The Horseshoe-Shaped Commissure of Wernekinck or the Decussation of the Brachium Conjunctivum Methodological Changes in the 1840s

Abstract

Up till the 1840s, gross dissection was the only method available to study the tracts and fascicles of the white matter of the human brain. This changed dramatically with the introduction by Stilling (1842, 1843, 1846) of the microscopy of serial sections and his demonstration of the discriminative power of this method. The decussation of the brachium conjunctivum (the superior cerebellar peduncle) (International Anatomical Terminology (1998)) originally was known as the horseshoe-shaped commissure of Wernekinck. The first use of this name and the first illustrations of this commissure date from a book by Wernekinck’s successor, Wilbrand (1840).Using gross dissection, he concluded that the commissure connects the dentate nucleus with the contralateral inferior olive. A few years later, Stilling (1846), using microscopy of serial sections through the human brain stem, illustrated the entire course of the brachium conjunctivum, its decussation,and its crossed ascending branch, up to the red nucleus. From his work, it became clear that Wernekinck and Wilbrand had included the central tegmental tract in their commissure, and that they had failed to identify its ascending branch.

Wernekink Commissure Syndrome Secondary to Bilateral Caudal Paramedian Midbrain Infarction Presenting with a Unique “Heart or V” Appearance Sign: Case Report and Review of the Literature

“…It decussates caudal to the brachium conjunctivum, followed by a dissension to the inferior olive. We are now able to clearly identify the descending bundle as Bechterews’s central tegmental tract ( 16 ). Wernekink commissure is positioned anterior to the aqueduct at the paramedian region of caudal midbrain.…”

Widespread higher fractional anisotropy associates to better cognitive functions in individuals at ultra‐high risk for psychosis

“…connection (Voogd & Baarsen, 2013), previously found to be aberrant in patients with schizophrenia (Thomason & Thompson, 2011). CTCconnectivity has been associated with symptom course in UHR-individuals, suggesting it may be a biomarker of disease progression (Bernard, Orr, & Mittal, 2017).…”

“…Left superior cerebellar peduncle is also considered a thalamo-cortical Table 3 shows the results from the exploratory interaction test on additional white matter-indices. Slopes are visualized in Table S5. connection (Voogd & Baarsen, 2013), previously found to be aberrant in patients with schizophrenia (Thomason & Thompson, 2011). Abbreviations: FA, fractional anisotropy; LV, latent variable; PLS-C, partial least square correlation; WM, white matter.…”

Collateralization of cerebellar output to functionally distinct brainstem areas. A retrograde, non-fluorescent tracing study in the rat

“…It has become abundantly clear that cerebellar nuclear efferents terminate, mostly contralaterally, in a great variety of brain stem regions. Ramón y Cajal (1911) already described that, immediately after its decussation in the midbrain, the superior cerebellar peduncle (scp) branches into ascending and descending bundles (also see Voogd and Van Baarsen, 2014). The descending branch is located in the ventromedial tegmentum and mainly terminates in the nucleus reticularis tegmenti pontis (NRTP), the basilar pontine nuclei, the pontine, and medullary reticular formation and in the inferior olive (IO).…”