scispace - formally typeset
Search or ask a question

Showing papers on "Rhinal sulcus published in 2002"


Journal ArticleDOI
TL;DR: The results demonstrate that the propagation of neuronal activity across the rhinal sulcus in the direction from thePRC to the EC is finely and diffusely distributed, and suggest that the PRC–EC pathway is highly regulated by inhibitory network interactions.
Abstract: The study of synaptic interactions within the parahippocampal region is crucial to understand the integrative functions performed by this region during memory information processing. Despite the extensive anatomical studies, the intrinsic physiology of the parahippocampal area has been poorly investigated. We describe here the organization pattern of the synaptic network formed by the temporal neocortex, areas 36 and 35 of the perirhinal cortex (PRC) and the entorhinal cortex (EC), in the in vitro isolated guinea-pig brain. Current source density analysis of laminar field potential profiles was performed with multichannel silicon probes positioned in different parahippocampal subfields. Stimulation of the temporal neocortex induced monosynaptic and polysynaptic potentials in areas 35 and 36, respectively. Area 36 stimulation evoked monosynaptic responses within areas 36 and 35. Stimuli in area 35 induced responses that propagated longitudinally along area 35 itself. No local field responses were observed in the EC after stimulation of both neocortex and areas 35/36. Despite the absence of a local extracellular response, intracellular recordings demonstrated that subpopulations of superficial layer neurons in medial and lateral EC showed polysynaptic EPSPs after stimulation of area 35 and area 36. The results demonstrate that the propagation of neuronal activity across the rhinal sulcus in the direction from the PRC to the EC is finely and diffusely distributed. In agreement with previous reports, these findings suggest that the PRC-EC pathway is highly regulated by inhibitory network interactions.

60 citations


Journal Article
TL;DR: Understanding the anatomical and functional organization of the temporal pole enables us to hypothesize about the role played by this structure in the pathogenesis of the forms of epilepsy originating in mesial temporal lobe structures.
Abstract: The temporopolar region is not clearly defined from an anatomical point of view. A line going through the rostral area of the inferior temporal, occipito temporal and superior temporal sulci is considered to represent its posterior limit on the lateral and inferior sides. On the internal side, this posterior limit corresponds to the rhinal sulcus, an anterior and internal extention of the collateral sulcus. From a cyto-architectonic point of view, the temporopolar region is caracterized by a dysgranular paralimbic cortex which ensures the transition between allo- and isocortical areas. The temporal pole is mainly connected with the amygadala, the hippocampus, the superior temporal gyrus, and the occipitobasal cortex, but also with the orbitary gyrus and the insula with which it forms the insulo-orbito-polar-temporo-complex. The temporal pole occupies the most rostral part of the temporal lobe and can only be accurately defined once the anatomy of the temporal lobe as a whole has been outlined. The architectonic configuration of this region as well as its connections with the limbic system, and the superior, orbital and insular temporal cortices make it a discrete temporal structure. Understanding the anatomical and functional organization of the temporal pole enables us to hypothesize about the role played by this structure in the pathogenesis of the forms of epilepsy originating in mesial temporal lobe structures.

48 citations