Automatic relevance detection in the absence of a functional amygdala

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.

Fig. 1

Recall facilitation (% correctly recalled aversive T2 − % correctly recalled neutral T2) for both control groups and patients AM and BG. Patients’ recall facilitation is almost identical to the control group mean and is significantly different from zero (see text for details).