Table 1. Class 1 and 2 Properties.

Class 1 (driver)	Class 2 (modulator)
Activates only ionotropic receptors	Activates metabotropic receptors
Synapses show paired-pulse depression (high p)a	Synapses show paired-pulse facilitation (low p)
Large initial EPSPs	Small initial EPSPs
Little or no convergence onto target	Much convergence onto target
Thick axons	Thin axons
Large terminals on proximal dendrites	Small terminals on distal dendrites
Dense, well localized terminal arbors	Delicate terminal arbors

EPSP = excitatory postsynaptic potential.

^aFor slight variation in this property among thalamocortical inputs, see Viaene and others (2011c).