Brain system

The evidence outlined so far does little to explain how monoamines or anti-anxiety drugs might influence anxiety states. To achieve this, an integrated view of the relevant brain systems is required, together with an appreciation of how their function is regulated. 

Ultrasonic vocalizations are emitted by rat pups (under the age of 14 days) when they are isolated from their mother, and are thought to reflect anxiety. This measure has proven sensitive to both anxiolytic and anxiogenic manipulation of GABA neurotransmission. However, the early developmental window used is problematic, in that chronic drug administration probably results in a variety of compensatory changes not seen in adulthood, and may alter development of relevant brain systems. Indeed, in contrast to the clinical situation, the antidepressant clomipramine has acute, but not chronic, anxiolytic efficacy in this model. 

McGaugh JL, McIntyre CK, Power AE. 2002. Amygdala modulation of memory consolidation interaction with other brain systems. Neurobiology of Learning Memory... 

Stimulants. Methylphenidate (Ritalin) and dextroamphetamine (Dexedrine) are the most widely used and perhaps the most effective medications when treating post-TBI apathy. They act by enhancing the activity of dopaminergic, noradrenergic and, to a certain extent, serotonergic brain systems. Stimulants act quickly to relieve the core symptoms of apathy, and they may also improve the impairments in attention and short-term memory that often follow TBl. Please refer to Chapter 8 for more information about the stimulants. 

Ashton, H. (1987). Brain systems, disorders and psychotrophic drugs. Oxford, Oxford University Press. 

A number of recently developed F-radiopharmaceuticals have great potential for the study of several brain systems of clinical importance in AD. These radiotracers will facilitate the exploration of patients with PET as they can be shipped to several satellite centers that rely on supply of radiopharmaceuticals from distributors. 

BRAIN SYSTEMS IN EARLY-ONSET ANXIETY DISORDER... 

Heim, C. and Nemeroff, C.B. (1999) The impact of early adverse experiences on brain systems involved in the pathophysiology of anxiety and affective disorders. Biol Psychiatry 46 1509-1522. 

BRAIN SYSTEMS IMPLICATED IN AGGRESSION Anatomic Evidence... 

The third part. Developmental Psychopathology, delves into detailed disease-specific overviews. Each of the chapters covers issues pertaining to nosology and classification, to genetic determinants, brain systems implicated, environmental influences, and nature-nurture interactions. Neurotransmission and neuromodulation, and hormonal and other developmental influences are addressed and, whenever available, relevant animal models are incorporated into the discussion. The interplay of normative and derailed development is a core concept for these chapters. Of the part s 12 chapters, 9 are devoted to traditionally defined disease categories, and 3 cover the overarching areas of early-life stress, aggression, and affiliative behaviors. 

It is likely that depression and anxiety disorders are associated with problems in several brain systems, and, indeed, different drugs appear to be effective in different people. Even though SSRIs are currently the first choice of drugs for treating many anxiety disorders, other classes of antidepressants are tried if the SSRIs prove ineffective. 

Barkai et al. (1978) reported that cerebrospinal fluid levels of inositol were lower in patients with depression than in psychiatrically healthy subjects. We hypothesized that inositol may be deficient in some brain systems in depression. This does not contradict the concept that Li reduces inositol levels and that Li" is an antidepressant, because the PI cycle serves as a second messenger for several balancing and mutually interactive neurotransmitters. Li+ could alleviate depression by reducing inositol and a primary hyperactivity of one hypothetical brain system low inositol levels in another system could cause second messenger dysfunction and thereby depression. 

The three kinds of disease process we have surveyed in this chapter are the natural analogues of experimental probes of the brain systems that normally alter brain states in animals. Not surprisingly, they alter consciousness in informative ways in humans. Strokes are the equivalent of electrolytic and excitatory neurotoxic lesions seizures are the equivalent of direct electrical and chemical stimulation alcohol is the equivalent of parenteral drug administration. In reading across the three disease classes in search of unifying concepts, I hope to stimulate a new era of experimental work in animals, as well as to celebrate what we have accomplished in the arena of human neuropsychology. 

Ecstasy affects a number of body systems. The effects of ecstasy on the brain system are what lead to both the desired and undesired mental effects of the drug. Within the brain, there are different groups of chemical messengers called neurotransmitters that are responsible for the communication within the brain and between the brain and the body. Neurotransmitters flow... 

In summary, the above evidence supports my hypothesis that neonatal REM sleep may increase the release of 5-HT and neurotrophic factors and may facilitate the development of multiple brain systems through the increase of 5-HT and neurotrophic factors. However, this hypothesis needs to be empirically tested. 

The chronic effects of abused drugs include tolerance and sensitization as well as the neurobiologic substrates for withdrawal symptoms. Much has been learned about these neurobiologic substrates for withdrawal in opioid dependence, including the activation of adrenergic brain systems such as the locus ceruleus during withdrawal. The latter findings have important treatment implications, such as the use of clonidine for opioid withdrawal. 

Lopes da Silva, F., Blanes, W., Kalitzin, S.N., Parra, J., Suffczynski, P., and Velis, D.N. Epilepsies as dynamical diseases of brain systems basic models of the transition between normal and epileptic activity. Epilepsia 2003,44[Suppl 12] 72 83. 

In this chapter, we look at the way in which the brain systems mediating dreaming can become exaggerated or distorted, with unwelcome consequences. Here, we are on the edge of the medicine of sleep disorders, a topic of great interest to modern sleep science. 

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