First-order neuron (primary sensory afferent) 
	Receptors in periphery 
	cell bodies in dorsal root ganglia 
	ipsilateral axons enter spinal cord 
	projections to second-order neurons in either spinal cord or 	brain stem (modality specific) 

Second-order neuron 
	Synaptic input from first-order neuron 
	cell bodies in either spinal collumn or brain stem (modality 	specific) 
	axons decussate to contralateral side 
	project to third-order neurons in thalamus 

third-order neuron 
	synapatic input from second-order neuron 
	cell bodies in thalamus 
	axons stay contralateral 
	project to somatosensory cortex