Why use two different samples to begin with, and how does this actually strengthen your findings?

So the first reason to use two different samples is it's always nice to be able to show that you can replicate an effect.

When we initially started doing this research in the discovery sample, we thought that we were going to see some difference in visual cortex thickness that was related to trauma and probably related to PTSD too.

And we did see something related to PTSD, but the thing that came out strongest was this difference in cortical thickness between individuals who've been recently exposed to traumatic event and individuals who had not recently been exposed to traumatic events, about 30-day window, and V1, where these recently trauma-exposed individuals showed greater thickness in visual area one, which I think that sort of as a heuristic, is sort of hard to wrap your head around at first, if only because a lot of the way in which we treat brain thickness or brain volume is that that is a measure of brain health.

So more thickness or more volume, that's better.

And stress is bad, so it should lead to less brain health.

So why is it that individuals who just experienced something really stressful, really traumatic, might actually show what we want to infer as greater brain health, but really let's think about it as just cortical thickness.

So what might V4's role overall in visual processing have to do with that, and why might those results not have replicated?

Why use two different samples to begin with, and how does this actually strengthen your findings?

So the first reason to use two different samples is it's always nice to be able to show that you can replicate an effect.

When we initially started doing this research in the discovery sample, we thought that we were going to see some difference in visual cortex thickness that was related to trauma and probably related to PTSD too.

And we did see something related to PTSD, but the thing that came out strongest was this difference in cortical thickness between individuals who've been recently exposed to traumatic event and individuals who had not recently been exposed to traumatic events, about 30 day window in V1, where these recently trauma exposed individuals showed greater thickness in visual area one, which I think that sort of as a heuristic, is sort of hard to wrap your head around at first, if only because a lot of the way in which we treat brain thickness or brain volume is that that is a measure of brain health.

So more thickness or more volume, that's better.

And stress is bad, so it should lead to less brain health.

So why is it that individuals who just experienced something really stressful, really traumatic, might actually show what we want to infer as greater brain health, but really let's think about it as just cortical thickness.

So what might V4's role overall in visual processing have to do with that, and why might those results not have replicated?