Serotonergic Modulation of Orientation Tuning of Neurons in Primary Visual Cortex of Anesthetized Mice

Introduction: Sensory processing is profoundly regulated by brain neuromodulatory systems. One of the main neuromodulators serotonin which influences higher cognitive functions, such as different aspects perceptual processing. Accordingly, malfunction in serotonergic system may lead to visual illusion psychiatric disorders, autism and schizophrenia. This study aims investigate modulation responses neurons stimulus orientation primary cortex. Methods: Eight-week-old naive mice were anesthetized a craniotomy was done on region interest Spontaneous visual-evoked activities recorded before during electrical stimulation dorsal raphe nucleus using vivo whole-cell patch-clamp recording. The square-wave grating 12 orientations presented. data analyzed Wilcoxon signed-rank test used compare two conditions that belong same neurons, with or without stimulation. Results: changed tuning nearly 60% decreasing mean firing rate independent response components, namely gain baseline response. It also increased small number (about 20%). Additionally, it left preferred sensitivity unchanged. Conclusion: Serotonergic showed bidirectional effect. causes predominately divisive subtractive decreases cortex can modify balance between internal external sensory signals result disorders.