Elimination of Inhibitory Synapses Is a Major Component of Adult Ocular Dominance Plasticity

• Published in: Neuron (Cambridge, Mass.) Mass.), 2012-04, Vol.74 (2), p.374-383
• Main Authors: van Versendaal, Daniëlle, Rajendran, Rajeev, Saiepour, M. Hadi, Klooster, Jan, Smit-Rigter, Laura, Sommeijer, Jean-Pierre, De Zeeuw, Chris I., Hofer, Sonja B., Heimel, J. Alexander, Levelt, Christiaan N.
• Format: Article
• Language: English
• Subjects: Age Factors; Animals; Brain; Carrier Proteins - genetics; Cell culture; Dendritic Spines - metabolism; Dendritic Spines - ultrastructure; Dominance, Ocular - physiology; Electroporation; Green Fluorescent Proteins - genetics; In Vitro Techniques; Luminescent Proteins - genetics; Membrane Proteins - genetics; Mice; Microscopy; Microscopy, Electron, Transmission; Neural Inhibition - genetics; Neural Inhibition - physiology; Neuronal Plasticity - physiology; Neurons; Neurons - physiology; Neurons - ultrastructure; Proteins; Sensory Deprivation; Synapses - physiology; Synapses - ultrastructure; Time Factors; Vesicular Glutamate Transport Protein 2 - metabolism; Vesicular Inhibitory Amino Acid Transport Proteins - metabolism; Visual Cortex - cytology; Visual Pathways - physiology
• ISSN: 0896-6273; 1097-4199
• DOI: 10.1016/j.neuron.2012.03.015

During development, cortical plasticity is associated with the rearrangement of excitatory connections. While these connections become more stable with age, plasticity can still be induced in the adult cortex. Here we provide evidence that structural plasticity of inhibitory synapses onto pyramidal neurons is a major component of plasticity in the adult neocortex. In vivo two-photon imaging was used to monitor the formation and elimination of fluorescently labeled inhibitory structures on pyramidal neurons. We find that ocular dominance plasticity in the adult visual cortex is associated with rapid inhibitory synapse loss, especially of those present on dendritic spines. This occurs not only with monocular deprivation but also with subsequent restoration of binocular vision. We propose that in the adult visual cortex the experience-induced loss of inhibition may effectively strengthen specific visual inputs with limited need for rearranging the excitatory circuitry. ► Plasticity in adult visual cortex is associated with rapid inhibitory synapse loss ► This loss of inhibition is matched by increased visual responsiveness ► Inhibitory synapse loss occurs predominantly on stable dendritic spines ► This may allow adult plasticity despite reduced plasticity of excitatory synapses van Versendaal et al. show that plasticity in the adult visual cortex is associated with the rapid loss of inhibitory synapses. This may represent a mechanism allowing adult plasticity to occur without the need for extensive reorganization of excitatory synapses.