Author Archives: apelduna

“We don’t perceive objects as they are, we perceive them as we are”

We’ve just started discussing how memories are processed, stored, and retrieved and how this relates to our perception of the world around us. Our lectures have focused mostly on memory and recall as they pertain to simple stimuli such as words and numbers, but we are able to apply what we know about memory processing and recall techniques to more complex stimuli. In addition to discussing the processing of memories, we’ve also addressed both how our previous experiences affect how we process stimuli (top-down processing) and how the stimuli we encounter can determine how higher processing proceeds (bottom-up processing).

I recently began re-watching The Brain with David Eagleman, a six-part documentary series that explores some of the mysteries and complexities of the human brain. The second episode, “What Makes Me?” addresses how our experiences and memories shape how we perceive the world around us. At one point, David Eagleman addresses the issue of false memories with researcher, Elizabeth Loftus. Loftus has conducted a number of experiments that reveal how unreliable memories can be. One study that I found both remarkable and unsettling is similar to something we have touched upon in class as well.

To investigate just how vulnerable we are to the power of suggestion, Loftus designed an experiment to test whether individuals could be persuaded to believe in an elaborate lie. Researchers contacted relatives of study participants and recorded three stories from each participant’s childhood. A fourth story was completely fabricated. During the experiment, Loftus described the four stories (three true and one false) to the participants and asked them if they could recall details from those experiences. Every participant not only remembered the false story (described as an account of the participant as a young child lost in the mall who was eventually assisted by a kind, elderly stranger), but when they returned for a follow-up interview a week later, had recalled additional details about the false experience (e.g. what the kind stranger looked like, what they were wearing, etc.).

While it’s not a groundbreaking revelation that our memories are not accurate, I think it’s incredible that not only can we be convinced to believe a false memory, we also become so invested in that false memory that we fabricate additional details without prompting. When we explored the fallibility of memories in class and in the “False Memory” ZAPS, it was more along the lines of forgetting an experience that we actually had or confusing two different, but similar experiences. Seeing such definitive evidence that we can be convinced to believe a “memory” that is completely false was disturbing to me. It not only pulled the proverbial rug out from under my confidence in my own memories and beliefs, it also gave me more reason to doubt what other people tell me when describing past experiences.

I think, however, this also reveals another perspective that I find encouraging: no two people will ever share the same experience. As much as we try to relate and share experiences with one another, we can never have anything but an entirely unique experience. Each moment is a fusion of past experiences and present stimuli. Our memories, emotions, and beliefs all influence how we perceive the present and because no two people can have exactly the same history, our experiences will always be unique …our one private possession. We use our current knowledge to reconstruct our memories, but we also allow our memories and beliefs to influence our perception of the present. The dynamic relationship between expectations and data produces a reality that is unique to each of us. As David Eagleman put it, “we don’t perceive objects as they are, we perceive them as we are.”

If you’d like to watch the episode, here’s a link:

The Brain That Changes Itself

A while back, I purchased the book The Brain That Changes Itself. I began reading it, but as I often do, got sidetracked and forgot about it. Recently, I found myself looking for a movie or documentary to watch while I worked around the house. I stumbled across the documentary The Brain That Changes Itself which features the author and some of the research presented in the book. I thought it could provide interesting fodder for my first blog post and I was certainly correct. The Brain That Changes Itself focuses on brain neuroplasticity and the power we have to change how brains function.

The movie opens with various images from the documentary and a man (I believe to be Dr. Michael Merzenich) saying, “There’s always a strong temptation to think of the brain or to call a brain a machine or talk about it as a computer.” Throughout the documentary, different researchers and neuroplasticians explore research and case studies that provide evidence that the wiring in the brain is not permanent and can be altered by changing one’s thoughts or behavior. Throughout the documentary, scientists use the various research techniques discussed in class and our text to gain insight into the plastic nature of the brain. By combining techniques such as neuropsychology, MRIs, fMRIs and TMS, researchers not only demonstrated how it’s possible to change cognitive function, but also how the underlying circuitry changes as well.

In class this past week, we focused on the visual system and how visual information is integrated and processed. Other senses, such as touch and proprioception are integrated similarly, by the routing of afferent information to different parts of the brain. What’s amazing is how quickly and proficiently our brains can learn to reroute and repurpose incoming signals to compensate for deficiencies. The first two case studies in The Brain That Changes Itself concern this ability of the brain (called sensory substitution) to reassign or create alternate pathways when the primary neural pathway is damaged.

Roger Behm, blind for most of his adult life (38 years, at the time the documentary was filmed), is fitted with a device that is held in his mouth and vibrates on his tongue, allowing him to “see.” I put that in quotes even though Roger explains, “Definitely people think, ‘Well, it’s touch.’ Well, not for me …as soon as I put that on, within a matter of seconds, I am seeing it. It’s drawing pictures in my head.” His brain is able to transform images drawn on his tongue with vibrations into visual images distinct enough that he can navigate his way through a path taped on the floor or point to specific features of shapes mounted on the wall.

Cheryl Schlitz lost 95-100% functionality in her vestibular apparatus as a side effect of a medication she was prescribed. Using the same device as Roger, Cheryl goes from wobbling and nearly falling over to being able to stand upright and completely still within minutes. Incredibly, Cheryl’s case not only demonstrates how quickly the brain adapts, but also that this adaptation is residual and cumulative. After each treatment, Cheryl’s sense of equilibrium was restored for longer until she no longer required use of the device at all.

Later in the film, Dr. Doidge, the author of The Brain That Changes Itself introduces what he calls the plastic paradox. We are all born with plastic potential, he explains. Our experiences and routines (or lack thereof) determine whether our brain becomes more flexible and adaptable as we age or more rigid and constrained. To emphasize this, Dr. Alvaro Pascual-Leone discusses the work he is doing to investigate neuroplasticity using TMS and visualization exercises. Dr. Pascual-Leone discusses a study he conducted comparing the brain scans of individuals who sat in front of a piano and practiced moving their fingers to the scans of those instructed to simply visualize the movements. After five days, the brain area associated with the movement of those fingers had gotten larger not only in the group that was actually performing the movements, but also in the group that was simply mentally rehearsing the movements. Similar to the study we discussed in class that illustrated the functional similarities in brains of patients making judgements about actual pictures and patients making judgements about mental pictures, Dr. Pascual-Leone’s study shows how thinking alone can activate and change the brain. He says, “The idea is that just thinking will change your brain …and what that ultimately means is that one needs to be careful with what one thinks.”

While I can’t possibly detail every case study presented in the documentary in one blog post, I’ve tried to present some of the most relevant and thought-provoking stories to hopefully inspire others to check it out. The ability of our brains to react and change in response to our thoughts, behaviors and environment makes them both resilient and vulnerable. Watching The Brain That Changes Itself certainly left me with thoughts about how I might improve my own cognitive function and teach my brain to better focus and adapt. As Dr. Doidge and Dr. Pascual-Leone point out, neuroplasticity is not a rare phenomenon, but instead an inherent quality of the brain. If we do not work to keep our brains flexible and instead allow our lives to be rigid and repetitive, our cognitive function may very well suffer.

To watch the documentary on YouTube, here’s the link: