Editing Insular cortex (section)

===Interoceptive awareness===
{{Further |Interoception}}
There is evidence that, in addition to its base functions, the insula may play a role in certain higher-level functions that operate only in humans and other [[Hominidae|great apes]]. The spindle neurons found at a higher density in the right frontal insular cortex are also found in the [[anterior cingulate cortex]], which is another region that has reached a high level of specialization in great apes. It has been speculated that these neurons are involved in [[Cognition|cognitive]]-[[emotion]]al processes that are specific to primates including great apes, such as [[empathy]] and [[metacognition|metacognitive]] emotional feelings. This is supported by functional imaging results showing that the structure and function of the right frontal insula is correlated with the ability to feel one's own heartbeat, or to empathize with the pain of others. It is thought that these functions are not distinct from the lower-level functions of the insula but rather arise as a consequence of the role of the insula in conveying homeostatic information to [[consciousness]].<ref>{{cite journal |author1=Benedetto De Martino |author2=Dharshan Kumaran |author3=Ben Seymour |author4=Raymond J. Dolan |title=Frames, Biases, and Rational Decision-Making in the Human Brain |journal=Science |volume=313 |issue=6|date=August 2006 |pages= 684–687 |doi=10.1126/science.1128356 |pmid=16888142 |pmc=2631940|bibcode=2006Sci...313..684D }}</ref><ref>{{cite journal |author1=Gui Xue |author2=Zhonglin Lu |author3=Irwin P. Levin d |author4=Antoine Bechara |title=The impact of prior risk experiences on subsequent risky decision-making: The role of the insula|journal=NeuroImage|volume=50 |year=2010 |pages= 709–716 |doi=10.1016/j.neuroimage.2009.12.097 |pmid=20045470 |issue=2 |pmc=2828040}}</ref> The right anterior insula is engaged in [[Interoception|interoceptive]] awareness of homeostatic emotions such as thirst, pain and fatigue,<ref>{{cite journal|title=Gut feelings: the emerging biology of gut–brain communication|author=Emeran A. Mayer|journal=Nature Reviews Neuroscience|volume=12|issue=8|pages=453–466|date=August 2011|doi=10.1038/nrn3071|url= |pmid=21750565|pmc=3845678}}</ref> and the ability to time one's own [[heart rate|heartbeat]]. Moreover, greater right anterior insular [[gray matter]] volume correlates with increased accuracy in this subjective sense of the inner body, and with [[negative emotion]]al experience.<ref>{{cite journal |vauthors=Critchley HD, Wiens S, Rotshtein P, Ohman A, Dolan RJ |title=Neural systems supporting interoceptive awareness |journal=Nat. Neurosci. |volume=7 |issue=2 |pages=189–95 |date=February 2004 |pmid=14730305 |doi=10.1038/nn1176|hdl=21.11116/0000-0001-A2FB-D |s2cid=13344271 |hdl-access=free }}</ref> It is also involved in the control of [[blood pressure]],<ref name="Lamb">{{cite journal |vauthors=Lamb K, Gallagher K, McColl R, Mathews D, Querry R, Williamson JW |title=Exercise-induced decrease in insular cortex rCBF during postexercise hypotension |journal=Med Sci Sports Exerc |volume=39 |issue=4 |pages=672–9 |date=April 2007 |pmid=17414805 |doi=10.1249/mss.0b013e31802f04e0 |doi-access=free }}</ref> in particular during and after exercise,<ref name="Lamb"/> and its activity varies with the amount of effort a person believes he/she is exerting.<ref>{{cite journal |vauthors=Williamson JW, McColl R, Mathews D, Mitchell JH, Raven PB, Morgan WP |title=Hypnotic manipulation of effort sense during dynamic exercise: cardiovascular responses and brain activation |journal=J. Appl. Physiol. |volume=90 |issue=4 |pages=1392–9 |date=April 2001 |pmid=11247939 |doi=10.1152/jappl.2001.90.4.1392 |s2cid=8653997 }}</ref><ref>{{cite journal |vauthors=Williamson JW, McColl R, Mathews D, Ginsburg M, Mitchell JH |title=Activation of the insular cortex is affected by the intensity of exercise |journal=J. Appl. Physiol. |volume=87 |issue=3 |pages=1213–9 |date=September 1999 |pmid=10484598 |doi=10.1152/jappl.1999.87.3.1213|citeseerx=10.1.1.492.2730 |s2cid=1078691 }}</ref>

The insular cortex also is where the sensation of [[pain]] is judged as to its degree.<ref>{{cite journal |vauthors=Baliki MN, Geha PY, Apkarian AV |title=Parsing pain perception between nociceptive representation and magnitude estimation |journal=J. Neurophysiol. |volume=101 |issue=2 |pages=875–87 |date=February 2009 |pmid=19073802 |pmc=3815214 |doi=10.1152/jn.91100.2008 }}</ref> Lesion of the insula is associated with dramatic loss of pain perception and isolated insular infarction can  lead to contralateral elimination of pinprick perception.<ref>{{Cite journal |last1=Birklein |first1=Frank |last2=Rolke |first2=Roman |last3=Müller-Forell |first3=Wibke |date=2005-11-08 |title=Isolated insular infarction eliminates contralateral cold, cold pain, and pinprick perception |journal=Neurology |language=en |volume=65 |issue=9 |pages=1381 |doi=10.1212/01.wnl.0000181351.82772.b3 |pmid=16275823 |issn=0028-3878|doi-access=free }}</ref> Further, the insula is where a person imagines pain when looking at images of painful events while thinking about their happening to one's own body.<ref>{{cite journal |vauthors=Ogino Y, Nemoto H, Inui K, Saito S, Kakigi R, Goto F |title=Inner experience of pain: imagination of pain while viewing images showing painful events forms subjective pain representation in human brain |journal=Cereb. Cortex |volume=17 |issue=5 |pages=1139–46 |date=May 2007 |pmid=16855007 |doi=10.1093/cercor/bhl023 |doi-access=free }}</ref>  Those with [[irritable bowel syndrome]] have abnormal processing of [[Viscus|visceral]] pain in the insular cortex related to dysfunctional inhibition of pain within the brain.<ref>{{cite journal |vauthors=Song GH, Venkatraman V, Ho KY, Chee MW, Yeoh KG, Wilder-Smith CH |title=Cortical effects of anticipation and endogenous modulation of visceral pain assessed by functional brain MRI in irritable bowel syndrome patients and healthy controls |journal=Pain |volume=126 |issue=1–3 |pages=79–90 |date=December 2006 |pmid=16846694 |doi=10.1016/j.pain.2006.06.017 |s2cid=21437784 }}</ref>

Physiological studies in rhesus monkeys have shown that neurons in the insula respond to skin stimulation.<ref>{{Cite journal |last1=Schneider |first1=Richard J. |last2=Friedman |first2=David P. |last3=Mishkin |first3=Mortimer |date=1993-09-03 |title=A modality-specific somatosensory area within the insula of the rhesus monkey |url=https://dx.doi.org/10.1016/0006-8993%2893%2990305-7 |journal=Brain Research |volume=621 |issue=1 |pages=116–120 |doi=10.1016/0006-8993(93)90305-7 |pmid=8221062 |s2cid=20207990 |issn=0006-8993|url-access=subscription }}</ref> PET studies have also revealed that the human insula can also be activated by vibrational stimulation to the skin.<ref>{{Cite journal |last1=Burton |first1=H. |last2=Videen |first2=T. O. |last3=Raichle |first3=M. E. |date=January 1993 |title=Tactile-Vibration-Activated Foci in Insular and Parietal-Opercular Cortex Studied with Positron Emission Tomography: Mapping the Second Somatosensory Area in Humans |url=http://www.tandfonline.com/doi/full/10.3109/08990229309028839 |journal=Somatosensory & Motor Research |language=en |volume=10 |issue=3 |pages=297–308 |doi=10.3109/08990229309028839 |pmid=8237217 |issn=0899-0220|url-access=subscription }}</ref>

Another perception of the right anterior insula is the degree of nonpainful [[Sense#Temperature|warmth]]<ref>{{cite journal |vauthors=Olausson H, Charron J, Marchand S, Villemure C, Strigo IA, Bushnell MC |title=Feelings of warmth correlate with neural activity in right anterior insular cortex |journal=Neurosci. Lett. |volume=389 |issue=1 |pages=1–5 |date=November 2005 |pmid=16051437 |doi=10.1016/j.neulet.2005.06.065 |s2cid=20068852 }}</ref> or nonpainful coldness<ref>{{cite journal |vauthors=Craig AD, Chen K, Bandy D, Reiman EM |title=Thermosensory activation of insular cortex |journal=Nat. Neurosci. |volume=3 |issue=2 |pages=184–90 |date=February 2000 |pmid=10649575 |doi=10.1038/72131|s2cid=7077496 }}</ref> of a skin sensation. Other internal sensations processed by the insula include stomach or [[abdominal distension]].<ref>{{cite journal |vauthors=Ladabaum U, Minoshima S, Hasler WL, Cross D, Chey WD, Owyang C |title=Gastric distention correlates with activation of multiple cortical and subcortical regions |journal=Gastroenterology |volume=120 |issue=2 |pages=369–76 |date=February 2001 |pmid=11159877 |doi=10.1053/gast.2001.21201|doi-access=free }}</ref><ref>{{cite journal  |vauthors=Hamaguchi T, Kano M, Rikimaru H, etal |title=Brain activity during distention of the descending colon in humans |journal=Neurogastroenterol. Motil. |volume=16 |issue=3 |pages=299–309 |date=June 2004 |pmid=15198652 |doi=10.1111/j.1365-2982.2004.00498.x |s2cid=20437580 }}{{dead link|date=February 2019|bot=medic}}{{cbignore|bot=medic}}</ref> A full [[Urinary bladder|bladder]] also activates the insular cortex.<ref>{{cite journal |vauthors=Matsuura S, Kakizaki H, Mitsui T, Shiga T, Tamaki N, Koyanagi T |title=Human brain region response to distention or cold stimulation of the bladder: a positron emission tomography study |journal=J. Urol. |volume=168 |issue=5 |pages=2035–9 |date=November 2002 |pmid=12394703 |doi=10.1016/s0022-5347(05)64290-5}}</ref>

One brain imaging study suggests that the unpleasantness of subjectively perceived [[dyspnea]] is processed in the right human anterior insula and [[amygdala]].<ref>{{cite journal|last=von Leupoldt|first=A.|author2=Sommer, T.|author3=Kegat, S.|author4=Baumann, H. J.|author5=Klose, H.|author6=Dahme, B.|author7=Buchel, C.|title=The Unpleasantness of Perceived Dyspnea Is Processed in the Anterior Insula and Amygdala|journal=American Journal of Respiratory and Critical Care Medicine|date=24 January 2008|volume=177|issue=9|pages=1026–1032|doi=10.1164/rccm.200712-1821OC|pmid=18263796|url=http://171.66.122.149/content/177/9/1026.full.pdf+html|url-access=subscription}}{{Dead link|date=April 2019 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

The cerebral cortex processing [[Vestibular system|vestibular]] sensations extends into the insula,<ref>{{cite journal  |vauthors=Kikuchi M, Naito Y, Senda M, etal |title=Cortical activation during optokinetic stimulation — an fMRI study |journal=Acta Otolaryngol. |volume=129 |issue=4 |pages=440–3 |date=April 2009 |pmid=19116795 |doi=10.1080/00016480802610226 |s2cid=42990194 }}
</ref> with small lesions in the anterior insular cortex being able to cause loss of [[Equilibrioception|balance]] and [[Vertigo (medical)|vertigo]].<ref>{{cite journal |vauthors=Papathanasiou ES, Papacostas SS, Charalambous M, Eracleous E, Thodi C, Pantzaris M |title=Vertigo and imbalance caused by a small lesion in the anterior insula |journal=Electromyogr Clin Neurophysiol |volume=46 |issue=3 |pages=185–92 |year=2006 |pmid=16918202 }}</ref>

Other noninteroceptive perceptions include passive listening to music,<ref>{{cite journal |vauthors=Brown S, Martinez MJ, Parsons LM |title=Passive music listening spontaneously engages limbic and paralimbic systems |journal=NeuroReport |volume=15 |issue=13 |pages=2033–7 |date=September 2004 |pmid=15486477 |doi=10.1097/00001756-200409150-00008|s2cid=12308683 }}</ref> laughter and crying,<ref>{{cite journal |vauthors=Sander K, Scheich H |title=Left auditory cortex and amygdala, but right insula dominance for human laughing and crying |journal=J Cogn Neurosci |volume=17 |issue=10 |pages=1519–31 |date=October 2005 |pmid=16269094 |doi=10.1162/089892905774597227 |s2cid=9509954 }}</ref> empathy and compassion,<ref>{{Cite web |url=http://ccare.stanford.edu/node/89 |title=Interview with Tania Singer &#124; the Center for Compassion and Altruism Research and Education |access-date=2010-07-04 |archive-url=https://web.archive.org/web/20100714152432/http://ccare.stanford.edu/node/89 |archive-date=2010-07-14 |url-status=dead }}</ref> and language.<ref>{{cite journal |vauthors=Bamiou DE, Musiek FE, Luxon LM |title=The insula (Island of Reil) and its role in auditory processing. Literature review |journal=Brain Res. Brain Res. Rev. |volume=42 |issue=2 |pages=143–54 |date=May 2003 |pmid=12738055 |doi=10.1016/S0165-0173(03)00172-3|s2cid=22339177 }}</ref>