New paper by PhD student Kristian Lensjø

Emerging evidence suggests a role for perineuronal nets (PNNs) in learning and regulation of plasticity but the underlying mechanisms remain unresolved. Here, we used chronic in vivo extracellular recordings to investigate how removal of PNNs affects plasticity and neural activity over time.

PV+ inhibitory neuron (red) covered by a perineuronal net (green). Synapses are in the holes in the net.

PNN removal caused reduced inhibitory activity, and reset the network to a juvenile state. Experimentally induced activity-dependent plasticity by monocular deprivation caused rapid changes in single unit activity, and a remarkable potentiation of gamma oscillations. Our results demonstrate how PNNs may be directly involved in stabilizing the neural network. Moreover, the immediate potentiation of gamma activity after plasticity onset points to potential new mechanisms for initiation of activity-dependent plasticity.

Lensjø K, Lepperød M, Dick G, Hafting T, Fyhn M.  Removal of perineuronal nets unlocks juvenile plasticity through network mechanisms of decreased inhibition and increased gamma activity. J Neurosci. 2016 Dec 30. pii: 2504-16. doi: 10.1523/JNEUROSCI.2504-16.2016.

Read more about the hypothesis about PNN and long-term memory in Science.

 

 

Tags: brain, Visual cortex, Plasticity, interneurons, perineuronal nets, extracellular matrix By Hafting
Published Jan. 6, 2017 2:28 PM - Last modified Jan. 6, 2017 3:32 PM