Editing Claustrum (section)

== Clinical significance ==

===Schizophrenia===
Damage to the claustrum may mimic various common diseases or mental disorders; delayed development of the structure appears to be linked to [[autism]]. The claustrum may be involved in [[schizophrenia]] as findings show an increase in positive symptoms, such as delusions, when the grey matter volume of the left claustrum and right insula is decreased.<ref name="Cascella2011" />
[[File:New-Onset-Refractory-Status-Epilepticus-with-Claustrum-Damage-Definition-of-the-Clinical-and-Video 1.ogv|thumb|225x225px|New-onset refractory [[status epilepticus]] with claustrum damage|alt=]]

===Epilepsy===
The claustrum is also seen to play a role in epilepsy; MRIs have found increased claustral signal intensity in people who have been diagnosed with epilepsy. In certain cases, seizures tend to appear to originate from the claustrum when they are involved in early [[Kainic acid#Pharmacological activity|kainic acid induced seizures]].

===Consciousness===
A single case-study showed that consciousness was disrupted when the area between the insula and claustrum was electrically stimulated; consciousness was regained when stimulation stopped.<ref name="Chau2015"/><ref name="Koubeissi-2014" /> Patients that had a lesion in their left claustrum were more likely to experience a loss of consciousness compared to those that presented with lesions outside of the claustrum.<ref name="Chau2015" /> For example, a patient that was subjected to electrode stimulation at the claustrum stopped reading, stared blankly and was unresponsive. Once the electrode was removed, the patient resumed reading and could not remember the events of being dazed.<ref name="Goll2015" />

A 2019 study consisting of electrical stimulation of the claustrum found no disruption of consciousness in any of the five patients that were subjected to the analysis. The tested patients reported subjective experiences in various sensory domains and exhibited reflexive movement, but none of them displayed loss of consciousness, thus questioning the claustrum's ability to disrupt consciousness when stimulated electrically.<ref name="Bickel2019">{{cite journal |last1=Bickel |first1=Stephan |last2=Parvizi |first2=Josef |title=Electrical stimulation of the human claustrum |journal=Epilepsy & Behavior |date=August 2019 |volume=97 |pages=296–303 |doi=10.1016/j.yebeh.2019.03.051 |pmid=31196825 |s2cid=182952015 |doi-access=free }}</ref>

A 2020 study involving artificial activation of the claustrum by optogenetic light stimulation silenced brain activity across the cortex, a phenomenon known as a "Down state," which can be seen when mice are sleeping or resting awake (quiet wakefulness).<ref name="Narikiyo2020"/> The authors state that 'The claustrum is a coordinator of global slow-wave activity, and it is so exciting that we are getting closer to linking specific brain connections and actions with the ultimate puzzle of consciousness.' 

However, [[Cognitive science|cognitive scientist]] [[Stevan Harnad]] does not consider the claustrum to be a "switch" for consciousness, but merely for wakefulness. He claims that if the claustrum were truly a switch for consciousness, artificial activation of the claustrum would not result in the patient passing out, but instead the patient would continue behaving normally, and later report that they experienced no sensations during the period of time when their claustrum was being stimulated.<ref>{{Cite web |title=Claustrum Nostrum: No On/Off Switch for Consciousness – Skywritings |url=https://generic.wordpress.soton.ac.uk/skywritings/2019/01/01/claustrum-nostrum-no-onoff-switch-for-consciousness/ |access-date=2023-12-02 |website=generic.wordpress.soton.ac.uk}}</ref>

=== Psilocybin ===
The claustrum expresses a high density of [[5-HT2A receptor|5-HT<sub>2A</sub> receptors]], meaning it is significantly affected by [[serotonergic psychedelics]] like [[psilocybin]]. Psilocybin appears to affect the functional connectivity of the claustrum with the [[default mode network]] (DMN), and the fronto-parietal task control network (FPTC). Psilocybin was found to significantly decrease functional connectivity of the right claustrum with the default mode network, and increase right claustrum connectivity with the fronto-parietal task control network.<ref>{{Cite journal |last1=Barrett |first1=Frederick S. |last2=Krimmel |first2=Samuel R. |last3=Griffiths |first3=Roland R. |last4=Seminowicz |first4=David A. |last5=Mathur |first5=Brian N. |date=September 2020 |title=Psilocybin acutely alters the functional connectivity of the claustrum with brain networks that support perception, memory, and attention |journal=NeuroImage |volume=218 |pages=116980 |doi=10.1016/j.neuroimage.2020.116980 |issn=1095-9572 |pmid=32454209|doi-access=free |pmc=10792549 }}</ref>

===Parkinsonism===
A team of investigators led by neuroscientists at [[Beth Israel Deaconess Medical Center]] has identified lesions in the claustrum as the likely origin of [[parkinsonism]] across different conditions. The team used a novel methodology called lesion network mapping to discover the origins of parkinsonism in 29 patients whose symptoms were not the result of Parkinson's disease but rather attributed to a brain lesion – an abnormality or injury to the brain visible on brain imaging. The mapping of the 29 lesions – which were located in different regions of the brain – revealed that connectivity to the claustrum was the single most sensitive and specific marker of lesion-induced parkinsonism.<ref name="Joutsa2018">{{cite journal | vauthors = Joutsa J, Horn A, Hsu J, Fox MD | title = Localizing parkinsonism based on focal brain lesions. | journal = Brain | volume = 141 | issue = 8 | pages = 2445–2456 | date = August 2018 | pmid = 29982424 | pmc = 6061866 | doi = 10.1093/brain/awy161 }}</ref>

===Anxiety and stress===
In mice, suppression of claustrum appears to attenuate [[anxiety]]/[[Psychological stress|stress]] and increase [[Chronic stress|chronic]] stress-resistance.<ref>{{cite journal |title=Claustrum mediates bidirectional and reversible control of stress-induced anxiety responses |journal=Science Advances |year=2022 |doi=10.1126/sciadv.abi6375| pmid=35302853  |last1=Niu |first1=M. |last2=Kasai |first2=A. |last3=Tanuma |first3=M. |last4=Seiriki |first4=K. |last5=Igarashi |first5=H. |last6=Kuwaki |first6=T. |last7=Nagayasu |first7=K. |last8=Miyaji |first8=K. |last9=Ueno |first9=H. |last10=Tanabe |first10=W. |last11=Seo |first11=K. |last12=Yokoyama |first12=R. |last13=Ohkubo |first13=J. |last14=Ago |first14=Y. |last15=Hayashida |first15=M. |last16=Inoue |first16=K. I. |last17=Takada |first17=M. |last18=Yamaguchi |first18=S. |last19=Nakazawa |first19=T. |last20=Kaneko |first20=S. |last21=Okuno |first21=H. |last22=Yamanaka |first22=A. |last23=Hashimoto |first23=H. |volume=8 |issue=11 |pages=eabi6375 |pmc=8932664 |bibcode=2022SciA....8I6375N }}<br/>News article: {{cite news |title='Switching off' certain brain cells may boost stress, anxiety response, study finds |url=https://www.upi.com/Health_News/2022/03/18/stress-anxiety-cells-brain-study/1321647610575/ |access-date=27 April 2022 |work=UPI |language=en}}</ref>