Gordon Johnson: Let’s focus on the concept of two hemispheres in the brain. Perhaps behind you we have a brain that we haven’t dissected.
Dr. Erin Bigler: Taken apart.
Gordon Johnson: Now the brain has two hemispheres and they’re not identical, they’re like one hand is close to but not exactly the same as the other.
Dr. Erin Bigler: Yes.
Gordon Johnson: There distinct functions from the left hemisphere versus the right?
Dr. Erin Bigler: There are some. I mentioned earlier that this region here is very important for auditory reception. This region right here in the inferior frontal area in individuals who are right handed is typically a language expression area.
Gordon Johnson:: And we’re on the left side.
Dr. Erin Bigler: We’re on the left side of the brain, so if you look at this, uh, this is the front, so this is the left, this is the right, and as I rotate it this way, this is what’s referred to as Brocca’ area, and this is Wernicke’s area named after two different anatomists who describe these.
Gordon Johnson: And what does Brocca’s areas do?
Dr. Erin Bigler: Brocca’s area is speech production.
Gordon Johnson: And the, and the second one was?
Dr. Erin Bigler: Wernicke’s area, which is speech reception.
Gordon Johnson: See, now my hippocampus worked on the word I recognized before.
Dr. Erin Bigler: Yes.
Gordon Johnson: But not on the one I didn’t know as well.
Dr. Erin Bigler: So in most individuals who are right handed, this area of the brain will be dedicated to receptive language and this area of the brain will be dedicated to expressive language. They have to be connected by a large highway called the arcuate fasciculus and they have to be also connected by some other pathways.
Gordon Johnson: So do people who are left-handed have it on the opposite side of their brain?
Dr. Erin Bigler: They may, or they may have actual bilateral representation of these receptive and expressive areas.
Gordon Johnson: And what happens to people who learn how to dribble with both hands?
Dr. Erin Bigler: So the individual who is ambidextrous may have different organization as well with regards to these more lateralized functions that we will typically see. But this also introduces the issue of uniqueness of each individual. The brain is what we call an ‘experienced dependent organ’ so each brain is uniquely organized and develops uniquely within the environment that that individual develops in. So no two brains are ever alike. They’re like a fingerprint.
Each brain is unique, and they connect in unique ways as well, and at one point in time, in fact, if you look at some of the earliest neuropsychology textbooks or early, uh, neurology textbooks, you would see these very precise arrows pointing to one region of the brain and this region controls precisely this function. We don’t believe that anymore.
We believe a much more holistic integrated, coordinated, network of functioning in the brain that then results in behavior. Certainly there are some areas that are more dedicated to certain functions like motor function. The touch perception that I mentioned, vision, smell, language and both expressive and receptive. But it’s really more the networks of the brain and how the network and the whole brain is integrated.