As outlined in the previous post, Ralph Adolphs and I have written a critique of the idea that a subcortical pathway conveys affective information to the amygdala in a rapid, automatic fashion. Our argument can be summarized as follows (details are provided in the paper):
- Affective information is not processed faster than other types of visual information;
- The processing of affective visual stimuli involves both coarse and fine (i.e., low and high spatial frequency) information;
- Recent studies suggest that the amygdala is not essential for rapid, non-conscious detection of affective information;
- A related point discussed elsewhere is that the processing of affective stimuli does not take place in a manner that is as independent of attention and awareness as frequently advanced (for additional discussion, see paper);
- Evidence for an uninterrupted anatomical pathway in primates linking the retina to the superior colliculus to the pulvinar to the amygdala is lacking;
- A related point is that the medial pulvinar (the part that is anatomically connected to the amygdala) is a highly integrative thalamic region that is bi-directionally connected with many cortical regions, including frontal, cingulate, insular, and parietal cortices. In other words, the medial pulvinar is not a passive relay of visual information, but likely integrates multiple sources of information in important ways.
- More broadly, I have argued that emotion and cognition are not separated in the brain (see paper), and are better conceptualized as co-determining each other.