Basal ganglia: From the bench to the bed.

The basal ganglia (BG) encompass a set of archaic structures of the vertebrate brain that have evolved relatively little during the phylogenetic process. From an anatomic point of view, they are widely distributed throughout brain from the telencephalon to the mesencephalon. The fact that they have been preserved through evolution suggests that they may play a critical role in behavioral monitoring. Indeed, a line of evidence suggests that they are involved in the building of behavioral routines and habits that drive most of our activities in everyday life. In this article, we first examine the organization and physiology of the basal ganglia to explain their function in the control of behavior. Then, we show how disruption of the putamen, and to a lesser extent of the cerebellum, might lead to various dystonic syndromes that frequently arise during childhood.

Bypassing use-dependent plasticity in the primary motor cortex to preserve adaptive behavior.

Behavioral adaptation, a central feature of voluntary movement, is known to rely on top-down cognitive control. For example, the conflict-adaptation effect on tasks such as the Stroop task leads to better performance (e.g. shorter reaction time) for incongruent trials following an already incongruent one. The role of higher-order cortices in such between-trial adjustments is well documented, however, a specific involvement of the primary motor cortex (M1) has seldom been questioned. Here we studied changes in corticospinal excitability associated with the conflict-adaptation process. For this, we used single-pulse transcranial-magnetic stimulation (TMS) applied between two consecutive trials in an interference flanker task, while measuring motor-evoked potentials (MEPs) after agonistic and antagonistic voluntary movements. In agonist movement, MEP amplitude was modulated by recent movement history with an increase favoring movement repetition, but no significant change in MEP size was observed whether a previous trial was incongruent or congruent. Critically, for an antagonist movement, the relative size of MEPs following incongruent trials correlated positively with the strength of behavioral adaptation measured as the degree of RT shortening across subjects. This post-conflict increase in corticospinal excitability related to antagonist muscle recruitment could compensate for a potential deleterious bias due to recent movement history that favors the last executed action. Namely, it prepares the motor system to rapidly adapt to a changing and unpredictable context by equalizing the preparation for all possible motor responses.

Predictors of haemoconcentration at delivery: association with low birth weight.

PURPOSE: [corrected] To assess the factors associated with risk of haemoconcentration at delivery, such as initial haemoglobin levels and alterations in the HFE gene, and its effect on low birth weight in pregnant women supplemented with moderate doses of iron. METHODS: Case-control study nested in a longitudinal study conducted on 217 healthy pregnant women taking moderate iron supplementation and their newborns. Women were classified according to the risk of haemoconcentration at delivery, defined as Hb > 130 g/L. Each subject's obstetric and clinical history, smoking habit, and iron biochemical parameters (haemoglobin (Hb), serum ferritin and transferrin saturation) were recorded at 1st, 2nd and 3rd trimester and at delivery. Polymorphisms of the HFE gene (C282Y, H63D and S65C) were also measured. RESULTS: The average of iron supplementation of all the women was 43.9 mg/dia (geometric mean, 95 % CI: 43.6-44.1). Higher levels of Hb at early gestation and the presence of HFE mutations were associated with greater risk of haemoconcentration at delivery, adjusted odds ratios of 1.14 (95 % CI: 1.05-1.25) and 5.35 (95 % CI: 1.6-17.8). Haemoconcentration at delivery was associated with a greater risk of low birth weight, adjusted odd ratio of 11.48 (95 % CI: 1.13-116.6). CONCLUSIONS: Moderate daily doses of supplementary iron may be harmful for foetal growth in women with alterations in HFE gene and who started pregnancy with good haemoglobin levels. Overall, this suggests the importance of determining a woman's iron status early in her pregnancy in order to establish a more appropriate pattern of supplementation.

[Early of late supplementation: similar evolution of the iron status during pregnancy]. / Suplementación temprana o tardía: similar evolución del estado de hierro durante el embarazo.

The highest iron demands during pregnancy occur in the third trimester, although preventive iron supplementation is recommended from early stages of the pregnancy. The aim of the study was to compare whether early supplementation with moderate iron doses better prevents the decrease of iron levels during gestation than the late supplementation. One hundred and eighty-four pregnant women participated. They received iron supplements before or after week 20 of pregnancy. At each quarter, serum ferritin (SF), transferrin saturation (TS) and hemoglobin (Hb) were determined. Gestational age-standardized hemoglobin (zHb) was calculated. The early supplementation group received a mean of 40.5 ± 15.7 mg/day and the late group 43.1 ± 11.9 mg/day. Iron deficiency (impaired SF and TS) iron deficiency anemia increased as pregnancy progressed without significant differences between the early and late supplementation groups. More than half of the women ended up their pregnancy with iron deficiency and more than 20% with iron deficiency anemia. In conclusion, although early intake of iron supplements is recommended in pregnancy, no better preventive effect is observed on the decrease of iron levels with early supplementation as compared to late supplementation when moderate iron doses are used.

Depleted iron stores without anaemia early in pregnancy carries increased risk of lower birthweight even when supplemented daily with moderate iron.

BACKGROUND: Gestational iron-deficiency anaemia has adverse pregnancy outcomes. Antenatal iron supplementation can be beneficial in anaemic women, but the effects in non-anaemic women are controversial. This observational study assessed the relationship of maternal iron stores (depleted or non-depleted) at gestational Weeks 8-12 with birthweight, in non-anaemic pregnant women following the guidelines of the Ministry of Health of Spain. METHODS: Healthy, non-anaemic pregnant women (n = 205) were studied. At the first antenatal visit, a general clinical assessment was conducted, and basal blood taken. Women were classified as having non-depleted or depleted iron stores [serum ferritin (SF) < 12 µg/l)]. Daily antenatal iron supplements (48 mg on average) were started at 17 (range: 16-18) weeks. Blood haemoglobin, SF and transferrin saturation (TS) were measured in each trimester. RESULTS: Of the study sample, 20, 54 and 66% had SF < 12 µg/l in the first, second and third trimesters, respectively. The prevalence of iron-depletion (SF < 12 µg/l) and iron-deficiency (SF < 12 µg/l and TS < 16%) was greater during the entire pregnancy in women with initial iron depletion versus no depletion (81.6 and 73.7% versus 61.7 and 55.4%, respectively, in the third trimester, P < 0.05). Women with initial iron-depletion delivered babies weighing on average 192 g less than that with initial iron stores, after adjusting for confounding variables (P = 0.028). CONCLUSIONS: Beginning pregnancy with non-depleted iron stores is beneficial for the maternal iron status during pregnancy and infant birthweight. These findings reaffirm the importance of health promotion to ensure that women have adequate iron stores prior to, or early in, pregnancy when supplemented with moderate daily iron doses.

Suplementación temprana o tardía: similar evolución del estado de hierro durante el embarazo / Early of late supplementation: similar evolution of the iron status during pregnancy

Las mayores necesidades de hierro durante el embarazo se sitúan en el tercer trimestre, no obstante se recomienda la suplementación preventiva con hierro desde fases más tempranas. El objetivo del estudio fue comparar si la suplementación temprana con dosis moderadas de hierro previene mejor la caída de los niveles de hierro durante la gestación que la más tardía. Participaron 184 mujeres embarazadas. Recibieron suplementos de hierro desde antes de la semana 20 de gestación o posteriormente. Se determinó ferritina sérica (FS), saturación de transferrina (ST) y hemoglobina (Hb) en cada trimestre de la gestación. Se calculó la hemoglobina estandarizada por la edad gestacional (zHb). El grupo de suplementación temprana tomó una media de 40,5 ± 15,7 mg/día y el de tardía 43,1 ± 11,9mg/día. El déficit de hierro (FS y ST alteradas) y la anemia por déficit de hierro aumentaron al avanzar la gestación, sin diferencias significativas entre los grupos de suplementación temprana y tardía. Más de la mitad de las mujeres finalizaron el embarazo con déficit de hierro y cerca de un 20% con anemia por déficit de hierro. En conclusión, aunque en la gestación se recomienda el inicio temprano de la toma de suplementos de hierro, no se observa mejor efecto preventivo sobre la caída de los niveles de hierro con la suplementación temprana respecto de la tardía, cuando se utilizan dosis de hierromoderadas (AU)

The highest iron demands during pregnancy occur in the third trimester, although preventive iron supplementation is recommended from early stages of the pregnancy. The aim of the study was to compare whether early supplementation with moderate iron doses better prevents the decrease of iron levels during gestation than the late supplementation. One hundred and eighty-four pregnant women participated. They received iron supplements before or after week 20 of pregnancy. At each quarter, serum ferritin (SF), transfer in saturation (TS)and hemoglobin (Hb) were determined. Gestational age standardized hemoglobin (zHb) was calculated. The early supplementation group received a mean of 40.5 ± 15.7mg/day and the late group 43.1 ± 11.9 mg/day. Iron deficiency (impaired SF and TS) iron deficiency anemia increased as pregnancy progressed without significant differences between the early and late supplementation groups. More than half of the women ended up their pregnancy with iron deficiency and more than 20% with iron deficiency anemia. In conclusion, although early intake of iron supplements is recommended in pregnancy, no better preventive effect is observed on the decrease of iron levels with early supplementation as compared to late supplementation when moderate iron doses are used (AU)