Can enhanced early sensory experience improve learning later in life? Using an enriched environment (EE) paradigm, we characterised the impact of enhanced sensory processing in early life during critical periods of cortical interneuron synaptic assembly, on changes in structural synaptic plasticity in vivo, functional cortical network activity and behaviour in adult mice. Using 2-photon longitudinal intravital microscopy, cranial window implantation and calcium imaging, we monitored the effects of early EE on functional cortical neuron population activity in mouse somatosensory (S1) cortex with GCaMP7f. Early EE significantly induced changes in the frequency of calcium transients of cortical layer2/3 excitatory pyramidal neurons and inhibitory parvalbumin interneurons (PV-INs) in EE adult animals compared to standard cage (SC) controls. High-resolution in vivo longitudinal structural 2-photon imaging of cortical L2/3 PV-IN axonal boutons and PV-IN dendritic spines revealed changes in synaptic dynamics in vivo. Early EE induced changes in the spine density and spine size of PV-INs at all adult imaging timepoints in vivo. PV bouton- and PV spine- turnover ratio, and proportions of spine formation, elimination and stable fractions will be compared between EE and SC control animals to reveal any changes in PV-IN structural dynamics in vivo. Further behavioural training experiments on a whisker-dependent texture-discrimination sensory learning task will investigate whether early EE animals (PV-Cre) have improved learning performance and/or sensory discrimination in later life. Future work will further clarify the long-term impacts of enhanced sensory processing in early life on assemblies of functional cortical circuits and behavioural learning performance in adults.