Iulian Iancu & Moshe KotlerY  I lYavne, Israel

Let’s meet the amygdala!ygFrom Anatomography, 

website maintained by Life The amygdala

website maintained by Life Science Databases(LSDB). 

Let’s meet the amygdala!ygMRI coronal view of the 

amygdala The amygdala 

The amygdalaygThe amygdalae (singular: amygdala; also corpusamygdaloideum; ‐amygdalē, 'almond', 'tonsil, listed inGray’s Anatomyas the nucleus amygdalæ)

Nuclei of amygdalal d h d f are almond‐shaped groups of

nuclei located deep within themedian temporal lobes.

One inch in length.

Has a primary role in theprocessing of memory andemotional reactions (also fearemotional reactions (also fearcircuit and aggression), theamygdalae are considered part ofthe limbic systems.y

My lecturey What about the Amygdala in Social Anxiety 

Di d ?Disorder?

What about the Amygdala in a condition that is characterized by hyper‐sociability?

What is the behavioral phenotype in a disorder with yAmygdala damage?

1. Amygdala in S.A.D.yg

I di id l i h SAD if b li i i h Individuals with SAD manifest abnormalities in theways in which they process social material.

Persons with generalized SAD show attentional biasf h i i f i d lik lfor threatening information and are more likely toremember faces with harsh (eg, angry) compared withaccepting (eg happ ) emotional e pressionsaccepting (eg, happy) emotional expressions.

Bickart, 2011,

S di  f d   li k b   h   i ’   d l   Studies found a link between the primate’s amygdala size and the size of their group.Bi k h d  h   h   l   f  h  h   Bickart showed that the volume of the human amygdala (and another 2 cortical regions that link to the A) in 58 (healthy) subjects was in correlation with the A) in 58 (healthy) subjects was in correlation with the size of their social network.

N   l ti hi    f d  ith th i   i l  ti f ti   No relationship was found with their social satisfaction from the network.

Amygdala volume correlates with social network sizenetwork size Panels A and B plot social network variables (Y–axis) against total adjusted amygdala volume (X–axis). Data points from

young participants are in black circles and older participants in grey triangles

IF IN SAD, THE SOCIAL NETWORK IS SMALL, THEN WHAT???  Irle et al (2010; J Psychiatry Neurosci. Reduced amygdalar and hippocampal size in adults with generalized social phobia) 

Irle et al. report for the first time volumetric results in ppatients with GSP.

24 patients with GSP and 24 healthy controls underwent 3‐24 patients with GSP and 24 healthy controls underwent 3dimensional structural MRI and a clinical investigation.

Compared with controls  GSP patients had significantly reduced Compared with controls, GSP patients had significantly reducedamygdalar (13%) and hippocampal (8%) size. The reduction in the size of the amygdala was statistically significant for men but not women  Smaller right‐sided hippocampal volumes of GSP not women. Smaller right sided hippocampal volumes of GSP patients were significantly related to stronger disorder severity. 

Increased Amygdala Activation to Angry and Contemptuous Faces in Generalized Social Phobia 

–Stein et al (2002)

15 subjects with GSP and 15 matched HC, free of psychotropic5 j 5 p y pmedication for at least 12 weeks, viewed 60 color photographsfrom a standardized set of human facial stimuli, during whichthe task was to identify the sex of the person in the photograph.

With fMRI, in the left allocortex (including the amygdala),subjects with GSP produced a significantly greater percent BOLDj p g y g psignal change than did HC for contemptous compared withhappy faces (GSP: 0.72% vs HC: −0.01%) and for angry comparedwith happy faces (GSP: 0.45% vs HC: −0.09%).

Subjects with GSP and HC did not produce a statisticallydifferent percent signal change for fearful or nonexpressive facescompared with the happy faces in this region.p ppy g

Klumpp et al, 2010pp , Investigated with fMRI 12 generalized SAD subjects and 12 controlsand 12 controls.

In the left amygdala  compared with the HC group  In the left amygdala, compared with the HC group, GSP exhibited greater reactivity for threatening faces at moderate (P < 0.03) and high intensity (P < 0.003),but not low intensity (P = 0.10).

Correlational analysis showed no relationship between amygdala activation and symptom severity (ps> 0.05).

a) Extracted estimate of BOLD signal change for threatening faces.(b) Whole brain t‐map (Puncorrected< 0.005, 20 voxel minimum) showing amygdala hyperactivity to moderate and high intensity threat.

Response to emotional expressions in generalized social phobia and generalized anxiety disorder: evidence for separate disorders.

Blair et al, 2008 Individuals matched on age, IQ, and gender with generalized SAD without 

GAD (N=17), GAD (N=17), or no psychopathology (N=17) viewed neutral, fearful, and angry expressions while ostensibly making a simple gender fearful, and angry expressions while ostensibly making a simple gender judgment.

The patients with gSAD without GAD showed increased activation to fearful relative to neutral expressions in several regions, including the amygdala, compared to healthy individuals. This increased amygdala response related to self‐reported anxiety in these patients. self reported anxiety in these patients. 

In contrast, patients with gSAD showed significantly less activation to fearfulrelative to neutral faces compared to healthy individuals. They did showi ifi tl i d t i l ti t h lthsignificantly increased response to angry expressions relative to healthyindividuals in a lateral region of the middle frontal gyrus. This increased lateralfrontal response related to self‐reported anxiety in patients with GAD.

Neural response to self‐ and other referential praise and criticism in generalized social phobia.

Blair et al 2008 Arch Gen PsyBlair et al, 2008 Arch Gen Psy

Unmedicated individuals with GSP (n=17) and matchedhealthy controls (n=17).D i fMRI i di id l d iti ( Y b tif l) During fMRI, individuals read positive (eg, You are beautiful),negative (eg, You are ugly), and neutral (eg, You arehuman) comments, about the self or about somebody else(eg He is beautiful)(eg, He is beautiful).

In the medial prefrontal cortex and bilateral amygdala, patientswith GSP showed significantly increased BOLD responseswith GSP showed significantly increased BOLD responses,relative to comparison individuals, to negative comments(criticism) referring to themselves.

In contrast, there were no significant group differences with respectto negative comments referring to others or neutral or positivecomments referring to self or others.g

Common Changes in (regional) Cerebral Blood Flow (rCBF) in Patients WithSocial Phobia Treated With Citalopram or Cognitive‐Behavioral Therapy‐

Furmark et al 2002Furmark et al, 2002

rCBF was assessed (PET with oxygen 15–labeled water) in 18 previously untreated patients with SAD in an in 18 previously untreated patients with SAD in an anxiogenic public speaking task. Patients were randomized to citalopram  CBT or WL  randomized to citalopram, CBT or WL. 

Scans were repeated after 9 weeks of treatment or waiting time  Outcome was assessed by subjective and waiting time. Outcome was assessed by subjective and psychophysiological state anxiety measures and self‐report questionnaires. Questions were readministeredreport questionnaires. Questions were readministeredafter 1 year.

Furmark et al, 2002, Symptoms improved significantly and roughly equally with 

citalopram and CBT, whereas the waiting‐list group remained p g g punchanged. 

Four patients in each treated group and 1 waiting‐list patient were classified as responders  Within both treated groups  and in were classified as responders. Within both treated groups, and in responders regardless of treatment approach, improvement was accompanied by a decreased rCBF‐response to public speaking bilaterally in the amygdala (among others)  Between group bilaterally in the amygdala (among others). Between‐group comparisons confirmed that rCBF in these regions decreased significantly more in treated groups than control subjects, and in 

d  th   d   ti l l  i  th   i ht responders than nonresponders, particularly in the right hemisphere. The degree of amygdalar‐limbic attenuation was associated with clinical improvement a year later.

Labuschagne et al (2010)g ( ) Oxytocin attenuates amygdala reactivity to fear in generalized social anxiety 

disorder.  

In a fMRI study utilizing a double‐blind placebo‐controlled within‐subjects design, we measured amygdala activation to an emotional face matching task of fearful, angry, and happy faces following acute intranasal administration of OXT  d  l b  i   8 GSAD  d  8  l  OXT and placebo in 18 GSAD and 18 controls. 

Both the CON and GSAD groups activated bilateral amygdala to all emotional faces during placebo  with the GSAD group exhibiting hyperactivity specifically faces during placebo, with the GSAD group exhibiting hyperactivity specifically to fearful faces in bilateral amygdala compared with the CON group. 

OXT had no effect on amygdala activity to emotional faces in the CON group, yg y g p,but attenuated the heightened amygdala reactivity to fearful faces in the GSAD group, such that the hyperactivity observed during the placebo session was no longer evident following OXT (ie, normalization). 

Goldin & Gross, 2010, Examined Mindfulness‐Based Stress Reduction (MBSR)‐related 

changes in the brain‐behavior indices of emotional reactivity and regulation of negative self beliefs in patients with SAD  regulation of negative self‐beliefs in patients with SAD. 

16 patients underwent functional MRI while reacting to negative self‐beliefs and while regulating negative emotions using 2 types of beliefs and while regulating negative emotions using 2 types of attention deployment emotion regulation‐breath‐focused attention and distraction‐focused attention. 

Compared with baseline, MBSR completers (14) showed improvement in anxiety and depression symptoms and self‐esteem. 

During the breath‐focused attention task, they also showed decreased negative emotion experience and reduced amygdala activity. 

2. Williams Syndromey“They love everyone, are loved by everyone, and are very charming”. What is WS?

WS is a neurodevelopmentaldisorder caused by a known chromosomal microdeletion on chromosomal microdeletion on chromosome 7.

Individuals with WS show: Individuals with WS show:‐ mild to moderate mental 

retardation, hypercalcemia, FTT  decreased muscle tone  FTT, decreased muscle tone, supravalvular aortic stenosis, very poor spatial abilities, comparatively strong language  p y g g gskills. 

WILLIAMS SYNDROMEThe most common symptoms of Williams syndrome are mental retardation, heart defects, and unusual facial features (small upturned nose, wide mouth, full li   ll  hi   id l   d  h)

WS d ib d   f i dl d lips, small chin, widely spaced teeth). described as friendly and 

‘hypersocial’ with highly affilliative and engaging social style.style.

They lack stranger anxiety! They are socially disinhibited and a e soc a y d s b ed a dtend to seek social interaction even with strangers.

Interestingly, beginning early in childhood, they show an unusually high level of interest in face to face social interactionin face‐to‐face social interaction.

Amygdala response to faces parallels social behavior in Williams syndrome‐Pauls et al 2009syndrome Pauls et al, 2009

P i i  i l d d   i di id l   i h WS  d    Participants included 17 individuals with WS and 2 groups of controls (chronological age‐matched controls  CA + typically developing 8 to 9 year old controls, CA + typically developing 8‐ to 9‐year‐old children (developmental age controls, DA)). 

While engaged in a face discrimination task, WS ti i t  f il d t   it th   d l  (fMRI)participants failed to recruit the amygdala (fMRI).

Pauls et al, 2009, The Amygdala is hypo‐active  in WS in response to negative yg yp p gsocial affect. The hypoactive amygdala does not monitor for social danger.

The absent amygdala responses to faces in WS is consistent with unusually positive approachability ratings of 

’ f  i  WSstrangers’ faces in WS.

Given the integral role of the amygdala in social behavior   Given the integral role of the amygdala in social behavior, the failure of WS participants to recruit this region during face processing may be a neural correlate of the abnormally high sociability that characterizes this disorder  high sociability that characterizes this disorder. 

Martens et al, 2009, 22 individuals with WS and 22 normal controls rated the approachability of 

40 faces.

Subjects had increased amygdala volume and a decreased overall brain volume.

Higher approachability ratings (hypersociability) of both positive and negative faces were found in WS. Unexpectedly, individuals with WS report using features other than the eyes and mouth to determine approachability, particularly when they are younger. 

A positive relationship between right amygdala volume and approachability ratings was found in individuals with WS, particularly ratings of 'negative' faces. particularly ratings of  negative  faces. 

It seems that the amygdala dysfunction in WS is related to the hypersociability   hypersociability.  

Oxytocin and Vasopressin Are Dysregulated in Williams Syndrome, a Genetic y p y g y ,Disorder Affecting Social Behavior

Dai et al, 2012 (PLoS ONE) 

R l l d i ifi l hi h di l l f Results revealed significantly higher median levels ofOT inWS versus controls at baseline.

InWS, baseline OT was correlated positively withapproach, but negatively with adaptive socialbehaviors.

SAD vs Williams synd.y Williams 

syndromeSocial phobia syndromephobia

Friendly, gregariousFearful, insecure, avoidantBehavioral phenotype

IncreasedSmallerAmygdala volume IncreasedSmallerAmygdala volume

HypoHyperAmygdala activation

High?high/lowOxytocin at baseline

??Reduces amygdala responseOxytocin as treatment

3. Social behavior with amygdala damage‐ Urbach Wiethe Disease, a developmental disorder characterized by focal calcifications in the bilateral 

amygdalaamygdala

Urbach Wiethe Disorder (Lipid Proteinosis)

Patients with UWD judge unfamiliar individuals to be more approachable and more trustworthy than did pp ycontrols. The impairment was most striking for faces to which normal subjects assigned the most negative ratings: unapproachable and untrustworthy individuals. pp y

According to rodent research, the basolateral amygadala(BLA) inhibits unconditioned  or innate  fear(BLA) inhibits unconditioned, or innate, fear.

In a groups of 5 subjects with Urbach Wiethe Disease In a groups of 5 subjects with Urbach Wiethe Disease (UWD), imaging showed focal bilateral BLA damage,  while other amygdala sub‐regions were intact.

Patients showed fear hyper vigilance   Patients showed fear hyper‐vigilance. 

Th t t l th d i di t th t th l i f th fi UWD bj t l t d iThe structural method indicates that the lesions of the five UWD‐subjects are located in the basolateral amygdala (BLA), whereas the functional method shows activation during emotion matching in the superficial amygdala (SFA) and the central‐medial amygdala (CMA) but not in the BLA(CMA), but not in the BLA.

4. Summaryy In SAD the amygdala (…as well as other regions) is implicated in the processing of

conditioned aversive stimuli.

SAD may be a dysregulation or hyperactivity of the amygdala’sevaluation of potential threat.

Amygdala hyperactivation (to social threat) has been consistentlyobserved among adults with SAD. However, it is unclear whether this isprimary or results from another dysfunction in the brain!primary or results from another dysfunction in the brain!

E th d SSRI t b h bit ti ti f Exposure therapy and SSRI may act by habituation‐ correction ofneuronal activity in these brain structures. It has beenpostulated that an increase in serotonin may inhibitthalamic and cortical inputs from activating the amygdala.

Summaryy These findings of increased activity of emotion‐processingregions, especially the amygdale, during the processing ofg , p y yg , g p ganxiety‐provoking stimuli are not specific to SAD, however.

Similar findings have been noted for a range of otheranxiety disorders (PTSD, OCD and PD).

Whereas many anxiety disorders are associated withincreased activity of the fear circuitry, the selectivity ofincreased activity of the fear circuitry, the selectivity ofresponse to particular “danger" stimuli may be whatdifferentiates them.

Optogenetics‐ optics and geneticsOptogenetics‐ optics and genetics combined, the latest progress, p g

Optogenetics is a newly developed procedure used to control individual or groups of nerve cells in the brain.

This is achieved by stereotactic of genetically modified viruses carrying a microbial opsin gene. Once an opsin gene product is y g p g p g pexpressed in the target cell population, its activity allows light‐based control over cellular physiology.

Researchers attach an optic cable to the mice’s heads that pdelivers pulses of light, resulting in control over the group of neurons’ activity. 

By simply shining a light, optogenetics can activate or inhibit y p y g g , p gneurons with light‐sensitive proteins, effecting radical cognitive or behavioral changes in the brain. 

Amygdala circuitry mediating reversible and bidirectional control of anxiety

Kay M et al.  Nature 2011y

“temporally precise optogenetic stimulation of basolateralamygdala (BLA) terminals in the central nucleus of the

d l ( ) h d b l d f hamygdala (CeA)—achieved by viral transduction of theBLA with a codon‐optimized channelrhodopsin followedby restricted illumination in the downstream CeA—yexerted an acute, reversible anxiolytic effect (increasedexploratory behavior in mice‐ a sign of alleviated anxiety).

Conversely selective optogenetic inhibition of the same Conversely, selective optogenetic inhibition of the sameprojection with a third‐generation halorhodopsinincreased anxiety‐related behaviors”.y

Essentially, the activity of these different proteins turnscells either on/off.

This might constitute an opportunity for progress in the  study of the amygdala and social behavior. May be in the future we could activate with light the inhibitory 

(anxiolytic) part of the amygdala ?!

Thanks!Thanks!