Exploring the NeuroBytes platform is a great way to understand how it works, but it's handy to know the basics in advance. This section will cover important "ground rules" that will help point experimenters in the right direction: powering and connecting NeuroBytes and changing the current operating mode. Subsequent sections discuss these specific operating modes, along with various physiological circuits that can be built with the simulators.

The image above shows the top side of a NeuroBytes neuron simulator. In the middle of the gear icon is an LED (unlit here) that indicates the current membrane potential.

Blue = Hyperpolarized
Green = Resting
Red = Depolarized
White Flash = Action Potential
 

Power

NeuroBytes are electronic simulators, and as such each one must have a power source. Fortunately for the user, any of the seven connectors on each NeuroBytes board can be used to introduce power to a neural circuit:

NeuroBytes v0.8 and previous versions do not have on-board regulators; as such, they should be powered by a regulated 5VDC supply, either via a 4xAA battery pack with a built-in regulator or using a USB power supply. Once power is fed into the circuit, other NeuroBytes will pull power through their signal cables, as shown in this simple 8-neuron network:

 

Connection

NeuroBytes have two types of signal connections: dendrites, which are inputs, and the axon terminal, which has two output connections. It's important to understand that, like neurons, NeuroBytes are directional; in other words, information flows from the dendrites to the axon, not vice-versa. That means connecting two NeuroBytes axon-to-axon or dendrite-to-dendrite won't result in any information transfer, although it will allow the two boards to share power which can still be useful when creating multiple isolated circuits.

“Neurotransmitter” cables are used to connect presynaptic (upstream) axon terminal outputs to postsynaptic (downstream) dendrite inputs. The balance of excitatory and inhibitory input determines if the NeuroBytes fire an action potential or not.


Blue = Inhibitory, Red = Excitatory .
Left: red excitatory cables. Right: blue inhibitory cables.

The cables have a locking connector on each end that only plugs in one way. To release the connector, use your thumb and forefinger to depress the tab and gently pull the connector out of the NeuroBytes board:

NeuroBytes accessories--mechanoreceptors (switches), servo adapters, extenders, etc--use the same connectors and cables. Note that most accessories can use either excitatory or inhibitory cables, but the cable type does not affect accessory behavior.

 

Changing Modes

NeuroBytes are designed to simulate a variety of different biologically inspired neurons. Rather than relying on physically distinct hardware to accomplish this goal, each board can be easily switched between different operating modes by pressing the MODE switch. The current operating mode is determined by observing the LED color when no excitatory or inhibitory signals are present on any of the board's dendrites:

In order to change modes, simply hold down the MODE button until the LED color changes.