Heterogeneous plasticity rules generate diverse structures in recurrent networks

Combining excitatory Hebbian, anti-Hebbian, and symmetric STDP rules generates the full repertoire of directed three-neuron motifs, unlike any single homogeneous rule, in analytical mapping.

• Why it matters: Diverse STDP forms across the brain make it hard to predict which circuit structures different plasticity rules can produce.
• What they did: The framework analytically maps excitatory Hebbian, anti-Hebbian, and symmetric STDP rules to directed three-neuron motifs, then tests generalization to larger recurrent networks.
• The result: Single homogeneous rules yield restricted motif subsets, while mixed rules produce motifs inaccessible to individual rules; however, multiple distinct rules can match similar motif distributions, implying structure constrains but does not uniquely identify plasticity rules.