Insula disorder induces malfunction of contemplation
Case 308
【Progress】
Brain function test revealed he is difficult to think things through, easily tired for doing something. His abilities for execution and care are markedly decreased, implying malfunction of high-grade brain function.
【Discussion】
The present patient experienced subarachnoid hemorrhage and received coil-embolization of anterior communicating cerebral artery approximately ten years before. Thereafter, he realized worsening of memorizing newly what happened. He received medical check to obtain welfare payments for a physically handicapped person. Our speech-language-hearing therapist evaluated that his high-grade brain function is markedly lowered; marked easily-fatigue and failure for general test; hard to ponder deeply; markedly lowering for attention and execution. It concluded that his daily life might be possible but needs some assistance from others. Meanwhile, medical findings revealed full extraocular movement, no facial palsy, negative Barre’s arm sign, no cerebellar sign and normal gait. Namely, he was seemingly normal from external findings.
Insula exists covering with frontal, temporal and parietal operculum, implying insula communicating with frontal, temporal and parietal lobes. Moreover, insula connects to limbic system and thalamus and basal ganglion. As a result, insula is present as hub of electric signals flowing significant areas of the whole brain (1-6). Further, it includes dense spindle neuron that are limited to exist only in high-level mammals (1-6).
Sylvian fissure is a CSF flid space formed by insula, frontal operculum, temporal operculum and parietal operculum. Sylvian fissure dilates as ages advance probably because atrophic changes of these surrounding structures.
Insula is blood-supplied by M2 of middle cerebral artery. Middle cerebral artery is divided into 4 segments; M1, horizontal/sphenoidal; M2, insular segment; M3, operculum segment: M4, cortical segment.
Until late twenty century, insula was an unknown brain area on function. The research on insula has activated since functional MRI was used for brain infarction. For an example, amygdala which is a center of emotion, and insula are densely communicated. Bipolar disorder and/or major depressive disorder are reported to be related with dysfunction of amygdala and insula (6, 7). Further, insula is becoming thicker in persons with a habit of meditation than before a habit of meditation (8).
In our patient whose left insula became selectively disappeared due to subarachnoid hemorrhage, most of brain components: each thalamus, pyramidal tract, extra-pyramidal tract or limbic system were preserved anatomically on MRI. Despite of this, high-grade brain dysfunction emerged in our case. The disorder of the hub connecting frontal lobe, parietal lobe, temporal lobe, limbic system and motor system induces high-grade brain dysfunction.
【Summary】
We presented a fifty-three-year-old male for brain functioning test. Ten years before, he experienced subarachnoid hemorrhage and realized worse of preserving memory. Brain function test revealed that marked easily-fatigue and failure for general test; hard to ponder deeply; markedly lowering for attention and execution, despite of seemingly intact of motor and sensory ability. Brain MRI depicted selective deficit of left insula. It is borne in mind that insula is a hub of various neuron coming frontal, parietal and temporal lobes, thalamus, basal ganglion, limbic system and insula histologically contains dens spindle neuron that is limited to exist in high-grade mammals. Insula is blood-supplied by M2 of middle cerebral artery. Middle cerebral artery is divided into 4 segments; M1, horizontal/sphenoidal; M2, insular segment; M3, operculum segment: M4, cortical segment. It might be able to say that insula is one of the candidates of human souls.
【References】
1.Iaria, G, et al. Neural activity of the anterior insula in emotional processing depends on the individuals' emotional susceptibility. Human brain mapping, 2008; 29(3), 363-73.
2.Sander, K., et al. Left auditory cortex and amygdala, but right insula dominance for human laughing and crying. Journal of cognitive neuroscience, 17(10), 1519-31.
3.Craig, A.D. (2009). How do you feel--now? The anterior insula and human awareness. Nature reviews. Neuroscience, 2009; 10(1), 59-70.
4.Lamm, C., et al. The role of anterior insular cortex in social emotions. Brain structure & function,2010; 214(5-6): 579-91.
5.Singer, T., et al. (2009). A common role of insula in feelings, empathy and uncertainty. Trends in cognitive sciences, 2009; 13(8), 334-40.
6.Ambrosi E, et al. Insula and amygdala resting-state functional connectivity differentiate bipolar from unipolar depression. Acta Psychiatr Scan. 2017 Jul;136(1):129-139.
7.Ponserre M, et al. The Insula Cortex Contacts Distinct Output Streams of the Central Amygdala. J Neurosci 2020 Nov 11;40(46):8870-8882.
8.Laneli D, et al. Mindfulness meditation regulates anterior insula activity during empathy for social pain. Hum Brain Mapp. 2017 Aug;38(8):4034-4046.
9.Bouros D, et al. Parapneumonic effusion and empyema: best therapeutic approach. Monaldi Arch Chest Dis. 2001;56(2):144–148.
10.Schiza S, et al. Clinical presentation and management of empyema, lung abscess and pleural effusion. Curr Opin Pulm Med. 2006;12(3):205–211.
11.McGrath EE, et al. Chylothorax: Aetiology, diagnosis and therapeutic options. Respiratory Medicine: 2010; 104: 1-8
12.Nair SK, et al. Etiology and management of chylothorax in adults. Eur J Cardiothorac Surg. 2007; 32: 362-369
2023.8.22