Matrix is primarily run by the board of the organisation. In practice, however, in addition to the actual board members, a number of hard-working representatives run the operation. Each officer and board member has a specific area of responsibility within the organisation.
The board is elected each year at the organization's autumn meeting and the representatives are elected at the organizational meeting of the new board in December, although it is possible to become a representative in some roles in the middle of the year. All the representatives are just ordinary Matrix people!