Fluoxetine and serotonin facilitate attractive-adaptation-induced orientation plasticity in adult cat visual cortex

• Published in: The European journal of neuroscience 2013-07, Vol.38 (1), p.2065-2077
• Main Authors: Bachatene, Lyes, Bharmauria, Vishal, Cattan, Sarah, Molotchnikoff, Stéphane
• Format: Article
• Language: English
• Subjects: adaptation; Adaptation, Physiological; Animals; Biological and medical sciences; Cats; Eye and associated structures. Visual pathways and centers. Vision; fluoxetine; Fluoxetine - pharmacology; Fundamental and applied biological sciences. Psychology; Neuronal Plasticity - drug effects; Neurons - drug effects; Neurons - physiology; plasticity; serotonin; Serotonin - pharmacology; Serotonin Uptake Inhibitors - pharmacology; Vertebrates: nervous system and sense organs; visual cortex; Visual Cortex - cytology; Visual Cortex - drug effects; Visual Cortex - physiology
• ISSN: 0953-816X; 1460-9568
• DOI: 10.1111/ejn.12206

Neurons in V1 display orientation selectivity by responding optimally to a preferred orientation edge when it is presented within their receptive fields. Orientation plasticity in striate cortex occurs either by ocular deprivation or by imposition of a non‐preferred stimulus for several minutes. Adaptation of neurons to a non‐optimal orientation induces shifts of tuning curves towards the adapting orientation (attractive shift) or away from it (repulsive shift). Here, we investigated the effects of the neurotransmitter serotonin and antidepressant fluoxetine (a selective serotonin reuptake inhibitor) on the modulation of adaptation‐induced orientation plasticity. We show that serotonin and fluoxetine promote mostly attractive shifts. Attractive shifts augmented in magnitude towards adapter, whereas repulsive neurons reversed their behavior in the direction of the forced orientation. Furthermore, neurons which retained their original preferred orientation expressed plasticity by shifting their tuning curves after drug administration mostly towards adapter. Our data suggest a pre‐eminent role of fluoxetine by inducing and facilitating short‐term plasticity in V1. Fluoxetine is a widely prescribed drug which is well known for its antidepressant activity by selective inhibition of recapture of serotonin in the brain. Using orientation tuning curve shifts as a model, we show that fluoxetine and serotonin facilitate attractive‐adaptation‐induced‐orientation short‐term plasticity in the primary visual cortex without modulating the firing rate of neurons.