Dissociable rhythmic mechanisms enhance memory for conscious and nonconscious perceptual contents.

Understanding the neural mechanisms of conscious and unconscious experience is a major goal of fundamental and translational neuroscience. Here, we target the early visual cortex with a protocol of noninvasive, high-resolution alternating current stimulation while participants performed a delayed target-probe discrimination task and reveal dissociable mechanisms of mnemonic processing for conscious and unconscious perceptual contents. Entraining ß-rhythms in bilateral visual areas preferentially enhanced short-term memory for seen information, whereas α-entrainment in the same region preferentially enhanced short-term memory for unseen information. The short-term memory improvements were frequency-specific and long-lasting. The results add a mechanistic foundation to existing theories of consciousness, call for revisions to these theories, and contribute to the development of nonpharmacological therapeutics for improving visual cortical processing.

Investigations on a polyherbal formulation for treatment of cognitive impairment in a cholinergic dysfunctional rodent model.

Alzheimer's disease is a multifactorial neurodegenerative condition manifested through acute cognitive decline, amyloid plaque deposits and neurofibrillary tangles. Complete cure for this disease remains elusive as the conventional drugs address only a single molecular target while Alzheimer's disease involves a complex interplay of different sets of molecular targets and signaling networks. In this context, the possibility of employing multi-drug combinations to rescue neurons from the dysregulated metabolic changes is being actively investigated. The present work investigates a poly-herbal formulation, Brahmi Nei that has been traditionally used for anxiolytic disorders and immunomodulatory effects, for its efficiency in ameliorating cognitive decline through a combination of behavioral, biochemical, histopathological, gene and protein expression analyses. Our results reveal that the formulation shows excellent neuroregenerative properties, rescues neurons from inflammatory damage, reduces neuritic plaque deposits and improves working memory in rodent models with scopolamine-induced dementia. The microarray analysis shows that the formulation induces the expression of pro-survival pathways and positively modulates genes involved in memory consolidation, axonal growth and proliferation in a concentration-dependent manner with therapeutic concentrations restoring the normal conditions in the brain of the diseased animals. The neuritic spine morphology confirms the long-term memory potentiation through improved mushroom spine density, increased dendritic length and connectivity. Taken together, our study provides mechanistic evidence to prove that the traditional formulation can be a superior therapeutic strategy to treat cognitive decline when compared to the conventional mono-drug treatment.