Help in understanding effect size in fMRI

[dentons]

Hello everyone, I'm a student of a Master's degree in Neuroscience and I'm preparing a journal club presentation on an article called "Differential extrageniculostriate and amygdala responses to presentation of emotional faces in a cortically blind field". I'm struggling to understand some of the results, in particular what a negative effect size means in fMRI. Is there someone that can explain that to me? I'm referring in particular to this picture of the paper https://d1gqps90bl2jsp.cloudfront.net/content/brain/124/6/1241/F4.large.jpg?width=800&height=600&carousel=1 the one attached).
What can I say about the "unseen CS-"? Why is it so negative? Does it mean that the amygdala has a very low degree of activation?
Thanks to anyone that can help me :)

 

[jim mcnamara]

This appears to be something @DiracPool could help with. I'm confused with your explanation as well. fMRI mesures blood flow in the brain which indirectly shows which brain tissues are active. Interpretation is, IMO, sometimes a bit subjective. Each area seems to require the reader to be in the know how the ground rules are applied. My opinion only. In particular you have to have a solid grip on the particular known aspects of certain kinds of responses.