Journal Article

Branch-specific dendritic Ca2+ spikes cause persistent synaptic plasticity

Cichon, Joseph, Gan, Wen-Biao

2015

Overview

The brain has an extraordinary capacity for memory storage, but how it stores new information without disrupting previously acquired memories remains unknown. Here we show that different motor learning tasks induce dendritic Ca 2+ spikes on different apical tuft branches of individual layer V pyramidal neurons in the mouse motor cortex. These task-related, branch-specific Ca 2+ spikes cause long-lasting potentiation of postsynaptic dendritic spines active at the time of spike generation. When somatostatin-expressing interneurons are inactivated, different motor tasks frequently induce Ca 2+ spikes on the same branches. On those branches, spines potentiated during one task are depotentiated when they are active seconds before Ca 2+ spikes induced by another task. Concomitantly, increased neuronal activity and performance improvement after learning one task are disrupted when another task is learned. These findings indicate that dendritic-branch-specific generation of Ca 2+ spikes is crucial for establishing long-lasting synaptic plasticity, thereby facilitating information storage associated with different learning experiences. Ca 2+ spikes are generated on different dendritic branches in the primary motor cortex of mice performing different motor learning tasks, causing long-lasting potentiation of postsynaptic dendritic spines; inactivation of a population of interneurons disrupts the spatial separation of Ca 2+ spikes and persistent dendritic spine potentiation, suggesting that the generation of Ca 2+ spikes on different dendritic branches is crucial for storing information in individual neurons. How old and new memories coexist In experiments designed to explore how the brain stores new information without disrupting older memories, Joseph Cichon and Wen-Biao Gan used calcium imaging of neurons in the motor cortex of mice performing a series of motor learning tasks. Different learned tasks triggered Ca 2+ spikes (a sign of plasticity) in non-overlapping dendrite branches, causing long-lasting potentiation of the spines found on those branches. This specific connection between task and dendrite branch was disrupted when populations of interneurons were inactivated, suggesting a role for inhibition in maintaining the separation between branches when new information is being stored in individual neurons.

• Publisher: Nature Publishing Group UK
• Subject: 14 / 14/69 / 59 / 631/378/1595/2618 / 631/378/2591/2592 / Humanities and Social Sciences / multidisciplinary / Science