The amygdala - not command central for our fear reactions?

Most of us have accepted for years, starting from LeDoux's early work, that there is an automatic unconscious 'downstairs' rapid pathway in our brain that does our most important affective processing, before other more 'upstairs' cortical networks fill in the consciousness perceptual details. A recent review by Pessoa and Adolphs (PDF here) has offered a more nuanced view, from a 'low road' to 'many roads' model for our processing the significance of affective stimuli, in which the cortex plays a much larger role in processing affective visual information than is typically acknowledged. Part of their argument is based on recent studies showing that reaction times for detecting fearful faces in a patient with complete bilateral amygdala lesions were normal, a finding now extended to several further patients.

Here is the abstract of that review:

A subcortical pathway through the superior colliculus and pulvinar to the amygdala is commonly assumed to mediate the non-conscious processing of affective visual stimuli. We review anatomical and physiological data that argue against the notion that such a pathway plays a prominent part in processing affective visual stimuli in humans. Instead, we propose that the primary role of the amygdala in visual processing, like that of the pulvinar, is to coordinate the function of cortical networks during evaluation of the biological significance of affective visual stimuli. Under this revised framework, the cortex has a more important role in emotion processing than is traditionally assumed.

This review has triggered extensive commentary, and I wanted to pass on to those MindBlog readers who are into brain and emotion details PDFs of two letters outlining the issues, the critique from de Gelder et al., and the convincing and balanced (to me) response from Pessoa and Adolphs.