40 Fun Facts About The Amygdala

Brain scans found which El Capitan free soloist's amygdala barely reacting to disturbing images?

Alex Honnold lay in an MRI scanner in 2016 while pictures that jolt most people flashed past, and his amygdala stayed almost silent. A year later he climbed Yosemite's El Capitan with no rope.

Patient S.M., who lost both amygdalae and nearly all fear, panicked after inhaling which gas?

Carbon dioxide set off a panic S.M. described as completely new to her, because a feeling of suffocation is an alarm from inside the body. The amygdala mainly handles threats from outside.

The amygdala, a fear-processing cluster deep in the brain, is named after the Greek for which nut?

Almond is what the Greek amygdale means, and a German physician picked the name in 1822 for the shape he saw. There are two of them, one in each half of the brain.

A Berkeley study found the amygdala 60 percent more reactive after 35 hours without what?

Sleep loss sent the amygdala into overdrive at gory pictures and weakened its link to the brain's reasoning areas. The study kept healthy young adults awake for a day, a night and another day.

The DC Comics villain Amygdala, a strongman prone to violent outbursts, fights which superhero?

Batman's foe Amygdala is Aaron Helzinger, who had that part of his brain removed in a failed attempt to cure his rage. Properly medicated, the character can be peaceful.

A study co-authored by actor Colin Firth tied a larger right amygdala to which political leaning?

Conservatism went with a larger right amygdala in young London adults, while liberal views went with more grey matter in the anterior cingulate. Firth commissioned the scans while guest-editing a BBC radio show.

Rats with Toxoplasma, a parasite whose cysts tend to gather in the amygdala, stop fearing which predator's urine?

Cats are the only hosts in which Toxoplasma reproduces sexually, so a rat that wanders toward one helps the parasite. Infected rats were not just fearless but attracted.

Which sense feeds the amygdala most directly, which helps explain why it stirs memories so strongly?

Smell is wired in closely: part of the amygdala takes input straight from the olfactory bulb. That is why a whiff of sunscreen or an old kitchen can bring back a feeling at once.

The amygdala helps trigger which three-word survival response, first described by Walter Cannon?

Fight or flight is the racing heart and tensed muscles that follow a threat. The amygdala sets it off so fast that people jump clear of a car before they have consciously seen it.

Teens lean on the amygdala because which rational brain region is not fully mature until about 25?

Prefrontal cortex wiring, the seat of judgment and long-term thinking, keeps maturing until about 25. Until then the amygdala does more of the deciding, which is why teens often cannot explain a rash choice.

The human amygdala sits deep inside which lobe of the brain, the one that also processes sound?

Temporal lobe tissue wraps around each amygdala, about halfway between the skull and the centre of the brain. Point a finger inward from just above each jaw joint and you are aiming at them.

The amygdala belongs to which set of emotion-linked brain parts, named from the Latin for border?

Limbic system comes from limbus, Latin for border, because its parts ring the boundary between the brain's two halves and the brainstem. French anatomist Paul Broca mapped that ring in 1878.

Which psychologist coined the term amygdala hijack in the 1995 book Emotional Intelligence?

Daniel Goleman used the phrase for a reaction far bigger than its trigger deserves, when the amygdala acts before the reasoning brain weighs in. He counted a fit of explosive laughter as one too.

Which New York University fear researcher sings in a rock band called The Amygdaloids?

Joseph LeDoux formed The Amygdaloids in 2006 with fellow NYU scientists and writes most of their songs about mind and brain. One 2012 EP used the word mind in every title.

On the fast 'low road' for threats, which sensory relay station signals the amygdala directly?

Thalamus signals take a rough shortcut to the amygdala, arriving before the slower, detailed route through the brain's outer layers. That is why you can jump at a shadow before working out what it is.

An autopsy on which 1966 University of Texas tower sniper found a brain tumor thought to have pressed on his amygdala?

Charles Whitman left a note asking doctors to examine his brain for a cause of his headaches and violent urges. The pecan-sized growth they found is still debated as a factor.

Which condition, first seen in amygdala-damaged monkeys, brings tameness and mouthing of objects?

Klüver–Bucy syndrome is named for the pair who removed parts of monkeys' brains in the 1930s while hunting for where the drug mescaline acts. The animals turned placid and fearless.

Which rare genetic disorder, known for a hoarse voice, destroyed both of patient S.M.'s amygdalae?

Urbach–Wiethe disease thickens the skin and vocal cords and, in at least half of cases, hardens tissue deep in the brain into calcium deposits. Only a few hundred cases have ever been reported.

Which German, who helped give the word biology its modern sense, named the amygdala in 1822?

Karl Burdach introduced the name in a three-volume study of the brain, where he also named the arcuate fasciculus for its arching fibres. A tract in the spinal cord still carries his name.

Fear conditioning, which amygdala damage blocks, builds on which scientist's work with salivating dogs?

Ivan Pavlov paired a signal with food until the signal alone made dogs drool. Pair a tone with a mild shock instead and a rat soon freezes at the tone, unless its amygdala is damaged.

Which disorder, once called shell shock, brings extra amygdala activity at the sight of fearful faces?

PTSD brains show an amygdala that fires hard at reminders of danger while the regions that should calm it respond too weakly. Shell shock was one of several names used during the world wars.

Which hormone, known for its role in childbirth, is reported to cut fear by quieting the amygdala?

Oxytocin given as a nasal spray has been reported to reduce fear, and in rodents it switches on a circuit inside the amygdala that inhibits it. In labour the same hormone drives contractions.

After an amygdala alarm, the adrenal glands release which hormone that keeps the body on high alert?

Cortisol arrives after the first jolt, at the end of a chain of signals that runs from the brain through the pituitary gland. When the threat passes its level falls and the body's brake takes over.

Which memory structure beside the amygdala takes its name from the Greek for seahorse?

Hippocampus was the name the Italian anatomist Julius Caesar Aranzi settled on in the 1500s after first likening the curved ridge to a silkworm. The amygdala flags events as emotional, which helps this neighbour store them.

Patient S.M. could not read fear in faces because she failed to look at which facial feature?

The eyes carry most of the signal for fear, and S.M. simply never fixed on them. When researchers told her to look there, her reading of frightened faces became entirely normal.

Caltech scientists found that a woman with no working amygdala lacked any sense of what?

Personal space meant nothing to her: she felt at ease nose to nose with a stranger. In healthy volunteers the amygdala lit up whenever someone stood very close.

A 2011 study of adults found amygdala volume rises with the size and complexity of a person's what?

Social network size and variety both tracked amygdala volume in the Boston study, and no other deep-brain structure showed a similarly strong link. Juggling many relationships seems to lean on it.

Patients with two damaged amygdalae rated strangers' faces as unusually approachable and what else?

Trustworthy was their verdict even on faces most people rate as the shadiest, in a 1998 study of three patients. The amygdala seems to supply the gut feeling that says keep your distance.

In betting games, two patients with amygdala damage showed far less of which well-known money bias?

Loss aversion is the habit of refusing a bet you might lose even when the possible win is much larger. Without an amygdala to apply the brakes, the two patients took such gambles calmly.

A 2011 Nature study found a more active amygdala under stress in people currently living where?

In cities, people put under pressure in the scanner showed a busier amygdala than those from towns or the countryside. Growing up urban altered a different region that helps regulate it.

Which religious group has been scanned altering amygdala activity during compassion meditation?

Buddhist monks practised in compassion meditation shifted activity in the amygdala and in regions tied to reading other people's feelings. Experts showed a stronger change than novices in one of those regions.

People with larger amygdalae gave more unique answers on which classic psychological assessment?

Rorschach test inkblots draw more one-of-a-kind answers from artists than from other people, so the researchers suggested a bigger amygdala may go with creative thinking.

Which famous amnesia patient had both amygdalae cut out in a 1953 operation for epilepsy?

Henry Molaison, long known only as H.M., could no longer form new memories after the surgery. Scientists studied him for half a century, until his death in 2008.

Which genetic condition, known for hugging strangers, dulls amygdala reactions to disapproving faces?

Williams syndrome comes from about 27 missing genes on chromosome 7 and brings a famously outgoing manner. The amygdala under-reacts to threatening people yet over-reacts to other dangers, such as scary animals.

Amygdala dysfunction and blunted reactions to fear cues are linked to which personality construct?

Psychopathy, marked by impaired empathy and remorse, goes with a muted bodily reaction to warnings that something unpleasant is coming. Faults in the amygdala and the frontal regions that regulate it are among the suspected causes.

Which part of the amygdala is its major output station, wired to the brainstem to drive freezing?

Central nucleus cells pass the amygdala's verdict down to the brainstem, which changes heart rate, blood pressure and stress hormones. Information from the senses mostly enters through the lateral nucleus.

Which belief that loved ones are impostors is blamed on a broken amygdala link to face areas?

Capgras delusion may arise when a face is recognised but the usual jolt of familiarity never arrives, so the brain decides the person must be a double. Neuroscientist V. S. Ramachandran proposed the idea.

To test her missing fear, scientists let amygdala patient S.M. handle spiders and which reptiles?

Snakes fascinated her: S.M. showed curiosity where most people recoil, and a tour of a haunted house and a run of frightening films left her just as unmoved.

Amygdalin, an apricot-kernel compound sharing the amygdala's Greek root, releases which poison?

Cyanide is released as the body breaks amygdalin down, which is why eating a lot of bitter kernels can poison. The compound and the brain structure are named after the same nut.

Despite its big role in emotion, the average human amygdala is only about the size of which food?

A shelled peanut is the Cleveland Clinic's comparison for an average amygdala, which is also slightly darker than the tissue around it. The exact size varies with the size of the whole brain.