**Preface**

Synaptic plasticity is a complex and crucial neuronal mechanism linked to principal memory and motor functions. During the developmental period into old age, the neural frame is subject to structural and functional modifications in response to external stimuli. This essential skill of neuronal cells underpins the ability to learn about mammalian organisms (Glanzman et al., 2010).

Synaptic plasticity phenomena include microscopic changes such as spine pruning and macroscopic changes such as cortical remapping in response to injury (Citri and Malenka 2008; Hofer et al., 2009). The increase in neurological and neuropsychiatric disorders in the current century—although this increase did not occur among the aging population—has resulted in a greater urgency to understand the aberrant processes connected to these diseases (Martella et al., 2016; 2018; Bonsi et al. 2018).

In the last decades, it has been highlighted that de novo protein synthesis (mRNA transcription, mRNA and protein degradation, histone acetylation, DNA methylation, and miRNA regulation), as well as a new set of signaling molecules (endogenously generated cannabinoids, peptides, Neurotrophins, protein kinases, and ubiquitindash proteasome system), have been implicated in synaptic transmission and plasticity.

> **Giuseppina Martella** *Editor*
