Editing Amygdala (section)

==Neuropsychological correlates of amygdala activity==
Early research on primates provided explanations as to the functions of the amygdala, as well as a basis for further research. As early as 1888, [[Rhesus macaque|rhesus monkeys]] with a lesioned temporal cortex (including the amygdala) were observed to have significant social and emotional deficits.<ref>{{cite journal | vauthors = Brown S, Shafer E | year =1888| title = An investigation into the functions of the occipital and temporal lobes of the monkey's brain| journal =Philosophical Transactions of the Royal Society B | volume =179 | pages =303–327| doi = 10.1098/rstb.1888.0011| doi-access =free}}</ref> [[Heinrich Klüver]] and Paul Bucy later expanded upon this same observation by showing that large lesions to the anterior temporal lobe produced noticeable changes, including overreaction to all objects, hypoemotionality, loss of fear, [[hypersexuality]], and [[hyperorality]], a condition in which inappropriate objects are placed in the mouth. Some monkeys also displayed an [[visual agnosia|inability to recognize familiar objects]] and would approach animate and inanimate objects indiscriminately, exhibiting a loss of fear towards the experimenters. This behavioral disorder was later named [[Klüver–Bucy syndrome]] accordingly,<ref>{{cite journal | vauthors = Klüver H, Bucy PC | title = Preliminary analysis of functions of the temporal lobes in monkeys | journal =  Archives of Neurology and Psychiatry| volume = 9 | issue = 4 | pages = 606–20 | year = 1939 | doi = 10.1001/archneurpsyc.1939.02270240017001 }}</ref> and later research proved it was specifically due to amygdala lesions. Monkey mothers who had amygdala damage showed a reduction in maternal behaviors towards their infants, often physically abusing or neglecting them.<ref>{{cite journal | vauthors = Bucher K, Myers RE, Southwick C | title = Anterior temporal cortex and maternal behavior in monkey | journal = Neurology | volume = 20 | issue = 4 | pages = 415 | date = April 1970 | pmid = 4998075 | doi = 10.1212/wnl.20.4.402 | s2cid = 219204628 }}</ref> In 1981, researchers found that selective [[Radio frequency lesioning|radio frequency lesions]] of the whole amygdala caused Klüver–Bucy syndrome.<ref>{{cite journal | vauthors = Aggleton JP, Passingham RE | title = Syndrome produced by lesions of the amygdala in monkeys (Macaca mulatta) | journal = Journal of Comparative and Physiological Psychology | volume = 95 | issue = 6 | pages = 961–77 | date = December 1981 | pmid = 7320283 | doi = 10.1037/h0077848 }}</ref>

===Social===
Increased activity in the amygdala following compassion-oriented meditation may contribute to social connectedness.<ref>{{cite journal | vauthors = Hutcherson CA, Seppala EM, Gross JJ | title = Loving-kindness meditation increases social connectedness | journal = Emotion | volume = 8 | issue = 5 | pages = 720–4 | date = October 2008 | pmid = 18837623 | doi = 10.1037/a0013237 }}</ref> Similarly, the structural white matter connectivity to other brain regions is also associated with social network size.<ref name="ReferenceB"/> The amygdala is also thought to be a determinant of the level of a person's [[emotional intelligence]]. It is particularly hypothesized that larger amygdalae allow for greater emotional intelligence, enabling greater societal integration and cooperation with others.<ref>{{cite book |title=The Human Amygdala |vauthors=Buchanan TW, Tranel D, Adolphs R |publisher=Guilford |year=2009 |isbn=978-1-60623-033-6 |veditors=Whalen PJ, Phelps EA |location=New York |pages=289–318 |chapter=The Human Amygdala in Social Function |chapter-url=https://books.google.com/books?id=275mEq72pkUC&pg=PA289}}</ref>

Amygdala volume correlates positively with both the size (the number of contacts a person has) and the complexity (the number of different groups to which a person belongs) of [[social network]]s.<ref>{{cite journal | vauthors = Bickart KC, Wright CI, Dautoff RJ, Dickerson BC, Barrett LF | title = Amygdala volume and social network size in humans | journal = Nature Neuroscience | volume = 14 | issue = 2 | pages = 163–4 | date = February 2011 | pmid = 21186358 | pmc = 3079404 | doi = 10.1038/nn.2724 }}</ref><ref>{{Cite magazine|url=https://healthland.time.com/2010/12/28/how-to-win-friends-have-a-big-amygdala/?xid=rss-topstories|title=How to Win Friends: Have a Big Amygdala?|magazine=Time|first=Maia|last=Szalavitz | name-list-style = vanc |date=28 December 2010|access-date=30 December 2010|url-status=live|archive-url=https://web.archive.org/web/20110717061203/http://healthland.time.com/2010/12/28/how-to-win-friends-have-a-big-amygdala/?xid=rss-topstories|archive-date=17 July 2011}}</ref> Individuals with larger amygdalae had larger and more complex social networks. The amygdala is responsible for facial recognition and allows others to respond appropriately to different emotional expressions.<ref>Lynn Ladel, Oxford University Press. "[https://books.google.com/books?id=A2s963AzymYC&q=human+amygdala+function%2F&pg=PA106 Cognitive Neuroscience of Emotion]." 9 October 2014. 1 July 2019.</ref> They were also better able to make accurate social judgments about other persons' faces.<ref>{{cite journal | vauthors = Bzdok D, Langner R, Caspers S, Kurth F, Habel U, Zilles K, Laird A, Eickhoff SB | title = ALE meta-analysis on facial judgments of trustworthiness and attractiveness | journal = Brain Structure & Function | volume = 215 | issue = 3–4 | pages = 209–23 | date = January 2011 | pmid = 20978908 | pmc = 4020344 | doi = 10.1007/s00429-010-0287-4 }}</ref> The amygdala's role in the analysis of social situations stems specifically from its ability to identify and process changes in facial features. It does not, however, process the direction of the gaze of the person being perceived.<ref>{{cite journal | vauthors = Mormann F, Niediek J, Tudusciuc O, Quesada CM, Coenen VA, Elger CE, Adolphs R | title = Neurons in the human amygdala encode face identity, but not gaze direction | journal = Nature Neuroscience | volume = 18 | issue = 11 | pages = 1568–70 | date = November 2015 | pmid = 26479589 | pmc = 4624486 | doi = 10.1038/nn.4139 }}</ref><ref>{{cite journal | vauthors = Huijgen J, Dinkelacker V, Lachat F, Yahia-Cherif L, El Karoui I, Lemaréchal JD, Adam C, Hugueville L, George N | title = Amygdala processing of social cues from faces: an intracrebral EEG study | journal = Social Cognitive and Affective Neuroscience | volume = 10 | issue = 11 | pages = 1568–76 | date = November 2015 | pmid = 25964498 | doi = 10.1093/scan/nsv048 | pmc = 4631154 }}</ref>

The amygdala processes reactions to violations concerning [[personal space]]. These reactions are absent in persons in whom the amygdala is damaged bilaterally.<ref name="Kennedy">{{cite journal | vauthors = Kennedy DP, Gläscher J, Tyszka JM, Adolphs R | title = Personal space regulation by the human amygdala | journal = Nature Neuroscience | volume = 12 | issue = 10 | pages = 1226–7 | date = October 2009 | pmid = 19718035 | pmc = 2753689 | doi = 10.1038/nn.2381 }}</ref> Furthermore, the amygdala is found to be activated in [[fMRI]] when people observe that others are physically close to them, such as when a person being scanned knows that an experimenter is standing immediately next to the scanner, versus standing at a distance.<ref name="Kennedy"/><ref>{{cite web |url-status=dead |first1=Kimberly |last1=Brown |website=Manifest Yourself |url=http://www.manifestyourself.com/event-sweat-city-sequel/ |title=Event: Sweat in the City: The Sequel! |archive-url=https://web.archive.org/web/20190329230852/https://www.manifestyourself.com/event-sweat-city-sequel/ |archive-date=29 March 2019 |date= 9 October 2014 }}</ref> Animal studies have shown that stimulating the amygdala appears to increase both sexual and aggressive behavior. Likewise, studies using brain lesions have shown that harm to the amygdala may produce the opposite effect. Thus, it appears that this part of the brain may play a role in the display and modulation of aggression.<ref>{{cite web |url=http://www.saylor.org/site/wp-content/uploads/2011/01/TLBrink_PSYCH04.pdf |title=Unit 4: The Nervous System |pages=61  |first1=T.L. |last1=Brink |date=2008 |work=Psychology: A Student Friendly Approach |access-date=2016-02-07 |url-status=live |archive-url=https://web.archive.org/web/20160303205950/http://www.saylor.org/site/wp-content/uploads/2011/01/TLBrink_PSYCH04.pdf |archive-date=3 March 2016}}</ref>

Recent studies have suggested possible correlations between brain structure, including differences in hemispheric ratios and connection patterns in the amygdala, and sexual orientation. [[Homosexual men]] tend to exhibit more feminine patterns in the amygdala than heterosexual males do, just as [[homosexual women]] tend to show more masculine patterns in the amygdala than heterosexual females do. It was observed that amygdala connections were more widespread from the left amygdala in homosexual males, as is also found in heterosexual females. Amygdala connections were more widespread from the right amygdala in homosexual females, as in heterosexual males.<ref name="pnas">{{cite journal |vauthors=Swaab DF |date=July 2008 |title=Sexual orientation and its basis in brain structure and function |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=105 |issue=30 |pages=10273–4 |bibcode=2008PNAS..10510273S |doi=10.1073/pnas.0805542105 |pmc=2492513 |pmid=18653758 |doi-access=free}}</ref><ref>{{cite journal |vauthors=Swaab DF |date=September 2007 |title=Sexual differentiation of the brain and behavior |journal=Best Practice & Research. Clinical Endocrinology & Metabolism |volume=21 |issue=3 |pages=431–44 |doi=10.1016/j.beem.2007.04.003 |pmid=17875490}}</ref>

===Alcoholism===
The amygdala appears to play a role in [[binge drinking]], being damaged by repeated episodes of intoxication and withdrawal.<ref>{{cite journal | vauthors = Stephens DN, Duka T | title = Review. Cognitive and emotional consequences of binge drinking: role of amygdala and prefrontal cortex | journal = Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences | volume = 363 | issue = 1507 | pages = 3169–79 | date = October 2008 | pmid = 18640918 | pmc = 2607328 | doi = 10.1098/rstb.2008.0097 }}</ref><ref name=":0">{{cite journal|vauthors=Marinkovic K, Oscar-Berman M, Urban T, O'Reilly CE, Howard JA, Sawyer K, Harris GJ|date=November 2009|title=Alcoholism and dampened temporal limbic activation to emotional faces|journal=Alcoholism: Clinical and Experimental Research|volume=33|issue=11|pages=1880–92|doi=10.1111/j.1530-0277.2009.01026.x|pmc=3543694|pmid=19673745}}</ref> [[PRKCE|Protein kinase C-epsilon]] in the amygdala is important for regulating behavioral responses to [[morphine]] and [[ethanol]] and controlling anxiety-like behavior. The protein is involved in controlling the function of other proteins and plays a role in the development of the ability to consume a large amount of ethanol.<ref>{{cite journal|vauthors=Newton PM, Ron D|date=June 2007|title=Protein kinase C and alcohol addiction|journal=Pharmacological Research|volume=55|issue=6|pages=570–7|doi=10.1016/j.phrs.2007.04.008|pmid=17566760}}</ref><ref>{{cite journal|vauthors=Lesscher HM, Wallace MJ, Zeng L, Wang V, Deitchman JK, McMahon T, Messing RO, Newton PM|date=July 2009|title=Amygdala protein kinase C epsilon controls alcohol consumption|journal=Genes, Brain and Behavior|volume=8|issue=5|pages=493–9|doi=10.1111/j.1601-183X.2009.00485.x|pmc=2714877|pmid=19243450}}</ref> The duration of chronic alcohol consumption and abstinence may affect dynamic brain network adaptations.<ref name=":0" /> When excessive drinking occurs, the amygdala is affected through behavioral changes and reduces the [[Neuroplasticity|brain's plasticity]]. Often, when binge drinking or alcoholism occurs, the amygdala is affected and leads to behavior damage. These behavioral damages can be lack of control, inability to conduct oneself in a mature manner, irritability and aggressive behavior, anxiety, depression, personality disorders, excessive drug intake, bipolar disorder, confusion, higher tolerance levels, and inappropriate sexual behaviors with others and self.<ref>{{Cite journal|last1=Stephens|first1=David N|last2=Duka|first2=Theodora|date=2008-10-12|title=Cognitive and emotional consequences of binge drinking: role of amygdala and prefrontal cortex|journal=Philosophical Transactions of the Royal Society B: Biological Sciences|volume=363|issue=1507|pages=3169–3179|doi=10.1098/rstb.2008.0097|issn=0962-8436|pmc=2607328|pmid=18640918}}</ref>

=== Anxiety ===
Feelings of anxiety start with an environmental stimulus that provokes stress. This can include various smells, sights, and internal sensations that result in anxiety. The amygdala reacts to this stimuli by preparing to either stand and fight or to turn and run. This response is triggered by the release of [[adrenaline]] into the bloodstream; the amygdala sends signals to the [[Paraventricular nucleus of hypothalamus|paraventricular nucleus of the hypothalamus]] for the initiation of the [[Hypothalamic–pituitary–adrenal axis|HPA axis]] response.<ref>{{Cite journal |last=Dedovic |first=Katarina |last2=Duchesne |first2=Annie |last3=Andrews |first3=Julie |last4=Engert |first4=Veronika |last5=Pruessner |first5=Jens C. |date=2009 |title=The brain and the stress axis: The neural correlates of cortisol regulation in response to stress |url=https://doi.org/10.1016/j.neuroimage.2009.05.074 |journal=NeuroImage |volume=47 |issue=3 |pages=864–871 |doi=10.1016/j.neuroimage.2009.05.074 |issn=1053-8119}}</ref> Consequently, blood sugar rises, becoming immediately available to the muscles for quick energy. Shaking may occur in an attempt to return blood to the rest of the body. Long-term changes in amygdala neurons may also increase anxiety after long-term or traumatic stress, led by the action of stress-related hormones within the amygdala.<ref>{{cite journal |last1=Mitra |first1=Rupshi |last2=Sapolsky |first2=Robert |year=2008 |title=Acute corticosterone treatment is sufficient to induce anxiety and amygdaloid dendritic hypertrophy |journal=Proc Natl Acad Sci U S A |volume=105 |issue=14 |pages=5573–8 |bibcode=2008PNAS..105.5573M |doi=10.1073/pnas.0705615105 |pmc=2291109 |pmid=18391224 |doi-access=free}}</ref> On the flip side, blocking the action of stress hormones in the amygdala reduces anxiety.<ref>{{cite journal |last1=Mitra |first1=Rupshi |last2=Sapolsky |first2=Robert |year=2010 |title=Expression of chimeric estrogen-glucocorticoid-receptor in the amygdala reduces anxiety |journal=Brain Res |volume=1342 |issue=1 |pages=33–8 |doi=10.1016/j.brainres.2010.03.092 |pmid=2038147 |s2cid=26769079}}</ref> There may also be a link between the amygdala and [[anxiety]].<ref name=":1">{{cite journal | vauthors = Ziabreva I, Poeggel G, Schnabel R, Braun K | title = Separation-induced receptor changes in the hippocampus and amygdala of Octodon degus: influence of maternal vocalizations | journal = The Journal of Neuroscience | volume = 23 | issue = 12 | pages = 5329–36 | date = June 2003 | pmid = 12832558 | pmc = 6741186 | doi = 10.1523/JNEUROSCI.23-12-05329.2003 }}</ref> In particular, there is a higher prevalence of females that are affected by [[anxiety disorders]].

The central nucleus of the amygdala has direct correlations to the [[hypothalamus]] and [[brainstem]]—areas directly related to fear and anxiety. (The central nucleus have high densities of [[Opioid receptor|opiate receptors]].<ref>{{Cite journal |last=Davis |first=Michael |date=1992 |title=The Role of the Amygdala in Fear and Anxiety |url=https://emotion.wisc.edu/wp-content/uploads/sites/1353/2021/03/Davis-The-Role-of-the-Amygdala-in-Fear-and-Anxiety-1992-Annual-Review-of-Neuroscience.pdf?utm_source=chatgpt.com |journal=Annual Reviews |volume=15 |issue=353-75}}</ref>) This connection is evident from studies of animals that have undergone amygdalae removal.<ref>{{Cite news |last=Bhanoo |first=Sindya N. |date=2010-12-16 |title=Humans, Like Animals, Behave Fearlessly Without the Amygdala |url=https://www.nytimes.com/2010/12/21/science/21obbrain.html |access-date=2025-02-15 |work=The New York Times |language=en-US |issn=0362-4331}}</ref> Such studies suggest that animals lacking an amygdala have less fear expression. In an experiment, [[common degu|degu]] pups were removed from their mother but allowed to hear her call. In response, the males produced increased [[serotonin receptor]]s in the amygdala but females lost them. This led to the males being less affected by the stressful situation.<ref name=":1" />

The clusters of the amygdala are activated when an individual expresses feelings of fear or aggression. This occurs because the amygdala is the primary structure of the brain responsible for [[fight-or-flight response]]. Anxiety and panic attacks can occur when the amygdala senses environmental stressors that stimulate fight-or-flight response.<ref>{{Cite journal |last=Coplan |first=Jeremy D |last2=Lydiard |first2=R.Bruce |date=1998 |title=Brain circuits in panic disorder |url=https://doi.org/10.1016/s0006-3223(98)00300-x |journal=Biological Psychiatry |volume=44 |issue=12 |pages=1264–1276 |doi=10.1016/s0006-3223(98)00300-x |issn=0006-3223|doi-access=free }}</ref><ref>{{Cite journal |last=Gorman |first=Jack M. |last2=Kent |first2=Justine M. |last3=Sullivan |first3=Gregory M. |last4=Coplan |first4=Jeremy D. |date=2000-04-01 |title=Neuroanatomical Hypothesis of Panic Disorder, Revised |url=https://psychiatryonline.org/doi/10.1176/appi.ajp.157.4.493 |journal=American Journal of Psychiatry |language=en |volume=157 |issue=4 |pages=493–505 |doi=10.1176/appi.ajp.157.4.493 |issn=0002-953X}}</ref> The amygdala is involved in the expression of [[Fear conditioning|conditioned fear]]. Conditioned fear is the framework used to explain the behavior produced when an originally neutral stimulus is consistently paired with a stimulus that evokes fear. Fear is measured by changes in autonomic activity including increased heart rate, increased blood pressure, as well as in simple [[reflex]]es such as flinching or blinking.<ref>{{Cite journal |last=Sehlström |first=Malcolm |last2=Ljungberg |first2=Jessica K. |last3=Claeson |first3=Anna-Sara |last4=Nyström |first4=Markus B. T. |date=2022 |title=The relation of neuroticism to physiological and behavioral stress responses induced by auditory startle |url=https://pubmed.ncbi.nlm.nih.gov/35403836 |journal=Brain and Behavior |volume=12 |issue=5 |pages=e2554 |doi=10.1002/brb3.2554 |issn=2162-3279 |pmc=9120885 |pmid=35403836}}</ref> Studies in 2004 and 2006 showed that normal subjects exposed to images of frightened faces or faces of people from another race will show increased activity of the amygdala, even if that exposure is [[subliminal message|subliminal]].<ref>{{cite journal |vauthors=Williams LM, Liddell BJ, Kemp AH, Bryant RA, Meares RA, Peduto AS, Gordon E |date=August 2006 |title=Amygdala-prefrontal dissociation of subliminal and supraliminal fear |journal=Human Brain Mapping |volume=27 |issue=8 |pages=652–61 |doi=10.1002/hbm.20208 |pmc=6871444 |pmid=16281289}}</ref><ref name="pmid15563325">{{cite journal |vauthors=Cunningham WA, Johnson MK, Raye CL, Chris Gatenby J, Gore JC, Banaji MR |date=December 2004 |title=Separable neural components in the processing of black and white faces |url=http://nrs.harvard.edu/urn-3:HUL.InstRepos:12164714 |journal=Psychological Science |volume=15 |issue=12 |pages=806–13 |doi=10.1111/j.0956-7976.2004.00760.x |pmid=15563325 |s2cid=82916}} [https://www.sciencedaily.com/releases/2004/12/041208231237.htm Lay summary] available from [[Science Daily]].</ref> However, the amygdala is not necessary for the [[Fear processing in the brain|processing of fear-related stimuli]], since persons in whom it is bilaterally damaged show rapid reactions to fearful faces, even in the absence of a functional amygdala.<ref>{{cite journal |vauthors=Tsuchiya N, Moradi F, Felsen C, Yamazaki M, Adolphs R |date=October 2009 |title=Intact rapid detection of fearful faces in the absence of the amygdala |journal=Nature Neuroscience |volume=12 |issue=10 |pages=1224–5 |doi=10.1038/nn.2380 |pmc=2756300 |pmid=19718036}}</ref>

===Psychological disorders===
With advances in [[neuroimaging]] technology such as [[MRI]], neuroscientists have made significant findings concerning the amygdala in the human brain. A variety of data shows the amygdala has a substantial role in mental states, and is related to many [[mental illness|psychological disorders]]. Some studies have shown children with [[anxiety disorder]]s tend to have a smaller left amygdala. In the majority of the cases, there was an association between an increase in the size of the left amygdala with the use of [[SSRI]]s (antidepressant medication) or psychotherapy. The left amygdala has been linked to [[social anxiety disorder]], [[Obsessive–compulsive disorder|obsessive and compulsive disorders]], and [[PTSD|post-traumatic stress disorder]] (PTSD), as well as more broadly to separation and [[generalized anxiety disorder]].<ref name="Arehart-Treichel2005">{{cite journal |last1=Arehart-Treichel |first1=Joan |name-list-style=vanc |year=2005 |title=Changes in Children's Amygdala Seen After Anxiety Treatment |journal=Psychiatric News |volume=40 |issue=9 |page=37 |doi=10.1176/pn.40.9.00400037 |issn=0033-2704}}</ref> Multiple studies have found that the amygdalae may be responsible for the emotional reactions of PTSD patients. One study in particular found that when PTSD patients are shown pictures of faces with fearful expressions, their amygdalae tended to have a higher activation than someone without PTSD.<ref>{{cite book |last=Carlson |first=Neil R. |url=https://archive.org/details/physiologybehavi00carl_811 |title=Physiology of Behavior |date=12 January 2012 |publisher=Pearson |isbn=978-0205239399 |page=[https://archive.org/details/physiologybehavi00carl_811/page/n628 608] |url-access=limited |name-list-style=vanc}}</ref>

In 2006, researchers observed [[hyperactivity]] in the amygdala when patients were shown threatening faces or confronted with frightening situations. Patients with severe [[social anxiety disorder|social phobia]] showed a correlation with increased response in the amygdala.<ref name="pmid16256956">{{cite journal |vauthors=Phan KL, Fitzgerald DA, Nathan PJ, Tancer ME |date=March 2006 |title=Association between amygdala hyperactivity to harsh faces and severity of social anxiety in generalized social phobia |journal=Biological Psychiatry |volume=59 |issue=5 |pages=424–9 |doi=10.1016/j.biopsych.2005.08.012 |pmid=16256956 |s2cid=34105191}} [https://www.sciencedaily.com/releases/2006/01/060118205940.htm Lay summary] available from [[Science Daily]].</ref> Individuals with [[psychopathy]] show reduced autonomic responses to instructed fear cues than otherwise healthy individuals.<ref>{{cite journal |vauthors=Blair RJ |date=August 2008 |title=The amygdala and ventromedial prefrontal cortex: functional contributions and dysfunction in psychopathy |journal=Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences |volume=363 |issue=1503 |pages=2557–65 |doi=10.1098/rstb.2008.0027 |pmc=2606709 |pmid=18434283}}</ref> Similarly, depressed patients showed exaggerated left amygdala activity when interpreting emotions for all faces, and especially for fearful faces. This hyperactivity was normalized when patients were administered antidepressant medication.<ref>{{cite journal |vauthors=Sheline YI, Barch DM, Donnelly JM, Ollinger JM, Snyder AZ, Mintun MA |date=November 2001 |title=Increased amygdala response to masked emotional faces in depressed subjects resolves with antidepressant treatment: an fMRI study |journal=Biological Psychiatry |volume=50 |issue=9 |pages=651–8 |doi=10.1016/S0006-3223(01)01263-X |pmid=11704071 |s2cid=8927264}}</ref>

In a 2003 study, subjects with [[borderline personality disorder]] showed significantly greater left amygdala activity than normal control subjects. Some borderline patients even had difficulties classifying neutral faces or saw them as threatening.<ref>{{cite journal |display-authors=8 |vauthors=Donegan NH, Sanislow CA, Blumberg HP, Fulbright RK, Lacadie C, Skudlarski P, Gore JC, Olson IR, McGlashan TH, Wexler BE |date=December 2003 |title=Amygdala hyperreactivity in borderline personality disorder: implications for emotional dysregulation |url=https://wesscholar.wesleyan.edu/cgi/viewcontent.cgi?article=1193&context=div3facpubs |journal=Biological Psychiatry |volume=54 |issue=11 |pages=1284–93 |doi=10.1016/S0006-3223(03)00636-X |pmid=14643096 |s2cid=7493725}}</ref> The amygdala has been observed to respond differently in people with [[bipolar disorder]]. Amygdala dysfunction during face emotion processing is well-documented in bipolar disorder. Individuals with bipolar disorder showed greater amygdala activity (especially the amygdala/medial-prefrontal-cortex circuit).<ref>{{cite journal |vauthors=Thomas LA, Kim P, Bones BL, Hinton KE, Milch HS, Reynolds RC, Adleman NE, Marsh AA, Blair RJ, Pine DS, Leibenluft E |date=January 2013 |title=Elevated amygdala responses to emotional faces in youths with chronic irritability or bipolar disorder |journal=NeuroImage: Clinical |volume=2 |issue=2 |pages=637–645 |doi=10.1016/j.nicl.2013.04.007 |pmc=3746996 |pmid=23977455}}</ref><ref>{{cite journal |vauthors=Keener MT, Fournier JC, Mullin BC, Kronhaus D, Perlman SB, LaBarbara E, Almeida JC, Phillips ML |date=September 2012 |title=Dissociable patterns of medial prefrontal and amygdala activity to face identity versus emotion in bipolar disorder |journal=Psychological Medicine |volume=42 |issue=9 |pages=1913–24 |doi=10.1017/S0033291711002935 |pmc=3685204 |pmid=22273442}}</ref> For people with manic [[bipolar I disorder]], a decreased negative functional connectivity between the [[orbitofrontal cortex]] and the amygdala was also observed.<ref>{{Cite journal |last=Foland |first=Lara C. |last2=Altshuler |first2=Lori L. |last3=Bookheimer |first3=Susan Y. |last4=Eisenberger |first4=Naomi |last5=Townsend |first5=Jennifer |last6=Thompson |first6=Paul M. |date=2008 |title=Evidence for deficient modulation of amygdala response by prefrontal cortex in bipolar mania |url=https://doi.org/10.1016/j.pscychresns.2007.04.007 |journal=Psychiatry Research: Neuroimaging |volume=162 |issue=1 |pages=27–37 |doi=10.1016/j.pscychresns.2007.04.007 |issn=0925-4927|pmc=2410029 }}</ref> A 2003 study found that adult and adolescent bipolar patients tended to have considerably smaller amygdala volumes and somewhat smaller [[hippocampus|hippocampal]] volumes.<ref>{{cite journal |vauthors=Blumberg HP, Kaufman J, Martin A, Whiteman R, Zhang JH, Gore JC, Charney DS, Krystal JH, Peterson BS |date=December 2003 |title=Amygdala and hippocampal volumes in adolescents and adults with bipolar disorder |journal=Archives of General Psychiatry |volume=60 |issue=12 |pages=1201–8 |doi=10.1001/archpsyc.60.12.1201 |pmid=14662552 |doi-access=}}</ref> Many studies have also focused on the connections between the amygdala and [[autism]].<ref>{{cite journal |vauthors=Schultz RT |year=2005 |title=Developmental deficits in social perception in autism: the role of the amygdala and fusiform face area |journal=International Journal of Developmental Neuroscience |volume=23 |issue=2–3 |pages=125–41 |doi=10.1016/j.ijdevneu.2004.12.012 |pmid=15749240 |s2cid=17078137}}</ref>