Table 2.

Comparison of advantages and limitations of different approaches for measuring neuronal activation and plasticity

	Genomic tools: immediate early genes	Electrophysiology/live (calcium) imaging	Circuit analyses/neuroanatomy: neuronal/synaptic connectivity
Investigating complex behaviors in freely moving animals	Yes	Limited (partially using implanted electrodes/objectives)	Yes
Investigating Pavlovian conditioning in harnessed animals	Yes	Yes	Yes
Accessing the brain in vivo	No	Yes	Very limited
Temporal resolution	Snapshot	Live image	Snapshot
Screening the complete brain for neuronal activity	Yes	No	Limited (requires quantitative screening for changes in synaptic circuits/neuropil volumes)