contains numerous inhibitory interneurons, which regulate the transmission of information perceived as touch, pain, or itch. Despite the importance of these cells, our understanding of their roles in the neuronal circuitry is limited by the difficulty in identifying functional populations. One group that has been identified and characterized consists of cells in the mouse that express green fluorescent protein (GFP) under control of the prion protein (PrP) promoter. Previous reports suggested that PrP-GFP cells belonged to a single morphological class (central cells), received inputs exclusively from unmyelinated primary afferents, and had axons that remained in lamina II. However, we recently reported that the PrP-GFP cells expressed neuronal nitric oxide synthase (nNOS) and/or galanin, and it has been shown that nNOS-expressing cells are more diverse in their morphology and synaptic connections. We therefore used a combined electrophysiological, pharmacological, and anatomical approach to reexamine the PrP-GFP cells. We provide evidence that they are morphologically diverse (corresponding to "unclassified" cells) and receive synaptic input from a variety of primary afferents, with convergence onto individual cells. We also show that their axons project into adjacent laminae and that they target putative projection neurons in lamina I. This indicates that the neuronal circuitry involving PrP-GFP cells is more complex than previously recognized, and suggests that they are likely to have several distinct roles in regulating the flow of somatosensory information through the dorsal horn.

Large projection neurons in lamina III of the rat spinal cord that express the neurokinin 1 receptor are densely innervated by peptidergic primary afferent nociceptors and more sparsely by low-threshold myelinated afferents. However, we know little about their input from other glutamatergic neurons. Here we show that these cells receive numerous contacts from nonprimary boutons that express the vesicular glutamate transporter 2 (VGLUT2), and form asymmetrical synapses on their dendrites and cell bodies. These synapses are significantly smaller than those formed by peptidergic afferents, but provide a substantial proportion of the glutamatergic synapses that the cells receive (over a third of those in laminae I-II and half of those in deeper laminae). Surprisingly, although the dynorphin precursor preprodynorphin (PPD) was only present in 4 -7% of VGLUT2 boutons in laminae I-IV, it was found in 58% of the VGLUT2 boutons that contacted these cells. This indicates a highly selective targeting of the lamina III projection cells by glutamatergic neurons that express PPD, and these are likely to correspond to local neurons (interneurons and possibly projection cells). Since many PPD-expressing dorsal horn neurons respond to noxious stimulation, this suggests that the lamina III projection cells receive powerful monosynaptic and polysynaptic nociceptive input. Excitatory interneurons in the dorsal horn have been shown to possess I A currents, which limit their excitability and can underlie a form of activity-dependent intrinsic plasticity. It is therefore likely that polysynaptic inputs to the lamina III projection neurons are recruited during the development of chronic pain states.

SummaryThis study provides evidence that nonpeptidergic Aδ nociceptive primary afferents selectively innervate lamina I spinoparabrachial projection neurons that lack the neurokinin 1 receptor.

Multiple attributes are expected of postgraduate research supervisors. Provision of timely and effective face-to-face feedback is one such skill that carries enormous significance in supervisee’s professional development. Feedback allows the supervisees to improve upon their performances. Unfortunately, both supervisors and supervisees have contrasting approaches towards the ongoing feedback practices. This incongruence is attributed, in part, to a lack of structured pedagogic training among the medical professionals. A standardized schema is therefore required to acquire and harmonize this pedagogical skill. One such systemized way is a training method called microteaching. Microteaching has long been used to enhance and incorporate old and new undergraduate teaching skills, respectively. Here we propose a similar structured approach of micro-feedback to inculcate effective feedback skills among postgraduate research supervisors using feedback-based scenarios, simulated students, standardized checklists and audiovisual aids. Thus, micro-feedback exercise may prove to be quite promising in improving feedback practices of postgraduate research supervisors.

Background: Doctoral supervision is a distinct form of supervision with clearly defined responsibilities. One of these is the delivery of effective face-to-face feedback to allow supervisees to improve upon their performances. Unfortunately, doctoral supervisors, especially of health sciences, are often not trained in supervisory skills and therefore practice mostly on a trial and error basis. Lack of understanding of the feedback process leads to incongruence in how supervisors and supervisees perceive feedback. However, standardized training practices like microteaching can allow supervisors to acquire effective feedback practices. In this study we employed a schematic approach of microteaching, that is micro-feedback, in a workshop to develop feedback skills of doctoral supervisors, and assessed the overall effectiveness of this training using the Kirkpatrick evaluation framework. Methodology: This was a Quasi-experimental study with a repeated measures and a two-group separate sample prepost test design. A micro-feedback skills workshop was organized to enhance feedback skills of doctoral supervisors using microteaching technique. The first two levels of the Kirkpatrick evaluation model were used to determine the workshop's effectiveness. An informal Objective Structured Teaching Exercise (OSTE) was used to assess feedback skills of the supervisors, both before and after the workshop. A questionnaire was developed to compare pre-and postworkshop perceptions of the supervisors (n = 17) and their corresponding supervisees (n = 34) regarding the ongoing feedback practice. Results: Despite the hectic schedule, most doctoral supervisors (17 of 24, 71%) were willing to undertake faculty development training. Participants indicated a high level of satisfaction with the workshop. A learning gain of 56% was observed on pre-post OSTE scores. Prior to the workshop, perceptions of how supervisees should be given the feedback differed significantly between supervisors and supervisees with an effect size difference of r = 0.30. After the workshop there was a negligible difference in perceptions between supervisors and supervisees (r = .001). Interestingly, supervisors shifted their perceptions more toward those that were originally held by the supervisees. Conclusions: These findings suggest that well-designed and properly assessed structured programs such as microfeedback workshops can improve how doctoral supervisors provide feedback to their supervisees and align supervisors' perceptions of that feedback with those of their supervisees.