Friday, 24 December 2010

Understanding the Cortex

If you want to understand the mammalian neocortex, and hence, seemingly, the back-end to most conscious human experience, I believe there are three fundamental areas one must first get to grips with. These are prediction, attention, and the generation and propagation of thought. I won't go into much detail, as I am not entirely clear yet myself.

Prediction is already known to be a fundamental, if not the primary (see Hawkins), function of the neocortex. Having an expectancy of what is to come is essential for learning and for bringing one's attention to important features of the world. Our attention is caught by things new, unexpected, or significantly different from their spatial or temporal surroundings. I get the feeling that these are all essentially the same: simply things that are not accurately predicted in the brain.

I feel that attention, that is the limitation of one's self to focus only on one thing at a time, must be important and must, like prediction, have a physical basis in the structure of the cortex. I believe that attention must be a fundamental function of the cortex. Despite the brain's parallelism, it appears to be almost a necessity that we solve problems by actively thinking about them, which necessarily entails paying attention solely to a specific thought. However, we must not forget that some answers do just spring to mind, so attention is not necessarily required for a solution. But it certainly plays a large role. Consider the following as an example that leads me to believe that attention must have a structural basis. Somehow, despite sound and vision being processed in completely different areas of the cortex, I still cannot pay attention to both simultaneously. Indeed, my attention is automatically drawn away from what I am looking at if I hear an alarming sound.

Thirdly, while we know a lot about how input from our senses is processed, we do not seem to have much of an idea how thoughts originate (if they do) or how they propagate through the cortex. This is very relevant to attention, as we actively think about what we are attending to. I find the reflexivity of thought bares an interesting light on this. The structure of the cortex is similar all over and, as first noted by Vernon Mountcastle in the 1950s, the way in which it works appears to be almost exactly the same throughout. The fact that I can reflect upon any particular thought, that I am aware that I am aware of any particular thought, regardless of what it is (visual, linguistic, auditory etc.) appears to me to be reflected by this repeating cortical structure.

I and others will continue to ponder these issues long into the future. It will be interesting to see whether these three areas do indeed prove to be fundamental, as I expect.

Sunday, 12 December 2010

Smelly Memories

It is often said that a smell can bring back a vibrant memory. Indeed, it has been singled out as different from your other senses as different, perhaps more sensitive, in this regard. There appear to be good biological grounds for this statement too, for the brain's olfactory system has close anatomical links with long-term and emotional memory. Yet I dispute this difference. I think that your other senses are just the same in this respect, or at least far more similar than we realise.

Often, I have exactly the same experience with my sense of hearing. This occurs, for example, when I listen to music that I haven't heard for a long time, or that I spent a long time listening to while engaging in a particular activity. When listening again, I suddenly get a vibrant memory of whatever I happened to be doing the last time I listened to the track, album or artist several times over. It is not only smells and sounds that bring back such memories, but every sense.

Furthermore, the majority of smells I experience don't remind me of anything at all, let alone bring back vibrant memories. Of course, I usually forget these - they're just everyday experiences of no significance.

Baring these things in mind, it seems more likely that uncommon experiences with emotional significance or that occurred a lot in a relatively short period, rather than simply your sense of smell, invoke these strong memories. The fact that many smells are uncommon means that your sense of smell brings back more vibrant memories than your others senses. There may be an element of increased sensitivity due to a physical connection with memory in the brain, but I am sure it is not entirely responsible.