Abstract: A neural network includes neurons and wires adapted for connecting the neurons. Some of the wires comprise input connections and exactly one output connection and/or a part of the wires comprise exactly one input connection and output connections. Neurons are hierarchically arranged in groups. A lower group of neurons recognizes a pattern of information input to the neurons of this lower group. A higher group of neurons recognizes higher level patterns. A strength value is associated with a connection between different neurons. The strength value of a particular connection is indicative of a likelihood that information which is input to the neurons propagates via the particular connection. The strength value of each connection is modifiable based on an amount of traffic of information which is input to the neurons and which propagates via the particular connection and/or is modifiable based on a strength modification impulse.