Transient compartmentalization and accelerated volume growth coincide with the expected development of cortical afferents in the human neostriatum.

The neostriatum plays a central role in cortico-subcortical circuitry underlying goal-directed behavior. The adult mammalian neostriatum shows chemical and cytoarchitectonic compartmentalization in line with the connectivity. However, it is poorly understood how and when fetal compartmentalization (AChE-rich islands, nonreactive matrix) switches to adult (AChE-poor striosomes, reactive matrix) and how this relates to the ingrowth of corticostriatal afferents. Here, we analyze neostriatal compartments on postmortem human brains from 9 postconceptional week (PCW) to 18 postnatal months (PM), using Nissl staining, histochemical techniques (AChE, PAS-Alcian), immunohistochemistry, stereology, and comparing data with volume-growth of in vivo and in vitro MRI. We find that compartmentalization (C) follows a two-compartment (2-C) pattern around 10PCW and is transformed into a midgestational labyrinth-like 3-C pattern (patches, AChE-nonreactive perimeters, matrix), peaking between 22 and 28PCW during accelerated volume-growth. Finally, compartmentalization resolves perinatally, by the decrease in transient "AChE-clumping," disappearance of AChE-nonreactive, ECM-rich perimeters, and an increase in matrix reactivity. The initial "mature" pattern appears around 9 PM. Therefore, transient, a 3-C pattern and accelerated neostriatal growth coincide with the expected timing of the nonhomogeneous distribution of corticostriatal afferents. The decrease in growth-related AChE activity and transfiguration of corticostriatal terminals are putative mechanisms underlying fetal compartments reorganization. Our findings serve as normative for studying neurodevelopmental disorders.

FORAMEN OVALE AND FORAMEN ROTUNDUM: CHARACTERIZATION OF POSTNATAL DEVELOPMENT.

The sphenoid bone development occurs in both prenatal and postnatal periods. Sphenoid bone openings are used as surgical landmarks and are of great importance for neurosurgeons in everyday practice. The aim of this study was to identify morphological characteristics, postnatal development and remodeling, as well as clinical aspect of the sphenoid bone openings and to investigate their relationship and difference in size. The macerated sphenoid bones analyzed in this study were scanned by micro-computed tomography. Areas and distance in-between foramen ovale and foramen rotundum were measured. In addition, different shapes of foramen ovale were described. The most common shape of foramen ovale on both sides was oval, followed by the round, almond and elongated shapes. Modest to strong positive correlations between all foramina and age for the whole sample and both subsamples were presented, except for the right foramen rotundum area in the male subsample, which did not show significant correlation with age. Our study revealed changes in postnatal development and anatomy of foramen ovale and foramen rotundum, primarily in the aspects of size and shape, and should contribute to reducing the risk of damage to neurovascular structures during surgical procedures.

The anatomy lesson of the SARS-CoV-2 pandemic: irreplaceable tradition (cadaver work) and new didactics of digital technology.

AIM: To compare the efficacy of different components of online and contact anatomy classes as perceived by medical students. METHODS: An anonymous course evaluation survey was conducted at the end of the academic year 2019/2020. The organization of classes due to the SARS-CoV-2 pandemic provided our students with a unique opportunity to compare online and contact classes. Students' responses were analyzed according to the type of obtained data (ratio, ordinal, and categorical). RESULTS: The response rate was 95.58%. Approximately 90% of students found anatomical dissection and practical work in general to be the most important aspect of teaching, which could not be replaced by online learning. During online classes, students missed the most the interaction with other students, followed by the interaction with student teaching assistants and teaching staff. Very few students found contact lectures useful, with most students reporting that they could be replaced with recorded video lectures. In contrast, recorded video lectures were perceived as extremely helpful for studying. Regular weekly quizzes were essential during online classes as they gave students adequate feedback and guided their learning process. Students greatly benefitted from additional course materials and interactive lessons, which were made easily available via e-learning platform. CONCLUSIONS: Anatomical dissection and interaction during contact classes remain the most important aspects of teaching anatomy. However, online teaching increases learning efficiency by allowing alternative learning strategies and by substituting certain components of contact classes, thus freeing up more time for practical work.

In the eye of the beholder - how course delivery affects anatomy education.

BACKGROUND: The COVID-19 pandemic caused major shifts in students' learning strategies as well as teaching environments that profoundly affected the delivery of anatomy courses in medical schools. The Department of Anatomy at the University of Zagreb School of Medicine had a unique experience where the anatomy course in 2019/2020 was first taught in-person before transferring to an online course delivery, while the inverse happened in 2020/2021. The core curriculum, course material and examination criteria were the same in both academic years. The aim of the study was to determine whether course delivery affected students' perceptions of the course and whether it impacted students' engagement and success. METHODS: The students' perceptions of the course were assessed via an anonymous course survey (student evaluation of teaching, SET). The questions in the SET assessed the usefulness of teaching modalities rather than students' satisfaction. Most questions were in the form of statements to which students responded with their level of agreement on a five-point Likert scale. Differences between responses in 2019/2020 and 2020/2021 were analyzed using the Mann-Whitney test. Effect size was estimated using Cliff's delta and association between responses was assessed using Spearman's r coefficient. RESULTS: Students' perceptions were significantly affected by changes in course delivery. Students' success and engagement were higher in 2019/2020 when in-person teaching preceded online teaching. Furthermore, students' views on course organization and the usefulness of continuous assessment were more positive in 2019/2020. Finally, students' perceptions of the usefulness of online materials and activities were more positive in 2019/2020. All comparisons between the two academic years were statistically significant (P ≤ 0.0001 for all comparisons, Mann-Whitney test). CONCLUSIONS: Students' perceptions of the anatomy course were dependent on the teaching environment they were exposed to at the beginning of the course. A transfer from in-person to online course delivery was more successful than vice-versa. This has important implications for structuring hybrid courses in medical education in the future.

Intraspinal calcinosis mimicking intervertebral disc extrusion: A clinical and surgical case report.

BACKGROUND: Subcutaneous calcinosis is a well-recognized manifestation of systemic sclerosis that usually involves multiple pressure points and may also be found in the paraspinal or intraspinal regions. In this case, intraspinal calcinosis uniquely led to a severe neurological deficit. CASE DESCRIPTION: A patient with severe systemic sclerosis/calcinosis exhibited left greater than right lower extremity radiculopathy attributed to intraspinal left-sided L4-L5 calcinosis. On examination, the patient exhibited bilateral positive Lasegue signs, distal lower extremity weakness (left greater than right), and bilaterally decreased Achilles responses. When the magnetic resonance imaging (MRI) revealed a significant intracanalicular mass on the left side at the L4-L5 level, the patient underwent a left-sided L4-L5 decompressive laminectomy. The MRI scan 5 years later revealed no recurrence of the calcinosis, and the patient had no residual neurological deficit. CONCLUSIONS: Spinal calcinosis rarely involves the lumbar spinal canal. Here, a patient with a large left-sided L4-L5 focus of intraspinal calcinosis, mimicking a disc herniation, required a laminectomy to resect the lesion. Lumbar calcinosis should be radiologically evaluated utilizing using X-ray, MRI, and computed tomography studies to adequately document the pathology. Patients, when symptomatic, may require surgical decompression and excision of these lesions.