Functional clustering of dendritic activity during decision-making

Area of Science:

• Neuroscience
• Cellular Neuroscience
• Systems Neuroscience

Background:

• Dendrites possess active properties enabling local nonlinear operations.
• Previous in vivo studies yielded conflicting data on the prevalence and selectivity of dendritic nonlinearities.

Purpose of the Study:

• To investigate the prevalence and spatial distribution of local nonlinearities in pyramidal cell dendrites during a tactile decision task.
• To resolve dendritic calcium signals at high resolution in vivo.

Main Methods:

• High-resolution in vivo imaging of mouse motor cortex pyramidal cell dendrites and spines using a custom microscope (15 Hz frame rate).
• Advanced analysis techniques to quantify activity frequency and spatial scales in dendritic branches and spines.
• Simultaneous imaging of soma and up to 300 μm of contiguous dendrite.

Main Results:

• Most dendritic calcium transients coincided with global neuronal events.
• Task-associated calcium signals within dendrites and spines exhibited compartmentalization by branching and spatial clustering (~10 μm).
• Diverse behavior-related signals were intermingled across the dendritic arbor.

Conclusions:

• Dendritic activity, while often global, shows compartmentalized and clustered task-specific signals.
• This compartmentalization and diversity of signals suggest a substantial capacity for learning within individual neurons.
• Findings reconcile previous conflicting views on dendritic nonlinearities in vivo.