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Increase in periventricular white matter hyperintensities parallels decline in mental processing speed in a non-demented elderly population.

OBJECTIVE: To investigate the influence of deep white matter hyperintensities (DWMH) and periventricular white matter hyperintensities (PVWMH) on progression of cognitive decline in non-demented elderly people. METHODS: All data come from the nested MRI sub-study of the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER). We performed a 3 year follow up study on 554 subjects of the PROSPER study using both repeated magnetic resonance imaging and cognitive testing. Cognitive decline and its dependency on WMH severity was assessed using linear regression models adjusted for sex, age, education, treatment group, and test version when applicable. RESULTS: We found that the volume of PVWMH at baseline was longitudinally associated with reduced mental processing speed (p = 0.0075). In addition, we found that the progression in PVWMH volume paralleled the decline in mental processing speed (p = 0.024). In contrast, neither presence nor progression of DWMH was associated with change in performance on any of the cognitive tests. CONCLUSION: PVWMH should not be considered benign but probably underlie impairment in cognitive processing speed.

Aged↗

EEG changes induced by carbamazepine therapy at rest and during mental processes.

The effects of carbamazepine (CBZ) on EEG background activity have been studied, at rest and during mental processes, in 18 epileptic patients suffering from focal epilepsy and starting antiepileptic treatment for the first time. The EEGs were recorded before and after CBZ therapy, at rest with eyes closed (EC), during blocking reaction (BR), fixation (FIX) and mental arithmetic (MA) tasks, and then evaluated by spectral analysis. All data underwent statistical evaluation utilizing the ANOVA and correlation coefficient. The following parameters were evaluated: mean absolute and relative power and mean frequency. The results have shown that CBZ induced a significant increase of slow activity at rest with EC, which was represented by delta potentials, and was correlated with CBZ plasma levels. In evaluating the different cortical activation patterns, a decrease of the alpha reactivity was noted during BR and FIX, while a significant increase of beta activity was observed during the performance of all tasks. The relationship between the increased beta power, possibly reflecting an increase of cognitive activity for processing information, and the lack of a significant decrease of alpha activity are discussed.

Adolescent↗

Cerebral blood flow and mental processes in schizophrenia.

The patterns of cerebral blood flow associated with three syndromes of schizophrenic symptoms are compared with the loci of cerebral activation in normal subjects during the performance of mental processes implicated in the three syndromes. The psychomotor poverty syndrome, which has been shown to involve a diminished ability to generate words, is associated with decreased perfusion of the dorsolateral prefrontal cortex at a locus which is activated in normal subjects during the internal generation of words. The disorganization syndrome, which has been shown to involve impaired suppression of inappropriate responses (eg in the Stroop test), is associated with increased perfusion of the right anterior cingulate gyrus at a location activated in normal subjects performing the Stroop test. The reality distortion syndrome, which evidence suggests arises from disordered internal monitoring of activity, is associated with increased perfusion in the medial temporal lobe at a locus activated in normal subjects during the internal monitoring of eye movements.

Adult↗

The roles of mental representations and mental processes in therapeutic action.

In this paper we describe two models of the psychoanalytic treatment of mental disturbance. The first describes the mechanism by which the patient is helped to recover threatening ideas and feelings which have been repudiated or distorted as a result of conflict and defense. The second points to the therapeutic effects of engaging previously inhibited mental processes within the psychoanalytic encounter. The two forms of therapeutic action imply two distinct means available to the individual to deal with psychological conflict. They highlight different aspects of the psychoanalytic process and technique in child and adult psychoanalysis.

Adult↗

Quantitative EEG evaluation in normal elderly subjects during mental processes: age-related changes.

Computerized EEG study was performed on 39 healthy elderly subjects (50-90 years), divided into two cohorts of increasing age (old, older) and on a group of 21 young controls. The EEG was recorded at rest, with eyes closed (EC) and during blocking reaction (BR), fixation (FIX) and mental arithmetic (MA) tasks. At rest with EC, the only significant variation was an increase of beta 1 relative power in old subjects which was positively correlated with age. During the performance of the mental tasks, in the elderly population when compared to young controls, the slow activity decreased slightly or was not significantly modified, while the alpha reactivity progressively decreased, showing a negative correlation with age in the older group. Beta 2 increased significantly in elderly subjects during BR and FIX but such change was less consistent with increasing age. Data show that at rest, the EEG in the elderly population differs only from that of young controls by showing a more pronounced fast activity, while only during mental processes is it possible to evidence changes that can be utilized as physiological "markers" of normal aging.

Adult↗

Dynamic neurophysiological correlates of mental processes.

The study of neurophysiological correlates of states and activity has revealed different mechanisms of the brain. Infraslow physiological processes (ISPP) as well as impulse activity of neurons and neuronal populations (NIA) were recorded during the performance of psychological and other trials by the subject. Subjects were neurological patients diagnosed and treated with implanted electrodes. We found correlates of mental activity to be reproducible (stable) in some brain areas and variable in others, which confirmed our concept that mental activity is maintained by cortical-subcortical functional system with links of different degrees of rigidity. One of the ISPP types, omega-potential, was shown to reflect quantitatively the state of the brain areas. We have described NIA rearrangements accompanying mental operations and revealed the complimentary character of various NIA rearrangements. Extremely promising in the investigation of neurophysiological correlates of mental processes, is the study of the relationship of local and distributed rearrangements in various neurophysiological processes, as well as combination of averaging with the study of correlates of single mental acts. Stability, combined with the dynamic character of rearrangements of physiological processes in the brain, seems to be its fundamental property responsible for informational capacity of the brain and adaptational ability of the organism.

Action Potentials↗

Brain plasticity and mental processes: Cajal again.

The year 2006 marks the 100th anniversary of the first Nobel Prize for Physiology or Medicine for studies in the field of the Neurosciences jointly awarded to Camillo Golgi and Santiago Ramón y Cajal for their key contributions to the study of the nervous system. This award represented the beginning of the modern era of neuroscience. Using the Golgi method, Cajal made fundamental, but often unappreciated, contributions to the study of the relationship between brain plasticity and mental processes. Here, I focus on some of these early experiments and how they continue to influence studies of brain plasticity.

Brain↗

Attention and mental processing speed in hemodialysis patients.

It has remained unclear whether well-dialyzed patients with end-stage renal disease (ESRD) show persisting neurocognitive deficits, especially in tasks that depend on sustained attention or psychomotor speed. We administered a battery of six attentional measures to 10 stable hemodialysis (HD) patients (age, 61+/-16 years; education, 12.4+/-3.8 years; Kt/V, 1.35+/-0.07) and 10 matched controls with normal renal function (age, 62+/-10 years; education, 11.6+/-1.0 years; estimated creatinine clearance, 92+/-25 mL/min). Results of the Trailmaking Test, Paced Auditory Serial Addition Test, Stroop Test, Digit Span, Continuous Performance Test (CPT), and Gordon Diagnostic System did not differ between groups. We conclude it is unlikely that well-dialyzed patients with ESRD manifest significant uremic neurocognitive deficits in the functional spheres related to sustained attention or mental processing speed.

Attention↗

Multi-stage mental process for economic choice in capuchins.

We studied economic choice behavior in capuchin monkeys by offering them to choose between two different foods available in variable amounts. When monkeys selected between familiar foods, their choice patterns were well-described in terms of relative value of the two foods. A leading view in economics and biology is that such behavior results from stimulus-response associations acquired through experience. According to this view, values are not psychologically real; they can only be defined a posteriori. One prediction of this associative model is that animals faced for the first time with a new pair of foods learn to choose between them gradually. We tested this prediction. Surprisingly, we find that monkeys choose as effectively between new pairs of foods as they choose between familiar pairs of foods. We therefore, propose a cognitive model in which economic choice results from a two-stage mental process of value-assignment and decision-making. In a follow-up experiment, we find that the relative value assigned to three foods in sessions in which we tested them against each other combine according to transitivity.

Analysis of Variance↗