Editing Claustrum (section)

=== Lesions and consciousness ===
Functionally, the claustrum will integrate various cortical inputs through its connections into consciousness. Based upon its structure and connectivity, its function is suggested to be related to coordination of different brain functions; i.e. the conductor analogy. Consciousness functionally can be divided into two components: (i) wakefulness, which is arousal and alertness; (ii) content of consciousness, which is the processing of content.

A study of traumatic brain injuries in war veterans was undertaken to better understand the functional role of the claustrum. Damage to the claustrum was associated with the duration of one's loss of consciousness, but not its frequency. Lesion size was correlated with a longer duration of LOC events. No consequences were shown to attenuate cognitive processing.<ref name="Chau2015" />

In a single-case study, consciousness was shown to be disrupted when there was stimulation to the extreme capsule of the brain – which is in close proximity to the claustrum – such that upon termination of stimulation, consciousness was regained.<ref name="Koubeissi-2014" /> Another study looking at the symptomology of schizophrenia established that the severity of delusions was associated with decreased grey matter volume of the left claustrum; postulating that correlations exist between the structure and positive symptoms seen in this psychiatric disorder. Further supporting this correlation between schizophrenia and the claustrum is that there is an increase in white matter volume entering the claustrum.<ref>{{cite journal | vauthors = Shapleske J, Rossell SL, Chitnis XA, Suckling J, Simmons A, Bullmore ET, Woodruff PW, David AS | s2cid = 33360335 | title = A computational morphometric MRI study of schizophrenia: effects of hallucinations | journal = Cerebral Cortex | volume = 12 | issue = 12 | pages = 1331–41 | date = December 2002 | pmid = 12427683 | doi = 10.1093/cercor/12.12.1331 | doi-access = free }}</ref> Inverse correlations between grey matter volume and severity of hallucinations in the context of auditory hallucinations of schizophrenia has been supported.<ref name="Cascella2011">{{cite journal | vauthors = Cascella NG, Gerner GJ, Fieldstone SC, Sawa A, Schretlen DJ | title = The insula-claustrum region and delusions in schizophrenia | journal = Schizophrenia Research | volume = 133 | issue = 1–3 | pages = 77–81 | date = December 2011 | pmid = 21875780 | doi = 10.1016/j.schres.2011.08.004 | s2cid = 45564142 }}</ref> As well, to see the total loss of function of the claustrum, lesions to both claustrums on each hemisphere would need to occur.<ref name="Crick2005" />

However, a study in 2019, 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"/>