Four Basic Neural Circuit Motifs

A. A feedforward circuit in which synaptic connections extend in a single direction from one processing level of neurons to another.

B. Divergent feedforward connections describe a small number of presynaptic neurons connecting to a larger number. Convergent connections describe a large number of presynaptic neurons connecting to a smaller number.

C. In a recurrent network, synaptic connections occur in multiple directions between neurons, forming looping pathways through the circuit.