The PFC is richly supplied with serotonergic (5‐HT) neurons and previous studies have reported age‐related reductions of 5‐HT receptor density, ligand affinity, and binding potential in this region. These vulnerabilities most likely all contribute to executive alterations in aging however, the contribution of neurotransmitter depletion is poorly understood.
In fact, the fronto‐striatal brain regions mediating these executive functions are more susceptible to age‐related structural alterations and neurotransmitter depletion than many other regions of brain. Studies consistently report that aging is associated with a decline in several functions modulated by the PFC, including executive functions like working memory, set shifting, and inhibitory control. The prefrontal cortex (PFC) has been one of the main areas of focus for understanding normal age‐related cognitive decline.
Neural adaptation to serotonin challenge during cognitive control may prove useful in determining cognitive vulnerability in older adults with a predisposition for serontonergic down‐regulation (e.g., in vascular or late life depression). Thus, serotonin modulates an anterior‐to‐posterior shift of activation during cognitive switching in older adults. The posterior (increased) activation clusters significantly and negatively correlated with the reduced prefrontal activation clusters suggesting a compensation mechanism for reduced prefrontal activation during ATD. In addition to the main effects of depletion condition, a comparison of the ATD relative to the sham condition confirmed this anterior‐to‐posterior shift in activation. In contrast, following ATD participants activated posterior regions of brain more during switch than repeat trials. During sham depletion women significantly activated the expected task‐relevant brain regions associated with the Switch task including prefrontal and anterior cingulate cortices. It did modulate brain functional recruitment. ATD did not significantly affect task performance. Ten healthy women over 55 years were tested on two separate occasions in this within‐group double‐blind sham‐controlled crossover study to compare behavioral and physiological brain functioning following ATD and following a (“placebo”) sham depletion condition. We investigated the modulatory effect of serotonin using acute tryptophan depletion (ATD) during a cognitive switching task involving visual‐spatial set shifting modified for a functional MRI environment. The neurochemical basis to this is poorly understood, but may include the serotonergic system. Remember, only a real Gibson is good enough.Studies have long reported that aging is associated with declines in several functions modulated by the prefrontal cortex, including executive functions like working memory, set shifting, and inhibitory control. At Gibson Brands, Inc., we care about our consumers, our legacy, and our name. We strongly urge all consumers to be careful and aware of this worldwide problem. Guitar Customer Service at 1-80 for any inquiries or advice. The best way for consumers to protect themselves against fraud is to purchase your guitar from an authorized dealer, or consult one in advance. If a guitar is being sold for a fraction of what it would typically sell for, it is likely not a real Gibson Brands, Inc. We would like to urge all our consumers not to be taken in by the works of dishonest sellers. The makers and sellers of counterfeits are scamming our global family of musicians and Gibson Brands, Inc. We continue to hear complaints from consumers and fans who have purchased one of these guitars from websites and auction sites thinking they were getting an authentic instrument. These low-budget, inferior guitars are pale imitations of the quality, performance, and craftsmanship of authentic originals. takes a firm and aggressive stance against all makers of counterfeit guitars and their distribution channels. In our constant effort to stand by our consumers, protect them, and bring them the finest products in the world, Gibson Brands, Inc. Click here to send a message to customer service.
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