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== INSULA Anatomi & funktion == [[Fil:Insula2.png|500px|thumb|Right|Insuala markeret med rødt]]
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== INSULA Anatomi & funktion == [[Fil:Insula2.png|400px|thumb|Right|Insuala markeret med rødt]]
  
Insula er den skjulte korteks, dækket af frontaltlappen og temporallappen i dybet af latteralfissuren (Fissura Sylvii).
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Insula er den skjulte korteks, dækket af frontaltlappen og temporallappen i dybet af lateralfissuren (Fissura Sylvii). Insula udgør fortsat en del hjernen hvor funktionerne er relativt ukendte. Insula har længe været, og betragtes fortsat af mange som et område der ikke er kirurgisk tilgængeligt. Dette skyldes at der er betydelige risici for funktionel skade relateret til kirurgiske procedurer i Insula. Dette skyldes nok ikke så meget de funktioner der varetages af Insula korteks men er snarere relateret til vaskulærskade eller skade på nervebaner i den hvide substans. Karskade ses både ved direkte påvirkning af a. cerebri media arterierne i lateral fissuren eller skade på perforanterne der kommer enten fra Insulas overflade eller i dybet fra hovedstammen af a. cerebri media, og har deres forløb svarende til lateral siden af Putamen.    [[Fil:Insula kar.png|400px|thumb|Right|Insuala markeret med rødt]]
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The insula is the fifth lobe of the brain and it is the least known. Hidden under the temporal, frontal and parietal opercula, as well as under dense arterial and venous vessels, its accessibility is particularly restricted. Functional data on this region in humans, therefore, are scarce and the existing evidence makes conclusions on its functional and somatotopic organization difficult. 5 patients with intractable epilepsy underwent an invasive presurgical evaluation with implantation of diagnostic invasive-depth electrodes, including insular electrodes that were inserted using a mesiocaudodorsal to laterorostroventral approach. Altogether 113 contacts were found to be in the insula and were stimulated with alternating currents during preoperative monitoring. Different viscerosensitive and somatosensory phenomena were elicited by stimulation of these electrodes. A relatively high density of electrode contacts enabled us to delineate several functionally distinct areas within the insula. We found somatosensory symptoms to be restricted to the posterior insula and a subgroup of warmth or painful sensations in the dorsal posterior insula. Viscerosensory symptoms were elicited by more anterior electrode contacts with a subgroup of gustatory symptoms occurring after stimulation of electrode contacts in the central part of the insula. The anterior insula did not show reproducible responses to stimulation. In line with previous studies, we found evidence for somato- and viscerosensory cortex in the insula. In addition, our results suggest that there is a predominantly posterior and central distribution of these functions in the insular lobe.

Versionen fra 22. sep 2012, 14:08

== INSULA Anatomi & funktion ==

Insuala markeret med rødt

Insula er den skjulte korteks, dækket af frontaltlappen og temporallappen i dybet af lateralfissuren (Fissura Sylvii). Insula udgør fortsat en del hjernen hvor funktionerne er relativt ukendte. Insula har længe været, og betragtes fortsat af mange som et område der ikke er kirurgisk tilgængeligt. Dette skyldes at der er betydelige risici for funktionel skade relateret til kirurgiske procedurer i Insula. Dette skyldes nok ikke så meget de funktioner der varetages af Insula korteks men er snarere relateret til vaskulærskade eller skade på nervebaner i den hvide substans. Karskade ses både ved direkte påvirkning af a. cerebri media arterierne i lateral fissuren eller skade på perforanterne der kommer enten fra Insulas overflade eller i dybet fra hovedstammen af a. cerebri media, og har deres forløb svarende til lateral siden af Putamen.

Insuala markeret med rødt


The insula is the fifth lobe of the brain and it is the least known. Hidden under the temporal, frontal and parietal opercula, as well as under dense arterial and venous vessels, its accessibility is particularly restricted. Functional data on this region in humans, therefore, are scarce and the existing evidence makes conclusions on its functional and somatotopic organization difficult. 5 patients with intractable epilepsy underwent an invasive presurgical evaluation with implantation of diagnostic invasive-depth electrodes, including insular electrodes that were inserted using a mesiocaudodorsal to laterorostroventral approach. Altogether 113 contacts were found to be in the insula and were stimulated with alternating currents during preoperative monitoring. Different viscerosensitive and somatosensory phenomena were elicited by stimulation of these electrodes. A relatively high density of electrode contacts enabled us to delineate several functionally distinct areas within the insula. We found somatosensory symptoms to be restricted to the posterior insula and a subgroup of warmth or painful sensations in the dorsal posterior insula. Viscerosensory symptoms were elicited by more anterior electrode contacts with a subgroup of gustatory symptoms occurring after stimulation of electrode contacts in the central part of the insula. The anterior insula did not show reproducible responses to stimulation. In line with previous studies, we found evidence for somato- and viscerosensory cortex in the insula. In addition, our results suggest that there is a predominantly posterior and central distribution of these functions in the insular lobe.