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Separable gain control of ongoing and evoked activity in the visual cortex by serotonergic input
Zohre Azimi1,2, Ruxandra Barzan1,2, Katharina Spoida3
1Optical Imaging Group, Institut für Neuroinformatik, Ruhr University Bochum, Bochum, Germany.
Elife
|April 8, 2020
Summary
Serotonin (5-HT) differentially controls brain activity. 5-HT1A receptors suppress spontaneous activity, while 5-HT2A receptors regulate visual response gain, balancing internal and external signals.
Area of Science:
- Neuroscience
- Computational Neuroscience
- Neuropharmacology
Background:
- Cortical activity gain control is crucial for balancing internal brain communication and external sensory input.
- Serotonergic (5-HT) systems play a key role in modulating neural processing and sensory perception.
Purpose of the Study:
- To investigate the distinct effects of serotonergic input on ongoing and evoked cortical activity.
- To elucidate the specific roles of serotonin 1A (5-HT1A) and serotonin 2A (5-HT2A) receptors in visual cortex gain control.
Main Methods:
- Optogenetic stimulation of the dorsal raphe nucleus (DRN) in mice.
- Wide-field calcium imaging and extracellular recordings in the visual cortex.
- Iontophoresis of serotonin receptor antagonists to assess receptor-specific functions.
Main Results:
- Serotonergic input exerts separable suppressive effects on ongoing and evoked visual activity.
- 5-HT1A receptors mediate divisive suppression of spontaneous neural activity.
- 5-HT2A receptors provide divisive gain control of visual responses, normalizing population activity across contrasts.
Conclusions:
- Serotonin provides balanced yet distinct suppressive modulation of cortical activity, impacting both internal states and sensory processing.
- Imbalances in 5-HT1A/2A receptor activation may alter the balance between internal brain activity and external sensory drive, with implications for neurological conditions.
