On neuroplasticity

Neuroplasticity, or brain plasticity as it is also known, is one of the most important recent discoveries about the brain, and will definitely make the deterministic perspective of the mind old-fashioned. According to this former post, the propagation of a signal in a neuron network can be described with a set of simple electrical rules and thus, in these terms, the response produced by a stimulus is unique. Now, what has been found out is that, while this is physically true, it’s incomplete. Scientists have discovered that the circuit, the neuron network, is not a static substratum.

Technically speaking, brain plasticity is a term used to describe the ability of the brain to change during the years. Traditional hypothesis used to assume that the brain can change during the early years, as it seems obvious, but, in general, very few or no scientists believed in the capacity of the brain to change after a certain age. Recent discoveries and our everyday life, though, challenge this perception. In fact, non-demented elderly people are certainly able to learn new things. Of course, this ability is limited, but haven’t your grandparents learnt how to use mobile phones, for instance? This simple fact puts us on a track in which we cannot assume that the brain remains immutable.

Consciousness has been totally impossible to recreate, but memory is another issue. We know fairly well how memory works, at least in unconscious systems: memory is based on changeable states of a circuit. This circuit is materialised by neurons in the brain, and, therefore, how can we create new memories? By making new connections between neurons that will change the states (signals) of the subcircuits within the brain. This is what neuroplasticity does. Neuroplasticity then allows us to create new memories, to learn new things. Nonetheless, this ability of our brain does a lot more.

Connection between neurons.

Recent studies show that this plasticity is also used by the brain to compensate for neural loss. This fact has been proved with people suffering from senile dementia, as these people have smaller dendrites (less connectivity among neurons) than non-demented people. Furthermore, it has been proved that dendrites (and thus connectivity among neurons) are longer and more branched in old people than in youngsters.

According to all of the above then, apart from the physics behind the neural network, we also need to know how it changes along time to physically predict behaviour. In the end, it’s no surprise, as what is being discovered is that environmental circumstances literally make up our brain, and, as a result, condition our decisions.