Short official Latin term

Libelle of note

The Mesocortex (Rose M 1927 Der Allocortex bei Tier und Mensch. I. Teil. J Psychol Neurol (Lpz) 34:1-11) comprises the Proisocortex, a transition area between the Isocortex and the Allocortex, and the Periallocortex, the adjoining part of the Allocortex (Filimonoff 1947); also known as Paralimbic cortex (Mesulam 1985). The Periallocortex can further be subdivided into the Peripaleocortex (Claustrum) and the Periarchicortex (Entorhinal, Presubicular and Retrosplenial cortices and part of the Cingulate gyrus; Filimonoff 1947; Zilles and Amunts 2012).

The Cortex perirhinalis (Perirhinal cortex; BA35) and the Transentorhinal subregion of Braak and Braak (1992) are somewhat synonymous terms (Augustinack JC, Huber KE, Stevens AA, et al. 2013 Predicting the location of human perirhinal cortex, Brodmann's area 35, from MRI. Neuroimage 64:32-42). In other studies (Ding S-L, Van Hoesen GW 2010 Borders, extent, and topography of human perirhinal cortex as revealed using multiple modern neuroanatomical and pathological markers. Hum Brain Mapp 31:1359-1379), BA 36 is included within the Perirhinal cortex. This is unfortunate since BA35 is periarchicortex but BA36 (Ectorhinal cortex) is truly isocortex. The Layers of BA35 are comparable to those of the adjacent Entorhinal cortex.

In the Cortex entorhinalis (Entorhinal cortex), Insausti et al. (Insausti R, Tuñón T, Sobreviela T, et al. 1995 The human entorhinal cortex: A cytoarchitectonic analysis. J Comp Neurol 355:171-198) distinguished 8 subfields (EO, ER, ELR, EMI, EI, ELC, EC and ECL). For the layers of the Entorhinal cortex, the subdivision by Insausti and Amaral (2012) into six Laminae is advocated. To avoid confusion with isocortical layers, here, arabic numerals are used as in the literature. TH Latin and English terms (H4.8.03.104/114) are added. For Layers 2 and 3, the general term External principal layer is advocated, for Layer 5 Internal principal layer, following Braak H, Braak E (1992 The human entorhinal cortex: Normal morphology and lamina-specific pathology in various diseases. Neurosci Res 15:6-31). Layer 2 is made up of islands of relatively large and darkly stained modified pyramidal and stellate cells (Braak and Braak 1992: Pre-a). Layer 3 corresponds to layers Pre-ß and Pre-? of Braak and Braak (1992). The layers Pre-a, Pre-ß and Pre-? form their External principal layer. Layer 5 corresponds to the Internal principal layer with sublayers Pri-a, Pri-ß and Pri-? of Braak and Braak (1992).

The complex Cortex retrosplenialis (Retrosplenial cortex) consists of Periarchicortical (BA26) and Proisocortical (BA29, 30) areas (Braak H 1980 Architectonics of the Human Telencephalic Cortex. Springer, Berlin-Heidelberg-New York; Zilles and Amunts 2012). The TH nomenclature (H4.8.03.122/129) seems to combine these different structures. The Cortex ectosplenialis (Ectosplenial cortex; BA26) has a primitive three-laminar pattern with Molecular, Densocellular and Multiform layers. The Cortex retrosplenialis granularis (Granular retrosplenial cortex; BA29) shows a four-layered structure: Molecular, External and Internal pyramidal and Multiform layers. The Cortex retrosplenialis dysgranularis (Dysgranular retrosplenial cortex; BA 30) shows a further progression of laminar differentiation with an additional (Internal) granular layer.

For further subdivision of the Cortex cingularis (Cingulate cortex) with Layers, see Vogt BA, Palomero-Gallager N (2012) Cingulate cortex. In: Mai JK, Paxinos G, eds: The Human Nervous System, 3rd ed. Elsevier, Amsterdam, pp 934-987.

TH subdivision into six layers (H4.8.03.115/121) suggested a well-divided structure. Insausti and Amaral (2012) emphasized that the laminar organization of the Presubiculum is complex and only poorly understood. They described a single, superficially located cellular layer made up of External and Internal principal layers. Their subdivision is followed here.