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SEEING DEEP INSIDE THE BRAIN
By nicole sweeney etter
Five young women clad in blue scrubs and gloves lean over a table to peer at a human brain. These graduate students from Pepperdine University traveled to Marquette for the chance to study and dissect the body’s most enigmatic organ.
Using tweezers they carefully strip away the arachnoid, the spider web-like membrane that envelops the brain. Then they use a scalpel to gingerly scrape away the external gray matter and expose the amygdala, the almond-shaped structure that controls fear, aggression and emotional memory.
None of the women expected a brain dissection to be part of their psychology training, but they’re grateful for the opportunity. “You can help somebody psychologically if you know the biology of what’s going on,” says Olivia Hannon, one of the graduate students.
This group of California students is attending the Neuroanatomical Dissection: Human Brain and the Spinal Cord, an intensive three-day seminar that has been offered at Marquette for 10 years. The seminar has a national reputation for excellent experiential learning, and it is taught by Dr. William E. Cullinan, an associate professor of biomedical sciences in the College of Health Sciences and director of Marquette’s Integrative Neuroscience Research Center.
The seminar stands out for one other key reason: Students learn blunt dissection, a rare but valuable method that emphasizes the brain’s deeper structures and connections. Even students in some of the nation’s top medical schools don’t have the chance to meticulously dissect the brain in this way. “It’s almost a lost art,” Cullinan says.
With blunt dissection, the specimen is treated chemically so that it hardens. Students carve away the external gray matter to uncover the brain’s deeper fiber pathways. Cullinan learned the technique as a graduate student at the University of Virginia, where he studied under the renowned Swedish neuroanatomist Dr. Lennart Heimer.
Blunt dissection was edged out in the 1990s by the simpler method of brain slicing, where students slice the brain into large cross sections and correlate what they see deep inside with what they’ve read in a textbook.
But those students, Cullinan stresses, are missing out in some important ways.
“As the field of neuroanatomy has become more cellular and molecular — and, of course, that’s the level at which we can study the brain to reveal its mechanisms — there has been a tendency to get away from some of the essentials,” he says. “This approach actually is an important first step because it helps one to think about the brain globally and in three dimensions, before getting mired down in a subsystem within asystem where you can’t see the forest for the trees so to speak.”
“Before a student even steps into the lab, we want them to understand how we respect and honor the donations. We view those rooms as somewhat of a hallowed ground.”
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Many have never seen a brain
The morning sessions are devoted to lectures to give students an anatomical framework before the afternoon dissection. But lectures can’t capture the wonder of actually handling the specimen and gradually, incrementally, taking it apart.
The Marquette seminar attracts professionals from a variety of disciplines, many who may never have seen a brain. Clinical psychologists and neuropsychologists make up 75-80 percent of the class. Students work in groups of three and six. First they dissect just a hemisphere; later, they can dissect a whole brain.
Students can also watch the removal of the brain and spinal cord in an adjacent room, where cadavers are largely covered to protect anonymity.
“I think they’re always surprised to see just how amazingly tethered to a skull the human brain is,” Cullinan says.
This group of students observes Cullinan as he completes the tedious, 45-minute process of removing the brain from its protective housing. He opens the skull and peels back the dura mater (the brain’s most external covering within the skull, the name of which literally translates to “tough mother”) to reveal the glistening brain. The procedure allows students to see where the important blood vessels and cranial nerves make their entrances and exits.
Nearby, Dr. Mary Cimrmancic, who teaches in the Marquette School of Dentistry, uses an oscillating bone saw to remove the spinal column and expose the spinal cord. Seeing this procedure is particularly important to physical therapists who work with spinal cord injury patients.
Gift of incalculable value
Each year, Marquette receives cadavers donated for scientific study — a gift the university does not take lightly.
Outside the gross-anatomy lab is a plaque that Cullinan requires his undergraduate students to memorize. It reads: “These rooms, and the scientific pursuits undertaken herein, are dedicated with utmost honor to our donors. Their gracious gifts are received here with profound respect and gratitude.”
Cullinan takes that commitment seriously.
“Before a student even steps into the lab, we want them to understand how we respect and honor the donations. We view those rooms as somewhat of a hallowed ground,” Cullinan says.
Marquette students are also invited to attend an annual memorial service where they can meet the donors’ families and publicly thank them for their gift. After a year or two, the cadavers are cremated individually and the ashes returned to the families.
For nearly 20 years, Marquette offered outside professionals the chance to attend Gross-dissection and Kinesiology of the Lower Extremity, a four-day course directed by Dr. Donald A. Neumann, a physical therapy professor. Cullinan saw the opportunity to expand the learning experience and added the neuroanatomical dissection option. Both courses are an anomaly at a time when universities nationwide are struggling to find gross-anatomy instructors. “In fact, some medical schools have resorted to hiring anthropologists to teach gross anatomy because they don’t have trained anatomists,” Cullinan says.
Several Marquette faculty and other visiting professors volunteer to assist with the seminar every year. Although the formal three-day course is geared toward professionals, a shorter summer class draws students from research programs across campus. Cullinan also teaches the three-part dissection to Marquette biomedical sciences undergraduates, as well as students in the graduate neuroscience track.
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