# Quantities and recording¶

In LEMS and NeuroML, quantities from all exposures and all events can be recorded by referring to them using paths. For examples, please see the Getting Started with NeuroML section.

## Recording events¶

In NeuroML, all events can be recorded to files declared using the EventOutputFile component. Once an EventOutputFile has been declared, events to record can be selected using the EventSelection component.

pyNeuroML provides the create_event_output_file function to create a EventOutputFile to record events to, and the add_selection_to_event_output_file function to record events to the declared data file(s).

## Recording quantities from exposures¶

In NeuroML, all quantities can be recorded to files declared using the OutputFile component. Once the OutputFile has been declared, quantities to record can be selected using the OutputColumn component.

pyNeuroML provides the create_output_file function to create a OutputFile to record quantities to, and the add_column_to_output_file function to select quantities to record to the declared data file(s).