Amygdala fMRI Signal as a Predictor of Reaction Time

Abstract

Reaction times (RTs) are a valuable measure for assessing cognitive processes. However, RTs are susceptible to confounds and therefore variable. Exposure to threat, for example, speeds up or slows down responses. Distinct task types to some extent account for differential effects of threat on RTs. But also do inter-individual differences like trait anxiety. In this functional magnetic resonance imaging (fMRI) study, we investigated whether activation within the amygdala, a brain region closely linked to the processing of threat, may also function as a predictor of RTs, similar to trait anxiety scores. After threat conditioning by means of aversive electric shocks, 45 participants performed a choice RT task during alternating 30 s blocks in the presence of the threat conditioned stimulus [CS+] or of the safe control stimulus [CS-]. Trait anxiety was assessed with the State-Trait Anxiety Inventory and participants were median split into a high- and a low-anxiety subgroup. We tested three hypotheses: (1) RTs will be faster during the exposure to threat compared to the safe condition in individuals with high trait anxiety. (2) The amygdala fMRI signal will be higher in the threat condition compared to the safe condition. (3) Amygdala fMRI signal prior to a RT trial will be correlated with the corresponding RT. We found that, the high-anxious subgroup showed faster responses in the threat condition compared to the safe condition, while the low-anxious subgroup showed no significant difference in RTs in the threat condition compared to the safe condition. Though the fMRI analysis did not reveal an effect of condition on amygdala activity, we found a trial-by-trial correlation between blood-oxygen-level-dependent signal within the right amygdala prior to the CRT task and the subsequent RT. Taken together, the results of this study showed that exposure to threat modulates task performance. This modulation is influenced by personality trait. Additionally and most importantly, activation in the amygdala predicts behavior in a simple task that is performed during the exposure to threat. This finding is in line with “attentional capture by threat”—a model that includes the amygdala as a key brain region for the process that causes the response slowing.

Questioning the role of amygdala and insula in an attentional capture by emotional stimuli task

“…Details of the recruitment, screening, and objectives of this study can be found in Marxen et al (2016). On Experimental Day 1, a T1-weighted MRI, a resting state fMRI sequence, the ACES task, and a further task (Riedel et al, 2016) were acquired. We will focus here on the ACES task (see below for details).…”

Impact of carbon monoxide on neural activation during a reaction time task

“…Whilst reaction time tasks are regarded a reliable and valuable measure for cognitive responses, the threat of attention loss and variability in speed between participants threatens its validity (Riedel et al, 2016). Additionally, the risk of habituation and associated attenuation of BOLD response remains.…”

“…As reaction time tests have the potential to reveal inter-individual differences in e.g. anxiety (Riedel et al, 2016) which could in turn influence BOLD response or slow reaction times (Ford et al, 2018), we assessed state anxiety pre and post scan for both protocols. There was no change in state anxiety, suggesting that the change in reaction times should not be attributed to feelings of participant apprehension.…”

“…Whilst reaction time tasks are regarded a reliable and valuable measure for cognitive responses, the threat of attention loss and variability in speed between participants threatens its validity (Riedel et al, 2016). While it is likely that any habituation to the respiratory breathing apparatus was minimal (Hayen et al, 2015), habituation could have impacted the reaction time task to some degree.…”

A case control study to assess and compare cognitive functions among chess players and non- chess players aged 11 to 16 years in Western India

“…Riedel P et al states that reaction times are a valuable measure for assessing cognitive processes [47].…”