“Temporal precedence of emotion over attention modulations in the lateral amygdala: Intracranial ERP evidence from a patient with temporal lobe epilepsy.”
Does the amygdala play it both ways?
There is the phrase “to play it both ways.” It seems that there were situations where it wasn’t clear whether the amygdala was playing it both ways, or which way it was more serious about.
What are the two ways that the amygdala is playing, then?
One is bottom-up information. The amygdala automatically reacts when you see something scary, dangerous, sexual, suspicious or unclear, or in other words, information that could relate to survival. It doesn’t matter if your teacher is telling you to look at the blackboard. No matter where your attention is focused, if something interests you, you react to it without thinking. Because of this, it was thought that the amygdala automatically reacts to emotional information, leaving no opportunity for attention to creep in. In other words, the thinking was that the amygdala only had eyes for bottom-up information.
The other line of thought is that the amygdala was more interested in top-down communications. Putting it another way, top-down communications are “attention.” When you are looking “attentively” at something, the amygdala is active. Even if some kind of emotional visual stimulus is presented to you, if there is no prior “attention” to get you to look at it, the amygdala will not be active. Because of this, the main interest of the amygdala is “attention,” or in other words, top-down communications.
These were the two ways of understanding.
In my view, this result is largely due to the way studies were conducted, but as a matter of fact, which of these is the amygdala mainly interested in? “Attention” or “emotion”—which does the amygdala have eyes for? The paper I discuss today investigates this question.
The study used magnetoencephalography to examine brain activity at millisecond resolution, and going straight to the conclusion, the amygdala is serious about both “attention” and “emotion.” What this means is that when an emotional visual stimulus is shown to a subject in the study, the amygdala automatically becomes active at an extremely early stage, whether the subject is paying attention to it or not. Because of this, the amygdala can be considered to react automatically to “emotional” information.
The problem is after this: if the subject’s attention is focused in advance by telling them to look at something, the amygdala becomes active following the “emotional” reaction. Strong activity is not observed if attention is not focused.
If we depict it as a simple diagram, it would look like this:
Communications from the prefrontal cortex (top-down)↓ (later in time)
Amygdala
↑ (earlier in time)
Emotional information from the retina (bottom-up)
In other words, it seems like the amygdala is going steady with both “emotion” and “attention” by including a delay between them.
[Abstract]
“Previous fMRI studies have reported mixed evidence for the influence of selective attention on amygdala responses to emotional stimuli, with some studies showing ‘automatic’ emotional effects to threat-related stimuli without attention (or even without awareness), but other studies showing a gating of amygdala activity by selective attention with no response to unattended stimuli. We recorded intracranial local field potentials from the intact left lateral amygdala in a human patient prior to surgery for epilepsy and tested, with a millisecond time resolution, for neural responses to fearful faces appearing at either task-relevant or task-irrelevant locations. Our results revealed an early emotional effect in the amygdala arising prior to, and independently of, attentional modulation. However, at a later latency, we found a significant modulation of the differential emotional response when attention was directed toward or away from fearful faces. These results suggest separate influences of emotion and attention on amygdala activation and may help reconcile previous discrepancies concerning the relative responsiveness of the human amygdala to emotional and attentional factors.”
