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On the speed of different senses and nerve transmission by Hirsch (1862).

A translation is given of Hirsch's pioneering paper of 1862 on chronoscopic experiments "On the speed of different senses and nerve transmission." Hirsch was the first (1) to use Hipp's chronoscope in scientific literature, (2) to study reaction time in connection to psychological interest, and (3) to study velocity of conduction in humans with appropriate techniques. Using Hipp apparatus, Hirsch showed differences in time for manual response (1) to auditory, visual, and tactile stimulation; (2) between observers; (3) in Hirsch's own results when fresh and when fatigued; (4) according to the locus of tactile stimulation and the hand used for response; and (5) according to whether the stimulus was expected or unexpected. Moreover, observations made on one of his colleagues relate the conduction speed in nerves, from which he concludes that the differences in reaction time were due to the varying lengths of nerves. The speed of transmission in sensory nerves was evaluated by Hirsch at about 34 m/s. This work constitutes a prelude of Donders' research on the speed of mental processes.

History, 19th Century↗

Vitamin D--soltriol the heliogenic steroid hormone: somatotrophic activator and modulator. Discoveries from histochemical studies lead to new concepts.

Evidence from autoradiographic studies with 3H 1,25(OH)2 vitamin D3 (soltriol) about its many sites of nuclear binding and multiple actions suggests that the traditional view of "vitamin D and calcium" is too limited and requires modification. A new concept has been developed which proposes that the skin-derived hormone of sunshine, soltriol, is a somatotrophic activator and modulator that affects all vital systems. Regulation of calcium homeostasis is only one of its many actions. Target tissues for soltriol include not only bone, intestine and kidney, but also brain, spinal cord, pituitary, thyroid, endocrine pancreas, adrenal medulla, enteroendocrine cells, thymus, and male and female reproductive organs. Accordingly, actions of soltriol involve effects on autonomic and endocrine regulation with changes in tissue and blood hormone levels, innervation of skeletal muscle, immune and stress response, digestion, blood formation, fertility, pregnancy and lactation, general energy metabolism, mental processes and mood, and others. The skin-mediated transduction of short-wave sunlight induces a purposeful modulation of growth, reproduction and other biological activities in tune with the conditions of the sun cycle and season. Synthesis and actions of vitamin D3-soltriol are dependent not only on the amount of sunlight, but also on the availability of precursor in the skin and access of sunlight, the rate of hydroxylation in liver and kidney, and the modulation of these events by the endocrine status, in particular growth and reproduction. A concept of a five-level control of soltriol synthesis is proposed, in which the hydroxylation steps provide for a sensitive tuning. Relationships between the heliogenic skin-derived hormonal system and the helioprivic pineal-derived hormonal system are recognized and a comprehensive concept of the "endocrinology of sunlight and darkness" is pointed out.

Calcitriol↗

Bioethics and the breakdown of the bicameral mind: Sacks and Luria revisited.

Since antiquity, individuals have attempted to relate mental processes to circumscribed areas of the brain. In 1935 the neurologist Wilder Penfield purported to know, "the humming of the mind's machinery, and where words come from," after he electrically stimulated areas of the exposed human cortex. Recent theories have suggested a functional separation of the dominant and the nondominant hemispheres, the right brain/left brain concept of thought and personality. One author has even proposed that human consciousness and modern civilization developed when the bicameral mind broke down, and the left brain achieved mastery over the right nondominant temporal lobe. Compared to these mechanistic approaches to brain function and human personality, the Russian neurologist, A.R. Luria and his American follower, Oliver Sacks, have developed a more intellectually satisfying and clinically useful approach which relies on a fuller understanding of the doctor-patient....

Bioethics↗

The Reaction Level Scale (RLS85). Manual and guidelines.

The Reaction Level Scale (RLS85) is a "coma scale" for the direct assessment of overall reaction level in patients with acute brain disorders. It is devised for reliable use even in the management of patients who are difficult to assess, such as intubated patients and patients with swollen eyelids. We here present the manual of the RLS85 and the guidelines for its use. The underlying concepts as well as limitations are outlined. Condensed information of known reliability and validity is presented. A training scheme for presumed observers (doctors, nurses and assistant nurses) is outlined. It is suggested that users of the RLS85 refer to these guidelines and in scientific reports clearly state any deviations from this present manual in order to facilitate valid comparisons between different studies and different groups of patients.

Acute Disease↗

Lorazepam and diazepam effects on memory acquisition in priming tasks.

Unlike diazepam, lorazepam has repeatedly been shown to impair perceptual priming as well as explicit memory. To determine whether this deleterious effect was due to an impairment in acquisition of information, 60 healthy volunteers were randomly assigned to five treatment groups (placebo, lorazepam 0.026 or 0.038 mg/kg, diazepam 0.2 or 0.3 mg/kg) and successively performed perceptual priming tasks and a free-recall task. Priming performance on information learned before or 2 h after drug administration, i.e. at the peak concentration of lorazepam, was assessed under the influence of the drugs, using a picture-fragment and a word-stem completion task. Free-recall performance was altered by both drugs. Lorazepam decreased priming performance when information was acquired after, but not before, drug administration, indicating that the drug alters the acquisition of information. Lorazepam also impaired the ability to identify fragmented pictures, but there was no evidence that this perceptual effect accounts for the priming impairment. Surprisingly, diazepam also decreased priming when information was acquired after drug administration, suggesting that, at least in certain circumstances, the two benzodiazepines may exert similar effects on priming measures.

Adult↗

Comparison of perioperative mental function after general anaesthesia and spinal anaesthesia with intravenous sedation.

This study compared the postoperative mental function in 44 elderly patients following general anaesthesia (GA) or spinal anaesthesia (SA) with sedation for transurethral resection of prostate. The Mini-Mental State (MMS) was done preoperatively and postoperatively at six hours, one day, three days, five days and one month. The geriatric mental status examination was performed preoperatively and one month after the anaesthetic. There was no significant intergroup difference in the MMS score in the preoperative, six hours, one day, three days, five days and 30 days postoperative scores between the GA and SA with sedation groups. A significant intragroup difference between preoperative and postoperative MMS score was detected in the GA group (P less than 0.02) and in the SA group with sedation (P less than 0.03). In the GA group, the significant decrease in MMS score occurred at 6 h postoperatively (P less than 0.002) whereas in the SA group with sedation, MMS score also decreased significantly at 6 h (P less than 0.005). In conclusion, there was no significant difference in perioperative mental function between the general and spinal anaesthetic groups when supplemental IV sedation was given. In both groups, perioperative mental function decreased significantly at 6 h postoperatively.

Aged↗

Cognitive decline in the elderly: a double-blind, placebo-controlled multicenter study on efficacy of phosphatidylserine administration.

This double-blind study assesses the therapeutic efficacy and the safety of oral treatment with phosphatidylserine (BC-PS) vs placebo (300 mg/day for 6 months) in a group of geriatric patients with cognitive impairment. A total of 494 elderly patients (age between 65 and 93 years), with moderate to severe cognitive decline, according to the Mini Mental State Examination and Global Deterioration Scale, were recruited in 23 Geriatric or General Medicine Units in Northeastern Italy. Sixty-nine patients dropped out within the 6-month trial period. Patients were examined just before starting therapy, and 3 and 6 months thereafter. The efficacy of treatment compared to placebo was measured on the basis of changes occurring in behavior and cognitive performance using the Plutchik Geriatric Rating Scale and the Buschke Selective Reminding Test. Statistically significant improvements in the phosphatidylserine-treated group compared to placebo were observed both in terms of behavioral and cognitive parameters. In addition, clinical evaluation and laboratory tests demonstrated that BC-PS was well tolerated. These results are clinically important since the patients were representative of the geriatric population commonly met in clinical practice.

Activities of Daily Living↗

Attachment theory, metacognitive functions and the therapeutic relationship in eating disorders.

J. Bowlby's attachment theory is used to explore a fundamental motivational force in human behaviour, namely the search for physical and emotional protective intimacy according to an integrated viewpoint remote from Freud's drive-based approach. This theory has received contributions from ethology, the neurosciences, psychoanalysis, cognitive psychology and evolutionary epistemology. Attachment patterns or styles express both the mental and behavioural strategies adopted by individuals to cope with their attachment needs, and their relational history in this area. Experiences of adequate quality promote metacognitive functions, namely a set of mental processes whose role is to protect the individual from psychopathological suffering and construct and articulate a sense of self. Attachment theory and metacognition are the underlying assumptions of reflections on the dynamics marking the development of sometimes very difficult relationships between therapists and eating disorder (ED) patients, who are being increasingly classed as "severe patients" on account of their interpersonal characteristics.

Defense Mechanisms↗

The social context of insight in schizophrenia.

BACKGROUND: Psychiatrists place great weight on impaired insight in schizophrenia, generally attributing it to pathological mental processes. However, denial of illness may be based on attitudes common in patients' social and cultural groups. Moreover, even where denial of illness has a pathological element, it may be affected by the social context. In this paper, we predicted that denial of illness would be associated with social distance between clinician and patient, and reduced by access to 'normalizing' social interaction. METHOD: One hundred and fifty patients with schizophrenia in the London arm of the European Schizophrenia cohort were assessed using the 'Awareness of Illness' (AI) subscale of David's Assessment of Insight. Clinical and social attributes were related to AI. RESULTS: There was little evidence for our social distance hypotheses: there was little variation in AI by social class, ethnicity, membership of a drug taking culture or the presence of strongly held religious beliefs. However, there were strong relations between AI and the size of primary group, consistent with our normalizing hypothesis. CONCLUSIONS: The normalizing function of social support is in line with modern psychological models of delusion formation. Longitudinal data will eventually be available from the current study that will assist in establishing the causal direction of this association.

Adult↗

Differential effects of mental load on proximal and distal arm muscle activity.

Work-related upper extremity disorders (WRUEDs) that result from keyboarding tasks are prevalent and costly. Although the precise mechanisms causing the disorder are not yet fully understood, several risk factors have been proposed. These include the repetitive nature of the motor task and the associated sustained static working postures, but also more psychological factors such as mental load. Epidemiological surveys have shown that WRUEDs are more prone to develop in the postural muscles of the neck/shoulder area than in the executive muscles controlling the hand. The present study investigated whether the activation patterns of these two muscle types are differentially affected by an additional mental load during the performance of a repetitive tapping task. Participants tapped various keying patterns with their dominant index finger at two prescribed tempi. Mental load was manipulated by means of an auditory short-term memory task. We recorded the EMG activity of two neck/shoulder muscles (trapezius and deltoid), two upper arm muscles (biceps and triceps), and four forearm muscles (flexor digitorum superficialis, extensor digitorum, extensor carpi radialis longus and extensor carpi ulnaris) and analyzed the kinematics and impact forces of the index finger. The results confirmed that the upper limb has two functions. Specifically, activity of the executive distal musculature was increased during tapping at the higher pace, while the activity of the postural upper limb musculature was elevated due to the memory task. We argue that continuously increased muscular activity can lead to fatigue and thus eventually cause musculoskeletal complaints. The results are discussed with respect to biomechanical adaptation strategies that deal with the consequences of increased noise in the neuromotor system due to enhanced mental processing.

Adult↗

Differential effects of subthalamic nucleus stimulation in advanced Parkinson disease on reaction time performance.

The aim of the present study was to assess the effect of bilateral subthalamic nucleus (STN) stimulation and dopaminergic medication on speed of mental processing and motor function. Thirty-nine patients suffering from advanced Parkinson disease (PD) were operated on. Motor function and reaction time (RT) performance [simple RT (SRT) and complex RT (CRT)] were evaluated under four experimental conditions with stimulation (stim) and medication (med) on and off: stim-on/med-on, stim-on/med-off, stim-off/med-off and stim-off/med-on. In the last condition, the patients received either low medication (usual dose) or high medication (suprathreshold dose). STN stimulation improved the motor performance in the SRT and CRT tasks. Furthermore, STN deep brain stimulation (DBS) also improved response preparation as shown by the significant improvement of the RT performance in the SRT task. This effect of STN DBS on the RT performance in the SRT task was greater as compared with the CRT task. This is due to the more complex information processing that is required in the CRT task as compared to the SRT task. These data suggest that treatment of STN hyperactivity by DBS improves motor function, confirming earlier reports, but has a differential effect on cognitive functions. The STN seems to be an important modulator of cognitive processing and STN DBS can differentially affect motor and associative circuits.

Activities of Daily Living↗

Cortical potentials at the frequency of absolute wrist velocity become phase-locked during slow sinusoidal tracking movements.

A 1-Hz rhythmic event-related potential was recorded at the scalp during performance of a 0.5-Hz tracking task. At cortical motor areas, negative peaks occurred 10-20 ms after peak tracking speeds. Analysis of single sweeps suggested that EEG phase was reset at initiation of the tracking motion and then maintained a constant relationship to wrist speed until task completion. Frequency analysis indicated that rhythm appearance in the averaged potential was predominantly due to phase-locking, because there was no tracking-related increase in 1 Hz amplitude within individual sweeps. While tracking, phase-locking was present over bilateral parieto-occipital and frontal regions, with a slight predominance at the contralateral frontal region. When subjects observed the target motion, phase-locking was localized to parieto-occipital regions. We suggest mental processes such as visual processing, visuomotor coordination and real-time motor planning are reflected in the pacing of localized cortical potential fluctuations.

Adult↗

Effects of contract-relax stretching training on muscle performance in athletes.

The effects of an 8-week unilateral contract-relax (CR) stretching training program (passive stretch after isometric contraction) on muscular performance were investigated in a group of 16 athletes. The flexibility, maximum torque and angular position as well as contraction work in movements of the knee joint were determined before training and after 4 and 8 weeks of training. The torque measurements were performed under isokinetic conditions, eccentrically at angular velocities of 60 degrees x s(-1) and 120 degrees x s(-1), isometrically at five different joint positions, and concentrically at angular velocities of 60, 120, 180 and 240 degrees x s(-1) using an isokinetic dynamometer. A surface electromyogram (EMG) of the thigh muscles (quadriceps and hamstrings) was recorded simultaneously. As compared to untrained control limbs, significant improvements in active and passive flexibility (up to 6.3 degrees in range of motion), maximum torque (up to 21.6%) and work (up to 12.9%) were observed, and these were especially pronounced under eccentric load conditions. A comparison between integrated EMG recordings during eccentric and concentric loads, as well as the interpretation of the training-induced changes in the EMG, suggest that muscular activity under eccentric loads may be impaired by mental processes.

Adaptation, Physiological↗

Somatization disorders in obstetrics and gynecology.

Somatization refers to the phenomenon of physical symptoms not being conditioned by physical structural defects but primarily by mental processes. The basic understanding integrating psychodynamic, cognitive behavioral and systemic views conceptualized the underlying process as a signal processing circle in which the perceptual, interpretative and the effective-behavioral part interact in a dysfunctional manner. The clinical entities of this basic mechanism are variable in the localization and intensity of the symptoms which is reflected in the existing classification of ICD 10 and DSM IV. These classifications do not differentiate between gender. In obstetrics and gynecology somatization disorders are quantitatively important and qualitatively distinct. The pathogenetic factors are linked to gender specific biopsychosocial conditions, psychoendocrine interactions and genital organ subjective experiences. Therefore we propose a gender-sensitive classification into three groups of somatization disorders: Somatizing reactions during specific life phases or transitional periods, pychoendocrine disorders and somatoform disorders of the female genital organs. In each group the dysfunction may manifest itself mainly on the perceptual part or the effective-behavioral part of the signal processing circle. The pathogenetic pathways, comorbidities, specific diagnostic and therapeutic interventions for these different groups are summarized.

Female↗

Fainting in animals.

Fainting (syncope) is unconsciousness due to insufficient cerebral circulation in the context of a temporary failure of the systemic circulation. This paper firstly aims to discuss fainting in animals, and secondly to discuss animal physiology to broaden the understanding of human fainting. Of the three major syncope types (cardiac, orthostatic and reflex syncope), only cardiac syncope occurs in animals as in man, through arrhythmia or output failure. Man's orthostatic fainting tendency has been blamed on his upright posture. A comparison with animals shows that giraffes, tree climbing snakes, and animals that quickly raise and lower their heads face more serious gravitational circulatory challenges than man, but do not appear to faint. Merely carrying the brain above the heart does not explain a fainting tendency, as the human heart-to-brain height is smaller than that of many mammals with similar blood pressure. Two evolutionary novelties may be to blame: the proportion of cardiac output going upwards to the brain is much larger than in apes, and man's large legs suggest that the volume lost to venous pooling is also larger. Emotional factors play a role in many reflex syncope events. Tonic immobility ('feigning death','playing possum') is not a good model, as it concerns immobility as a survival strategy of an attentive brain, rather than unconsciousness due to circulatory breakdown. Whether orienting and defense responses form a valid model remains to be proven. Emotional fainting may be uniquely human; how mental processes can shut down the circulation and thereby the brain needs serious study, as it may hold the key to syncope prevention.

Animals↗

Characteristics of interhemisphere interactions at different levels of consciousness.

The relationship between the level of consciousness and the level of brain activation was studied. A model for a gradual decrease in the level of consciousness was provided by the transition from waking to drowsiness. Measures of the level of consciousness, assessed by the subjects themselves, consisted of changes in the content of consciousness, i.e., the intensity and quality of involuntarily arising mental processes. In each subject, the level of consciousness was found to correspond to a pert EEG profile. The results obtained from these studies showed that the lowest level of activation corresponded to the state in which the subject noted inhibition of "inner speech," a "lapse of thoughts," and in this state the interhemisphere associations involving the major mechanism of transmission of cognitive information, i.e., the high-frequency EEG rhythm, was weakened.

Adolescent↗

Theory of mind, social development, and psychosis.

The difficulty in interpreting other people's mental states found in children with autism and in people affected by schizophrenia may be explained in terms of a unique mental process called Theory of Mind. The paper discusses the main operational issues of such a peculiar aspect of social cognition, the Theory of Mind, and its implication in schizophrenia, including a review of its related neural structures. Theory of Mind abilities may be a relevant aspect of social interaction involving people affected by schizophrenia, and they need to be further investigated in clinical research.

Autistic Disorder↗