Somatostatin-Expressing Inhibitory Interneurons in Cortical Circuits

Area of Science:

• Neuroscience
• Cellular Neuroscience
• Computational Neuroscience

Background:

• Cortical inhibitory neurons display significant diversity in structure and function.
• Somatostatin-expressing (SOM) interneurons are a key inhibitory cell type in the cortex.
• Understanding SOM neuron subpopulations is crucial for deciphering cortical circuitry.

Purpose of the Study:

• To review the functional roles of somatostatin-expressing (SOM) inhibitory interneurons, particularly in the sensory cortex.
• To highlight the heterogeneity and distinct computational roles of SOM neuron subpopulations.
• To explore how SOM neurons are modulated by behavioral states and contribute to learning and memory.

Main Methods:

• Review of existing literature on SOM interneurons.
• Analysis of morphological, connectivity, and molecular characteristics of SOM subpopulations.
• Examination of optogenetic studies investigating SOM neuron function.
• Discussion of disinhibitory circuits involving SOM neurons.

Main Results:

• SOM neurons exhibit diverse subclasses with unique properties like facilitating synapses and specific projections.
• These subclasses are differentially modulated by behavioral states, impacting learning, memory, and task performance.
• SOM neurons participate in distinct disinhibitory circuits, regulating cortical activity based on behavioral relevance.
• Associative learning induces long-term changes in SOM cell connectivity.

Conclusions:

• SOM neurons, despite their heterogeneity, form distinct molecular and functional subclasses.
• These subclasses perform unique neural computations, contributing significantly to sensory processing and cognitive functions.
• SOM neurons are critical regulators of cortical activity and plasticity through disinhibitory mechanisms.