Fluoxetine‐induced plasticity in the visual cortex outlasts the duration of the naturally occurring critical period

Abstract

Heightened neuronal plasticity expressed during early postnatal life has been thought to permanently decline once critical periods have ended. For example, monocular deprivation is able to shift ocular dominance in the mouse visual cortex during the first months of life, but this effect is lost later in life. However, various treatments, such as the antidepressant fluoxetine, can reactivate a critical period‐like plasticity in the adult brain. When monocular deprivation is supplemented with chronic fluoxetine administration, a major shift in ocular dominance is produced after the critical period has ended. In the current study, we characterized the temporal patterns of fluoxetine‐induced plasticity in the adult mouse visual cortex, using in vivo optical imaging. We found that artificially induced plasticity in ocular dominance extended beyond the duration of the naturally occurring critical period and continued as long as fluoxetine was administered. However, this fluoxetine‐induced plasticity period ended as soon as the drug was not given. These features of antidepressant‐induced plasticity may be useful when designing treatment strategies involving long‐term antidepressant treatment in humans.

Chronic fluoxetine treatment impairs motivation and reward learning by affecting neuronal plasticity in the central amygdala

“…On the other hand, fluoxetine treatment has been shown to induce neuronal plasticity and to alleviate impairments of certain types of learning, which can, at least partially, explain its therapeutic effects (Ampuero et al, 2019;Eavri et al, 2018;Levy et al, 2019;Maya Vetencourt et al, 2008;Ohira, Hagihara, Miwa, Nakamura, & Miyakawa, 2019;Rossi, 2016;Steinzeig, Cannarozzo, & Castrén, 2019;Sun et al, 2017). Markedly, some animal studies showed that the drug reverses anhedonia induced by stress as severe as that stemming from repeated social defeat and boosts performance in highly complex cognitive tasks performed with the use of automated behavioural assays (Gottschalk et al, 2018;Marwari & Dawe, 2018).…”

Facilitation of TRKB Activation by the Angiotensin II Receptor Type-2 (AT2R) Agonist C21

“…However, the evidence of a direct effect from AT2R agonists on behavior and BDNF/TRKB signaling remains limited. Therefore, understanding the functional interaction between AT2R and BDNF/TRKB signaling may facilitate development of new AT2R agonists able to reinstate plasticity in the adult brain, as described for classical antidepressants [ 17 , 20 , 21 ].…”

Binocular vs. monocular recovery experience differentially promote recovery from visual deficits in a mouse model of amblyopia

“…Many factors can affect the degree of ODP initiated by MD in animal models of amblyopia, including behavioral state (35,44,45), and neuropharmacology (10,(46)(47)(48), and emerging data suggests that these factors may also affect recovery from amblyopia (47,49,50). However, recent findings have raised debate about whether dominant-eye patching, the decades-long standard of care for amblyopia, provides the optimal sensory stimulus for promoting recovery of vision (18,22,51,52).…”