12th May 2014
We have over 100 billion neurons in our brain, firing thousands of synapses per second.
Looking at ions and ion channels is crucial to understand the mechanics of thinking, as they can be seen as the molecular roots of our actions, thoughts and feeling, as well as being the building block to our genetic code. Even when imagining the future of intelligence, such as SIM’s (substrate independent minds), ions channels play a key role.
Firstly we need to look at the structure and ecosystem of an ion channel. The environment of the ion channel lies with the neurons, which are one of the main structures of the brain and serve to communicate most of our bodily functions. From muscle contractions to thinking, all are governed by neuronal communication. Neurons are not inherently good conductors, so they have unfolded elaborate mechanisms which include synapses, neurotransmitter diffusion, and ion channels. There are two groups of neurons. The first are called ‘afferent’ and carry information to the brain. The second are ‘efferent’ neurons, which carry information away from the brain. The synapsis is a structure that allows neurons to pass information to each other. Synapses can be either chemical or electrical, differing overwhelmingly from each other in their transmission mechanism. Electrical synapses allow transmission of ions to happen quickly through a flow, by contrast chemical synapses pass information directionally from a presynaptic cell to a postsynaptic cell, thus having no continual flow. It is here where the ion channels have their function, sitting in the gap between the cell, opening and closing when neurotransmitters bind to the ion receptors.
The ion channels are proteins that are penetrable to only certain types of ions, allowing them to flow in the direction of their concentration gradient, creating selective permeability, which in return generates a membrane potential, acting as a selective barrier, allowing some chemicals to pass through and not others. Once the neurotransmitter has bond to the receptor the gated ion channel opens, allowing the termination of the synaptic transmission to start.
Ion channels play a key role in the initiation, mediation and termination of synaptic transmissions, making them significant in everything from finding cures for cancer to how the brain generates thoughts. Technology will continue to play an incredible influential role in the understanding of the microbiological functions of ion channels and other neurological mechanisms.