“Automatic relevance detection in the absence of a functional amygdala”

How does the process differ between amygdala damage at a young age and damage when an adult?

The way that people’s gaze tends to move unconsciously towards things like spiders and snakes, corpses, and erotic images is said to be due to the operation of the amygdala.

The amygdala picks up information directly connected to life and death without fail and makes arrangements so that the individual can respond quickly. This rapid information processing is supposed to be thanks to the amygdala.

The theoretical basis for this amygdala operation is an experiment on patients who suffered damage to the amygdala after reaching adulthood, but the paper I discuss today challenges the thinking that “the amygdala is necessary for rapid detection of emotional stimuli.”

The experiment was conducted on patients who suffered damage to their amygdala on both sides when they were still children, but it did not detect any great difference from normal people in the detection of emotional stimuli.

In other words, the ability to detect emotional stimuli changed little whether the person had an amygdala or not.

The paper suggests because of this that the amygdala may not be essential in detecting emotional stimuli, and that the difference observed between prior research and this study may have been caused by the fact that in the prior research, the subjects suffered damage to their amygdala once they had reached adulthood, while in this study, the subjects suffered damage to their amygdala in youth and in the case of damage in youth like this, the functions of the amygdala could be substituted by other regions, such as the pulvinar.

[Abstract]
The idea that the amygdala is crucially involved in automatically prioritising relevant events rests on evidence from a single lesion study where a patient with bilateral temporal lobe lesions, acquired in adulthood, was impaired in recall facilitation during the attentional blink. Here, in a comparable task, we show that two individuals with selective bilateral amygdala lesions retain facilitated recall of aversive words during the attentional blink. Recall facilitation was statistically significant for both patients and akin to that seen in young students and age- and education-matched controls. This challenges the amygdala's role as a crucial hub in prioritising attention and at a minimum implies that this role can be compensated for when lesions are acquired early in life. Previous findings might be explained by the described fact that lesions were acquired later in life and encompassed areas beyond the amygdala, including visual pathways. We propose that in the absence of a functioning amygdala, prioritised visual processing may rely on alternative structures such as pulvinar and cortical visual areas.

Reference URL: Automatic relevance detection in the absence of a functional amygdala.

Comments

The pulvinar links information that enters from the retina to the amygdala. This diagram shows it clearly. Looking at this diagram, it seems like we could manage without the amygdala.

SC: superior colliculus

URL for the above diagram

If the amygdala is damaged while young, a substitution system is rebuilt, but I thought that whether you’re talking about the brain or life, rebuilding is easier when you’re young.

In system theory as well, it’s better to fail while you’re still young. The words “you can do over” could be replaced by “system can be easily rebuilt.”