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Different Underlying Mechanisms (different + underlying_mechanism)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Risk factors predicting onset and persistence of subthreshold expression of bipolar psychopathology among youth from the community

ACTA PSYCHIATRICA SCANDINAVICA, Issue 3 2010
M. J. A. Tijssen
Tijssen MJA, Van Os J, Wittchen HU, Lieb R, Beesdo K, Wichers M. Risk factors predicting onset and persistence of subthreshold expression of bipolar psychopathology among youth from the community Objective:, To examine factors increasing the risk for onset and persistence of subthreshold mania and depression. Method:, In a prospective cohort community study, the association between risk factors [a family history of mood disorders, trauma, substance use, attention-deficit/hyperactivity disorder (ADHD) and temperamental/personality traits] and onset of manic/depressive symptoms was determined in 705 adolescents. The interaction between baseline risk factors and baseline symptoms in predicting 8-year follow-up symptoms was used to model the impact of risk factors on persistence. Results:, Onset of manic symptoms was associated with cannabis use and novelty seeking (NS), but NS predicted a transitory course. Onset of depressive symptoms was associated with a family history of depression. ADHD and harm avoidance (HA) were associated with persistence of depressive symptoms, while trauma and a family history of depression predicted a transitory course. Conclusion:, Different risk factors may operate during onset and persistence of subthreshold mania and depression. The differential associations found for mania and depression dimensions suggest partly different underlying mechanisms. [source]

Something old, something new: a developmental transition from familiarity to novelty preferences with hidden objects

DEVELOPMENTAL SCIENCE, Issue 2 2010
Jeanne L. Shinskey
Novelty seeking is viewed as adaptive, and novelty preferences in infancy predict cognitive performance into adulthood. Yet 7-month-olds prefer familiar stimuli to novel ones when searching for hidden objects, in contrast to their strong novelty preferences with visible objects (Shinskey & Munakata, 2005). According to a graded representations perspective on object knowledge, infants gradually develop stronger object representations through experience, such that representations of familiar objects can be better maintained, supporting greater search than with novel objects. Object representations should strengthen with further development to allow older infants to shift from familiarity to novelty preferences with hidden objects. The current study tested this prediction by presenting 24 11-month-olds with novel and familiar objects that were sometimes visible and sometimes hidden. Unlike 7-month-olds, 11-month-olds showed novelty preferences with both visible and hidden objects. This developmental shift from familiarity to novelty preference with hidden objects parallels one that infants show months earlier with perceptible stimuli, but the two transitions may reflect different underlying mechanisms. The current findings suggest both change and continuity in the adaptive development of object representations and associated cognitive processes. [source]

Isofurans, but not F2 -isoprostanes, are increased in the substantia nigra of patients with Parkinson's disease and with dementia with Lewy body disease

JOURNAL OF NEUROCHEMISTRY, Issue 3 2003
Joshua P. Fessel
Abstract F2 -isoprostanes (F2 -IsoPs) are well-established sensitive and specific markers of oxidative stress in vivo. Isofurans (IsoFs) are also products of lipid peroxidation, but in contrast to F2 -IsoPs, their formation is favored when oxygen tension is increased in vitro or in vivo. Mitochondrial dysfunction in Parkinson's disease (PD) may not only lead to oxidative damage to brain tissue but also potentially result in increased intracellular oxygen tension, thereby influencing relative concentrations of F2 -IsoPs and IsoFs. In this study, we attempted to compare the levels of F2 -IsoPs and IsoFs esterified in phospholipids in the substantia nigra (SN) from patients with PD to those of age-matched controls as well as patients with other neurodegenerative diseases, including dementia with Lewy body disease (DLB), multiple system atrophy (MSA), and Alzheimer's disease (AD). The results demonstrated that IsoFs but not F2 -IsoPs in the SN of patients with PD and DLB were significantly higher than those of controls. Levels of IsoFs and F2 -IsoPs in the SN of patients with MSA and AD were indistinguishable from those of age-matched controls. This preferential increase in IsoFs in the SN of patients with PD or DLB not only indicates a unique mode of oxidant injury in these two diseases but also suggests different underlying mechanisms of dopaminergic neurodegeneration in PD and DLB from those of MSA. [source]

Panic disorder: from respiration to the homeostatic brain

ACTA NEUROPSYCHIATRICA, Issue 2 2004
Giampaolo Perna
There is some experimental evidence to support the existence of a connection between panic and respiration. However, only recent studies investigating the complexity of respiratory physiology have revealed consistent irregularities in respiratory pattern, suggesting that these abnormalities might be a vulnerability factor to panic attacks. The source of the high irregularity observed, together with unpleasant respiratory sensations in patients with panic disorder (PD), is still unclear and different underlying mechanisms might be hypothesized. It could be the result of compensatory responses to abnormal respiratory inputs or an intrinsic deranged activity in the brainstem network shaping the respiratory rhythm. Moreover, since basic physiological functions in the organism are strictly interrelated, with reciprocal modulations and abnormalities in cardiac and balance system function having been described in PD, the respiratory findings might arise from perturbations of these other basic systems or a more general dysfunction of the homeostatic brain. Phylogenetically ancient brain circuits process physiological perceptions/sensations linked to homeostatic functions, such as respiration, and the parabrachial nucleus might filter and integrate interoceptive information from the basic homeostatic functions. These physiological processes take place continuously and subconsciously and only occasionally do they pervade the conscious awareness as ,primal emotions'. Panic attacks could be the expression of primal emotion arising from an abnormal modulation of the respiratory/homeostatic functions. [source]