In humans, theory of mind, or ToM, means that we can imagine what another person might be thinking. Reflecting the importance of humans’ social lives, most of our large frontal lobes seem to be concerned with this function. We spend huge amounts of mental energy navigating the complex social structure of human society. Knowing how to read people and how to behave in distinct social settings is the difference between success and failure. And at the extreme, autism may represent a failure of the ToM system in the brain.
If dogs have ToM abilities, they are probably simpler than ours. The small frontal lobes in the dogs’ brains are clear evidence of that. But even if dogs have only a rudimentary ToM, that would mean dogs are not just Pavlovian stimulus-response machines. It would mean that dogs might have about the same level of consciousness as a young child.
As Callie and I honed our performance, I had a growing sense that we were beginning to read each other’s mind. Of course, there was no way to prove this. The thought was so crazy I didn’t even voice it in the lab. But we were about to discover that my intuition wasn’t completely off the mark.
The second scan day arrived on a drizzly February afternoon. Under cover of umbrellas, the entourage once again made the trek from lab to hospital. The novelty had faded somewhat, so fewer people were in attendance, and the overall atmosphere was calmer and more businesslike. Robert and Sinyeob greeted us at the scanner. This time they weren’t laughing. Everyone knew the dogs could do this, and we were there to do science.
There was no need to fiddle with the scanner settings. Robert simply pulled up the final parameters from last time, and we were good to go. The plan was to do the shimming and localizer, two five-minute functional runs of hot dogs versus no hot dogs, and then a thirty-second structural scan. If there were no hiccups, we could blaze through the procedure in thirty minutes for each dog.
It really helped that everyone knew what to do now. Rebeccah worked her magic touch with the earmuffs and head wrap on Callie. Andrew took up his position at the rear of the magnet, ready to record the repetition type—hot dog or no hot dog. Melissa and Mark settled McKenzie in her pup tent until it was her turn. I motioned to Callie to go into the scanner.
To avoid startling the dogs with the sudden onset of buzzing, Mark had hit on the great idea of playing the recordings that we had used during the training procedure. Every MRI has an intercom to allow communication between the patient and the technician. After Callie got settled in the chin rest, the team in the control room held an MP3 player up to the intercom and began playing the recording of the localizer noise. Softly at first, then they gradually cranked up the volume. Pretty soon I could hear the familiar swarm of bees emanating from the speakers built into the magnet. Because it came on gradually, Callie didn’t budge.
Callie’s localizer with box indicating field of view.
(Gregory Berns)
I nodded to Andrew. The buzzing continued. And then it stopped.
“What happened?” I asked. Andrew shrugged. Callie followed me into the control room. “Why did you stop the scan?”
Robert looked confused. “We didn’t,” he said. “Look.”
There, on the computer screen, was a perfect image of Callie in profile. The image was sliced right down the middle of her head, giving a beautiful view of her brain and spinal cord. Robert had already placed the bounding box for the field of view in place. The use of the recording through the intercom had worked so well that neither Callie nor I had noticed when the real scan started!
With the field of view set, we cued up the functional runs. I showed Callie the container of hot dogs, and her eyes widened. All I had to do was point to the magnet, and she scooted in.
This time, we played the recordings from the functional sequence through the intercom. The volume was gradually increased, and after a few seconds, I could hear the real scans begin. They sounded almost identical. Callie didn’t care. Her eyes were lasers on mine. I held up my left hand to indicate that she had done well and gave her a piece of hot dog.
We were off and running. I alternated repetitions for hot dogs and no hot dogs but kept it somewhat unpredictable, throwing in runs of two or three of the same trial type. Callie stayed cool as a cucumber. Every time I put up the sign for “no hot dog,” she stared at me and waited until I put up the sign for “hot dog.” I began to appreciate that rather than being disappointed during the no hot dog trials, Callie viewed those hand signals as uninformative. Being told that she wouldn’t get a hot dog said nothing about when she would get one. This interpretation would soon be borne out by her brain activation.
Unlike the previous scan session, this time we were much more efficient. In short order, we had acquired two five-minute runs of functional scans, nearly four hundred images in total. The only thing that remained was the thirty-second structural scan. At this point, Callie looked either tired or bored, but in she went for the fourth time. The recordings of the structural sequence were slowly ramped up through the intercom, and then the real scan started. The structural sequence sounds much like the localizer, but Callie stayed put throughout.
She had done it. She hadn’t moved at all. I ran around the scanner and gave her a handful of hot dog.
“You are such a good girl!” I exclaimed. “You are a SuperFeist!”
Robert already had the structurals on the screen. There, in breathtaking clarity, was the first detailed structural image of a completely awake dog. My jaw dropped. We had just acquired nearly four hundred functional scans and a structural image that rivaled anything we got in humans.
The first detailed structural image of Callie’s brain rivals the quality of human scans.
(Gregory Berns)
Even if McKenzie bombed on her turn, I was confident that we had achieved our goal of getting enough functional scans.
“How many repetitions did we get?”
“It looks like she did twenty trials with hot dog and nineteen trials of no hot dog,” Andrew said.
“Damn,” I marveled. “That should be plenty for analysis. Let’s hope the SNR is high enough.”
Callie sat down next to me. I looked into her eyes, and she knew. Yeah, I’m the top dog.
If I’d had any lingering concerns about Melissa and McKenzie, those quickly disappeared. The trick of playing the recordings through the intercom worked wonders for them too. We finally got a localizer image for McKenzie, which allowed us to precisely place the field of view to avoid chopping off half her brain this time. For the functional scans, Melissa was more collected than I had been. She really took her time with the repetitions, requiring McKenzie to hold still for fifteen seconds for each trial, where I had required Callie to hold still for only ten.
McKenzie was like a rock. Robert and I watched her images stream on the console in real time. She was not moving. Not at all. They blazed through the two functional runs, and, for the first time, we got a structural image of McKenzie’s brain.