In addition to a gradual loss of neurons in various brain regions, major biochemical changes in the brain affect the neuronal membrane that is the "site of action" for many essential functions including long-term potentiation (LTP), learning and memory, sleep, pain threshold, and thermoregulation. Normal physiological functioning includes the transmission of axonal information, regulation of membrane-bound enzymes, control of ionic channels and various receptors. All are highly dependent on membrane fluidity, where rigidity is increased during aging. The significantly higher level of cholesterol in aging neuronal membrane, the slow rate of cholesterol turnover, and the decreased level of total polyunsaturated fatty acids (PUFA) may result from poor passage rate via the blood-brain barrier, or from a decreased rate of incorporation into the membrane, or a decrease in the activities of delta-6 and delta-9 desaturase enzymes. The added oxidative stress, which leads to an increase of free radicals leading to a decrease in membrane fluidity, may respond to a restricted diet, and thereby overcome the damaging effects of the free radicals. A central focus of this review is that a specific ratio of n-3/n-6 PUFA can restore many of these age-related effects.

Major advances have been made in understanding the biochemistry of essential fatty acids (FA) and their interactions with metabolic pathways leading to the production of longer and more complex fatty acids and lipids. Less understood are the roles played by FA which are known to affect neurotransmitters, peptides, releasing factors, hormones, and a variety of physiological and cognitive processes. Based on empirical findings we propose that (a) FA exert a controlling function in the modulation of neuronal membrane fluidity, and (b) the critical factor in FA action and efficacy is not absolute level but rather the ratio between various groups of FA. This approach unifies the biochemical and cognitive results obtained from many different and unrelated fields of research.

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If residents cannot to be interviewed about their LS, then the parent is the preferred person to respond on behalf of the resident. The current study highlights the importance of including both objective measures (e.g. functional assessment characteristics) and subjective measures (e.g. LS) in order to get a better understanding of the QoL of people with ID.

Test anxiety is an incapacitating academic syndrome. This study shows that administration of a polyunsaturated fatty acid mixture of omega-3 and -6 can improve the behavioral variables associated with this type of anxiety, i.e. appetite, mood, mental concentration, fatigue, academic organization and poor sleep, as well as lowering elevated cortisol level, with a corresponding reduction of anxiety.