The X-Axis of the diagram is heat, and it actually goes down in heat.
The Y-Axis is for brightness, and it works like a regular axis, meaning as it goes up, the number or unit of some sort, in this case luminosity, goes up.
Soma is the site at which the error of integrating an excitatory signal with other incoming signals occurred. Another name for Soma is perikaryon.
This signal integrates chemical encoding of signal transduction from all other incoming signals and this signal is not integrated properly with other incoming signals to that neuron.
