Alpha-band EEG suppression as a neural marker of sustained attentional engagement to conditioned threat stimuli.

Attention helps us to be aware of the external world, and this may be especially important when a threat stimulus predicts an aversive outcome. Electroencephalogram (EEG) alpha-band suppression has long been considered as a neural signature of attentional engagement. The present study was designed to test whether attentional engagement, as indexed by alpha-band suppression, is increased in a sustained manner following a conditioned stimulus (CS) that is paired with an aversive (CS+) vs neutral (CS-) outcome.

Lateralized Suppression of Alpha-Band EEG Activity As a Mechanism of Target Processing.

Alpha-band (8-12 Hz) EEG activity has been linked to visual attention since the earliest EEG studies. More recent studies using spatial cuing paradigms have shown that alpha is suppressed over the hemisphere contralateral to a to-be-attended location, suggesting that alpha serves as a mechanism of preparatory attention. Here, we demonstrate that alpha also plays a role in active target processing.

Event-related potential components as measures of aversive conditioning in humans.

For more than 60 years, the gold standard for assessing aversive conditioning in humans has been the skin conductance response (SCR), which arises from the activation of the peripheral nervous system. Although the SCR has been proven useful, it has some properties that impact the kinds of questions it can be used to answer. In particular, the SCR is slow, reaching a peak 4-5 s after stimulus onset, and it decreases in amplitude after a few trials (habituation).

The allocation of attention and working memory in visual crowding.

When the distance between a visual target and nearby flankers falls below a critical distance, target discrimination declines precipitously. This is called "crowding." Many researchers have proposed that selective attention plays a role in crowding.

The debate about death: an imperishable discussion?

In this concise review we discuss some of the complex edges of the concept of death that arose after the notorious advances in science and medicine over the last 50 years, in which the classical cardio-pulmonary criteria have led to the neurological criteria of death. New complicated questions like the definition of death and the operational criteria for diagnosing it have arisen and we think that they are far from being adequately and satisfactorily solved. A number of important issues--like the reliability and differences between cardio-pulmonary versus brain based criteria of death, if death is an event or a process, the meaning of integration and irreversibility--have not yet received sufficient attention.

[Attention deficit hyperactivity disorder in adults].

The attention deficit hyperactivity disorder (ADHD) is the most common diagnosis in child psychiatry, and persists very often in adulthood. These patients have poor lifestyles, especially in affective, work and social areas. Although patients with ADHD have a high rate of comorbidity (e.

Single photon emission computed tomography with technetium-99m hexamethyl propylenamino oxime in the clinical assessment of cerebral ischemia. A preliminary evaluation.

94 subjects, 64 with cerebral ischemia of varying severity and outcome, and 30 controls were studied with technetium-99m hexamethyl propylenamino oxime single photon emission computed tomography in order to evaluate the suitability of this technique in the assessment of cerebral ischemia. Decreased uptake corresponding to the side of clinical symptomatology and/or to CT lesion was found in 93% of the patients with complete stroke and in 28% of the patients with transient ischemic attack. This procedure can be a useful tool in the routine examination of ischemic patients, although the mechanism underlying brain uptake is far from being completely understood and the possible quantitative evaluation of regional cerebral blood flow is worthy of further assessment.

[Late degeneration of spinal motor neurons in patients with previous poliomyelitis].

The Authors describe 5 cases of "motor neuron disease" in patients who had suffered from an acute episode of poliomyelitis. The literature and the fundamental pathogenetic theories have been reviewed.

[Enlargement of the cerebral ventricles and cognitive efficiency in chronic schizophrenia].

The cerebral ventricular size of 15 patients with chronic schizophrenia and 20 age and sex matched controls, has been measured on the basis of the TC scan examination. The schizophrenic patients underwent also a psychometric evaluation by means the WAIS and PM 38 tests. The ventricular size was larger in patients than in normal controls.

[Transitory global amnesia].

The authors studied 18 cases of transient global amnesia, a syndrome occurring in middle age, characterized by a sudden memory loss of recent events and transient inability to acquire new knowledge, while consciousness and personal identity are preserved. Chemical and laboratory findings indicates that TGA is probably due to transient ischemia in the temporal lobe and hippocampus.

[Huntington chorea. Review of the most recent aspects of research].

The authors are presenting a review concerning the most visible aspects of the research directed to emphasize that Huntington's Chorea cannot be compared, either clinically or pathologically, to Parkinson's Disease. It is a hereditary disease in which we can discern an alteration of some neurotransmitters, neuromodulators, neurohormones that are not necessarily opposite in respect to pathophysiological findings of Parkinson disease.

[Effect of fenfluramine in Huntington Chorea].

Serotoninergic function has been evaluated in 15 H.C. patients.