Causal effect of disconnection lesions on interhemispheric functional connectivity in rhesus monkeys

Our new paper just came out in PNAS: O’Reilly Croxson et al. Causal effect of disconnection lesions on interhemispheric functional connectivity in rhesus monkeys.

Screen Shot 2013-08-07 at 16.15.39Sectioning the corpus callosum in monkeys leads to breakdown in functional connectivity between the hemispheres. However, when the anterior commissure is left intact, a surprising amount of functional connectivity between the hemispheres remains. The relationship between cortico-cortical structural connections and functional connectivity is not as simple as we once thought.

Reversal of fortune

Mark Baxter and I wrote a commentary on this great paper by Rudebeck et al. They showed that the orbitofrontal cortex, a brain region thought to be involved in behavioural flexibility and emotion processing, may actually have a more restricted role than previously thought. Damage to the orbitofrontal cortex in monkeys and in humans can also lead to damage to the white matter tracts passing through it, and if those tracts are spared then the effect of the damage to orbitofrontal cortex is limited. It shows that we should be cautious when interpreting the effects of lesion studies. The orbitofrontal cortex is more likely to have a specific role in goal-directed behaviour and outcome expectation.

Screen Shot 2013-07-29 at 20.33.40Artwork by Katie Vicari