Rhinal sulcus

About: Rhinal sulcus is a research topic. Over the lifetime, 116 publications have been published within this topic receiving 14784 citations.

Differential projection from the motor and limbic cortical regions to the mediodorsal thalamic nucleus in the dog.

Abstract: The cortical afferents to the mediodorsal thalamic nucleus in the dog were studied by using horseradish peroxidase. Small injections allowed to establish two specific projection zones connected separately with the lateral and medial segments of the nucleus. The lateral segment received the major projection from the dorsal half of the hemisphere. It included premotor and part of the motor cortices in the anterior sigmoid gyrus and precruciate areas as well as the presylvian cortex. The medial segment of the nucleus was innervated by the limbic areas of the ventral half of the hemisphere. These areas included the medioventrally located genual, subcallosal and piriform cortices, as well as the cortex of the ventral bank of the anterior rhinal sulcus and the caudal part of the orbital gyrus. The cortical fields situated between these two main cortical zones, both on the lateral and medial surfaces (rhinal and sylvian sulci and anterior cingular gyrus, respectively) sent projections to both medial and lateral segments of the nucleus. These results indicate that in the mediodorsal thalamic nucleus may take place the integration of information from two functionally defined systems, the motor and limbic ones.

Three-Dimensional Probabilistic Maps of Mesial Temporal Lobe Structures in Children and Adolescents' Brains.

Abstract: The hippocampus and the adjacent perirhinal, entorhinal, temporopolar, and parahippocampal cortices are interconnected in a hierarchical MTL system crucial for memory processes. A probabilistic description of the anatomical location and spatial variability of MTL cortices in the child and adolescent brain would help to assess structure-function relationships. The rhinal sulcus (RS) and the collateral sulcus (CS) that border MTL cortices and influence their morphology have never been described in these populations. In this study, we identified the aforementioned structures on magnetic resonance images of 38 healthy subjects aged 7-17 years old. Relative to sulcal morphometry in the MTL, we showed RS-CS conformation is an additional factor of variability in the MTL that is not explained by other variables such as age, sex and brain volume; with an innovative method using permutation testing of the extrema of structures of interest, we showed that RS-SC conformation was not associated with differences of location of MTL sulci. Relative to probabilistic maps, we offered for the first time a systematic mapping of MTL structures in children and adolescent, mapping all the structures of the MTL system while taking sulcal morphology into account. Our results, with the probabilistic maps described here being freely available for download, will help to understand the anatomy of this region and help functional and clinical studies to accurately test structure-function hypotheses in the MTL during development. Free access to MTL pediatric atlas: http://neurovault.org/collections/2381/.

Lesions of the Posterior Insular Cortex Impair Water Maze Performance in the Rat

Abstract: Performance of rats in the Morris water maze was measured after small excitotoxic lesions were produced bilaterally in two areas in the insular cortex, 0.3 and 2.3 mm posterior to bregma in the upper bank of the rhinal sulcus. The rats were trained and tested in two successive days to find an underwater platform. Compared to intact animals groups with lesions at AP-0.3 and AP-2.3 were impaired as measured by latency. These animals also did not prefer the correct quadrant while searching for the platform. There were no differences between the groups in percentage of time spent in periphery and speed of swimming. The results do not support the hypothesis that the destruction of an autonomic center at AP-0.3 will impair performance while the destruction of a more posterior part of the insular cortex will not, and are interpreted as further evidence for multifactor sensitivity of the water maze task.

Temporal lobe anatomy: eight imaging signs to facilitate interpretation of MRI.

Abstract: The temporal lobe is anatomically and functionally complex. However, relatively few radiologic signs are described to facilitate recognition of temporal lobe sulci and gyri in clinical practice. We devised and tested 8 radiologic signs of temporal lobe anatomy. Images from volumetric magnetization-prepared rapid gradient-echo imaging were analyzed of 100 temporal lobes from 26 female and 24 male patients. Patient age ranged from 1 to 79 years (mean 19 years; standard deviation 16 years). Standardized axial, coronal, and sagittal planes were evaluated and cross-referenced. Eight signs to delineate the superior temporal gyrus, Heschl gyrus (HG), parahippocampal gyrus, rhinal sulcus, collateral sulcus proper, or the occipitotemporal sulcus, or a combination, were evaluated in the sagittal or axial plane. Two neuroradiologists independently evaluated each sign; the sign was considered present only with positive reader agreement. All 8 signs were present in most patients. The most frequent signs were the posterior insular corner to identify HG in the axial plane (100 %), pointed STG to identify STG in the axial plane (98 %), and parahippocampal Y to identify the posterior parahippocampal gyrus in the sagittal plane (98 %). The frequencies were similar between the right and left cerebral hemispheres. Temporal lobe gyri and sulci can be reliably identified in multiple planes using anatomic signs.

Pigmentarchitectonic subfields of the entorhinal region as revealed in tangential sections.

Abstract: The entorhinal region is an important center of the limbic system involved in many dementing disorders The boundaries of the entorhinal region of the left and right hemispheres were investigated in tangential sections (5 individuals, age range 21 to 29 years) This method preserves the rostral portion of the entorhinal region which is usually lost in coronal sectioning The sections were stained with the pigment-Nissl-method The superficial cellular layer of the centromedial part of the entorhinal region consists of large heavily pigmented neurons forming islands clearly separated from each other The anterior and posterior parts of the entorhinal region display an opposite pattern consisting of small islands and stripes with ill-defined boundaries The islands contain small and sparsely pigmented neurons surrounded by large and well pigmented cells Close to the adjacent proisocortex, the small cell containing islands confluent while the large and well pigmented neurons disappear Hence, the medial side of the entorhinal region extends up to the uncus and the lateral side into the main branch of the rhinal sulcus The entorhinal region covers the frontal portion of the parahippocampal gyrus up to the periamygdaloid cortex and the posterior part ends acute-angled within the medial portion of the parahippocampal gyrus