The Psychopath Whisperer: The Science of Those Without Conscience (15 page)

Figure
3. Brain wave plots for psychopaths from Kiehl et al. (2005; left plot) and Yamaguchi and Knight (19393; right plot) for auditory oddball stimuli. Both plots have been adapted to the same time scale and amplitude. Negative amplitude is plotted up. Note the similarities between the psychopaths’ brain waves and those of patients with temporal lobe damage. Both groups show enlarged negative response at 200 milliseconds, reduced positive response at 350 milliseconds, and an enlarged negative response at 400–800 milliseconds compared to control subjects.

Armed with my answer to the riddle of the psychopaths’ weird P3 brain waves, I was feeling confident about the next set of studies I wanted to do with them to further elucidate what might be going wrong inside their brains.

Most of the studies I designed sought to examine whether the medial and lateral aspects of the temporal lobe were abnormal in psychopaths. These regions include the amygdala, the hippocampus, and the temporal pole (the full name is anterior superior temporal gyrus; see
Figure 4
).

The amygdala is an almond-shaped region deep in the brain that is responsible for amplifying salient information. The amplification of salient information interrupts ongoing thinking and makes us pay attention. For example, you are walking along a crowded street and you hear a loud bang and quickly turn to identify the cause and location of the noise. This noise has just been amplified by the amygdala, causing a startle reflex, alerting you that it might be critical to pay attention to what’s going to happen next. The startle response requires the amygdala.

Figure 4
. Renderings of the lateral (top) and medial (bottom) of the human brain. The medial view is as if you sliced the brain down the middle and pulled the two halves apart to look inside. The numbers represent areas defined by a labeling system developed by anatomist Korbinian Brodmann in 1909. Scientists use the Brodmann numbering system to help them compare results across studies and across laboratories. The results from the weird P3 brain wave in psychopaths implicated the amygdala (Brodmann area 34), the hippocampus (Brodmann area 27), and the temporal pole (Brodmann area 38).

The amygdala also helps us learn what stimuli are important to amplify and raises this information into awareness; for example, learning that a hot stove is not something to be touched or that an electrical socket is not something to lick with your tongue. The amygdala assists learning these basic fear and emotion contingencies.

The hippocampus is the seat of memory in the brain. It’s responsible for the consolidation and storage of memories. It’s one area of the brain that continues to grow throughout life, becoming thicker as one ages.
²
The hippocampus is particularly good at storing emotional memories.

The temporal pole is a bit of an outlier here. The amygdala and hippocampus are classic members of the limbic system, which is generally considered to be responsible for the control of affective and emotional processes in the brain. But the temporal pole was not part of the limbic system first described by neuroanatomists Paul Broca (1824–1880) and James Papez (1883–1958). The temporal pole is an area of what is called the
heteromodal association cortex
. This means it is a region where lots of sensory information arrives and is integrated. So auditory information and visual information converge at the temporal pole and are merged for subsequent higher processing, similar to how filmmakers integrate sound and video to make movies.

Studies have shown that brain damage to the right temporal pole can lead to impairment in prosody of speech.
³
Prosody
is the affective intonation in speech. Individuals who suffer damage to the temporal pole can’t describe, or have problems indicating, what type of emotion is being conveyed by affective speech. Similarly, damage to the temporal pole may cause impairments in understanding abstract representations of speech, like metaphors.
⁴

My literature review on the functions of the amygdala, hippocampus, and temporal pole led to a number of new lines of research. Some of these new studies continued to use brain wave recordings. But what was really exciting were the studies we had been planning that used a new technique called
functional magnetic resonance imaging
, or fMRI.

MRIs, or magnetic resonance imaging devices, use a combination of strong magnetic fields and radio waves to create amazing images of human anatomy. MRIs have been around since the mid-1980s and today are present in every hospital in the United States. MRIs do not use radiation or x-rays and are thus considered noninvasive and very safe for research purposes.

In addition to creating beautiful pictures of brain anatomy, the latest advances in MRI permit scientists to study the brain in action.
The most common technique in the neuroscientist’s arsenal in this regard uses a souped-up MRI system to quantify changes in levels of oxygen-labeled blood in the brain. Just like muscles, neurons in the brain need oxygen when they are working. The lungs function to attach oxygen to the hemoglobin molecule in blood, and the artery system transports oxygen-loaded hemoglobin to the brain (and to muscles). Blood with a lot of oxygen in it has a different MRI signal than blood with less oxygen in it. Blood with a lot of oxygen is a bright red color (arterial blood), and blood with less oxygen is blue (venous blood). The MRI scanner can be tuned to record snapshot images that map the precise location in the brain where oxygen is being delivered and consumed (i.e., changing from red to blue in color). Over the course of a few minutes, scientists can determine which brain regions are consuming oxygen while participants are doing specific tasks in the MRI scanner. This is known as
blood oxygen level dependent (BOLD) imaging
. We typically refer to this technique as functional MRI, or fMRI.

Functional MRI was discovered in 1992
⁵
while I was still at UC Davis. I was working for Professors Mike Gazzaniga and Ron Mangun, who both quickly started using fMRI in their laboratories. The amazing research environment at UC Davis allowed me to immerse myself in the technical aspects of MRI from the very beginning of the field.

When I left for graduate school in the summer of 1994, I had been working with fMRI data for over two years. As I settled into my new home in Vancouver, I started searching for the best MRI system in the city where we might be able to do fMRI studies of psychopaths. The BOLD fMRI technique places a lot of demand on the MRI system since it pushes the hardware to its max when collecting functional brain imaging data. In a normal MRI session, about ten or twenty images will be collected. But in fMRI, ten or twenty
thousand
images will be collected. In addition to the special hardware on the MRI, the room needs to be equipped with high-resolution projection systems, custom video screens, fiber-optic response devices, and special communication cables that all have to be MRI compatible. “MRI compatible,” I often muse, is a euphemism for dollar signs. For example, a regular joystick for a video game might be $20, but
a fiber-optic MRI-compatible joystick typically costs $2,000. Thus, it takes a lot of customization and money to make fMRI possible on plain-vanilla MRI systems.

My search revealed that the University of British Columbia Hospital had just purchased a brand-new General Electric (GE) 1.5T MRI system. I called around until I found out who was in charge of the new system. Dr. Bruce Forster, a radiologist, was the man I needed to meet.

I started my reconnaissance of the University Hospital by circumnavigating the grounds searching for the MRI bay. I found that the MRI bay had been built right into the side of the hospital and had its own brick service road. I assumed the brick road had been built to facilitate delivery of the MRI system. Clinical MRI scanners can weigh up to sixty thousand pounds and require special installations.

I entered the University Hospital through the basement cafeteria and looked for signs to the MRI area. The signs led down a long hallway to the main entrance of the MRI suite. I approached the receptionist, introduced myself, and asked if I could speak with Dr. Forster. The receptionist noted that Dr. Forster’s office was upstairs, but he was just preparing to leave for the day so I had better hurry if I wanted to catch him.

I sprinted down the hallway and up the stairs. Two floors up, I opened the door and briskly walked down the corridor of radiology offices. It was about 6 p.m. and one of the offices at the end of the hallway had its door open and lights still on.

As I approached the door, a man exited the office, and I walked right into him. I managed to mutter a quick apology. Recognizing I was a stranger, he asked if he could help me find my way. I had completely ignored the sign on the hallway door that said
AUTHORIZED PERSONNEL ONLY
.

“Yes. I am looking for Dr. Forster.”

“That’s me. What can I help you with?” he answered.

“I’m a graduate student here at UBC studying criminal psychopaths. I want to know if I can bring them out of the maximum-security prison and scan them on your new MRI,” I said flatly.

He coughed, took a step back, and reevaluated the situation.

Dr. Forster was dressed perfectly; even his socks matched his suit. He had a flawless goatee, and his hair was brushed back along his scalp. He looked like a contemporary Sigmund Freud.

When he finally spoke, in a very deep yet softly commanding voice, he said, “Let’s sit down for a minute so you can tell me more about what you are thinking.”

He pointed to the chairs in his immaculately clean office. I walked over and sat down. He positioned himself behind the desk, closest to the door.

“So tell me again what you are interested in doing,” he asked.

I explained my research and that of my supervisor, Dr. Hare. I told him about my training in fMRI with Drs. Gazzaniga and Mangun at UC Davis. Another graduate student in Dr. Hare’s lab and I were planning to ask the Canadian Department of Corrections whether they would transport inmates from the prison to the hospital so we could scan their brains. I wanted to know if his MRI scanner was capable of doing fMRI.

He leaned back in his chair and told me that never in his life had he expected someone would ask him to use his MRI scanner to scan criminal psychopaths.

“Tell me more,” he asked.

After a thirty-minute conversation, Dr. Forster took me back downstairs to the MRI suite.

We headed into the MRI bay and he introduced me to the lead physicist, Dr. Alex Mackay. Dr. Mackay headed up the research group studying white matter lesions in the brain. The MRI was very busy with clinical patients during the day, but Mackay had a deal to do research every Wednesday night from 6 p.m. to midnight or later.

I gave Dr. Mackay a quick rundown of my background and fMRI training.

“Oh,” he said. “We built this MRI with the best hardware just in case someone wanted to do fMRI.”

Dr. Forster chimed in that he would love to be the first group in Canada to use fMRI for presurgical mapping.

Presurgical mapping
refers to a procedure that brain surgeons complete prior to removing a tumor and adjacent brain tissue. Brain surgeons want to remove any bad tissue without removing any
tissue that is critical or eloquent.
Eloquent cortex
refers to areas of the brain that control things such as your ability to speak or move your tongue. The old way to do presurgical mapping is to remove the skull and electrically stimulate the brain in order to figure out what bits of the brain do what. Surgeons painstakingly map out with electrical recording devices, not that different from EEG, which brain regions are eloquent before they go in and remove tumors and adjacent tissue that might also be affected.

But fMRI can do this presurgical mapping without using a scalpel. Using an MRI, scientists can map out the regions involved with language and motor functions. The brain surgeon is then given a map of the patient’s eloquent cortex without any need to remove the skull and resort to electrical stimulation.

The University of British Columbia is also the home of Dr. Juhn Wada, who pioneered a technique to put one hemisphere of the brain or the other to sleep with anesthesia. In this way surgeons could figure out what side of the brain contained language. In most people, language is in the left hemisphere. But in a few people—about 10 percent of the population—language is handled in the right hemisphere. It’s safer to remove brain tissue from the nonlanguage hemisphere when resecting tumors. The Wada technique helps to localize which hemisphere has language in it. But the Wada technique is invasive, and sometimes people die from the procedure before they get into brain surgery to remove tumors. Replacing the Wada technique with noninvasive fMRI would be very valuable.

So I volunteered to do the presurgical mapping for Dr. Forster. Dr. Mackay also generously allowed me to volunteer to work with his group on MRI studies of white matter lesions. We all agreed that we would work together to figure out how to get prisoners scanned on the brand-new University Hospital MRI.