The aim of the present study was to analyze the location of degenerating neurons in the dorsal (insular) claustrum (DCL, VCL) and the dorsal, intermediate and ventral endopiriform nucleus (DEn, IEn, VEn) in rat pups following lithium-pilocarpine status epilepticus (SE) induced at postnatal days [P]12, 15, 18, 21 and 25. The presence of Fluoro-Jade B-positive neurons was evaluated at 4, 12, 24, 48 h and 1 week later. A small number of degenerated neurons was observed in the CL, as well as in the DEn at P12 and P15. The number of degenerated neurons was increased in the CL as well as in the DEn at P18 and above and was highest at longer survival intervals. The CL at P15 and 18 contained a small or moderate number of degenerated neurons mainly close to the medial and dorsal margins also designated as DCl ("shell") while isolated degenerated neurons were distributed in the VCl ("core"). In P21 and 25, a larger number of degenerated neurons occurred in both subdivisions of the dorsal claustrum. The majority of degenerated neurons in the endopiriform nucleus were found in the intermediate and caudal third of the DEn. A small number of degenerated neurons was dispersed in the whole extent of the DEn with prevalence to its medial margin. Our results indicate that degenerated neurons in the claustrum CL and endopiriform nucleus are distributed mainly in subdivisions originating from the ventral pallium; their distribution correlates with chemoarchitectonics of both nuclei and with their intrinsic and extrinsic connections.

Institute of Anatomy 1st Medical Faculty Charles University 12000 Prague Czech Republic

Institute of Anatomy 2nd Medical Faculty Charles University 15006 Prague Czech Republic

Laboratory of Developmental Epileptology Institute of Physiology Czech Academy of Sciences 14200 Prague Czech Republic

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Pitkanen A., Kharatishvili I., Karhunen H., Lukasiuk K., Immonen R., Nairismägi J., Gröhn O., Nissinen J. Epileptogenesis in experimental models. Epilepsia. 2007;48((Suppl. 2)):13–20. doi: 10.1111/j.1528-1167.2007.01063.x. PubMed DOI

Cavalheiro E.A., Silva D.F., Turski W.A., Calderazzo-Filho L.S., Bortolotto Z.A., Turski L. The susceptibility of rats to pilocarpine-induced seizures is age-dependent. Brain Res. 1987;465:43–58. doi: 10.1016/0165-3806(87)90227-6. PubMed DOI

Covolan L., Mello L.E. Temporal profile of neuronal injury following pilocarpine or kainic acid-induced status epilepticus. Epilepsy Res. 2000;39:133–152. doi: 10.1016/S0920-1211(99)00119-9. PubMed DOI

Druga R., Kubová H., Suchomelová L., Haugvicová R. Lithium/pilocarpine status epilepticus-induced neuropathology of piriform cortex and adjoining structures in rats is age-dependent. Physiol. Res. 2003;52:251–264. doi: 10.33549/physiolres.930296. PubMed DOI

Druga R., Mares P., Otáhal J., Kubová H. Degenerative neuronal changes in the rat thalamus induced by status epilepticus at different developmental stages. Epilepsy Res. 2005;63:43–65. doi: 10.1016/j.eplepsyres.2004.11.001. PubMed DOI

Kubova H., Druga R., Haugvicová R., Suchomelová L., Pitkanen A. Dynamic changes of status epilepticus-induced neuronal degeneration in the mediodorsal nucleus of the thalamus during postnatal development of the rat. Epilepsia. 2002;43((Suppl. 5)):54–60. doi: 10.1046/j.1528-1157.43.s.5.36.x. PubMed DOI

Kubova H., Druga R., Lukasiuk K., Suchomelová L., Haugvicová R., Jirmanová I., Pitkänen A. Status epilepticus causes necrotic damage in the mediodorsal nucleus of the thalamus in immature rats. J. Neurosci. 2001;21:3593–3599. doi: 10.1523/JNEUROSCI.21-10-03593.2001. PubMed DOI PMC

Turski W.A., Cavalheiro E.A., Bortolotto Z.A., Mello L.M., Schwarz M., Turski L. Seizures produced by pilocarpine in mice: A behavioral, electroencephalographic and morphological analysis. Brain Res. 1984;321:237–253. doi: 10.1016/0006-8993(84)90177-X. PubMed DOI

Turski W.A., Cavalheiro E.A., Schwarz M., Czuczwar S.J., Kleinrok Z., Turski L. Limbic seizures produced by pilocarpine in rats: Behavioural, electroencephalographic and neuropathological study. Behav. Brain Res. 1983;9:315–335. doi: 10.1016/0166-4328(83)90136-5. PubMed DOI

Ashwell K.W., Hardman C., Paxinos G. The claustrum is not missing from all monotreme brains. Brain Behav. Evol. 2004;64:223–241. doi: 10.1159/000080243. PubMed DOI

Druga R. The claustrum of the cat (Felis domestica) Folia Morphol. 1966;14:7–16. PubMed

Druga R., Salaj M., Barinka F., Edelstein L., Kubová H. Calretinin immunoreactivity in the claustrum of the rat. Front. Neuroanat. 2014;8:160. doi: 10.3389/fnana.2014.00160. PubMed DOI PMC

Edelstein L.R., Denaro F.J. The claustrum: A historical review of its anatomy, physiology, cytochemistry and functional significance. Cell Mol. Biol. 2004;50:675–702. PubMed

Narkiewicz O. Degenerations in the Claustrum after Regional Neocortical Ablations in the Cat. J. Comp. Neurol. 1964;123:335–355. doi: 10.1002/cne.901230304. PubMed DOI

Druga R. The structure and connections of the claustrum. In: Edelstein L.R., Smythies J.R., Ramachandran V.S., editors. The Claustrum. Structural, Functional and Clinical Neuroscience. Elsevier; San Diego, CA, USA: 2014. pp. 29–84.

Medina L., Legaz I., González G., De Castro F., Rubenstein J.L., Puelles L. Expression of Dbx1, Neurogenin 2, Semaphorin 5A, Cadherin 8, and Emx1 distinguish ventral and lateral pallial histogenetic divisions in the developing mouse claustroamygdaloid complex. J. Comp. Neurol. 2004;474:504–523. doi: 10.1002/cne.20141. PubMed DOI

Puelles L., Kuwana E., Puelles E., Bulfone A., Shimamura K., Keleher J., Smiga S., Rubenstein J.L. Pallial and subpallial derivatives in the embryonic chick and mouse telencephalon, traced by the expression of the genes Dlx-2, Emx-1, Nkx-2.1, Pax-6, and Tbr-1. J. Comp. Neurol. 2000;424:409–438. PubMed

Davila J.C., Real M.A., Olmos J.L., Legaz I., Medina L., Guirado S. Embryonic and postnatal development of GABA, calbindin, calretinin, and parvalbumin in the mouse claustral complex. J. Comp. Neurol. 2005;481:42–57. doi: 10.1002/cne.20347. PubMed DOI

Druga R., Chen S., Bentivoglio M. Parvalbumin and calbindin in the rat claustrum: An immunocytochemical study combined with retrograde tracing frontoparietal cortex. J. Chem. Neuroanat. 1993;6:399–406. doi: 10.1016/0891-0618(93)90014-U. PubMed DOI

Guirado S., Real M.A., Olmos J.L., Dávila J.C. Distinct types of nitric oxide-producing neurons in the developing and adult mouse claustrum. J. Comp. Neurol. 2003;465:431–444. doi: 10.1002/cne.10835. PubMed DOI

Kowianski P., Moryś J.M., Wójcik S., Dziewiatkowski J., Luczyńska A., Spodnik E., Timmermans J.P., Moryś J. Neuropeptide-containing neurons in the endopiriform region of the rat: Morphology and colocalization with calcium-binding proteins and nitric oxide synthase. Brain Res. 2004;996:97–110. doi: 10.1016/j.brainres.2003.10.020. PubMed DOI

Kowianski P., Timmermans J.P., Morys J. Differentiation in the immunocytochemical features of intrinsic and cortically projecting neurons in the rat claustrum—Combined immunocytochemical and axonal transport study. Brain Res. 2001;905:63–71. doi: 10.1016/S0006-8993(01)02408-8. PubMed DOI

Real M.A., Davila J.C., Guirado S. Expression of calcium-binding proteins in the mouse claustrum. J. Chem. Neuroanat. 2003;25:151–160. doi: 10.1016/S0891-0618(02)00104-7. PubMed DOI

Kowianski P., Dziewiatkowski J., Moryś J.M., Majak K., Wójcik S., Edelstein L.R., Lietzau G., Moryś J. Colocalization of neuropeptides with calcium-binding proteins in the claustral interneurons during postnatal development of the rat. Brain Res. Bull. 2009;80:100–106. doi: 10.1016/j.brainresbull.2009.06.020. PubMed DOI

Erwin S.R., Sullivan K.E., Kendrick R.M., Marriott B., Wang L., Clements J., Lemire A.L., Jackson J., Cembrowski M.S. Spatially patterned excitatory neuron subtypes and projections of the claustrum. Elife. 2021;10:e68967. doi: 10.7554/eLife.68967. PubMed DOI PMC

Paxinos G., Watson C. The Rat Brain in Stereotaxic Coordinates. 6th ed. Academic Press; San Diego, CA, USA: 2007.

Obst-Pernberg K., Medina L., Redies C. Expression of R-cadherin and N-cadherin by cell groups and fiber tracts in the developing mouse forebrain: Relation to the formation of functional circuits. Neuroscience. 2001;106:505–533. doi: 10.1016/S0306-4522(01)00292-5. PubMed DOI

Morello T., Kollmar R., Ramzaoui A., Stewart M., Orman R. Differential distribution of inhibitory neuron types in subregions of claustrum and dorsal endopiriform nucleus of the short-tailed fruit bat. Brain Struct. Funct. 2022;227:1615–1640. doi: 10.1007/s00429-022-02459-0. PubMed DOI

Narkiewicz O., Mamos L. Relation of the insular claustrum to the neocortex in Insectivora. J. Hirnforsch. 1990;31:623–633. PubMed

Mathur B.N., Caprioli R.M., Deutch A.Y. Proteomic analysis illuminates a novel structural definition of the claustrum and insula. Cereb. Cortex. 2009;19:2372–2379. doi: 10.1093/cercor/bhn253. PubMed DOI PMC

Majak K., Kowiánski P., Morýs J., Spodnik J., Karwacki Z., Wisniewski H.M. The limbic zone of the rabbit and rat claustrum: A study of the claustrocingulate connections based on the retrograde axonal transport of fluorescent tracers. Anat. Embryol. 2000;201:15–25. doi: 10.1007/PL00008225. PubMed DOI

Minciacchi D., Molinari M., Bentivoglio M., Macchi G. The organization of the ipsi- and contralateral claustrocortical system in rat with notes on the bilateral claustrocortical projections in cat. Neuroscience. 1985;16:557–576. doi: 10.1016/0306-4522(85)90192-7. PubMed DOI

Druga R. Cortico-claustral connections. II. Connections from the parietal, temporal and occipital cortex to the claustrum. Folia Morphol. 1968;16:142–149. PubMed

Sherk H., LeVay S. Contribution of the cortico-claustral loop to receptive field properties in area 17 of the cat. J. Neurosci. 1983;3:2121–2127. doi: 10.1523/JNEUROSCI.03-11-02121.1983. PubMed DOI PMC

Crick F.C., Koch C. What is the function of the claustrum? Philos. Trans. R. Soc. Lond. B Biol. Sci. 2005;360:1271–1279. doi: 10.1098/rstb.2005.1661. PubMed DOI PMC

Fu W., Sugai T., Yoshimura H., Onoda N. Convergence of olfactory and gustatory connections onto the endopiriform nucleus in the rat. Neuroscience. 2004;126:1033–1041. doi: 10.1016/j.neuroscience.2004.03.041. PubMed DOI

Majak K., Morys J. Endopiriform nucleus connectivities: The implications for epileptogenesis and epilepsy. Folia Morphol. 2007;66:267–271. PubMed

Majak K., Pikkarainen M., Kemppainen S., Jolkkonen E., Pitkänen A. Projections from the amygdaloid complex to the claustrum and the endopiriform nucleus: A Phaseolus vulgaris leucoagglutinin study in the rat. J. Comp. Neurol. 2002;451:236–249. doi: 10.1002/cne.10346. PubMed DOI

Hoffman W.H., Haberly L.B. Kindling-induced epileptiform potentials in piriform cortex slices originate in the underlying endopiriform nucleus. J. Neurophysiol. 1996;76:1430–1438. doi: 10.1152/jn.1996.76.3.1430. PubMed DOI

Ben-Ari Y., Tremblay E., Ottersen O.P. Injections of kainic acid into the amygdaloid complex of the rat: An electrographic, clinical and histological study in relation to the pathology of epilepsy. Neuroscience. 1980;5:515–528. doi: 10.1016/0306-4522(80)90049-4. PubMed DOI

Sperk G., Lassmann H., Baran H., Kish S.J., Seitelberger F., Hornykiewicz O. Kainic acid induced seizures: Neurochemical and histopathological changes. Neuroscience. 1983;10:1301–1315. doi: 10.1016/0306-4522(83)90113-6. PubMed DOI

Schmued L.C., Hopkins K.J. Fluoro-Jade B: A high affinity fluorescent marker for the localization of neuronal degeneration. Brain Res. 2000;874:123–130. doi: 10.1016/S0006-8993(00)02513-0. PubMed DOI

McDonald A.J., Mott D.D. Functional neuroanatomy of amygdalohippocampal interconnections and their role in learning and memory. J. Neurosci. Res. 2017;95:797–820. doi: 10.1002/jnr.23709. PubMed DOI PMC

Real M.A., Davila J.C., Guirado S. Immunohistochemical localization of the vesicular glutamate transporter VGLUT2 in the developing and adult mouse claustrum. J. Chem. Neuroanat. 2006;31:169–177. doi: 10.1016/j.jchemneu.2005.12.002. PubMed DOI

Kim J., Matney C.J., Roth R.H., Brown S.P. Synaptic Organization of the Neuronal Circuits of the Claustrum. J. Neurosci. 2016;36:773–784. doi: 10.1523/JNEUROSCI.3643-15.2016. PubMed DOI PMC

Behan M., Haberly L.B. Intrinsic and efferent connections of the endopiriform nucleus in rat. J. Comp. Neurol. 1999;408:532–548. doi: 10.1002/(SICI)1096-9861(19990614)408:4<532::AID-CNE7>3.0.CO;2-S. PubMed DOI

Demir R., Haberly L.B., Jackson M.B. Voltage imaging of epileptiform activity in slices from rat piriform cortex: Onset and propagation. J. Neurophysiol. 1998;80:2727–2742. doi: 10.1152/jn.1998.80.5.2727. PubMed DOI

Tseng G.F., Haberly L.B. Deep neurons in piriform cortex. II. Membrane properties that underlie unusual synaptic responses. J. Neurophysiol. 1989;62:386–400. doi: 10.1152/jn.1989.62.2.386. PubMed DOI

Demir R., Haberly L.B., Jackson M.B. Epileptiform discharges with in-vivo-like features in slices of rat piriform cortex with longitudinal association fibers. J. Neurophysiol. 2001;86:2445–2460. doi: 10.1152/jn.2001.86.5.2445. PubMed DOI

Arimatsu Y., Matney C.J., Roth R.H., Brown S.P. Organization and development of corticocortical associative neurons expressing the orphan nuclear receptor Nurr1. J. Comp. Neurol. 2003;466:180–196. doi: 10.1002/cne.10875. PubMed DOI

Arimatsu Y., Kojima M., Ishida M. Area- and lamina-specific organization of a neuronal subpopulation defined by expression of latexin in the rat cerebral cortex. Neuroscience. 1999;88:93–105. doi: 10.1016/S0306-4522(98)00185-7. PubMed DOI

Arimatsu Y., Nihonmatsu I., Hatanaka Y. Localization of latexin-immunoreactive neurons in the adult cat cerebral cortex and claustrum/endopiriform formation. Neuroscience. 2009;162:1398–1410. doi: 10.1016/j.neuroscience.2009.05.060. PubMed DOI

Arimatsu Y., Nihonmatsu I., Hirata K., Takiguchi-Hayashi K. Cogeneration of neurons with a unique molecular phenotype in layers V and VI of widespread lateral neocortical areas in the rat. J. Neurosci. 1994;14:2020–2031. doi: 10.1523/JNEUROSCI.14-04-02020.1994. PubMed DOI PMC

Kubova H., Mares P. Are morphologic and functional consequences of status epilepticus in infant rats progressive? Neuroscience. 2013;235:232–249. doi: 10.1016/j.neuroscience.2012.12.055. PubMed DOI

Sankar R., Shin D.H., Liu H., Mazarati A., Pereira de Vasconcelos A., Wasterlain C.G. Patterns of status epilepticus-induced neuronal injury during development and long-term consequences. J. Neurosci. 1998;18:8382–8393. doi: 10.1523/JNEUROSCI.18-20-08382.1998. PubMed DOI PMC

Scantlebury M.H., Heida J.G., Hasson H.J., Velísková J., Velísek L., Galanopoulou A.S., Moshé S.L. Age-dependent consequences of status epilepticus: Animal models. Epilepsia. 2007;48((Suppl. 2)):75–82. doi: 10.1111/j.1528-1167.2007.01069.x. PubMed DOI

Verrotti A., Mazzocchetti C. Epilepsy: Timely treatment of refractory convulsive status epilepticus. Nat. Rev. Neurol. 2018;14:256–258. doi: 10.1038/nrneurol.2018.38. PubMed DOI

Klitgaard H., Matagne A., Vanneste-Goemaere J., Margineanu D.G. Pilocarpine-induced epileptogenesis in the rat: Impact of initial duration of status epilepticus on electrophysiological and neuropathological alterations. Epilepsy Res. 2002;51:93–107. doi: 10.1016/S0920-1211(02)00099-2. PubMed DOI

Mazarati A.M., Baldwin R.A., Sankar R., Wasterlain C.G. Time-dependent decrease in the effectiveness of antiepileptic drugs during the course of self-sustaining status epilepticus. Brain Res. 1998;814:179–185. doi: 10.1016/S0006-8993(98)01080-4. PubMed DOI

Torolira D., Suchomelova L., Wasterlain C.G., Niquet J. Phenobarbital and midazolam increase neonatal seizure-associated neuronal injury. Ann. Neurol. 2017;82:115–120. doi: 10.1002/ana.24967. PubMed DOI PMC

Kubova H., Mares P., Suchomelová L., Brozek G., Druga R., Pitkänen A. Status epilepticus in immature rats leads to behavioural and cognitive impairment and epileptogenesis. Eur. J. Neurosci. 2004;19:3255–3265. doi: 10.1111/j.0953-816X.2004.03410.x. PubMed DOI