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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A number of measures of brain function have suggested that depression is associated with cerebral hypoactivity. This study examines the late components of the event-related potential (ERP), in particular the P300 component, in depression. The P300 component is thought to index the updating of neurocognitive models which are concerned with the prediction of future events. Cognitive theories of depression include the proposition that depression may be characterized by abnormalities in the prediction of future events. The P300 component may therefore provide one neurophysiological index of cognitive dysfunction in depression. Twenty-seven subjects (14 medicated, 13 drug-free) fulfilling DSM-III criteria for Major Depression were compared to 27 age- and sex-matched normal controls. The amplitudes and latencies of N100, P200, N200 and P300 ERP components, reaction time and task accuracy were recorded during a standard auditory discrimination task. No significant differences were found in any ERP component measure or in reaction-time between the groups. Depressed subjects performed the experimental task significantly less accurately than normal controls, but this was not reflected in the ERPs.
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PMID:The P300 ERP component: an index of cognitive dysfunction in depression? 804 58

Using a dual-task paradigm with an oddball secondary task, P300 amplitude and latency were studied as a function of factorially manipulated oddball probability (low = .22, high = .44) and primary task type. In addition to a Baseline condition (oddball task only), three primary tasks were used: (1) Pure Sensory; watching a movie; (2) Pure Motor (manipulating a flashlight); and (3) Sensory/Motor (using the flashlight to trace the outlines of characters in a movie). The findings included the usual significant effects of probability on amplitude. There was also a significant effect of task type on amplitude, and a significant interaction of oddball probability with task type. In the low but not high probability condition, a pure Sensory task depressed P300 amplitude. In both probability conditions, the Sensory/motor task depressed P300 amplitude. Only task type had a significant effect on P300 latency. The results confirm the ability of other labs (using Sensory/motor primary tasks) to demonstrate P300 depression at high oddball probability, in view of the difficulty in our lab of achieving P300 depression with pure sensory tasks and high oddball probabilities. The results are discussed in terms of partial overlap of processing resource pools.
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PMID:Interaction of oddball probability and primary task type on P300 in the dual-task paradigm. 816 61

P300 event related potential (ERP) was recorded using the auditory 'oddball' paradigm in 17 melancholic, drug-free depressive patients and 22 normal controls. Repeat ERP recordings were obtained from 13 patients after recovery with ECT. Pretreatment P300 latencies were not different between patients and controls, nor did they change in the depressives following recovery. Pretreatment P300 amplitudes in depressives were smaller (P < 0.02) than in controls and negatively correlated with severity (P < 0.05). P300 amplitudes significantly increased in patients following recovery (P < 0.05) and normalized. P300 may be a state marker for melancholic depression.
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PMID:P300 amplitude in non-bipolar, melancholic depression. 832 81

In rats lesioned by injecting the ibotenic acid (8 micrograms/site) into the unilateral nucleus basalis magnocellularis (NBM), the effect of treatment with bifemelane hydrochloride (BIF) or autotransplantation of the vagal nodosal ganglion was studied electrophysiologically by serial measurement of the event-related potential (ERP, P300) for 4 weeks. In addition, the effects on cholinergic markers were assessed by determining the specific binding of [3H]QNB (quinuclidinyl benzilate) to the muscarinic acetylcholine receptor (mAChR) as well as the activity of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE). The P300 latency was delayed and its amplitude remained low for 4 weeks in NBM-lesioned rats. In contrast, a return to normal occurred after 2-3 weeks in rats given daily intraperitoneal injections of BIF (15 mg/kg) and in autotransplanted rats. In lesioned rats, the cortical ChAT and AChE activities on the affected side did not recover, but the postsynaptic receptor response was transiently activated soon after lesioning. BIF increased specific mAChR binding (an early increase of affinity and a subsequent increase of receptor density) as well as presynaptic ChAT activity. Transplantation achieved the early activation of mAChR binding (increased receptor density) and continuously increased ChAT activity. Thus, the postsynaptic compensatory receptor mechanism of denervation supersensitivity acted as an early response to the depression of presynaptic cholinergic activity, but it could not improve the P300 response until the subsequent increase of cortical ChAT activity. Improvement of P300 combined with cortical cholinergic recovery after nodosal ganglion grafting or administration of BIF suggests that the neocortical ACh level may play an important role in regulating ERP.
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PMID:Effect of vagal autotransplantation and bifemelane hydrochloride on cholinergic markers and event-related potentials in rats with lesions of the nucleus basalis magnocellularis. 854 4

Twenty-two patients with Parkinson's disease (PD) were studied by clinical evaluation, assessments of dementia and depression, as well as electrophysiologic examinations for blink reflex (BR), cortical somatosensory evoked potentials (CSEP), brain stem, and long-latency auditory evoked potentials (BAEP, and LAEP), and cerebrospinal fluid (CSF) assays for monoamine metabolites. Results show that PD patients have a significant decrease of Mini-Mental State Examination (MMSE) scores (p < 0.05) and an increase of Hamilton Depression Scale (HDS) scores (p < 0.01), as well as a longer latencies of R2 in BR, N19 and P22 in CSEP, W4 and W5 in BAEP and P300 in LAEP (p < 0.01), and lower CSF levels of HVA and MHPG (p < 0.05). The findings suggest a correlation between dementia/depression and mesocorticolimbic and mesostriatocortic dysfunction with dopaminergic and noradrenergic deficiencies in PD patients. Furthermore, parkinsonian dementia parallels the length of duration of the disease, but not the severity of motor disability. Parkinsonian depression parallels both the length of duration of the disease and the severity of motor disability.
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PMID:Studies of dementia, depression, electrophysiology and cerebrospinal fluid monoamine metabolites in patients with Parkinson's disease. 858 35

P300 and contingent negative variation (CNV) were recorded in depressive inpatients with and without history of suicide attempt. The results showed a significant reduction of P200, P300, and CNV and a significant increase of postimperative negative variation (PINV) in patients who had attempted suicide compared to patients with a negative history. Moreover, P300 amplitude was negatively related with the Suicidal Risk and the Hopelessness but not with the Hamilton scales. These results stress the need to differentiate clinical subgroups of patients to assess the psychophysiology of depression, and indicate that patients who attempted suicide exhibit lower cortical resources and poorer cortical performance than patients without history of suicide attempt.
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PMID:Suicidal behavior in depressive disorder: an event-related potential study. 879 43

In large families with affective illness, identification of a biological variable is needed that reflects brain dysfunction at an earlier point than symptom development. Eye movement disorder, a possible vulnerability marker in schizophrenia, is less clearly associated with affective illness, although a subgroup of affective disorders shows smooth-pursuit eye movement disorder. The auditory P300 event-related potential may be a useful marker for risk to schizophrenia, but a role in bipolar illness is less certain. The distribution of these two biological variables and their association with symptoms in two multiply affected bipolar families is described. In a single, five-generation family identified for linkage studies through two bipolar I (BPI) probands, 128 members (including 20 spouses) were interviewed. The 108 related individuals had diagnoses of BPI (7), bipolar II (2), cyclothymia (3), or major depressive disorder (19). Eight others had generalised anxiety (1), minor depression (5), intermittent depression (1), or alcoholism (1). Sixty-nine subjects had no psychiatric diagnosis. P300 latency (81) and eye tracking (71) were recorded from a subgroup of relatives within the pedigree. Eye tracking was abnormal in 11 of 71 relatives (15.5%) and was bimodally distributed. In these 11 relatives, clinical diagnoses included minor depression (1), alcoholism (1) and generalised anxiety disorder (1). P300 latency was normally distributed and did not differ from controls. In a second family in which five of seven siblings have BPI illness, P300 latency and eye movement disorder were found in affected relatives and in some unaffected offspring. In these large families, clinical diagnoses of general anxiety, alcoholism and minor depression, when associated with eye tracking abnormality, may be considered alternative clinical manifestations of the same trait that in other relatives is expressed as bipolar illness.
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PMID:Implications of comorbidity for genetic studies of bipolar disorder: P300 and eye tracking as biological markers for illness. 886 53

The aim of the present paper was to perform a single trial analysis of event-related potentials in order to elucidate the mechanisms behind a reduced P300 amplitude occurring in unmedicated depressives (n = 11) and schizophrenics (n = 18). For this purpose, tools from linear system theory were applied to single trials in an oddball paradigm. This analysis provides estimates of the magnitude of the positive deflection occurring around the latency of P300 following target and nontarget simuli. According to the density functions of these amplitude distributions, we operationally defined "false-negative" (P300 amplitude lower than an individual threshold under target conditions) as well as "false-positive" responses (P300 amplitude higher than the threshold following nontarget stimuli). Our investigations revealed a reduction of the single-trial P300 amplitude in depression and a combination of amplitude reduction along with fewer elicited single-trial P300 waves in schizophrenics.
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PMID:Single trial analysis of event related potentials: a comparison between schizophrenics and depressives. 889 70

Forty-three patients with Parkinson's disease (PD) and thirty-seven normal volunteers were subjected to clinical, neuropsychological, neurophysiological (P300 component of the event-related potentials ERP) and radiological (cranial computerized tomographic scanning CCT) evaluation. Intentional memory was more impaired in PD than in normal controls, more so in the demented group of patients, and was related to enlargement of third ventricular size in CCT. While intentional memory was age related in PD patients, perception was age-related in normal controls. Neither global nor specific cognitive functions were related to duration, severity of parkinsonian motor disability, or depression. However, depression in PD was significantly related to parkinsonian motor disability. P300 latency was more prolonged in PD patients than normal controls. P300 parameters of PD patients were not influenced by age, cognitive functions, duration or severity of motor disability, or depression. The reaction time was the only P300 parameter that was age-related in normal controls. Subcortical atrophy as indicated by CCT was more marked in PD and correlated with age in both patients and controls. Subcortical atrophy was significantly related to cognitive functions in PD but not in normal controls. It was concluded that cognitive impairment in PD could be attributed to complex cognitive changes rather than age. It is a disease process, though not directly related to parkinsonian motor disability or depression. PD differed from normal aging as regards the effect of age on the specific cognitive functions, where in PD patients, age was related to intentional memory, yet in normal controls, it was related to perception. Intentional memory deterioration was found to be specific of PD, being related to subcortical atrophy as well as being more pronounced in the demented group of patients.
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PMID:Parkinson's disease, cognition and aging. Clinical, neuropsychological, electrophysiological and cranial computerized tomographic assessment. 898

In the past it was reported in several studies that both depressive and schizophrenic patients exhibit reduced P300 amplitudes compared to healthy controls. In order to elucidate the underlying mechanisms of spectral P300 generation, we analysed P300 responses in depression and schizophrenia by a frequency based approach. Herefore, the amplification (poststimulus/prestimulus) of spectral power in different frequency bands was evaluated for non-target and target epochs. Generally, we found that P300 responses are accompanied by a pronounced frequency amplification in the delta and theta range. For the depressive patients we detected only under target condition a statistically significant reduction of alpha and gamma amplification compared to controls. In contrast to this, we observed a highly significant reduction of delta amplification in schizophrenic patients, under both target and non-target conditions.
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PMID:Spectral analysis of P300 generation in depression and schizophrenia. 909 3


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