Hippocampal structure

Thestructureofthehippocampus:

Thestructureofthehippocampusincludesthecompletestructureandfunctionofthehippocampusanditsnearbydentategyrus,fasciculargyrus,superiorcorpuscallosum,hippocampalgyrusandlowerfeet.body.Itiscloselyrelatedtotheprocessingoflearning,memory,attention,emotion,sensoryinformationandmotorfunctions.

Themorphologicalstructureofthehippocampus:

Thehippocampusisthecorticalpartoftheolfactorysystem.Duringtheembryonicperiod,thecoastalhorsecleftattachedtotheinnerwallofthehemisphere,locatedabovethechoroidalcleft.Withtheformationofthetemporallobe,thehippocampalfissureandchoroidalfissurearesqueezeddownandforward.Thearcuatehippocampalstructuredevelopsunevenly.Duetotheinvasionofthelateralfibersofthecorpuscallosum,thepartofthehippocampusabovethecorpuscallosumseldomdifferentiatesandformsgrayThelowerpartisnotaffectedbythecorpuscallosumanddevelopsintothemainpartofthehippocampusstructure,thatis,thehippocampusthatsinksintothebottomofthelateralventricle,thedentategyrusonbothsidesofthehippocampuscleft,andthebackofthehippocampusadjacenttothehippocampalcleft,becometheunderpin.Thehippocampusstructureisanimportantpartofthelimbicsystem,anditisalsoamuch-anticipatedpartinmodernepilepsyresearch.Somepeoplethinkthatthehippocampusstructureissimilartotheamplifierofepileptiformactivity.Alargenumberofexperimentalandclinicalstudieshavefoundthathippocampalsclerosisormedialtemporallobesclerosisiscloselyrelatedtotemporallobeseizures.Inaddition,therelationshipbetweenmanysmalllesionsinthissite,suchasintractableepilepsyassociatedwithlow-gradeastrocytomaandhippocampalneuronloss,hasalsobeenconfirmedandaffirmedbypathologicalstudies.Althoughthecausalrelationshipbetweenepilepsyandhippocampalstructuresclerosisisstilluncertain,itisgenerallybelievedthatthetwointeractandinfluenceeachother,andhippocampalsclerosisisthebasisof"epilepticmaturity".Differentsurgicalmethodsdesignedbycliniciansbasedonthecharacteristicsofhippocampalstructurehaveachievedsatisfactoryresultsincontrollingepilepsy.

Theappearanceofthehippocampusstructure:

Thehippocampusstructureisanteroposterior,occupyingthelowerpartofthetemporallobe,andprotrudingfromtheinnersideofthecollateralfissureatthebottomofthetemporalhornofthelateralventricle.Thenaminganddistinctionofhippocampalstructurehavenotyetbeenunified.Itisusuallydividedintoparahippocampalgyrus,inferiorsupport,hippocampalsulcus,dentategyrus(hornofhippocampus),ventricularbed,andhippocampalumbrellafromtheoutsidetotheinside(orfrombottomtotop).Thehippocampusisformedbyseveralsmallgyrusthatcurlinwardandcoverthehippocampalsulcus.Itisnamedafteritlookslikeahippocampus.Thehippocampusseenwhenthetemporalhornofthelateralventricleisopenedlooksmorelikeasilkwormpupaorhorn,soitisalsocalledit.Itisthehippocampushorn;thehippocampusisabout5cmlong,andthefrontpartisthehippocampusfootslightlybenttotheinside,whichisconnectedwiththeamygdalaclusterthatstraddlestheapexofthetemporalhornofthelateralventricle.Theventricularbedisalayerofshiningwhitematterspreadontheventricleofthehippocampus.Thislayerofwhitematterextendsbacktoformthehippocampusumbrella,whichfurtherextendsbackanduptoformadome.

1.Grayquilt:

Thegrayquiltisalsocalledthesuperiorgyrusofthecorpuscallosum.Itisathinlayerofgraymatteronthebackofthecorpuscallosum.Bringbackthecortex.Itbypassesthekneesofthecorpuscallosumforward,andmovesonthelowergyrusofthecorpuscallosumonbothsides;itbypassesthepressureofthecorpuscallosumbackward,andmovesonthefasciculargyrusonbothsides.Thefasciculargyrusisagraymatterthatmovesforward,downward,andoutwardinthedentategyrusandhippocampus.Therearetwolongitudinalfiberbundlesinthesuperiorgyrusofeachsideofthecorpuscallosum.Thelongitudinalfibersconnectthecorpuscallosumforwardandreturntothehippocampusinabundle.Thefibersofthecorpuscallosummaypenetratethecorpuscallosumandenterthefornix.

2.Dentategyrus:

Thedentategyrusisanarrowstripofgraymatter,whichissurroundedbythehippocampusexceptfortheinnersurface,andthefreesurfaceoftheinnersideisdividedintoteethwithtransversegrooves.,Hencethenamedentategyrus.Therearendisseparatedfromthehippocampusandmigratesinthefasciculargyrus.Fromthefrontendtothenotchofthehippocampalgyrus,itcurvesinwardatanacuteangleandcrossestheundersideofthehippocampalgyrus.Thishorizontalbandiscalledthedentategyrus.Thishorizontalbanddividesthehippocampusintotwoparts,thefrontpartiscalledtheditchback,andthebackpartiscalledtheinneredgeback.

3.Hippocampus:

Thehippocampusisanarcuatebulgeonthebottomofthefootwallofthelateralventricle.Forhippocampus.Theposteriorendofthehippocampusmigratesinthefasciculargyrus.Thesurfaceofthehippocampusiscoveredwithventricularmembrane,andthedeepsurfaceofthemembraneisalayerofwhitematter,whichbecomestheventricularbed.Thefibersgathertowardtheinneredgeofthehippocampustoformalongitudinalfiberbundle,whichiscalledthehippocampalumbrella.Thehippocampusumbrellamovesbackwardinthedome.

4.Lowersupport:

Thelowersupportisthetransitionalcortexbetweenthehippocampalgyrusandhippocampalcortex,fromthesixthlayeroftheparahippocampalgyrustothethirdlayerofthehippocampalThecortexofthepedestalareagraduallychangedfromfivelayerstofourlayers,andtheconnectionsbetweenthevariouspartswerealsodifferent.Therefore,thelowersupportisoftendividedinto4belt-shapedareas:sidelowersupport,frontlowersupport,lowersupportandlowersupporttip.Generally,thefirsttwobelt-shapedareasareclassifiedasentorhinalarea,andthelattertwobelt-shapedareasareclassifiedashippocampus.

Thefunctionofthehippocampusstructure:

Anatomyandphysiologyhaveshownthatthehippocampusstructurehasnothingtodowiththesenseofsmell,andthesizeofthehippocampusinmammalsisnotdirectlyrelatedtothedevelopmentofthesenseofsmell.Forexample,thehippocampusanddentategyrusofbluntolfactorywhaleslackingtheolfactorybulbandnervearewelldeveloped.Inhumanbrainspecimenslackingtheolfactorybulbandtract,thehippocampusiswelldeveloped.Thehippocampusdoesnotreceivedirectolfactoryfibersfromtheolfactorybulb,butindirectlycomesfromtheentorhinalarea.Animalexperimentshaveshownthatwhenthehippocampusisremoved,itdoesnotaffecttheabilitytodistinguishthesenseofsmell,andtheconditionedreflexfunctionofthesenseofsmellstillexists.Existingdataindicatethatthehippocampusmayberelatedtoshort-termmemory.Whenthehippocampusonbothsidesofthehippocampusaredamagedinalargerange,itcancauseahighlossofshort-termmemory,whilelong-termmemoryisusuallynotaffected.Thepatient'slossoftheabilitytolearnnewthingsandnewtechniquesisconsistentwiththesymptomscausedbybilateralmiddletemporalloberesection.Somepeoplebelievethatthehippocampusinthetemporallobemayworkinconjunctionwithotherneuralstructuresintheprocessofmemoryandrecall.Accordingtoclinicalreports,afterremovingthehippocampusonbothsides,includingthehippocampusandparahippocampalgyrus,patientshavesevere"recentmemory"disorders.Thedegreeofdisorderusuallydependsonthescopeofthehippocampusinjury,butonlywhenthemostanteriortemporallobeisinjured,Itdoesnotaffectmemory,andmemoryimpairmentoccursonlywhentheinjuryrangeextendsbackwardandinvolvesthehippocampus,dentategyrusandpartofthehippocampus.Memorylossusuallyoccursafterdamagetothebilateralhippocampalstructureandparahippocampalgyrus.Sometimes,somepatientsmayhaveaslightlanguagedisorderormemorydisorderafterpartialremovalofthetemporallobeofthedominanthemisphere.Itisgenerallybelievedthattheremustbedamagetothehippocampusonthecontralateralsideinthesecases.InsomeAlzheimer'spatientswithmemoryloss,themostobviousdamagecanbefoundinthehippocampus.Researchreportsalsopointedoutthatthehippocampusparticipatesinemotionalresponseoremotionalcontrol,participatesincertainvisceralactivities,andhasanimpactontheascendingexcitationsystemofthebrainstemnetworkstructure.[1]

Hippocampalstructureandepilepsy:

Thehippocampushasaverylowseizurethreshold.Paroxysmalfiringoriginatesfromacertainpartoftheolfactorybrain,whichquicklyspreadstootherareasoftheolfactorybrainandthehypothalamus,orbecomesdiffuse.Inthehippocampusandthenearmidlineofthetemporallobe,thestructuralsclerosisoftheadjacenthippocampusisthemostcommonpathologicalchangeinthebrainofepilepticpatientsduringautopsy.Therefore,itisbelievedthatthenearmidlinesclerosisofthetemporallobeisthemostcommoncauseofepilepticseizuresinchildhood.Duringhippocampalseizures,variouspsychomotoreffectscanoccur,includingsmell,sight,touch,andothertypesofhallucinations.Evenifthepatientlosesconsciousness,knowingthatthisisillusion,itcannotbesuppressed.