A review is presented of the most important microinstability based models of anomalous transport. Possible experimental evidences in favour of electrostatic or electromagnetic turbulence are discussed. Focusing the attention on the eta i-mode driven transport ( eta i=d 1n Ti/d 1n n), the most relevant results of the stability analysis of such a mode are reviewed and discussed in connection with the improved confinement regimes observed in the presence of peaked density profiles. Then, after a brief analysis of the other microinstability based models, the connection with the scaling laws for the global energy confinement time is discussed.