Suzana Herculano-Houzel


Closed for inventory

Somedays, I might as well wear a sign that says that. I’m inside my own head – and happily so, mind you. It’s just that pulling me outside of my own mind to engage with the external world seems to require an extra effort that.I may not have that day. I’m not deaf or suddenly dumb or incapacitated. I’m just having an Inside Day. To those around me, however, I may appear dysfunctional: aloof, slow to respond, hard of hearing (I will have to ask you to repeat what you just said), and oblivious to what happens around me.

I wonder if this comes from an overactive self-reference network . This is a core network in the brain that ties together everything that pertains to the self: Your location, position, physiological and mental state. The self-reference network (also called default mode network ) is a set of densely interconnected cortical areas in the brain that effectively serve as hubs to the spatial senses (retrosplenial cortex and posterior cingulate), emotional and cognitive states (ventral medial prefrontal cortex), and to the circuits that tie past, present and future together (the hippocampus).

The structures of the self-reference network are more intensely active, and in a highly coordinated manner, when we are awake and focused on our internal thoughts. Actually, it is probably the highly coordinated activity of these structures that makes us focused on our internal thoughts, regardless of what is going on outside the body. That’s a very important capability, which allows us to have an internally-guided life instead of being automatons dominated by the events. When we switch focus to something out there – say, when you hear your name -, it’s because the novel event broke the spell of  coordinated activity and pulled you out into a different mental mode (in this case, one of attending to what you see and hear). The activity of the self-reference network structures decreases when we engage with the outside world; their internal coordination falls apart when we fall asleep, or lose consciousness with anesthesia. Or rather, the other way around, probably: When activity is no longer coordinated across the self-reference network, the network disintegrates, and we are no longer self-referenced.

Which makes me suspicious that my self-reference network might be extremely good at keeping itself together, and my behavior self-focused, especially so on those days when either this network is particularly hyperactive, or when whatever is required to break its spell is not strong enough. So there: I’m not self-centered. I’m self-referenced, and strongly so.

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