Electroencephalographic Indicators in Default Mode, Habituation, and Visual-motor Association in Female College Students.

Background: Oscillations, action, and postsynaptic potentials in glial-neuronal ensembles integrate the spectral power (SP) of electroencephalographic (EEG). Our objective is to propose SP indicators of healthy brains (control groups) based on the default mode and their modifications by habituation and visual-motor association (VM-asso), to support diagnostic and rehabilitation processes. However, important differences seem to exist between men and women.

Desynchronization/synchronization of parasagittal EEG rhythms during habituation to photostimulation in adults.

Introduction: Learning by habituation implies a gradual diminution of the organism's responses to non-relevant stimuli. These responses, resulting from electrical oscillations of the brain, can be analyzed through quantitative electroencephalography (qEEG).

Objective: To characterize the absolute power (AP) in the range of delta (δ), theta (θ), alpha (α), beta (β) in cortical parasagittal regions during habituation to photostimulation (RPh).

[Desynchronization/synchronization of lateral EEG rhythms during habituation to photostimulation in adults].

Background: Berger related the EEG with cognition; we are attempting to identify which rhythms and circuits participate in habituation, a learning that decreases responses to meaningless stimuli which, changed the absolute power (AP) of EEG oscillations.

Objective: To characterize habituation, analyzing the AP of four rhythms in lateral regions of both hemispheres (BH), proposing that their diminution, desynchronization (D), means activation whereas their increase, synchronization (S), means inhibition.

Material And Methods: qEEG analysis in 83 college students, in waking state with closed eyes, and photostimulated (RPh).

[Absolute power of cortical oscillations and their topographical distribution in a sample of young adults during resting wakefulness and unspecific attention].

Introduction: The EEG records neuronal membrane potential oscillations that depend on the morpho-functional characteristics of the membrane and of modifications by postsynaptic excitatory (PSEP) and inhibitory (PSIP) potentials. The quantitative EEG (qEEG) measures the absolute power (AP) of oscillations separated in frequencies, resulting from the interaction among subcortical-cortical-subcortical ensembles. The hypothesis is that neuronal networks function at a given frequency and that their APs are codes that, by becoming synchronized in diverse ensembles, generate behavior.

Assisted diagnosis of attention-deficit hyperactivity disorder through EEG bandpower clustering with self-organizing maps.

The electroencephalogram is an attractive clinical tool given its non-invasive nature, its ability to reflect real-time changes in local cortical activity, and the load of objective bioelectrical measurements that can be derived from it. For decades, the electroencephalogram has been successfully used for diagnosing epilepsy and schizophrenia, among other brain disorders. This paper focuses in the design and implementation of a computer-aided diagnostic tool for establishing the likelihood of presence of Attention-Deficit Hyperactivity Disorder in children, out of routine electroencephalographic recordings obtained during a specific visual stimulation protocol.

[Efficiency of oxidant gas generator cells powered by electric or solar energy].

Diseases caused by microbial contaminants in drinking water continue to be a serious problem in countries like Mexico. Chlorination, using chlorine gas or chlorine compounds, is one of the best ways to treat drinking water. However, difficulties in handling chlorine gas and the inefficiency of hypochlorite solution dosing systems--due to sociopolitical, economic, and cultural factors--have reduced the utility of these chlorination procedures, especially in far-flung and inaccessible rural communities.

[Exercise test in young steers at 2800 M above sea level].

Among its different activities the Mexican Health Ministry (SSA) promotes: 1) the specification of biological standards for the Mexican population; 2) mechanisms for early detection of physiopathological changes and 3) development of the appropriate technology as a basis for primary health care. As part of this program we studied a random sample of students at the "Colegio de Bachilleres" of Cuajimalpa a suburban area of Mexico City, situated at 2800 m above sea level, part of the equipment used was produced at the Center for Development and Technological Applications (CE-DAT), an agency of SSA. Height, weight, heart rate (HR), systolic and diastolic blood pressures (SBP/DBP) were measured at rest in sitting position, standing up and walking on a treadmill.

[Evaluation of heart rate and blood pressure in residents of Milpa Alta, D.F].

Both the altitude of Mexico City (D.F.) and the increase in atmospheric pollutants make it important to establish parameters of comparison for cardiovascular variables, such as heart rate (HR) and blood pressure (BP).

Installation of a water disinfection system in a Mexico City hospital.

With a view to evaluating a small-scale water disinfection system based on production and application of oxidizing gases, the level of equivalent residual chlorine and the degree of contamination by fecal and total coliform bacteria was assessed at various points in the drinking water system of a Mexico City hospital before and after installation of the disinfection equipment. Tests done in May and June 1989, prior to installation of the equipment, showed that residual chlorine concentrations were lower than the national standard in most of the samples and that a sizable portion of these samples were also contaminated with fecal and total coliform concentrations exceeding national standards. After installation of the disinfection system at the main inflow to the hospital's drinking water supply in August 1989, the equivalent residual chlorine concentrations were found adequate and no coliform bacteria were detected.

[Measurement of heart rate and blood pressure in the population of Ajusco, Tlalpan, Federal District, Mexico, using CEDAT equipment].

To improve the procedures for cardiovascular health care in Mexico it is necessary to be able to perform accurate measurements of the cardiovascular parameters with appropriate equipment and to count with standard values for the Mexican population at the primary health level. Cardiac frequency (CF), systolic arterial pressure (SAP) and diastolic arterial pressure (DAP) were analyzed in O2 consenting volunteers under resting (seated) and standing conditions as well as during exercise (30 sitting), and again after exercise under resurge conditions. A direct relation was found between CF, SAP and DAP with body surface and age.

[The evaluation of the integral water treatment system of a general hospital in Mexico City].

The Mexican Health Office (SSA) promotes the use and progeny of the appropriate technology for the bacteriological quality evaluation and disinfect the water by means of the in situ progeny of the clorus and ozonus gases when needed, for the human consumption in suburban and rural communities. The clorus water disinfecting conventional methods by many reasons are useless, even in urbanized cities. CEDAT has built and design a group of apparatus, called: "Water treatment whole equipment for small communities", and it's build up by: Membrane Filter, Double Chamber Incubator, ultraviolet Light Sterilizer and a clorus and ozonus progenic gas electrolytic cell with CA and CD power box and a Venturi Tube.

[Quality of potable water and incidence of gastroenteritis in 2 cities in the state of Sonora, Mexico].

Based on the fact that drinking-water is of great significance in the transmission of infectious diseases, the incidence of diarrheal disorders was examined in two cities similar in their demographic composition and in their use of health services, but not in the quality of the drinking-water supply. In Navojoa, a city with high incidence of diarrheal diseases (116/1000 pop. in 1985), high rates of drinking-water contamination with fecal coliforms were found (43% of water samples); on the contrary, in Ciudad Obregón, a city with lower rates of diarrheal diseases (49/1000 pop.

[Removal of arsenic from water for human consumption in homes in rural communities in the Comarca Lagunera, Mexico].

This paper presents the results of an intradomiciliary procedure for arsenic removal from water, by means of flocculation with ferric sulphate. The reaction was carried out in a specifically designed tank with a manual agitator (reactor) installed in a vertical support. The salts to flocculate were handed in two small envelopes, whose contents were added independently, agitating the water and letting it settle for two to three hours.

Lever pressing and active avoidance conditioning after electrolytic lesions of the entopeduncular nucleus in cats.

Several authors have shown that CN participates in the acquisition of motor conditioned responses (MCR), probably as the integrating structure. Most of CN's efferent fibers in the cat end in the entopeduncular nucleus (EPN), therefore the command for the motor pattern could be exerted through EPN, representing part of the efferent link of the neuronal circuitry involved in MCR. Thirty-two cats were trained to avoid actively an electrical stimulus when a series of flashes appeared, and to press a lever to obtain 0.

Caudate unit activity and somal diameters in intact and nigral lesioned cats.

In a search for morphofunctional relationships in the head of the caudate nucleus (CN), we recorded extracellular unit activity in intact cats and in cats that had received bilateral injections of 6-OHDA into the substantia nigra (SN) 30 days previously. Only units firing spontaneously and continuously for 2 min were studied. In dorsal regions, potentials were small and iterative at almost constant intervals; the somal diameters were relatively small.

Effects of general anesthesia, neodecortication and spreading depression upon somatic evoked responses in caudate and entopeduncular nuclei, and their electrophysiological correlates in cats.

The electrophysiological relationship among an afferent somatic input (radial nerve), the caudate and the entopeduncular nuclei was studied in intact animals under chloralose anesthesia and in decorticated ones. The results confirm the hypothesis that the cerebral cortex is not essential to record somatic evoked responses in both nuclei, nor for the reciprocal responses in these nuclei when one of them is stimulated, suggesting the existence of direct somatic projections to these nuclei from the subcortical structures. On the other hand, the spreading depression by microinjection of KCl 3M into the CN does not modify the ERs in EPN, but the spreading depression in EPN does modify the CN response.

Electrophysiological correlates among the radial nerve, the caudate and the entopeduncular nuclei in cats.

The entopeduncular nucleus (EPN), as the medial part of the globus pallidum, has been considered the efferent structure of the striatum. Based on this, we decided to study its possible somatosensory projections and the electrophysiological relationship with the caudate nucleus (CN). Radial nerve stimulation produced evoked responses (ER) in CN and EPN.

Modification of motor activity, passive avoidance conditioning and evoked potentials by microinjections of strychnine in both caudate nuclei in cats.

Passive avoidance conditioning (PAC) seems to depend on inhibitory actions within the caudate nucleus (CN). Thus topical application of strychnine could block these influences. In cats, with permanently implanted cannulae in the head of the CN, bilateral microinjections of 100 micrograms of strychnine produced a stereotyped behavior of grooming and running with the extremities flexed to dark places.

Facilitation of the suppressing effect of dopamine upon a motor conditioned response by 6-hydroxydopamine applied into the caudate nucleus in cats.

It has been described that the application of DA in the Caudate Nucleus improves the learning of an inhibitory motor conditioned response (SMCR). However, the application of 6-hydroxydopamine (6-OHDA) at low doses of 5, 10 and 20 micrograms produced a clear increment of the inhibition, while higher doses of 80 or 160 micrograms diminished markedly the suppression of the MCR. We postulated that although low doses of 6-OHDA produce lesions in the dopaminergic structures they cause hypersensitization by denervation.

Modification of motor activity, passive avoidance conditioning and evoked potentials by microinjections of picrotoxin in both caudate nuclei in cats.

Inhibition of movements is the result of the caudate nucleus (CN) activity. This action seems to be necessary for passive avoidance conditioning (PAC). Much data indicates that GABA has inhibitory effects in the CN.