Revisiting the Morphology and Classification of the Paracingulate Gyrus with Commentaries on Ambiguous Cases

Abstract

The anterior cingulate cortex is considered to play a crucial role in cognitive and affective regulation. However, this area shows a high degree of morphological interindividual variability and asymmetry. It is especially true regarding the paracingulate sulcus and paracingulate gyrus (PCG). Since the reports described in the literature are mainly based on imaging techniques, the goal of this study was to verify the classification of the PCG based on anatomical material. Special attention was given to ambiguous cases. The PCG was absent in 26.4% of specimens. The gyrus was classified as present in 28.3% of cases. The prominent type of the PCG was observed in 37.7% of the total. Occasionally, the gyrus was well-developed and roughly only a few millimeters were missing for classifying the gyrus as prominent, as it ended slightly anterior the level of the VAC. The remaining four cases involved two inconclusive types. We observed that the callosomarginal artery ran within the cingulate sulcus and provided branches that crossed the PCG. Based on Klingler’s dissection technique, we observed a close relationship of the PCG with the superior longitudinal fascicle. The awareness of the anatomical variability observed within the brain cortex is an essential starting point for in-depth research.

Anatomy of the occipital lobe using lateral and posterior approaches: a neuroanatomical study with a neurosurgical perspective on intraoperative brain mapping

“…The anterior functional borders of the resection within the white matter regardless of the side are the AF/SLF complex, cortico-spinal, or thalamo-cortical tracts. When the dominant hemisphere AF/SLF complex is stimulated, language deficits, such as phonemic paraphasias, are mainly observed [12,32,15]. In the nondominant hemisphere, the AF/SLF is related to visuospatial function, and its stimulation elicits rightward deviation during the line bisection test [2].…”

Cingulate sulcus morphology and paracingulate sulcus variations: Anatomical and radiological studies

“…The paracingulate sulcus is divided into three subtypes: present, absent, and prominent (Yücel et al, 2001). A vertical line passing through the anterior commissure horizontally is drawn, and the paracingulate sulcus was considered to be prominent if the paracingulate sulcus extended this line (Wysiadecki et al, 2021).…”

Structural and functional connectivity associations with anterior cingulate sulcal variability

“…In bvFTD presence of a right PCS is associated with disease expression and survival (Harper, Lindberg et al 2022, Harper, de Boer et al 2023 ), whilst a reduced frequency of leftward paracingulate sulcation dominance is observed in individuals with schizophrenia ( Yücel, Stuart et al 2002 , Le Provost, Bartres-Faz et al 2003 , Yücel, Wood et al 2003 , Marquardt, Levitt et al 2005 , Fujiwara, Hirao et al 2007 ). Furthermore, left hemisphere PCS presence is reportedly less frequently in patients with obsessive compulsive disorder (OCD)( Shim, Jung et al 2009 ) and altered PCG connectivity has been correlated with generalized epilepsy ( Kay, Holland et al 2014 ) and epilepsy drug resistance ( Szaflarski, Kay et al 2013 ) ( Wysiadecki, Mazurek et al 2021 ).…”

“…Cortical folding, according to the tension-based morphogenesis theory is considered to be pathway specific, partially dependent on underlying tensions between short association fibres connecting neighbouring cortical regions which shorten to reduce wiring ( Van Essen 1997 , Van Essen 2020 ). Reflecting this process, the PCG primarily contributes U-fibres connecting it with the AC proper which forms a localised white matter network not present where a PCS is absent ( Wysiadecki, Mazurek et al 2021 ). There fibres may influence the observed underlying cytoarchitectural differences of the AC observed in the presence of a PCS ( Vogt, Nimchinsky et al 1995 ).…”

“…Deep of the superficial U-fibres lie longitudinal fibres which course within the PCG when present and are identified medial and slightly inferior to the cingulate sulcus, within the cingulate gyrus where the PCS is absent ( Komaitis, Skandalakis et al 2019 ). This tract is regarded by some as subcomponent Ia of the superior longitudinal fasciculus (SLF), ( Komaitis, Skandalakis et al 2019 ) ( Wysiadecki, Mazurek et al 2021 ) and by others as a division of the cingulate bundle ( Wu, Sun et al 2016 ) or even U-fibres ( Maldonado, Mandonnet et al 2012 ). To the best of our knowledge no neuroanatomical tracing or tractography studies have been performed with respect to PSC presence.…”