Keywords
dissection - medical education - neuroanatomy - neuroscience - neurosurgery
Introduction
The term “neurophobia” was first coined in 1994 in response to a trend among medical
students' perceptions around the difficulty of neuroscience topics.[1] It remains a prevalent concern among the medical students of today across multiple
year groups and institutions.[1]
[2]
[3]
[4]
[5] Reasons for this remain variable—neuroscience, neuroanatomy in particular, has always
been viewed as one of the more difficult topics covered in traditional medical school
curricula.[5] Ineffective teaching strategies, insufficient time to spend on learning, and the
stereotypes associated with the field are all thought to contribute negatively to
students' perceptions of neuroscience and by extension its associated career prospects.[3]
[5]
[6]
In light of an aging population and increasing burden of neurological disease on a
global scale, there is growing concern that “neurophobia” could lead to an insufficient
number of specialists in this field, putting ever-increasing pressure on those who
do choose it as their career path.[3]
[5]
[7] This phenomenon is arguably compounded by pervading stereotypes about which individuals
pursue neurosurgical or neurological careers.[6]
[8] Neurosurgery is understood by medical students to be a demanding specialty, requiring
extensive commitment; simultaneously, they are less and less exposed to the field
as medical schools are increasingly shifting toward a generalist approach to teaching,
so the opportunity to challenge stereotypes and nurture genuine interest is curtailed;
it has since been shown that neurophobia is inversely related to the positive influence
of lecturers.[3]
[8]
[9]
[10]
As such, there is an increasing need to address and improve teaching to help combat
neurophobia and improve neuroanatomy learning.[2] Globally, it has been acknowledged that the methods used for teaching neuroanatomy
are ever evolving. In particular, in the post-COVID-19 pandemic era, there has been
increasing use of digital teaching modalities alongside traditional techniques.[11] These include new methods of plastination (which have predominantly been assessed
on animal tissue rather than human specimens) and use of artificial intelligence and
three-dimensional printing to create learning tools that are accessible, accurate,
and beneficial to learners.[12]
[13] However, although these innovations are undoubtedly valuable, particularly in the
instances where dissection or prosected specimens are unavailable, there is also considerable
evidence in favor of preserving more traditional approaches.[14]
[15]
[16]
[17] One way this could be done is by introducing or promoting dissection, particularly
of deeper cerebral structures such as the basal nuclei, which are often seen as more
“abstract” concepts to grasp when it comes to initial learning; it has been previously
shown that doing so leads to significantly higher retention of knowledge in the long
term, from as early as the first year of medical school.[5]
[15] However, most students do not have the opportunity to perform more complex dissections,
often due to the fast-paced nature of university teaching and an overarching shift
toward a hybrid teaching model.[9]
[14] The student experiences detailed in this manuscript hope to highlight how making
neuroanatomy a rewarding and engaging process for students helps address this limitation
and create meaningful educational opportunities for interested students.
In this article, the authors present their experience of medical student–led white
matter dissection without Klingler's method, through their involvement in organizing
the National Undergraduate Neuroanatomy Competition (NUNC) 2023 ([Fig. 1]). Here, we encapsulate, for the first time, the experience of students in creating
a singular collection of neuroanatomical specimens outside of their set curriculum—a
novel development for their institution and the NUNC organization as a whole.
Fig. 1 The 2023 National Undergraduate Neuroanatomy Competition (NUNC) at a glance. (A) Committee members connecting over shared interests. (B) NUNC 2023 Welcome Address from Primary Chair Ameerah Gardee. (C) The Single best answer examination about to begin. (D) Marking underway under the guidance of our external examiner Prof. Ceri Davies.
(E) Our keynote speaker, Mr. Henry Marsh. (F) The NUNC 2023 Committee.
This experience, in light of the fact that overall time allotted to dissection-based
teaching has decreased substantially over time across the United Kingdom medical schools,
arguably, has the potential for far-reaching impact on student knowledge and attitude
toward learning; on average, students presently get 24 hours of neuroanatomy teaching
across their 5 years at medical school.[18] As such, ensuring the time that is allotted is used as efficiently as possible is
essential to ensure students benefit from the experience of early exposure. As a result,
white matter was chosen as a focus for this experience, in light of evidence that
many medical students struggle with learning this particular element of neuroanatomy
and have previously benefited from more focused dissection experiences.[14]
[15] The authors report their experience in creating a unique opportunity for a select
group of students to develop as future leaders in neuroanatomy and clinical neuroscience,
with three main aims underpinning this process:
-
Cultivation of role models and mentors, within and beyond the students' own institution.
-
Early career development and guidance.
-
Development of early expertise in neuroanatomy.
Discussion
The National Undergraduate Neuroanatomy Competition
The NUNC exists as an annual competition open to undergraduate students in the United
Kingdom and Ireland undertaking a degree with a neuroanatomy component, for example,
medicine or neuroscience. Over the last decade it has been running, the NUNC has registered
a total of 841 students from 29 of 33 United Kingdom medical schools and has become
increasingly popular with each subsequent competition. In 2022, the NUNC moved from
the University of Southampton to the University of Glasgow and is now being led by
the University of Glasgow medical students under the oversight from the professor
of anatomy, Scott Border ([Fig. 1]). The NUNC consists of two examinations focused on neuroanatomy and its clinical
considerations, written by the organizing committee, principally the Primary Chair,
with the guidance of internal university staff, practicing doctors with an interest
in clinical neuroscience, and an external examiner. The examinations are equally weighted;
they comprise of a multiple-choice, single best answer examination focusing on clinically
applied neuroanatomy and a spotter examination using the specially dissected specimens
highlighting less commonly displayed structures; this format of assessment has been
previously validated in the literature as a means of allowing students to perform
confidently and best showcase their knowledge.[19] The content of both examinations is based on the curriculum framework set out by
Moxham et al, which enables competitors to prepare using defined parameters ahead
of the event.[20]
The dissections described here focus on white matter dissection, as it has been previously
reported that undergraduate students do not achieve a clear comprehension regarding
white matter fiber tracts.[21] Shell et al have found that dissection has a direct impact on medical students'
motivation and a positive correlation between performance on laboratory-based examinations
and overall desire to learn.[17] Klinger's method is widely regarded as the optimal approach to white matter dissection;
the process fixes white matter tracts via freezing, following 2 to 3 months of preservation
in 5% formalin, which causes the water molecules to expand, helping separate fibers.[21]
[22]
[23] Although widely recognized as beneficial, Klingler's method is time-consuming, so
it is not always feasible for medical students to perform the procedure.[14]
[21] In light of this, neuroanatomy teaching tools are an increasing area of study as
there is a clear need to consider new approaches to develop medical education.[11]
Organizing the NUNC provides students serving on the committee with a unique opportunity
to garner experience and knowledge far beyond what they would ordinarily be exposed
to, which many on the committee members have cited as being a highlight of their NUNC
experience. It also serves as an incentive for students interested in neurosciences
to improve their own knowledge through self-directed learning and offers recognition
for the efforts of the very best. To better understand our participants' preparation
process and academic experiences of neuroanatomy, they were asked in a survey to choose,
out of a range of potential teaching modalities, a particular modality that was not
provided to them but that they would wish to have and 14% of the respondents cited
dissection.
The overwhelming majority of the 2023 NUNC attendees view neuroanatomy as highly important
to their future career aspirations ([Fig. 2]), which aligns with trends in the existing literature detailing that students are
eager for more neuroanatomy teaching, despite established “neurophobia.”[2]
[3]
[4] As the majority of neurological disease presentations will be seen first by a non-neurological
doctor, it is arguably essential that all clinicians are familiar with initial diagnosis
and management of neurological disease, for which an initial grasp of neuroanatomy
is arguably key. It has been found that final-year medical students and junior clinicians
occasionally struggle with neuroanatomy due to inadequate exposure and deficiencies
in teaching.[3]
[24] Subsequently it has been highlighted that there is a growing need for alternative
strategies to make neuroanatomy teaching more accessible and engaging, with greater
integration of clinical and preclinical concepts.[2]
[3]
[4] The latter aspect is arguably of most significance, as it has been shown that neurophobia
is associated with a lack of knowledge combined with limited clinical exposure during
medical school.[3]
[4] Simultaneously, the pervading stereotypes about clinical neuroscience careers may
further hamper student enjoyment and engagement with neuroanatomy; hence, opportunities
to connect with senior professionals and like-minded individuals (which happen through
initiatives such as the NUNC) are of significant importance alongside innovative teaching
strategies.[5]
[6]
Fig. 2 Results of the 2023 National Undergraduate Neuroanatomy Competition (NUNC) participant
survey. (A) Bar chart showing the majority of students believe neuroanatomy will be useful to
their future career (strongly agree, n = 30; agree, n = 23; neutral, n = 5; disagree, n = 0; and strongly disagree, n = 0). (B) Bar chart demonstrating students' feelings toward the importance of neuroanatomy
(strongly agree, n = 35; agree, n = 17; neutral, n = 6; disagree, n = 0; and strongly disagree, n = 0). (C) Bar chart illustrating the majority of students' wish for more teaching on the subject
of neuroanatomy (yes, n = 47; no, n = 2; and maybe, n = 9). (D) Bar chart showcasing that students view understanding neuroanatomy as important
(strongly agree, n = 34; agree, n = 22; neutral, n = 2; disagree, n = 0; and strongly disagree, n = 0).
At a more specialist level, La Rocca et al[16] highlight neuroanatomy as the “initial step of all neurosurgeons' education” and
advise detailed planning based on textbook guidance ahead of dissection, as has been
performed by the 2023 NUNC committee ([Fig. 3]). The planning approach is viewed as the hardest step and full details of the process
undertaken by these authors is detailed in [Supplementary Material] (available in the online version); thus, this narrative aims to serve as a guide
for any institution or student group keen to fill this void, as there is increasing
evidence that cadaveric central nervous system (CNS) dissections are key in bridging
the gap between neuroanatomy and clinical neuroscience, but are rarely done due to
a combination of factors discussed here.[14]
[16]
Fig. 3 An example of predissection planning from the National Undergraduate Neuroanatomy
Competition 2023 dissections. This figure shows the process of dissecting the Papez
Circuit in situ and alongside a color-coded reference drawing based on extensive subject reading
prepared by Primary Chair, Ameerah Gardee.
Student Experience
White matter anatomy is, in general, a topic undergraduate students do not get to
learn through dissection for reasons previously outlined. Dissecting for the NUNC
was an exercise in precision, patience, and diligence; above all else, it offered
a unique chance to develop an ability to translate the two-dimensional images students
become intimately familiar with from textbook learning to the three-dimensional, variable
reality of human tissue. For more details on the stepwise method prepared by the lead
author (A.G.) ahead of dissection, see [Supplementary Material] (available in the online version).
In the beginning, these authors made a thorough study of Klinger's dissection methods,
in order to appreciate how it became to be the “gold standard” for white matter dissection,
all the while knowing that due to time constraints for delivering the NUNC, we would
be unable to replicate it on this occasion. Images of prosections were crucial at
all stages of this process'; however, it was difficult at times to bridge the gap
between the finished dissections and how the specimen must have looked in the process
of performing it. Due to the extracurricular nature of the NUNC, all dissections had
to be performed in stages, when the anatomy department were able to accommodate extra
student activity. In some ways, this proved both beneficial and detrimental, as it
meant that there was a loss of continuity of activity at times, which slowed the process,
but also facilitated time to reflect on the process as it unfolded, allowing for continuous
revision and deep learning, which, in these authors' view, greatly enhanced the final
results.
The fact that all research and preparation for dissection are done in students' personal
time is a testament to the dedication of the NUNC committee and a commendable way
of demonstrating commitment and interest in neuroanatomy and, by extension, clinical
neurosciences. Giving students the freedom to choose and plan dissection was an empowering
experience that challenged these authors profoundly; as we worked with a limited number
of specially retained specimens, there was a need for judicious planning in order
to maximize the potential of our resources and prevent inadvertent damage to fragile
white matter tracts. Use of radiological imagery, particularly diffusion tensor imaging
(DTI), is valuable as it highlights the structures of interest in vivo, while still
allowing for the identification of neighboring structures useful in orientating the
approach.[25] By examining DTI and other radiological medium's images of the structures chosen
for dissection, these authors were able to estimate the depth of these structures
and appreciate their orientation alongside neighboring structural landmarks ([Fig. 3]). In comparison to more traditional means of white matter dissection, such as Klingler's
method, which fixes white matter tracts and has been shown to greatly aid medical
student comprehension of the relationship between neuroanatomical structures, this
narrative offers the viewpoint that the methodologies outlined here are comparable
in terms of anatomical accuracy and efficacy.[21] All specimens were inspected and reviewed by a team of internal examiners and validated
by NUNC's external examiner, Prof. Ceri Davies, who is based at a different institution
from the NUNC. Through this process, the anatomical accuracy and efficacy of the dissections
performed by the students is held to the highest standard possible under the circumstances.
As the NUNC grows at the University of Glasgow, these authors hope to be able to produce
Klinger's specimens alongside the ones described in this narrative to better compare
the two techniques and further validate the potential for dissecting white matter
without utilizing Klinger's method. At present, the amount of research required to
perform the dissections discussed here limited the number of them that could be produced
at any one time; as student experience grows with the NUNC's increasing collection,
these authors suggest that this issue will naturally resolve.
Combining practical “physical” knowledge of the three-dimensional proportions of the
white matter tracts of interest gained from radiological study with research across
several neuroscience textbooks and neurosurgical atlases, these authors formed stepwise
plans for each dissection described in this narrative, which allowed us to circumvent
the difficulty of having to dissect in stages over time, as the steps could be spread
across several sessions and progress measured ([Fig. 3]). By illustrating the steps, these authors found they were more prepared to appreciate
the anatomy in situ as opposed to purely observational learning, a trend that has
been noted in the literature on this topic.[26]
This discussion and its technical domains reflect the dissection work conducted by
the lead author (A.G.).
Papez Circuit
The Papez Circuit ([Fig. 4]) was first identified in 1937 by Hames Wenceslaus Papez and encompasses the hippocampus,
hypothalamus, anterior thalamus, cingulate gyrus, and their connections.[27] It was first identified as the anatomical basis of emotion, but is now understood
to be more significant for memory and, in instances of dysfunction, epileptogenisis.[27]
[28]
[29] Knowledge of this region is important clinically for neoplastic, vascular, and other
pathological lesions that affect circuit structures directly, or indirectly, by exerting
physical pressure on them.[30]
Fig. 4 The Papez circuit as dissected by Ameerah Gardee for the National Undergraduate Neuroanatomy
Competition 2023. Dissected in a median sagittal view, all the components can be carefully
visualized as demonstrated here (A = anterior nucleus of the thalamus; B = mammillothalamic
tract; C = mamillary body; D = column of the fornix; E = crus of the fornix; F = hippocampus).
The posterior end of the thalamus has been removed in order to view E clearly.
This was the first dissection completed specifically for the NUNC 2023 ([Fig. 4]); the majority of the preparation was based on textbook descriptions rather than
images and DTI studies that showed the structure in relation to the surrounding tissue.
Figures from Catani et al were used as a basis for planning the approach; radiological
images such as these were key in helping identify tissue that could be dissected rapidly
in order to expose structures of interest.[31] In-depth discussion of the steps followed can be read in [Supplementary Material] (available in the online version).
When performing the dissection, it was a surprise to find that with a superior approach
through the lateral ventricle, the pulvinar groove could be felt and used as a landmark
to identify the superior portion of the anterior nucleus of the thalamus. This provided
a clear target to aim for and expose first, leaving the visible mamillary body intact
([Fig. 4]) to approach later, and thereby better visualize the connection between it and the
anterior thalamic nucleus.
The fragility of the deeper structures rapidly became evident and improvising with
alternative tools proved extremely beneficial—namely a 3-mm crochet hook ([Fig. 5]) and a straight pin. The former was useful to resect without breaking the tissue
in order to identify the directionality of the fibers and overall size of the tracts.
The latter was useful to separate blood vessels from adjacent tissue and to separate
individual fibers to create a greater appreciation of the target structures.
Fig. 5 The 3-mm crochet hook used for the National Undergraduate Neuroanatomy Competition
2023 dissections.
The hardest part of the process was trying to identify structures before they were
fully exposed, as there was substantial concern about potentially dissecting tissue
that should be preserved. Historical accounts of dissection, while immeasurably helpful
in supporting planning, did not account for the difficulty encountered when trying
to identify the circuit components in isolation—as almost all textbooks show them
as a group, without their surroundings, but unrelated structures that are present
in a cadaveric specimen. For more detail on the orientation process of this dissection,
please see [Supplementary Material] (available in the online version).
In future, if one were to replicate this process, it would be useful to be mindful
that the postcomissural fornix is deeper than it can appear in textbooks ([Fig. 4]), which would enable one to complete later parts of the process faster (see [Supplementary Material], available in the online version) as it was at times difficult to determine how
much medial temporal lobe should be resected to expose it and it took several sessions
as opposed to a single one due to excess caution. The impact of the experience of
performing this first dissection had a profound effect on the clinical learning of
the medical students organizing the NUNC 2023 as, although initially time-consuming,
provided the initial immersive, hands-on learning experience that streamlined the
dissection process for the subsequent two specimens discussed here.
Corticospinal Tract
The corticospinal tract (CST; [Fig. 6]) is one of the main efferent tracts in the corticospinal system, descending from
the superior cortical centers to the brainstem, passing through the corona radiata,
internal capsule, and cerebral peduncles before decussating in the lower third of
the medulla, before traversing the spinal cord.[32]
[33] Like the Papez circuit, DTI was exceptionally useful in predissection planning,
as white matter fibers can be hard to separate into distinct groups, particularly
toward the tract's origins.[31]
[32]
[33] In this instances, figures from Bozkurt et al[34] and Guevara[32] served as templates for planning the dissection.
Fig. 6 The CST fibers as dissected by Ameerah Gardee for the National Undergraduate Neuroanatomy
Competition 2023. (1) The specimen positioned to show its inferior surface. (2) The specimen in a lateral position. Across both images, A = descending CST fibers;
also demarcated are the optic chiasm (B) and the inferior horn of the lateral ventricle
(C), which are useful landmarks to note during the process of dissection. The majority
of the temporal lobe and a portion of the posterior frontal lobe have been resected
for optimal visualization of the structure of interest.
Dissecting the CST at a cranial level presented a singular set of challenges as often
teaching related to it is centered on its path and position in the spinal cord. Detailed
directions used for this dissection are found in [Supplementary Material] (available in the online version). Furthermore, brainstem anatomy had been previously
presented to these authors as transverse sections, so one of the first tasks undertaken
to prepare for this dissection was translation of these to relate to the three-dimensional
structure of the brainstem.
Older textbooks proved to be of most value in doing this as their more traditional
style of illustration was more relatable to cadaveric specimens.[32]
[35] Upon reflection, the initial dissection through the medullary olive and superior
cerebral peduncle ([Fig. 6.1]) could have benefited from a magnifying glass or microscope, as the lack of either
meant this process took several sessions in order to complete due to a slower pace
resulting from the size of the target structure.
Again, improvised dissection tools proved useful here as several tracts pass very
close to the CST, so having the crochet hook ([Fig. 5]) and straight pin was key in making initial distinctions. In addition, a size 8
knitting needle proved helpful in appreciating the texture differences between tracts
and nuclei without breaking the tissue. The opportunity to test novel tools for dissection
was a unique opportunity for creative problem-solving and micro-innovation, giving
students a chance to build confidence in their own ideas and abilities.
Another unexpected conundrum was deciding which portion of the corona radiata to define
in order to complete the path of the CST, given that it contributes to multiple pathways
and, for a CST, is most clear in a coronal section, as opposed to a three-dimensional
dissection. In determining how to proceed, DTI images were again a key reference,
together with discussion among senior staff members at the anatomy department. The
final specimen is shown in [Fig. 6].
Throughout all dissections performed for the NUNC, one of the most beneficial parts
of the process for personal development of the dissector was the opportunity to work
more closely with teaching staff on a long-term project and gain insight into how
they visualize anatomy and the process of dissection. Their advice proved insightful
and invaluable in supporting the development of student knowledge and practical skills
alike. Going forward, this knowledge will hopefully enable better clinical application
of textbook knowledge and facilitate a smoother transition from academic to clinical
learning.
Uncinate and Inferior Longitudinal Fasciculi
The uncinate fasciculus ([Fig. 7]) was first described by Johann Christian Reil in 1809 and is a bidirectional tract
connecting the orbitofrontal cortex and anterior temporal lobe.[36]
[37] It has been implicated in episodic memory and socioemotional processing, although
its exact role is unclear.[37] The inferior longitudinal fasciculus (ILF) is another associative white matter tract
that connects occipital and temporo-occipital regions to anterior temporal structures.[38] It is a bidirectional tract and is thought to be involved in processing visual cues
and thus visually directed decisions and actions; this is important clinically as
studies have shown that disruption of the ILF can lead to impairments of visual cognition,
which in some instances may be the basis of visual hallucinations.[38] Like all white matter dissection, use of DTI was highly beneficial in identifying
the correct fibers on dissection and anticipating the depth required to dissect in
order to reach them.[39]
Fig. 7 A dissection of the uncinate fasciculus and inferior longitudinal fasciculus for
the National Undergraduate Neuroanatomy Competition 2023 by Ameerah Gardee. This dissection
was performed with the specimen in a lateral orientation; A = uncinate fasciculus;
B = inferior longitudinal fasciculus. Other structures shown that serve as useful
landmarks are C = deep fibers of the arcuate fasciculus and D = deep white matter
of the insular gyri and E = the inferior horn of the lateral ventricle sitting below
B. The majority of the temporal lobe, fronto-orbital lobe, and posteroinferior temporal
lobe have been resected in order to view the structures of interest.
This specimen was prepared later in the academic year, closest of these examples to
the NUNC 2023, and benefited significantly from experience in performing the previous
two dissections described above. For details of the process, see [Supplementary Material] (available in the online version). The final dissection is shown in [Fig. 7].
With the benefit of experience from the approaches previously discussed, it was clear
that looking at DTI images as opposed to textbook illustrations was a key step in
the planning process as they proved more reflective of what was encountered while
dissecting. The angle of the tract was more acute than expected when exposed in this
particular specimen, but with detailed prior study and advice from senior anatomists,
it was possible to remain confident it had been correctly identified; it was then
possible to proceed to define it in a similar manner to the previous two specimens
described here.
It proved easiest to identify the anterior portion of the ILF due to its proximity
to the uncinate fasciculus ([Fig. 7]).[39] Once identified, following it posteriorly was the most straightforward approach
until the arcuate fasciculus was reached. This was a locus of interest, so it was
predominantly preserved, while simultaneously penetrating and exposing a window into
the inferior horn of the lateral ventricle ([Fig. 7]). This last decision was not initially included in the dissection plan prepared
for this specimen, but over time, it became clear that it was both possible and enhanced
the specimen as a whole, both aesthetically and in terms of its potential use in questions
for the NUNC spotter examination.
Of the three dissections described, this was the easiest to perform. It is likely
on reflection that this is partially because prior dissection experience yielded an
enhanced understanding of the gross anatomy of these tracts and their functions, and
in this instance did not have to identify and isolate nuclei or brainstem structures.
These authors also likely benefited from a growth in confidence having gained experience
starting on arguably harder dissections and received more focused guidance in the
process.
Conclusion
White matter dissection is often a daunting task for students as often they are commonly
inadequately prepared, although many interested in neuroanatomy readily acknowledge
the importance of dissection to their current and future education/career aspirations.
This narrative aims to serve as a starting point for more accessible white matter
dissection protocols, by providing a step-by-step guide to white matter dissection
on cadaveric specimens, rather than relying on Klinger's method. This deviation from
the accepted “gold standard” of white matter dissection is an attempt to mitigate
the time and resource constraints faced by most students and institutions in the present
day, while still facilitating meaningful learning. Going forward, the NUNC hopes to
grow its presence at medical schools across the United Kingdom by recruiting local
medical student NUNC representatives and, where possible, encourage students to undertake
dissection as part of their preparation for the competition with the support of their
respective departments of anatomy. It is these authors' hope that this manuscript
serves as evidence of what is possible for student-directed learning and can serve
as a template for this process, both in the United Kingdom and further afield, for
those who wish to undertake similar initiatives. To assess the long-term impact of
the NUNC and similar opportunities, utilization of follow-up surveys of past NUNC
participants and committee members alike could provide valuable longitudinal observations
on the impact of early dissection and specimen exposure on medical students' career
choices and trajectories.
