Abstract
The computational abilities of recurrent networks of neurons with
a
linear activation function above threshold are analyzed. These networks
selectively realise a linear mapping of their input. Using this property,
the dynamics as well as the number and the stability of stationary states
can be investigated. The important property of the boundedness of neural activities
can be guaranteed by global inhibition. If used together with self-excitation,
the global inhibition gives rise to a multi stable Winner-Take-All
(WTA) mechanism. A condition for a neuron to be a potential winner of the
competing dynamics is derived. The network becomes a largest input selector
when the self-excitation is marginal.
Slowing down the global inhibition produces oscillations. The study of
oscillations of random networks suggests that all cyclic trajectories of linear
threshold networks are due to the existence of partitions with undamped linear
oscillations. Chaotic dynamics were never encountered in computer simulations
and perhaps do not exist at all in small networks.