When Times staff photographer Rob Gauthier and I first visited the Bryant family last April to begin reporting a story, (“Little-known brain disease rips apart lives of victim, loved ones,”), about a rare type of dementia, known as frontotemporal dementia, we realized that we needed to explore the science behind the malady. FTD, as the disease is known, is similar to Alzheimer's but affects the front portions of the brain and leads to behavioral problems such as the Bryants experienced with Stu.

I knew about Phineas Gage, the railroad foreman who in 1848 lost the front portion of his brain in a terrible construction accident and who survived as a radically changed man. I had read the work of Hanna and Antonio Damasio, neuroscientists who almost 20 years ago pioneered our understanding of the biology of emotions, and I was eager to see how frontotemporal dementia was being studied to further this research. 

In the course of our reporting, Rob and I took a number of trips to UCLA and the West Los Angeles Veterans Affairs hospital to interview Mario Mendez, the physician and neuroscientists treating Stu. In our conversations, Mendez helped us understand what Oliver Sacks meant when he wrote, “Without the great development of the frontal lobes in the human brain, civilization could never have arisen.”

By studying the effects of frontotemporal dementia – and its slow diminishment of personality – Mendez is able to see more clearly the so-called social brain, a portion of our frontal and temporal lobes that plays a role in allowing us to successfully interact with each other and build relationships. Take away this portion of the cortex and we are no longer able to moderate our emotions. 

Moderation – the inhibition of emotional impulses – can take the form of empathy and embarrassment and is critical in helping us negotiate complex social environments. Without either, as Rob and I learned during the time we spent with Stu, humans grow untethered to the world, unable to read feelings or behave in an appropriate manner.

By steering the discussion about morality, normally the providence of ethicists and philosophers, away from the symposium and putting it inside the laboratory where thoughts are considered to be not so much conscious choices, but instead reflexes based on a neurological network, Mendez and other neuroscientists are furthering the inquiry into the nature of right and wrong. In this light, religion, family, even Freud's notions of superego, ego and id matter less than biology.

Mendez argues that specific behaviors – not harming another person, respecting hierarchy and authority, accepting communal goals, recognizing equity and fairness – evolved among humans.  Good manners, therefore, have as much to do with what we are born with as they do with how we were raised and what our parents taught us.

“Much of the social behavior that we take for granted and that we often consider to be learned or cultural or developmental is actually behavior that is deeply ingrained in the nervous system and in the frontal lobes,” Mendez says.

Consider that the next time you’re in a crowded restaurant and watching the kaleidoscope of interactions. Never mind the ability to speak and communicate. Never mind the opposable thumbs. The frontal lobes make humans human.

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The science behind frontotemporal dementia