Recent Publications by CFE Educators

The component parts and development of a comprehensive system to evaluate and improve teaching in a school of medicine are described by the author in this paper. This system integrates quantitative measures of teaching (student/resident ratings of classroom and clinical teaching), descriptive documentation (faculty teaching load, innovations, and research on teaching), and qualitative judgments (peer review) on the full spectrum of instruction in medicine. Medical school policies have standardized evaluation criteria, instrumentation, and procedures while granting departments flexibility in conducting peer review. The results of two studies indicate that the evaluation system described here has had a positive impact both on the improvement of teaching and on academic promotions.

To clarify the circuitry through which opioid compounds modulate spinal and trigeminal nociceptive transmission, we have examined the synaptic associations formed by leucine-enkephalin-containing (enkephalin) neurons in the superficial dorsal horn of the cat. As described previously, punctate enkephalin immunoreactivity is concentrated in the marginal layer (lamina I) and in both the outer and inner layers of the substantia gelatinosa (lamina IIo and IIi). In colchicine treated cats, enkephalin perikarya are most numerous in lamina I and at the border between laminae I and II. Ultrastructural analysis reveals that enkephalin cells receive a diverse afferent input. The majority of afferent inputs are presynaptic to the enkephalin dendrites; few axosomatic synapses are seen. Among these presynaptic axonal profiles are unlabeled axons which resemble primary afferent terminals, including the characteristic central axonal varicosity. Enkephalin dendrites are also postsynaptic to enkephalin immunoreactive axons. Two types of enkephalin axonal profiles appear in the superficial dorsal horn. Class I profiles are only found in lamina I. These are large profiles which form few synapses; those synapses made are axodendritic. Class II enkephalin axons are smaller and are distributed in both layers I and II. While Class II axons most commonly form axo-dendritic synapses, they also form axo-axonic synapses with flat vesicle-containing profiles; the latter are generally presynaptic to the enkephalin terminals. Serial analysis further revealed that both the enkephalin and the flat vesicle-containing profile synapse onto a common dendrite. Although enkephalin axons frequently lie adjacent to round vesicle-containing profiles, anatomical evidence that opioid axons form synapses with this type of ending was not found. An additional type of enkephalin vesicle containing-profile is found in layer IIi; its morphological features do not clearly distinguish its axonal or dendritic origin. These endings are typically postsynaptic to unlabelled central endings, and provide minimal presynaptic input to other elements in the neuropil. Like some class II axons, these labelled profiles contain vesicles which cluster at the membrane immediately adjacent to unlabelled central axons. These results indicate that spinal enkephalin neurons receive a variety of synaptic inputs. These include inputs which may derive from primary afferent axons. Enkephalin neurons, in turn, influence nociceptive transmission predominantly through postsynaptic mechanisms. Finally, while we did not observe enkephalin terminals presynaptic in an axoaxonic relationship, the possibility that enkephalin neurons modulate the excitability of fine fiber nociceptive and nonnociceptive afferents via "nonsynaptic interactions" is discussed.

Despite the important contribution of the midbrain periaqueductal gray (PAG) to endogenous pain suppression systems, little is known about the neuroanatomical basis of its functional organization. In a previous study of the distribution of the endogenous opiate leucine-enkephalin (ENK) in the PAG (Moss, M. S., E. J. Glazer, and A. I. Basbaum (1983) J. Neurosci. 3: 603-616), we found that immunoreactive ENK-containing neurons and terminals are clustered in discrete populations. In this study we have extended our analysis of the neurochemical organization of the PAG by using immunocytochemistry to map the distribution of two non-opiate peptides that produce potent analgesia when administered at central gray levels: substance P (Sub P) and vasoactive intestinal polypeptide (VIP). Immunoreactive Sub P neurons and terminal fields are clustered in discrete populations throughout the PAG. The distribution pattern of these populations changes at different rostral-caudal levels of the PAG. For example, there is a ventral-to-dorsal shift in the location of Sub P-like immunoreactivity from the caudal to the rostral PAG. Few immunoreactive Sub P neurons are found in the nucleus raphe dorsalis although moderately dense terminal field staining is present. The staining pattern of immunoreactive VIP is totally different from that of Sub P. Regardless of the rostral-caudal level examined, VIP-containing neurons are found tightly clustered in the subependymal neuropil of the ventromedial PAG. Only a few immunoreactive VIP-containing neurons are found in the ventral PAG or nucleus raphe dorsalis. The striking differences between the distribution of Sub P- and VIP-like immunoreactivity in the PAG indicates that the neural circuitry underlying pain suppression by Sub P and VIP may also differ.

The design, development, and implementation of procedures for peer review of teaching are described. Peer review is one component of a comprehensive system to evaluate and improve teaching in a school of medicine. Colleague observations and judgments are used to augment student/resident ratings of teaching for purposes of instructional improvement and academic promotions. School policies have standardized evaluation criteria and instrumentation while granting departments flexibility in conducting peer review. Three different departmental peer review committee structures and procedures are reviewed. With the emphasis upon improvement, faculty acceptance of peer review of teaching has been positive. Peer review reports have had a positive impact on academic promotions. The inherent strengths and limitations of peer review of teaching are discussed in relation to the literature and to the medical school environment.

The purpose of the research reported in this article was to test the effects of mental practice on clinical skill acquisition. The clinical skill to be acquired was the pelvic examination. Four instructional designs provided learning experiences for 160 second-year medical students at the University of Washington. The usual instructional sequence was the control, and three experimental sequences incorporated mental practice at premotor, postmotor, and combined premotor and postmotor stages of skill acquisition. Mental practice was facilitated by the use by students of audiotapes and headphones. Learner performance measures consisted of the evaluation of student ability to list the examination sequence, evaluations of an actual pelvic examination write-up, including both sequencing and findings, and observation ratings of skill performance. Mental practice produced better performance on the ability to list the examination sequence and the ability to record findings than no mental practice. Methods for providing mental practice created an orderly and efficient learning environment. Students found it helpful.

Despite the significant contribution of the periaqueductal gray (PAG) to an endogenous pain suppression system, little is known about its neurochemical organization. Previous pharmacological and physiological studies have indicated regional variations in the effectiveness with which the midbrain PAG can generate potent analgesia in response to either opiate microinjection or electrical stimulation. There is, however, no anatomical correlate of this regional variation. As a first step toward elucidating the neural circuitry underlying the PAG's contribution to endogenous pain suppression systems, we have mapped the distribution of leucine enkephalin (ENK)-like immunoreactivity in the cat PAG. Throughout the rostral-caudal extent of the PAG, ENK-containing neurons are clustered in discrete populations. ENK terminal field staining is somewhat more diffuse; however, there are several regions where terminal staining is consistently more intense. The distribution of ENK perikarya and terminals undergoes a ventral to dorsal shift from caudal to rostral PAG. Conceivably, the clustered distribution of ENK cells and terminals contributes to the differential effectiveness of various PAG regions in generating analgesia. The ventral-dorsal shift of ENK immunoreactivity may (1) correspond to a somatotopic organization within the PAG or (2) mirror the topographic relationship of the PAG's interactions with other components of the endogenous analgesia system. In addition, the changing pattern of ENK immunoreactivity may also reflect the involvement of the PAG and of endogenous opiates in systems other than those of pain control.

Previous descriptions of immunoreactive vasoactive intestinal polypeptide (VIP) in small-diameter dorsal root ganglion cells in the superficial dorsal horn implicated this 28 amino acid peptide in nociceptive transmission. In this study, we examined the distribution of immunoreactive VIP in the spinal cord and caudal medulla of cats and rats. The PAP method was used on paraffin and frozen sections of 4% paraformaldehyde-fixed tissue, using antibodies to VIP that were raised in rabbits. The distribution of immunoreactive VIP, while similar to that of substance P (SP), a putative primary afferent peptide neurotransmitter, is more restricted. VIP staining is found in sacral dorsal roots and densely in the Lissauer tract. Dorsal horn staining is concentrated in lamina I. In contrast to SP, lamina II is almost devoid of staining. Labeled VIP axons course along the lateral curvature of the dorsal horn and arborize across lamina V and around the central canal. A collateral branch of these fibers distributes to the sacral autonomic nucleus. A few fibers could be traced from the root entry zone to the contralateral central gray. VIP axons also terminate between ependymal cells of the central canal. Unlike SP, immunoreactive VIP was restricted, almost exclusively, to the sacral cord. The few fibers in the lumbar enlargement and in the coccygeal cord apparently derive from ascending and descending sacral primary afferents. In fact, the VIP pattern is almost identical to that reported for afferents from the pelvic viscera, including a discontinuous rostrocaudal distribution. Since the staining pattern is also very similar to that of A-delta high-threshold mechanoreceptors, the possibility is discussed that whereas VIP is not a general "somatic" primary afferent transmitter, it may transmit nociceptive input from the pelvic viscera.