The extracellular matrix (ECM) of the brain plays a crucial role in providing optimal conditions for neuronal function. Interactions between neurons and a specialized form of ECM, perineuronal nets (PNN), are considered a key mechanism for the regulation of brain plasticity. Such an assembly of interconnected structural and regulatory molecules has a prominent role in the control of synaptic plasticity. In this review, we discuss novel ways of studying the interplay between PNN and its regulatory components, particularly tenascins, in the processes of synaptic plasticity, mechanotransduction, and neurogenesis. Since enhanced neuronal activity promotes PNN degradation, it is possible to study PNN remodeling as a dynamical change in the expression and organization of its constituents that is reflected in its ultrastructure. The discovery of these subtle modifications is enabled by the development of super-resolution microscopy and advanced methods of image analysis.

To better understand adult neurogenesis, the biomolecular specificity of the subgranular zone should be investigated in comparison to other layers of the hippocampus. Adult neurogenesis occurs at a reduced rate in adulthood compared to the period of development, but it can be increased with exposure to an enriched environment (EE). This can be used to investigate the regulatory role of molecules present in the extracellular matrix, such as tenascin C (TnC). This study, using Synchrotron radiation Fourier Transform Infrared spectroscopy (SR-FTIR), shows that the differences between the hippocampal layers in adolescence are maintained as subtle and significant in adulthood. The main difference in FTIR spectra was observed for nucleic acid and carbohydrate and for the comparison of the subgranular zone (SGZ) with hippocampal CA3. Moreover, we have detected changes in the protein and nucleic acid content of the SGZ that accompany the process of neurogenesis under the influence of an enriched environment. The latter effects are, however, lacking in mice with a gene ablation for tenascin C. Overall, these results show that observed discrete biomolecular differences in hippocampal layers follow the rate of neurogenesis that is enhanced by EE and dependent on TnC.

To better understand adult neurogenesis, the biomolecular specificity of the subgranular zone should be investigated in comparison to other layers of the hippocampus. Adult neurogenesis occurs at a reduced rate in adulthood compared to the period of development, but it can be increased with exposure to enriched environment. This can be used to investigate the regulatory role of molecules present in the extracellular matrix, such as tenascin C. This study using Synchrotron radiation Fourier Transform Infrared spectroscopy (SR-FTIR) shows that the differences between the hippocampal layers in adolescence are maintained as subtle and significant in adulthood. Moreover, we have detected biomolecular changes that accompany the process of neurogenesis under the influence of enriched environment, while these effects are lacking in mice with a gene ablation for tenascin C.