Did you ever whisper a secret in your friend’s ear? You share your secret messages using words. Do you know how your nerve cell share their messages? Let me tell you that your neurons use chemicals and electric signals to share the message. Neurons, without touching each other sends messages through the synapse, which is the gap between which neurotransmitters travel to communicate between neurons – made from organic materials. Synapses are the meeting points of axons and dendrites that allow neurons in the human brain to send and receive nerve signals.
Artificial synapse is a device that mimics the brain’s excitatory and inhibitory signals. The biological hybrid version of artificial synapses communicates faster with living cells.
Basic Of Nervous System
The 100 billion neurons in the CNS allows entry of incoming signals through synapses located on the neuronal dendrites and the cell body. For different types of neurons, there may be only a few hundred or as many as 200,000 such synaptic connections from input fibers. Conversely, the output signal travels by way of a single axon leaving the neuron. Then, this axon has many separate branches to other parts of the nervous system or peripheral body. The special feature of the synapse is that the signal normally passes only in the forward direction, from the axon of a preceding neuron to dendrites on cell membranes of subsequent neurons. This forces the signal to travel in required directions for performing specific Nervous functions like information storage and processing, massively parallel computation.
Artificial synapses are the electronic device that mimics the important functions of the biological synapses like the brain efficient and neural learning process. Artificial synapses mimic biological synaptic functions such as spatiotemporally-correlated signal processing, paired-pulse facilitation, spike-timing-dependent plasticity, short-term potentiation, etc. Researchers have taken inspiration from the working of this organ to develop artificial synapses that are capable of learning autonomously. They have modeled the device which is considered the next step in the creation of more complex circuits.
Working Of Artificial Synapses
The team of researchers developed a nanoscale device called ‘memristor’ i.e., resistors with memory. This idea of the memristor is to create an electronic equivalent of the brain neurons and synapses. The biological synapse can process and store information with incredible efficiency. Simply by putting the synaptic junction between 2 nerve cells that open or close depending on the nerve impulse that reaches it. The communication between artificial synapses and living cells occurs through electrochemistry just like another neuron receiving messages from its neighbor. The ultrathin electric film is sandwiched between 2 electrodes, separated by a trench filled with an electrolyte solution that plays a part of the synaptic cleft. Living cells are placed on top of one electrode, neurotransmitters released by those neurons react with that of the electrode to produce ions. Neurotransmitters cross the gap to pass the impulses on to the next neuron. Those ions travel across the trench to other electrodes and modulate the conductive state of this electrode. Thus, its ability to change and learn is achieved via conductance, low-resistance corresponds to a strong synaptic connection and high resistance to weak connection. Every time the crossing is made, the connection gets stronger.
The chemical interactions are responsible for biological synapse at synaptic junction whereas, in biohybrid synapse, cells communicate by using this chemistry. Biohybrid synapses interact with the brain’s natural chemistry gives the device added utility. This mimicry of biohybrid synapse is highly efficient in terms of energy because computing and memory storage happens in one action. In traditional computer systems, data is processed first and later moved to storage. This was successfully tested by researchers in rat neuroendocrine cells that release the neurotransmitter dopamine. This reaction is irreversible.
However, the brain is an incredibly intelligent machine, even as you read this, neurons in your brain are firing electrical impulses and connecting in every change and configuration.
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