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  1. Article ; Online: Optogenetic activation of the reticular nucleus of the thalamus attenuates limbic seizures via inhibition of the midline thalamus.

    Wicker, Evan / Forcelli, Patrick A

    Epilepsia

    2021  Volume 62, Issue 9, Page(s) 2283–2296

    Abstract: Objective: The nucleus reticularis of the thalamus (nRT) is most studied in epilepsy for its role in the genesis of absence seizures; much less is known regarding its role in other seizure types, including those originating in limbic structures and the ... ...

    Abstract Objective: The nucleus reticularis of the thalamus (nRT) is most studied in epilepsy for its role in the genesis of absence seizures; much less is known regarding its role in other seizure types, including those originating in limbic structures and the temporal lobe. As it is a major source of inhibitory input to higher order thalamic nuclei, stimulation of the nRT may be an effective strategy to disrupt seizure activity that requires thalamic engagement.
    Methods: We recorded single unit activity from the nRT prior to and after infusion of bicuculline into the area tempestas. We monitored single unit activity time-locked with interictal spikes. We optogenetically activated the nRT in both the area tempestas and amygdala kindling models. We tested a role for projections from the nRT to higher order midline thalamic nuclei through the use of retrogradely trafficked viral vector.
    Results: Mean firing rate in the nRT was decreased after infusion of bicuculline into the area tempestas as compared to the preinfusion baseline. nRT unit firing in response to interictal spikes was heterogeneous, with an approximately equal proportion of neurons displaying (1) no change in firing, (2) increased firing, and (3) decreasing firing. Optogenetic activation of the nRT significantly suppressed seizure activity in both the area tempestas and amygdala kindling models. Optogenetic activation of contralaterally targeting projections but not ipsilaterally targeting projections from the nRT to the midline thalamus significantly suppressed seizures in the kindling model.
    Significance: Although the nRT is typically thought of in the context of absence seizures, our data show that it may be a viable target for other seizure types. In two models that recapitulate the seizure types seen in temporal lobe epilepsy, nRT activation suppressed both electrographic and behavioral seizures. These data suggest that the nRT should be considered more broadly in the context of epilepsy.
    MeSH term(s) Bicuculline ; Epilepsy, Absence/genetics ; Humans ; Optogenetics ; Seizures ; Thalamus
    Chemical Substances Bicuculline (Y37615DVKC)
    Language English
    Publishing date 2021-07-26
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 216382-2
    ISSN 1528-1167 ; 0013-9580
    ISSN (online) 1528-1167
    ISSN 0013-9580
    DOI 10.1111/epi.17016
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Pathway-specific inhibition of critical projections from the mediodorsal thalamus to the frontal cortex controls kindled seizures.

    Wicker, Evan / Hyder, Safwan K / Forcelli, Patrick A

    Progress in neurobiology

    2022  Volume 214, Page(s) 102286

    Abstract: There is a large unmet need for improved treatment for temporal lobe epilepsy (TLE); circuit-specific manipulation that disrupts the initiation and propagation of seizures is promising in this regard. The midline thalamus, including the mediodorsal ... ...

    Abstract There is a large unmet need for improved treatment for temporal lobe epilepsy (TLE); circuit-specific manipulation that disrupts the initiation and propagation of seizures is promising in this regard. The midline thalamus, including the mediodorsal nucleus (MD) is a critical distributor of seizure activity, but its afferent and efferent pathways that mediate seizure activity are unknown. Here, we used chemogenetics to silence input and output projections of the MD to discrete regions of the frontal cortex in the kindling model of TLE in rats. Chemogenetic inhibition of the projection from the amygdala to the MD abolished seizures, an effect that was replicated using optogenetic inhibition. Chemogenetic inhibition of projections from the MD to the prelimbic cortex likewise abolished seizures. By contrast, inhibition of projections from the MD to other frontal regions produced partial (orbitofrontal cortex, infralimbic cortex) or no (cingulate, insular cortex) attenuation of behavioral or electrographic seizure activity. These results highlight the particular importance of projections from MD to prelimbic cortex in the propagation of amygdala-kindled seizures.
    MeSH term(s) Amygdala/physiology ; Animals ; Frontal Lobe/physiology ; Humans ; Kindling, Neurologic/physiology ; Rats ; Seizures ; Thalamus/physiology
    Language English
    Publishing date 2022-05-12
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 185535-9
    ISSN 1873-5118 ; 0301-0082
    ISSN (online) 1873-5118
    ISSN 0301-0082
    DOI 10.1016/j.pneurobio.2022.102286
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Serum Amyloid A is Expressed in the Brain After Traumatic Brain Injury in a Sex-Dependent Manner.

    Soriano, Sirena / Moffet, Bridget / Wicker, Evan / Villapol, Sonia

    Cellular and molecular neurobiology

    2020  Volume 40, Issue 7, Page(s) 1199–1211

    Abstract: Serum amyloid A (SAA) is an acute phase protein upregulated in the liver after traumatic brain injury (TBI). So far, it has not been investigated whether SAA expression also occurs in the brain in response to TBI. For this, we performed a moderate ... ...

    Abstract Serum amyloid A (SAA) is an acute phase protein upregulated in the liver after traumatic brain injury (TBI). So far, it has not been investigated whether SAA expression also occurs in the brain in response to TBI. For this, we performed a moderate controlled cortical impact injury in adult male and female mice and analyzed brain, blood, and liver samples at 6 h, 1, 3, and 10 days post-injury (dpi). We measured the levels of SAA in serum, brain and liver by western blot. We also used immunohistochemical techniques combined with in situ hybridization to determine SAA mRNA and protein expression in the brain. Our results revealed higher levels of SAA in the bloodstream in males compared to females at 6 h post-TBI. Liver and serum SAA protein showed a peak of expression at 1 dpi followed by a decrease at 3 to 10 dpi in both sexes. Both SAA mRNA and protein expression colocalize with astrocytes and macrophages/microglia in the cortex, corpus callosum, thalamus, and hippocampus after TBI. For the first time, here we show that SAA is expressed in the brain in response to TBI. Collectively, SAA expression was higher in males compared to females, and in association with the sex-dependent neuroinflammatory response after brain injury. We suggest that SAA could be a crucial protein associated to the acute neuroinflammation following TBI, not only for its hepatic upregulation but also for its expression in the injured brain.
    MeSH term(s) Animals ; Astrocytes/metabolism ; Brain/metabolism ; Brain Injuries/metabolism ; Brain Injuries, Traumatic/metabolism ; Disease Models, Animal ; Female ; Inflammation/metabolism ; Male ; Mice, Inbred C57BL ; Microglia/metabolism ; Serum Amyloid A Protein/metabolism ; Sex Factors
    Chemical Substances Serum Amyloid A Protein
    Language English
    Publishing date 2020-02-14
    Publishing country United States
    Document type Journal Article
    ZDB-ID 283404-2
    ISSN 1573-6830 ; 0272-4340
    ISSN (online) 1573-6830
    ISSN 0272-4340
    DOI 10.1007/s10571-020-00808-3
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Chemogenetic silencing of the midline and intralaminar thalamus blocks amygdala-kindled seizures.

    Wicker, Evan / Forcelli, Patrick A

    Experimental neurology

    2016  Volume 283, Issue Pt A, Page(s) 404–412

    Abstract: Temporal lobe epilepsy is the most common form of medically-intractable epilepsy. While seizures in TLE originate in structures such as hippocampus, amygdala, and temporal cortex, they propagate through a crucial relay: the midline/intralaminar thalamus. ...

    Abstract Temporal lobe epilepsy is the most common form of medically-intractable epilepsy. While seizures in TLE originate in structures such as hippocampus, amygdala, and temporal cortex, they propagate through a crucial relay: the midline/intralaminar thalamus. Prior studies have shown that pharmacological inhibition of midline thalamus attenuates limbic seizures. Here, we examined a recently developed technology, Designer Receptors Exclusively Activated by Designer Drugs (DREADDs), as a means of chemogenetic silencing to attenuate limbic seizures. Adult, male rats were electrically kindled from the amygdala, and injected with virus coding for inhibitory (hM4Di) DREADDs into the midline/intralaminar thalamus. When treated with the otherwise inert ligand Clozapine-N-Oxide (CNO) at doses of 2.5, 5, and 10mg/kg, electrographic and behavioral seizure manifestations were suppressed in comparison to vehicle. At higher doses, we found complete blockade of seizure activity in a subset of subjects. CNO displayed a sharp time-response profile, with significant seizure attenuation seen 20-30min post injection, in comparison to 10 and 40min post injection. Seizures in animals injected with a control vector (i.e., no DREADD) were unaffected by CNO administration. These data underscore the crucial role of the midline/intralaminar thalamus in the propagation of seizures, specifically in the amygdala kindling model, and provide validation of chemogenetic silencing of limbic seizures.
    MeSH term(s) Amygdala/physiopathology ; Analysis of Variance ; Animals ; Anticonvulsants/pharmacology ; Anticonvulsants/therapeutic use ; Clozapine/analogs & derivatives ; Clozapine/therapeutic use ; Disease Models, Animal ; Dose-Response Relationship, Drug ; Electric Stimulation/adverse effects ; Evoked Potentials/physiology ; Intralaminar Thalamic Nuclei/drug effects ; Intralaminar Thalamic Nuclei/physiology ; Kindling, Neurologic/physiology ; Male ; Maze Learning/drug effects ; Midline Thalamic Nuclei/drug effects ; Midline Thalamic Nuclei/physiology ; Rats ; Rats, Sprague-Dawley ; Seizures/drug therapy ; Seizures/etiology
    Chemical Substances Anticonvulsants ; Clozapine (J60AR2IKIC) ; clozapine N-oxide (MZA8BK588J)
    Language English
    Publishing date 2016-09
    Publishing country United States
    Document type Journal Article
    ZDB-ID 207148-4
    ISSN 1090-2430 ; 0014-4886
    ISSN (online) 1090-2430
    ISSN 0014-4886
    DOI 10.1016/j.expneurol.2016.07.003
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  5. Article: The Effect of Traumatic Brain Injury on Sleep Architecture and Circadian Rhythms in Mice-A Comparison of High-Frequency Head Impact and Controlled Cortical Injury.

    Korthas, Holly T / Main, Bevan S / Harvey, Alex C / Buenaventura, Ruchelle G / Wicker, Evan / Forcelli, Patrick A / Burns, Mark P

    Biology

    2022  Volume 11, Issue 7

    Abstract: Traumatic brain injury (TBI) is a significant risk factor for the development of sleep and circadian rhythm impairments. In this study we compare the circadian rhythms and sleep patterns in the high-frequency head impact (HFHI) and controlled cortical ... ...

    Abstract Traumatic brain injury (TBI) is a significant risk factor for the development of sleep and circadian rhythm impairments. In this study we compare the circadian rhythms and sleep patterns in the high-frequency head impact (HFHI) and controlled cortical impact (CCI) mouse models of TBI. These mouse models have different injury mechanisms key differences of pathology in brain regions controlling circadian rhythms and EEG wave generation. We found that both HFHI and CCI caused dysregulation in the diurnal expression of core circadian genes (
    Language English
    Publishing date 2022-07-08
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2661517-4
    ISSN 2079-7737
    ISSN 2079-7737
    DOI 10.3390/biology11071031
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  6. Article: The Effect of Traumatic Brain Injury on Sleep Architecture and Circadian Rhythms in Mice—A Comparison of High-Frequency Head Impact and Controlled Cortical Injury

    Korthas, Holly T. / Main, Bevan S. / Harvey, Alex C. / Buenaventura, Ruchelle G. / Wicker, Evan / Forcelli, Patrick A. / Burns, Mark P.

    Biology. 2022 July 08, v. 11, no. 7

    2022  

    Abstract: Traumatic brain injury (TBI) is a significant risk factor for the development of sleep and circadian rhythm impairments. In this study we compare the circadian rhythms and sleep patterns in the high-frequency head impact (HFHI) and controlled cortical ... ...

    Abstract Traumatic brain injury (TBI) is a significant risk factor for the development of sleep and circadian rhythm impairments. In this study we compare the circadian rhythms and sleep patterns in the high-frequency head impact (HFHI) and controlled cortical impact (CCI) mouse models of TBI. These mouse models have different injury mechanisms key differences of pathology in brain regions controlling circadian rhythms and EEG wave generation. We found that both HFHI and CCI caused dysregulation in the diurnal expression of core circadian genes (Bmal1, Clock, Per1,2, Cry1,2) at 24 h post-TBI. CCI mice had reduced locomotor activity on running wheels in the first 7 d post-TBI; however, both CCI and HFHI mice were able to maintain circadian behavior cycles even in the absence of light cues. We used implantable EEG to measure sleep cycles and brain activity and found that there were no differences in the time spent awake, in NREM or REM sleep in either TBI model. However, in the sleep states, CCI mice have reduced delta power in NREM sleep and reduced theta power in REM sleep at 7 d post-TBI. Our data reveal that different types of brain trauma can result in distinct patterns of circadian and sleep disruptions and can be used to better understand the etiology of sleep disorders after TBI.
    Keywords brain ; brain damage ; circadian rhythm ; etiology ; head ; locomotion ; mice ; risk factors ; sleep
    Language English
    Dates of publication 2022-0708
    Publishing place Multidisciplinary Digital Publishing Institute
    Document type Article
    ZDB-ID 2661517-4
    ISSN 2079-7737
    ISSN 2079-7737
    DOI 10.3390/biology11071031
    Database NAL-Catalogue (AGRICOLA)

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  7. Article ; Online: Serum Amyloid A Protein as a Potential Biomarker for Severity and Acute Outcome in Traumatic Brain Injury.

    Wicker, Evan / Benton, Leah / George, Kershina / Furlow, William / Villapol, Sonia

    BioMed research international

    2019  Volume 2019, Page(s) 5967816

    Abstract: Traumatic brain injury (TBI) causes a wide variety of neuroinflammatory events. These neuroinflammatory events depend, to a greater extent, on the severity of the damage. Our previous studies have shown that the liver produces serum amyloid A (SAA) at ... ...

    Abstract Traumatic brain injury (TBI) causes a wide variety of neuroinflammatory events. These neuroinflammatory events depend, to a greater extent, on the severity of the damage. Our previous studies have shown that the liver produces serum amyloid A (SAA) at high levels in the initial hours after controlled cortical impact (CCI) injury in mice. Clinical studies have reported detectable SAA in the plasma of brain injury patients, but it is not clear if SAA levels depend on TBI severity. To evaluate this question, we performed a mild to severe CCI injury in wild-type mice. We collected blood samples and brains at 1, 3, and 7 days after injury for protein detection by western blotting, enzyme-linked immunosorbent assay, or immunohistochemical analysis. Our results showed that severe CCI injury compared to mild CCI injury or sham mice caused an increased neuronal death, larger lesion volume, increased microglia/macrophage density, and augmented neutrophil infiltration. Furthermore, we found that the serum levels of SAA protein ascended in the blood in correlation with high neuroinflammatory and neurodegenerative responses. Altogether, these results suggest that serum SAA may be a novel neuroinflammation-based, and severity-dependent, biomarker for acute TBI.
    MeSH term(s) Animals ; Biomarkers/blood ; Brain/pathology ; Brain Injuries, Traumatic/blood ; Brain Injuries, Traumatic/pathology ; Disease Models, Animal ; Humans ; Mice ; Serum Amyloid A Protein/metabolism ; Trauma Severity Indices
    Chemical Substances Biomarkers ; Serum Amyloid A Protein
    Language English
    Publishing date 2019-04-16
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2698540-8
    ISSN 2314-6141 ; 2314-6133
    ISSN (online) 2314-6141
    ISSN 2314-6133
    DOI 10.1155/2019/5967816
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: Divergent Effects of Systemic and Intracollicular CB Receptor Activation Against Forebrain and Hindbrain-Evoked Seizures in Rats.

    Santos, Victor R / Hammack, Robert / Wicker, Evan / N'Gouemo, Prosper / Forcelli, Patrick A

    Frontiers in behavioral neuroscience

    2020  Volume 14, Page(s) 595315

    Abstract: Cannabinoid (CB) receptor agonists are of growing interest as targets for anti-seizure therapies. Here we examined the effect of systemic administration of the CB receptor agonist WIN 55,212-2 (WIN) against audiogenic seizures (AGSs) in the Genetically ... ...

    Abstract Cannabinoid (CB) receptor agonists are of growing interest as targets for anti-seizure therapies. Here we examined the effect of systemic administration of the CB receptor agonist WIN 55,212-2 (WIN) against audiogenic seizures (AGSs) in the Genetically Epilepsy Prone Rat (GEPR)-3 strain, and against seizures evoked focally from the
    Language English
    Publishing date 2020-11-17
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2452960-6
    ISSN 1662-5153
    ISSN 1662-5153
    DOI 10.3389/fnbeh.2020.595315
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Mediodorsal thalamus is required for discrete phases of goal-directed behavior in macaques.

    Wicker, Evan / Turchi, Janita / Malkova, Ludise / Forcelli, Patrick A

    eLife

    2018  Volume 7

    Abstract: Reward contingencies are dynamic: outcomes that were valued at one point may subsequently lose value. Action selection in the face of dynamic reward associations requires several cognitive processes: registering a change in value of the primary ... ...

    Abstract Reward contingencies are dynamic: outcomes that were valued at one point may subsequently lose value. Action selection in the face of dynamic reward associations requires several cognitive processes: registering a change in value of the primary reinforcer, adjusting the value of secondary reinforcers to reflect the new value of the primary reinforcer, and guiding action selection to optimal choices. Flexible responding has been evaluated extensively using reinforcer devaluation tasks. Performance on this task relies upon amygdala, Areas 11 and 13 of orbitofrontal cortex (OFC), and mediodorsal thalamus (MD). Differential contributions of amygdala and Areas 11 and 13 of OFC to specific sub-processes have been established, but the role of MD in these sub-processes is unknown. Pharmacological inactivation of the macaque MD during specific phases of this task revealed that MD is required for reward valuation and action selection. This profile is unique, differing from both amygdala and subregions of the OFC.
    MeSH term(s) Animals ; Behavior, Animal/drug effects ; Goals ; Kynurenic Acid/pharmacology ; Macaca ; Male ; Thalamus/drug effects ; Thalamus/physiology ; Time Factors
    Chemical Substances Kynurenic Acid (H030S2S85J)
    Language English
    Publishing date 2018-05-31
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, N.I.H., Intramural
    ZDB-ID 2687154-3
    ISSN 2050-084X ; 2050-084X
    ISSN (online) 2050-084X
    ISSN 2050-084X
    DOI 10.7554/eLife.37325
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  10. Article ; Online: Anticonvulsant effect of cannabinoid receptor agonists in models of seizures in developing rats.

    Huizenga, Megan N / Wicker, Evan / Beck, Veronica C / Forcelli, Patrick A

    Epilepsia

    2017  Volume 58, Issue 9, Page(s) 1593–1602

    Abstract: Objective: Although drugs targeting the cannabinoid system (e.g., CB1 receptor agonists) display anticonvulsant efficacy in adult animal models of seizures/epilepsy, they remain unexplored in developing animal models. However, cannabinoid system ... ...

    Abstract Objective: Although drugs targeting the cannabinoid system (e.g., CB1 receptor agonists) display anticonvulsant efficacy in adult animal models of seizures/epilepsy, they remain unexplored in developing animal models. However, cannabinoid system functions emerge early in development, providing a rationale for targeting this system in neonates. We examined the therapeutic potential of drugs targeting the cannabinoid system in three seizure models in developing rats.
    Methods: Postnatal day (P) 10, Sprague-Dawley rat pups were challenged with the chemoconvulsant methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate (DMCM) or pentylenetetrazole (PTZ), after treatment with either CB1/2 mixed agonist (WIN 55,212-2), CB1 agonist (arachidonyl-2'-chloroethylamide [ACEA]), CB2 agonist (HU-308), CB1 antagonist (AM-251), CB2 antagonist (AM-630), fatty acid amide hydrolase inhibitor (URB-597), or G protein-coupled receptor 55 agonist (O-1602). P20 Sprague-Dawley pups were challenged with DMCM after treatment with WIN, ACEA, or URB. Finally, after pretreatment with WIN, P10 Sprague-Dawley rats were challenged against acute hypoxia-induced seizures.
    Results: The mixed CB1/2 agonist and the CB1-specific agonist, but no other drugs, displayed anticonvulsant effects against clonic seizures in the DMCM model. By contrast, both CB1 and CB2 antagonism increased seizure severity. Similarly, we found that the CB1/2 agonist displayed antiseizure efficacy against acute hypoxia-induced seizures (automatisms, clonic and tonic-clonic seizures) and tonic-clonic seizures evoked by PTZ. Anticonvulsant effects were seen in P10 animals but not P20 animals.
    Significance: Early life seizures represent a significant cause of morbidity, with 30-40% of infants and children with epilepsy failing to achieve seizure remission with current pharmacotherapy. Identification of new therapies for neonatal/infantile epilepsy syndromes is thus of high priority. These data indicate that the anticonvulsant action of the CB system is specific to CB1 receptor activation during early development and provide justification for further examination of CB1 receptor agonists as novel antiepileptic drugs targeting epilepsy in infants and children.
    MeSH term(s) Animals ; Animals, Newborn ; Anticonvulsants/pharmacology ; Cannabinoid Receptor Agonists/pharmacology ; Disease Models, Animal ; Female ; Male ; Rats ; Rats, Sprague-Dawley ; Seizures/drug therapy
    Chemical Substances Anticonvulsants ; Cannabinoid Receptor Agonists
    Language English
    Publishing date 2017-09
    Publishing country United States
    Document type Journal Article
    ZDB-ID 216382-2
    ISSN 1528-1167 ; 0013-9580
    ISSN (online) 1528-1167
    ISSN 0013-9580
    DOI 10.1111/epi.13842
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