Thaler v Commissioner of Patents [2021] FCA 879 5
cord are key components. In addition to coordinating these everyday functions, the
central nervous system subsumes other roles such as thinking (cognition) and feeling
(emotion).
Neurotransmission is the process by which small molecules (neurotransmitters)
transmit signals (electrical impulses) from one neuron to the next. Neurotransmission
takes place at a “synapse”, ie where two axons (ie neurons) are in close proximity but
not touching one another. These are the sites of communication between neurons in
the central nervous system. The gap between the two adjacent neurons is the
“synaptic cleft” or “synaptic gap”. It is across this gap that impulses are transmitted
by the use of specialised chemicals known as neurotransmitters. When the nerve
impulses arrive at a synapse, neurotransmitters are released, which in turn can
influence another neuron, either by inhibitory or excitatory impulses. Further, the
receiving neuron may “on-transmit” to many other neurons which then influence
these neurons and so on. The neurotransmitters are released by a “presynaptic
neuron” which bind to and activate “receptors” …
Neurotransmission occurs when an action potential (ie an electrical impulse) is
initiated in a neuron and arrives at the nerve terminal of the pre-synaptic neuron. The
mechanism of the action potential is a function of the electrical potential across part
of the neuron, being the axon. It involves “travelling” switching polarity across the
membrane of the axon in one direction only mediated by the action of the opening
and closing of voltage gated ion channels. The action potential or electrical impulse
when it arrives at the nerve terminal causes the release of chemical neurotransmitters.
Neurotransmission then takes place, but in one direction, ie from the pre-synaptic cell
to the post-synaptic cell. When neurotransmitters bind to their receptors on the
postsynaptic neuron this may result in short term changes, such as changes in the
membrane potential (ie the electrical charge contained by that postsynaptic neuron)
called a postsynaptic potential; this may trigger a further action potential. …
Neurons are arranged in the form of networks (neural networks) through which
signals can travel. Information arrives at each neuron from many others. The human
brain has approximately 100 billion neurons which make about 100 trillion synapses.
Information is transferred in the brain, and signals are propagated throughout the
body, by way of nerve impulses. Signals are sent to and from the central nervous
system by efferent (ie conducting away) and afferent (ie conducting to) neurons in
order to coordinate functions essential for survival.
22 Artificial neural networks in their software structure and in their mathematical elements
roughly model natural neural networks. They are a more sophisticated form of machine
learning. A simple example is an object recognition system that might be fed thousands of
labelled images of a particular item so as to then find visual patterns in the images that
consistently correlate with particular labels.
23 An artificial neural network consists of thousands or even millions of simple processing
nodes that are densely connected. Neural networks are organised into layers of nodes, which
are feedforwarding in the sense that generally speaking data moves through them in only one
direction; I will discuss backpropagation in a moment. In terms of feedforwarding, simply
put, an individual node might be connected to several nodes in the earlier layer, from which it
receives data, and several nodes in the succeeding layer, to which it sends data.