I am in a church. It was once a church, anyway. Now it's a university building. I'm here for a neuroscience symposium and people are milling around taking coffee before the final morning session. I keep an eye on the time because I'm presenting a paper.
The programme has reunited me with two colleagues from my postgraduate days. I haven't seen them for 20 years. We stand in a triangle. Mundane facts of biography slot together as planks in the conversational platform. We all have wives and children and dogs. Rick affects embarrassment. So bourgeois. Why haven't we had more interesting lives? "You don't like commitment, you get married. You don't want kids, they take over your life. You get a dog, you're forever scooping shit into plastic bags." Steve and I concur, but we don't mean it either. Steve has been ten years in the US. His voice follows mid-Atlantic contours. "I guess the myth of romantic love is where the rot sets in," he says. "If you let it." Life and relationships are more random than we think but in the end most of us fall into a pattern. With whom, it doesn't much matter. It's the pattern that counts.
I climb the spiral stairway to the upper lecture theatre. The sun-filled, stained-glass window sends curves of purple, yellow and red along the steel handrails. My audience trickles in. There are not many of them. They are scattered about the place like a congregation. With a click of the mouse, a quotation rolls across the screen behind me. "We should take care not to make the intellect our god. It has, of course, powerful muscles but no personality." This was Einstein. It sets the tone of my talk, which is about how the brain generates emotions and how emotions regulate social behaviour. There are structures for analysing the geometry of the face, and others for interpreting expressions. These feed into systems for decoding people's intentions and dispositions, calculating their desires and beliefs. Then there are mechanisms for selecting programs of action, for manoeuvring the self through the social landscape. The amygdala, a small structure in the temporal lobe, is a crucial component of the social brain. It acts as a control centre, linking higher cortical processes, including rational thought, to the more ancient emotional machineries lower down. In particular, it is believed to be involved in the production of fear and anger.
On the screen now is a large image of one of my patients-Maggie. She is in her early fifties. A few years ago she suffered a disease, herpes simplex encephalitis, which ripped away large areas of the anterior temporal lobes of her brain, including the amygdalae. She is having a laugh with a research assistant, two girls together. It's Maggie back in her twenties telling risqu? stories about her boss. He was a one. Somewhere off camera, the gentle voice of Don, her husband, persuades her back onto safer ground. He doesn't want to cause embarrassment. I've set the video in the wrong place. I intended to show Maggie and Don talking about their Spanish holiday. But at least they can see she is not a cabbage. She is upbeat and animated. I'll have to tell the story myself.
They'd been out for a meal. The two boys leapt from nowhere. They grabbed Maggie. Don was thrown against a wall. One hand gripped his throat, the other took his wallet. But Don is a big man. He fought back. He gave the boy a pounding. All the time, with Don's amygdalae trilling like fire bells, jolting his body from visceral fear to thrashing, mechanical anger, pupils dilated, cardiovascular system in overdrive, blood draining from gut to straining muscles, fists like hammer heads-all the time Maggie smiles benignly. The fluid-filled spaces in her head where the amygdalae used to nestle are pools of tranquillity. Back at the hotel, Don was still shaking. Maggie couldn't fathom it. She thought the boys were larking around.
So far, so good. No amygdala, no fear. It's a nice anecdote to colour the standard explanation of fear production: the cortex perceives, the amygdala interprets and triggers a response. But then, back home, Maggie sits watching television. It's a soap. There's a spark of aggression between two female characters, nothing extreme. It gets to her, though, enough to swipe her breath and start her heart thumping. "No, don't," she says. "Please, no." Fear rises until the flesh of her face is pulled taut in a rictus of terror. The anecdote becomes a window of insight into the true functions of the amygdala-or that's how I try to present it. Evidently, fear can be triggered without the amygdala. Its function is to perform appraisals of danger. Maggie, minus amygdala, is oblivious to the real threat of the mugging, then shows excessive fear in response to a television programme. "Interesting," someone says, "but only anecdotal." I have to agree. But I'm all for anecdotes.
In his presentation, Steve talks about his dog. He grants the animal a rudimentary awareness, but nothing like human consciousness. His wife and kids disagree. They value emotion over intellect. They are convinced the dog has feelings-primitive and inarticulated but at root like ours. What perplexes Steve is that he can't help himself behaving as if he believes this too. "I guess it's my social brain," he says. It's a sign that he's human, I tell him.
