Airborne particulate matter integral assessment in Magdalena department, Colombia: Patterns, health impact, and policy management.

The relevance of atmospheric particulate matter (PM) to health and the environment is widely known. Long-term studies are necessary for understanding current and future trends in air quality management. This study aimed to assess the long-term PM concentration in the Magdalena department (Colombia). It focused on the following aspects: i) spatiotemporal patterns, ii) correlation with meteorology, iii) compliance with standards, iv) temporal trends over time, v) impact on health, and vi) impact of policy management. Fifteen stations from 2003 to 2021 were analyzed. Spearman-Rho and Mann-Kendall methods were used to correlate concentration with meteorology. The temporal and five-year moving trends were determined, and the trend magnitude was calculated using Teil-Sen. Acute respiratory infection odd ratios and risk of cancer associated with PM concentration were used to assess the impact on health. The study found that the maximum PM10 concentration was 194.5 µg/m3, and the minimum was 3 µg/m3. In all stations, a negative correlation was observed between PM10 and atmospheric water content, while the wind speed and temperature showed a positive correlation. The global trends indicated an increasing value, with five fluctuations in five-year moving trends, consistent with PM sources and socio-economic behavior. PM concentrations were found to comply with national standard; however, the results showed a potential impact on population health. The management regulation had a limited impact on increasing concentration. Considering that national regulations tend to converge towards WHO standards, the study area must create a management program to ensure compliance.

Diferencias en procesamiento cerebral visual temprano en niños con trastorno del déficit de atención / Differences in early visual cerebral processing in children with attention deficit / hyperactivity disorders with predominance of no attention

Para evaluar los procesos atencionales a estímulos visuales que no requieren repuesta motora, se llevó a cabo un estudio con potenciales evocados a 17 niños con trastornos del déficit de atención/ hiperactividad (TDAH-I) con predominio inatento y a 15 controles de edades entre 7 y 11 años. Se analizó la latencia y localización de fuentes de los potenciales evocados visuales tempranos P100 y N100 durante la realización de una tarea oddball visual (20% rayas horizontales y 80% verticales) en que las rayas verticales no exigían respuesta motora. Los resultados indican que los niños con TDAH-I procesan la información visual que no requiere respuesta motora con un mayor aumento de la actividad cerebral y mediante la vía temporal ventral mientras que el grupo control lo hace mediante la vía parietal dorsal. Este proceso neurobiológico de procesamiento de la información visual vía temporal ventral de los niños con TDAH-I podría deberse a alteraciones en los procesos emocionales que influyen directamente en el reconocimiento visual o a un déficit en el control de los procesos atencionales por parte de la vía parietal dorsal.

To evaluate attentional processes to visual stimuli that do not require motor response, a study with evoked potentials was carried out on 17 children with attention deficit disorder predominantly inattentive (ADDH-I) and 15 controls between the ages of 7 and 11 years. The latency and localization of sources of the early visual evoked potentials P100 and N100 were analyzed during the performance of a visual oddball task (20% horizontal and 80% vertical lines) where the vertical lines did not require motor response. The results indicate that ADDH-I group process visual information that does not require motor response with a greater increase in brain activity and through the ventral temporal pathway, while the control group does so by means of the dorsal parietal stream. This neurobiological process of visual information processing by ventral temporal pathway of ADDH-I group could be due to alterations in emotional processes that directly influence visual recognition or as consequence of deficit in the control of attentional processes by the dorsal parietal pathway.

Emisiones biogénicas de monoterpenos en el parque nacional natural Tayrona, santa marta (Colombia) / Monoterpenes ioggenic emissions in the tayrona natural park, santa marta (Colombia)

Los monoterpenos y otros compuestos orgánicos volátiles emitidos por la vegetación (emisiones biogénicas) juegan un papel significativo en la química troposférica por su participación en la formación de oxidantes fotoquímicos (p.e. ozono troposférico). Es así como la estimación de emisiones biogénicas resulta útil para establecer valores aproximados de la concentración, fundamental en la elaboración de programas de mejoramiento de calidad del aire. El objetivo del trabajo consistió en estimar las emisiones biogénicas de monoterpenos en el Parque Nacional Natural Tayrona, seleccionado por contar con áreas de vegetación autóctona de la región tropical con escasa o nula intervención antropogénica. Se aplicaron sensores remotos para la clasificación de cobertura vegetal, obteniendo la distribución espacial de la vegetación típica e identificando las familias de mayor dominancia. Las emisiones de monoterpenos se calcularon en 3,54 x 10(4) kg d-1, representadas 60% por la familia Leguminosae, 37,4% por la familia Euphorbiaceae, 2,4% por la familia Anacardiaceae y menos de 1% por las familias Rubiaceae y Polygonaceae. Durante las horas de sol en el área del parque (de las 6 a las 18 horas) se registraron las mayores temperaturas diarias y las más altas tasas de emisión de monoterpenos (59,6%); la cuarta parte de las emisiones ocurren entre las 10 y las 15 horas (24,2%), periodo en el que la radiación solar presenta máximos diarios y establece condiciones críticas para la formación de oxidantes fotoquímicos. La influencia de los vientos en la distribución espacio-temporal de las emisiones en el ambiente y la información de la rosa de vientos, evidencia que el 26% de las masas de aire proceden del N y el 15% del NE en el último trimestre del año, situación que podría favorecer la dispersión de monoterpenos a centros urbanos próximos al parque natural, pudiendo alterar la química atmosférica local con la formación de oxidantes fotoquímicos.

Monoterpenes and other volatile organic compounds emitted by vegetation (biogenic emissions) play a significant role in tropospheric chemistry because of their participation in the formation of photochemical oxidants (i.e. troposfheric ozone). This is how the estimation of biogenic emissions is useful for determining approximate values of monoterpenes concentration, which is essential in developing programs to improve air quality. The aim of this work was to estimate biogenic emissions of monoterpenes in the Tayrona National Park, that was selected because of the presence of native vegetation of the tropics with little or no human interference. Remote sensing was applied for classification of vegetation, coverage obtaining the spatial distribution of the typical vegetation and identifying the most dominant families. Monoterpenes emissions were estimated at 3.54 x 104 kg d-1, represented 60% of the Leguminosae family, 37.4% of the Euphorbiaceae family, 2.4% of the Anacardiaceae family and less than 1% of Rubiaceae and Polygonaceae families. During daylight hours in the park area (from 6:00 a.m. to 6:00 p.m.) the highest daily temperatures were registered and the highest emission rates of monoterpenes (59.6%); one fourth of the emissions occur between 10:00 a.m. and 3:00 p.m. (24.2%), period in which solar radiation presents daily maximums and establishes critical conditions for the formation of photochemical oxidants. The influence of winds on the spatial-temporal distribution of emissions shows that 26% of the air mass come from the N and 15% of NE in the last quarter of year, a situation that could favor the spread of monoterpenes to urban centers near the natural park, which could alter the local atmospheric chemistry with the formation of photochemical oxidants.

rTMS stimulation to induce plastic changes at the language motor area in a patient with a left recidivant brain tumor affecting Broca's area.

INTRODUCTION: Extent of resection is one of the most powerful predictors of outcome in surgery of gliomas. Tumors located within areas governing eloquence may impede a total tumor resection. Functional plasticity may be induced by therapeutic means, such as cortical stimulation with repetitive transcranial magnetic stimulation (rTMS). Thus, rTMS is a potential tool to induce an improvement of functions of eloquence menaced by brain tumors. MATERIAL AND METHODS: We report a case of a 59-year-old woman operated for a left sided precentral oligodendroglioma with awake intraoperative stimulation, whose tumor could not be completely removed because it affected areas governing language. Nine months later the tumor progressed and the motor language functions worsened. We submitted the patient to rTMS directed to Broca's area, next to the anterior pole of the tumor, with the aim of improving motor language function before a new tumor resection attempt. We performed 12 daily sessions of theta-burst rTMS followed by intensive language rehabilitation for 10 minutes, and 5 different aspects of language were measured before, immediately after and 10 minutes after each session. RESULTS: Repetition and nomination worsened immediately after each rTMS session, and improved after 10 min of rehabilitation. However, basal values improved globally along the experiment. Also, the impact of rTMS on motor language was increasingly less along the procedure. CONCLUSIONS: rTMS induces changes in Broca's area and this effect can be potentially used to improve language function in tumors located at or close to eloquent cortical areas.

The ex-illiterate brain: the critical period, cognitive reserve and HAROLD model / O cérebro ex-analfabeto: o período crítico, reserva cognitiva e o modelo HAROLD

Abstract ? The lifelong acquisition of cognitive skills shapes the biology of the brain. However, there are critical periods for the best use of the brain to process the acquired information. Objectives: To discuss the critical period of cognitive acquisition, the concept of cognitive reserve and the HAROLD (Hemispheric Asymmetry Reduction in Older adults) model. Methods: Seven women who learned how to read and to write after the age of 50 (ex-illiterates) and five women with 10 years of regular schooling (controls) were submitted to a language recognition test while brain activity was being recorded using magnetoencephalography. Spoken words were delivered binaurally via two plastic tubs terminating in ear inserts, and recordings were made with a whole head magnetometer consisting of 148 magnetometer coils. Results: Both groups performed similarly on the task of identifying target words. Analysis of the number of sources of activity in the left and right hemispheres revealed significant differences between the two groups, showing that ex-illiterate subjects exhibited less brain functional asymmetry during the language task. Conclusions: These results should be interpreted with caution because the groups were small. However, these findings reinforce the concept that poorly educated subjects tend to use the brain for information processing in a different way to subjects with a high educational level or who were schooled at the regular time. Finally, the recruiting of both hemispheres to tackle the language recognition test occurred to a greater degree in the ex-illiterate group where this can be interpreted as a sign of difficulty performing the task.

Resumo ? A aquisição ao longo da vida de competências cognitivas moldam a biologia do cérebro. No entanto, existem períodos críticos para o cérebro processar melhor as informações adquiridas. Objetivos: Discutir o período crítico de aquisição cognitiva, o conceito de reserva cognitiva e o modelo HAROLD (Redução da Assimetria Hemisférica em Idosos). Métodos: Sete mulheres que aprenderam a ler e escrever após a idade de 50 anos (ex-analfabetos) e cinco mulheres com 10 anos de escolaridade regular (controles) foram submetidas a um teste de reconhecimento de palavras enquanto a atividade cerebral estava sendo registrada mediante magnetoencefalografia. As palavras foram ouvidas com o emprego de dois tubos plásticos conectados a cada orelha e as gravações foram feitas com um magnetômetro de cabeça inteira com 148 bobinas de registro. Resultados: Ambos os grupos tiveram desempenho semelhante na identificação das palavras-alvo. Análise do número de fontes de atividade no hemisfério esquerdo e no hemisfério direito revelou diferenças significativas entre os dois grupos, mostrando que os ex-analfabetos tiveram menor assimetria cerebral funcional no desempenho da tarefa. Conclusões: Estes resultados devem ser interpretados com cautela, pois os grupos são pequenos. No entanto, reforçam o conceito que os indivíduos com baixa escolaridade tendem a usar o cérebro para processar informações de uma forma diferente do que indivíduos com nível educacional elevado ou que tenham o adquirido na época regular. Finalmente, o recrutamento de ambos os hemisférios para reconhecer as palavras ocorreu mais intensamente no grupo de ex-analfabetos e pode ser interpretado como um sinal de maior dificuldade na tarefa.

A clinical and magnetoencephalography study of MRI-negative startle epilepsy.

OBJECTIVE: The goal of this study was to investigate clinical findings, ictal semiology, and results of video/electroencephalography (video/EEG), and magnetoencephalography (MEG) in patients with startle epilepsy and normal brain MRI. METHODS: Four patients (mean age 12.5 years) with startle epilepsy were investigated with MRI, video/EEG, and MEG. RESULTS: Epilepsy diagnosis was established in childhood, and all had spontaneous and reflex seizures. Reflex seizures were triggered by sudden, unexpected sounds and tactile stimuli. The neurological examinations and MRIs were normal. MEG recordings showed focal epileptiform activity. An ictal MEG was obtained in one patient. Source modeling yielded dipole sources in right central frontal region. CONCLUSION: The present study demonstrates that the origin of epileptiform activity in startle epilepsy can be localized in brain areas associated with supplementary motor seizures, even in patients with normal brain MRI. MEG adds complementary information to the localization of epileptiform activity and can be useful in planning invasive studies in cases evaluated for epilepsy surgery.

Hypofunction of right temporoparietal cortex during emotional arousal in depression.

CONTEXT: Neuropsychological models of depression highlight temporoparietal hypofunction associated with low emotional arousal in major depressive disorder (MDD). These models were derived from indirect measures such as neuropsychological tests and electroencephalography alpha band power. OBJECTIVE: To determine if high-arousing stimuli directly modulated activity in attention and arousal-related sensory brain regions in patients with MDD. DESIGN: Between-group comparison (patients with MDD vs healthy control subjects) of neuromagnetic oscillatory activity driven by flickering emotional and neutral pictures (steady-state visual evoked fields [ssVEFs]). SETTING: Center of magnetoencephalography at a public university and public ambulatory mental health service. PARTICIPANTS: Fifteen female low-anxious patients with MDD and 15 female controls. The groups were matched with respect to age and handedness. INTERVENTION: Magnetoencephalographic recordings and self-report ratings. MAIN OUTCOME MEASURES: Modulation of current source strengths obtained by frequency domain minimum norm source localization of ssVEFs. RESULTS: Controls and patients with MDD showed enhanced current source strengths at ssVEF frequency in occipital and parietal cortex for high-arousing emotional pictures (P < .05 for permutation statistics). While this arousal modulation in controls was pronounced in the right temporoparietal cortex, weak arousal modulation characterized that brain region in patients with MDD (F(1,28) = 7.2, P < .05 for interaction group by quadraticcontrast). CONCLUSIONS: Although emotional pictures engaged the dorsal visual stream to a greater extent than neutral pictures in both study groups, only controls showed strong arousal modulation in the right temporoparietal cortex. Because the right temporoparietal cortex is associated with the arousal dimension of emotion, subjects with depression may have difficulties in activating arousal-related brain areas, whereas basic stimulus processing related to activation of the dorsal visual stream is intact.

Activity in human medial temporal lobe associated with encoding process in spatial working memory revealed by magnetoencephalography.

Animal studies have suggested that working memory may be affected after lesions in the medial temporal lobe, although this assumption has not been corroborated by neuropsychological studies in humans. However, very recently, several functional neuroimaging studies in humans have successfully observed activation of the medial temporal lobe during working memory tasks. The main aim of this study was to investigate the contribution of the medial temporal lobe to the encoding process in spatial working memory. To address this issue we registered the neuromagnetic brain patterns of eight adult volunteers while they performed a spatial working memory task and more perceptual task using identical stimuli. After a initial phase (between 200 and 400 ms) without differences in activation, the medial temporal lobe showed a sustained activity, more evident in the right hemisphere, lasting up to 800 ms during the encoding stage of the spatial working memory task, while the activation in the perceptual task terminated earlier (approximately 400 ms after stimulus onset). The finding of a continued activation of the medial temporal lobe strongly suggests the contribution of this brain region to encoding operations in working memory.

Is medial temporal lobe activation specific for encoding long-term memories?

Several neuroimaging studies have consistently demonstrated the critical involvement of prefrontal cortices and medial temporal lobes during long-term encoding. While the contribution of prefrontal lobes to working memory is well established, the role of the MTL structures remains controversial. To address this issue, we registered the neuromagnetic brain patterns of eight adult volunteers while they performed two working memory tasks (verbal and spatial) using magnetoencephalography (MEG). MEG recordings can provide real-time measures of brain activity, thus allowing detailed tracking of the time-course of brain activation during the encoding phase. We detected sustained and material-specific activity on the MTLs during the encoding phase of a working memory task, based on verbal and spatial information. Two peaks of activation were noted in the left MTL during word encoding in two non-consecutive time periods (500-600 ms and 700-800 ms after stimulus onset). Right MTL laterality was found for encoding locations when we collapsed activity sources in a wider time period (400-800 ms). In addition, we provided the spatiotemporal profiles of what seems to be two different brain circuits specific for each type of material. Finally, following an emerging conceptualization of working memory, we hypothesized that encoding processes mediated by the MTL to long-term memory would also apply to working memory.

Crisis del lóbulo temporal registrada mediante magnetoencefalografía: caso clínico / Temporal lobe seizure recorded by magnetoencephalography: case report

La localización del inicio de las crisis es un factor importante para la evaluación prequirúrgica de la epilepsia. En este trabajo se describe la localización del inicio de una crisis registrada mediante magnetoencefalografía (MEG) en un niño de 12 años que presenta crisis parciales complejas farmacorresistentes. La RM muestra una lesión de 20mm de diámetro en el hipocampo izquierdo. EEG de superficie con ondas theta temporales izquierdas. Registro MEG interictal con punta-onda aislada posterior e inferior a la lesión de la RM. Registro MEG ictal con punta-onda (2 Hz). La localización de los dipolos indica el inicio de la crisis en la circunvolución temporal inferior en la misma localización que la actividad interictal MEG. Esta actividad ictal se propaga bilateralmente a áreas frontales. El registro corticográfico intraquirúrgico confirma los resultados de la localización interictal mediante MEG.

Can small lesions induce language reorganization as large lesions do?

Shift of the cortical mechanisms of language from the usually dominant left to the non-dominant right hemisphere has been demonstrated in the presence of large brain lesions. Here, we report a similar phenomenon in a patient with a cavernoma over the anterolateral superior temporal gyrus associated with epilepsy. Language mapping was performed by two complementary procedures, magnetoencephalography, and electrocorticography. The maps, indicated right temporal lobe dominance for receptive language and left frontal lobe dominance for expressive language. These results indicate that a small lesion, associated with epilepsy, may produce selective shifting of receptive language mechanisms as large lesions have been known to produce.

Magnetoencephalographic localization of peritumoral temporal epileptic focus previous surgical resection.

UNLABELLED: Magnetoencephalography (MEG) is suggested as a localizing technique of epileptogenic areas in drug-resistant seizure patients due to intracraneal lesions. A male 42-year-old patient who begins at 26 with partial complex drug-resistant seizures is put forward. MRI shows a 9 mm diameter lesion located in left superior temporal gyrus which seems compatible with cavernoma. Both conventional and sleep deprivation EEGs have proved normal. Sleep EEG shows sharp waves in left temporal region. MEG helps to localize interictal spike and spike-wave activity, as well as wide slow wave (2-7 Hz) activity areas. Craniotomy under analgesia and aware sedation conditions is carried out. Intrasurgery cortical electric stimulation assisted by neuronavigator causes a limited partial complex seizure which the patient recognizes to be exactly like his. Thus, MEG localization of the epileptogenic area is confirmed. Surgical resection of both the lesion and the epileptogenic area is carried out. The patient remains free from seizures 9 months after surgery. A control MEG study reveals no epileptogenic nor slow wave activity. CONCLUSION: in this particular case, MEG has proven to be a useful presurgical evaluation technique to localize epileptogenic activity, validated by intrasurgical cortical stimulation.