Rev Neuroscience
-
Cholinergic signaling mediated by nicotinic receptors has been associated to a large number of physiological and behavioral processes such as learning, memory, attention, food-intake and mood disorders. Although it is well established that many nicotinic actions are mediated through an increase in serotonin (5-HT) release, the physiological mechanisms by which nicotine produces these effects are still unclear. The dorsal raphe nucleus (DRN) contains the major amount of 5-HT neurons projecting to different parts of the brain. ⋯ We also describe the inhibitory effects of nicotine and the role of 5-HT1A receptors in this effect. These nicotinic actions modulate the activity of different neuronal subpopulations in the DRN, changing the 5-HT tone in the brain areas where these groups of neurons project. Some of the physiological implications of nicotine-induced 5-HT release are discussed.
-
In recent years, researchers have embarked on a search of computer-aided methods for diagnosis of the Alzheimer's disease (AD) to help clinicians make the diagnosis earlier and more accurately such that treatment of the disease can begin sooner when there is a higher chance of success in slowing down the progression of this disease. This article presents a review of journal articles on brain signal- and image-based diagnosis of AD published in the past few years. The areas of signal processing, electroencephalogram and magnetoencephalogram are considered. ⋯ Computer-aided early diagnosis of the AD would be a major breakthrough with a very significant worldwide impact because medications would be able to slow down the progression of the disease. This review shows that this is a very active area in the frontier of brain research, with many multidisciplinary researchers exploring a variety of approaches using various types of brain signals and imaging technologies. The brain signal-based approaches will be able to point toward early onset diagnosis of the AD, but as the disease progresses, a multimodal approach can increase the accuracy of the diagnosis.
-
Migraine is the most common neurologic condition. One-third of migraineurs experience transient neurologic symptoms, the so-called aura. There is strong evidence that spreading depression (SD) is the electrophysiologic substrate of migraine aura. ⋯ S218L mice display additional signs such as seizures and coma when SD propagates into hippocampus and thalamus. In hyperexcitable FHM brains, SD may propagate between cortex and subcortical structures via permissive gray matter bridges, or originate de novo in subcortical structures, to explain unusual and severe aura signs and symptoms. Reciprocal spread and reverberating waves can explain protracted attacks.