By Roland Watson

At the end of the last article, I discussed how thoughts can be divided into two rough groups, ideas that come from reason, and feelings and emotions. Given, for the moment, this breakdown, we might then ask, how do we have new thoughts? What drives a new emotion, or inspiration?

How do ideas develop?

We saw that a thought is an organized firing, or wiring, of neurons. The question then becomes, how does our mind progress from the firing of one pattern of neurons to the next?

I believe there are a number of possible mechanisms at work, all of which have an underlying electrochemical source. The first of these is simply the unconscious mind's reactive function: the direction of our senses to follow continually changing external stimuli, and also its focus on the body's internal functioning.

Of course, these are actually both reactive and proactive. Our unconscious mind anticipates the external environment, and plans our response to it, including through its management of our bodily systems. For instance, you only need to think of how you brace for impact, when you are about to be hit.

The mechanism of overlap

The second mechanism, on the other hand, involves our conscious mind: our reflective abilities. In this case, I believe the actual physical mechanism is simply "overlap." When we consider our stream of consciousness, it is amazing how the mind jumps about, seemingly at random, from one idea or feeling or memory or sensation to the next. However, perhaps this series is not as random as we think.

Most ideas are highly complex. They involve input from many parts of the brain. For instance, a memory may include the sensory inputs relating to an experience, the thoughts that you had during the experience, and your later reflection or reasoning on the experience, including the language that you used to frame the reflection.

The instant that you have the memory, all of the neurons for all of the different parts of your brain that are required for it are wired together. But then, the moment passes and the memory fades away.

What I term overlap is that your next thought may well, or very often will, involve some of these same neurons. For some reason they will stay active, and furthermore their continued activity will initiate the activity of other neurons, the neurons that are necessary to create fully this next new thought.

For example, language and other stimuli, such as the notes of a song, frequently serve as overlap triggers. The words and songs that you hear regularly cause your mind to link into established neural networks: to memories.

Moreover, overlap triggers can work within or across thought categories. One smell may trigger the memory of another; or it may trigger a vision, something that you have seen, that is associated with the smell; or, it can trigger an idea that is associated with that vision, all the while leaving the link, the intermediate vision, hidden in the unconscious, so that your self-conscious mind is baffled by the transition.

Searching for an idea

Another way to think of this is to consider what happens when you look for an idea, when you search your memory for something that you have previously thought. When you cast your mind around, when you fire up different neural circuits, what you are really doing is looking for an overlap to the idea, an overlap that is strong enough, which involves enough neurons, that it triggers a faint recollection, which you can then latch onto and hold.

The question is, in your stream of consciousness, why does a particular subset of neurons stay active? Many, many such overlaps are possible. And how, or why, does it stimulate other neurons to create your next thought?

What is memory?

People have considered the nature of memory for a long time, and it is still being debated what it is and how it functions. However, I think a few observations can be made.

The first of these is that memory is the basis of personal consciousness. As such, it is an essential aspect of life. I once read an article by Michael Lemonick, called Smart Genes, which pointed out that without memory there would be no context. In a way, then, memory is the foundation of your identity. You are who you are, because you remember who you are.

Memory is the mind's way of organizing the realm of experience. It is used to distinguish, or position ourselves relative to, many different things. The first of these is our perception of space, including objects and their physical attributes, and their position relative to each other.

Next is our perception of time, including such things as sequence, duration, and the distinction between something that happened recently and something else that occurred far in the past. This is the distinction between short-term and long-term memory.

Memory also serves a role in your body's activity, including its autonomous processes, and your motor skills, both conscious and unconscious. For the first, you can say that the mind "remembers" to keep your heart beating.

The commonly accepted use of the word memory covers our experiences, including everything that happens to us, and also what we learn through the repetition of experience, such as the distinction between old, as in previously experienced, and new.

Finally, we remember our rational ideas; our feelings, emotions and dreams; and the symbols that we use to describe them, such as numbers and words.

Also, I believe that instincts can be considered to be memories - species' memories - as well. These include when newborns know to seek out their mother for food, when they "imprint" with the first animal that feeds them, and also how they know to fight or flee if attacked.

Interestingly, these types of memories vary by species. Four-legged animals know to stand at birth, and salt-water turtles to head for the sea. Indeed, all of the common behavior of species that are not raised by their parents, including how to feed, and to breed, has an instinctual memory element.

Characteristics of memories

Furthermore, while a particular memory may have many different aspects, one component will typically be its initial or primary focus. In addition, memory can vary by process, and difficulty. For the former, you can remember something consciously, by concentrating on it, or it can happen automatically, through a prompting from your unconscious.

Also, different parts of the brain are required for different types of memories. Activity in the hippocampus is necessary for a long-term memory, and in the amygdala to recall the feeling of a prior instance of emotion.

What this implies is that memories are always present in your mind, but that their conscious recollection requires some sort of mechanical trigger - in addition to overlap. For instance, if the hippocampus is damaged, the trigger for long-term memory is lost. The memories are still there - in the brain - they are just never recalled.

Regarding the difficulty of memory, this applies both to having them, such as the challenge of remembering the words of a foreign language, and also to not having them, such as to not recalling a bad experience.

The overlap mechanism further explains why singular experiences stand out, and repetitive experiences are blurred together. The precise overlap to a specific memory of something that we have done many times is difficult for the mind to grasp. Singular experiences are also typically associated with great pleasure, or pain.

Memory is in the synapses

One other way to generalize memory, underneath all of these different categories, is to recall that it - a memory - is an organized set of neurons, connecting whatever parts of the brain, and relating to an experience - including the sensory inputs thereof, or an idea - including its language, that have been fired in the past. Any time that same set is re-fired, even if only approximately, our mind will recreate the experience or idea and we will remember it.

Scientific research, for which the 2000 Nobel Prize in medicine was awarded, has demonstrated that memory is located in the synapses. The ability of the neural networks that represent memories to form is dependent on bio-mechanical activity in the synapses.

Further, these researchers distinguished explicit or declarative memory, or memories of people, places and things, which is for the most part conscious, from implicit or procedural memory, or memories of motor skills and perceptions, and which can be conscious or unconscious.

In addition, they considered the issue of short-term versus long-term memory to be one of "storage," and even isolated the bio-mechanical functions in the synapses that underlie the distinction. For a short-term memory, the ion channels in the synapses are increased, temporarily, allowing the flow of more electrical charge. For a long-term memory, the actual shape of the synapse changes, mechanically cementing the enlarged electrochemical channel.

This is known as long-term potentiation - LTP. Also, it is worth noting that there are two rates of synaptic transmission: slow, for thoughts that constitute such things as alertness and mood; and fast, for speech, movement and perception.

Are our memories true?

To close this article, I want to consider one other implication of the fact that the brain is continually changing. This means our memories are also changing. A memory is the thought consequence of the firing of a particular neural circuit. The next time the circuit fires, though, it may be different. If so, the memory will be different. I don't mean to suggest that such changes will dramatically alter the memory, but it will be different. Of course, we are already familiar with this, through the experience of remembering something in a new way.

Since recollection is always after the fact, this means that it is usually if not always slightly different from what really happened, from objective reality. Indeed, memory can premeditatively be altered, through the repetition of education and of behavioral form. And, for the latter, if you accept what you hear, your brain may even form false memories, neural circuits that have no bearing on reality.

In the next article, I will consider how we use our free will to control our thought.

© Roland Watson 2014