ABSTRACT
In response to a wide-spread decline in forest vitality associated with acid rain in the 1980s, liming of soils has been implemented in many federal states in Germany to buffer further acid deposition and improve availability of nutrients such as calcium and magnesium. As a consequence, it may also increase vitality and depth of fine-root systems and hence improve the drought tolerance of species such as Norway spruce [Picea abies (L.) Karst.], which occurs mostly on acidic forest soils. However, the influence of repeated liming on drought tolerance of trees has never been studied. Here we compared the resistance, recovery and resilience of radial growth in P. abies in relation to drought in limed and control stands and assessed how the dosage and interval between lime application and drought year influences the radial growth response of P. abies. We analyzed radial growth in 198 P. abies trees of six experimental sites in south-west Germany. An analysis of the radial increment over the last 30 years allowed the analysis of drought events shortly after the first liming (short-term effect) as well as posterior drought events (mid- to long-term effects). Generalized linear models were developed to assess the influence of drought intensity, site and period since first liming on the drought tolerance of Norway spruce. Regardless of drought intensity, there was no general increase in drought resistance of Norway spruce in response to liming. However, drought resistance of radial growth improved on a loamy site that was additionally treated with wood ash 30 years after the first lime application. Furthermore, recovery and resilience of radial growth after severe drought events were generally better in spruce trees of limed treatments. This indicates a shorter stress period in spruce trees growing on limed soil, which may reduce their susceptibility to secondary, drought-related pests and pathogens.
ABSTRACT
Studies of schizophrenia with functional MRI have shown hyper- and hypoactivations in various brain regions including the prefrontal cortex. Functional anomalies have also been reported in first-degree relatives of schizophrenic patients. The aim of this study was to examine working memory related brain functions in healthy subjects, schizophrenic patients and unaffected relatives and to determine the influence of psychopathology on these processes. A parametric n-back working memory task and functional MRI were used to examine 61 patients with schizophrenia, 11 nonpsychotic relatives of schizophrenic patients and a comparison group of 61 healthy subjects. The results indicated increased as well as decreased brain functions in schizophrenic patients compared to the control group depending on the task difficulty and the performance: during the attention task (0-back), which served as control condition, behavioral responses of patients and healthy subjects hardly differed but BOLD responses were considerably enhanced in schizophrenic patients. With increasing task difficulty differences between groups in BOLD responses diminished whereas behavioral deficits of patients increased. The examination of attention-independent working memory-functions (2- vs. 0-back) produced hypoactivations in patients, especially in frontal, temporal and subcortical brain regions. Furthermore, positive symptoms were associated with parietal dysfunctions. Behavioral performance and neural responses of unaffected relatives of schizophrenic patients were intermediate between schizophrenic patients and controls indicating slight brain dysfunctions. In addition, compensatory strategies were demonstrated. These findings suggest that the genetic risk for schizophrenia is accompanied by neural inefficiency which is associated with cognitive deficits, especially in difficult tasks.
Subject(s)
Brain Mapping , Brain/physiopathology , Memory, Short-Term/physiology , Schizophrenia/pathology , Schizophrenic Psychology , Adult , Analysis of Variance , Attention/physiology , Brain/blood supply , Family , Female , Humans , Image Processing, Computer-Assisted/methods , Magnetic Resonance Imaging/methods , Male , Middle Aged , Neuropsychological Tests , Oxygen/blood , Psychiatric Status Rating Scales , Schizophrenia/genetics , Schizophrenia/physiopathologyABSTRACT
OBJECTIVE: The profile of psychiatric patients, who write within the online discussion forum of the German Research Network on Depression and Suicidality, is described. The question of which diagnoses are predominant among the forum members and the question of their treatment status shall be answered. Furthermore, the effects of participation in the forum on individual handling of the illness are examined. METHODS: 55 active users were interviewed by telephone using a computer-assisted version of a fully structured psychiatric interview (DIA-X) and online with the Beck Depression Inventory (BDI). Moreover, their treatment status and their motivation to use the online forum were asked for. RESULTS: 52 study participants (94.5%) received the diagnosis depression. Currently, 36.5% of the respondents suffer from a depressive episode. Frequent comorbid disorders are phobic disorders and somatoform disorders. 90.2% received outpatient treatment before, 64.7% inpatient treatment. In the year before this study started, 78.2% of participants were treated by a psychiatrist / neurologist and 63.6% by a psychological psychotherapist. By participating in the online discussion forum, the respondents expect to receive information about the disorder, support in coping with depressive symptoms as well as an exchange with other affected persons and their relatives. The respondents stated that their trust in medical treatment was raised (63.3%) and that they were encouraged to seek professional help (61.2%). Furthermore, 32.7% of the interviewed participants rated their attitudes towards the treatment with medication more positive than before being a member in the discussion forum. CONCLUSIONS: The forum reaches its targets and the users do not see it as an alternative, but rather as a supplement to professional and psychological care. By participating in the forum, aspects of self-help, especially a strengthened sense of community and acceptance of and coping with the own illness-related situation can be accomplished.
