Sensory integration

This garden universe vibrates complete. Some we get a sound so sweet. Vibrations reach on up to become light, and then thru gamma, out of sight. Between the eyes and ears there lay, the sounds of color and the light of a sigh.  ~   Moody Blues

   

A recent study shows that baboons can learn to tell the difference between word and non-word strings [ link ]. In an accompanying editorial, Dr Michael Platt says this evidence suggests dyslexia might be more of a visual problem than a problem matching sounds to letters. It’s a rare opportunity that I get to hear a neuroscientist jump to an either-or conclusion like that. Reading is an integrated process that coops many areas of the brain. A problem in the visual system can produce a reading deficit just as profound as a problem in the auditory system. These systems are integrated by higher centers of the brain during reading. What these investigators discovered with baboons is a better example of pattern recognition. It’s a process shared by any species that survives in the wild. Over time, the visual system is tuned to distinguish what’s meaningful from what isn’t by a process of ‘statistical regularity’. Statistical regularity simply means that certain signal combinations appear more frequently with meaningful objects than with non-meaningful objects. It’s no surprise that a baboon can perform this with a string of letters just as easily as it can a set of racing stripes. And I have no doubt that humans require a working visual system as well as a sound system to be able to read coherently. The written word hasn’t been around long enough to evolve an area of it’s own in the brain like it has for speech and vision.

 

The heart of interpretation

According to a recent study published in the New England Journal of Medicine, people who receive a diagnosis of cancer are 5 to 6 times more likely to suffer a heart attack or other cardiovascular complication within seven days after receiving the news (compared to people with similar backgrounds who are cancer-free). This is well before the disease or treatment has a chance to compromise health. Just hearing and interpreting information has an immediate impact on the cardiovascular system. This is a dramatic illustration of the relationship that exists between the mind and body [ link ].

 

Warning of a life-threatening event elicits conditioned fear. Conditioned fear depends on prior experience with a signal (hearing the term for an illness) paired with an adverse consequence. Once established, conditioned fear always involves blood pressure changes. In fact, practitioners of behavioral medicine can track fluctuations in blood pressure to fleeting psychological states ..in real-time. Blood pressure reliably follows the steps of a conditioned fear response. Changes can be observed when a signal arrives, while memories are retrieved, as the response is felt, and either panic or post-fear calm sets in [ link ].