Robust coupling of body movement and gaze in young infants

In the first few months after birth, rapid bursts of body movement precede and possibly facilitate shifts of gaze during free looking, with potential consequences for perception and cognition. Here we report that the characteristic features of movement-gaze coupling found during free looking are preserved when attention is perturbed by a salient change in the visual environment. Twenty-four 3-month-olds looked at two attractive 3-dimensional objects while body movement and corneal reflections of the objects were recorded. Lateral head movement was measured offline. After approximately 2 s of looking at one stimulus, the nonfixated stimulus either began to rotate back and forth (distracter events) or remained motionless (control events). In distracter events, the motion of the nonfixated stimulus triggered substantial motor quieting, shortened the duration of the look, and shortened the time to reorient gaze compared to control events. Abbreviated motor quieting and small increases in lateral head movement occurred during control events at the same time in the look as the protracted motor quieting and increased head movement in distracter events. Despite these perturbations, the characteristic bursts of body movement that precede shifts of gaze during free looking occurred in both distracter and control events. The results demonstrate the robust nature of early movement-gaze coupling, raise questions about the specific role of attention in the dynamic links between body movement and gaze, and highlight the potential short and long term functional significance of movement-gaze-attention coupling.     

Focused attention, heart rate deceleration, and cognitive development in preterm and full-term infants

The majority of children who are born very preterm escape major impairment, yet more subtle cognitive and attention problems are very common in this population. Previous research has linked infant focused attention during exploratory play to later cognition in children born full‐term and preterm. Infant focused attention can be indexed by sustained decreases in heart rate (HR). However there are no preterm studies that have jointly examined infant behavioral attention and concurrent HR response during exploratory play in relation to developing cognition. We recruited preterm infants free from neonatal conditions associated with major adverse outcomes, and further excluded infants with developmental delay (Bayley Mental Development Index [MDI < 70]) at 8 months corrected age (CA). During infant exploratory play at 8 months CA, focused attention and concurrent HR response were compared in 83 preterm infants (born 23–32 weeks gestational age [GA]) who escaped major impairment to 46 full‐term infants. Focused attention and HR response were then examined in relation to Bayley MDI, after adjusting for neonatal risk. MDI did not differ by group, yet full‐term infants displayed higher global focused attention ratings. Among the extremely preterm infants born <29 weeks, fewer days on mechanical ventilation, mean longest focus, and greater HR deceleration during focused attention episodes, accounted for 49% of adjusted variance in predicting concurrent MDI. There were no significant associations for later‐born gestational age (29–32 weeks) or full‐term infants. Among extremely preterm infants who escape major impairment, our findings suggest unique relationships between focused attention, HR deceleration, and developing cognition. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:383–400, 2012.     

Spatial conditional discrimination learning in developing rats

The present study established an effective procedure for studying spatial conditional discrimination learning in juvenile rats using a T-maze. Wire mesh located on the floor of the maze as well as a second, identical T-maze apparatus served as conditional cues which signaled whether a left or a right response would be rewarded. In Experiment 1, conditional discrimination was evident on Postnatal Day (PND) 30 when mesh+maze or maze-alone were the conditional cues, but not when mesh-alone was the cue. Experiment 2 confirmed that mesh-alone was sufficiently salient to support learning of a simple (nonconditional) discrimination. Its failure to serve as a conditional cue in Experiment 1 does not reflect its general ineffectiveness as a stimulus. Experiment 3 confirmed that the learning shown in Experiment 1 was indeed conditional in nature by comparing performance on conditional versus nonconditional versions of the task. Experiment 4 showed that PND19 and PND23 pups also were capable of performing the task when maze+mesh was the cue; however, the findings indicate that PND19 subjects do not use a conditional strategy to learn this task. The findings suggest postnatal ontogeny of conditional discrimination learning and underscore the importance of conditional cue salience, and of identifying task strategies, in developmental studies of conditional discrimination learning.     

Spatial anisotropy in the encoding of three-dimensional passive limb position by the spinocerebellum

In an earlier study, we found that the encoding of limb position in the sagittal plane across the population of spinocerebellar Purkinje cells was anisotropic with a preferential gradient along horizontal direction. The aim of this study was to extend to a three-dimensional (3D) workspace the analysis of the relationships between Purkinje cells activity and rat's forelimb spatial position. In anesthetized animals, the extracellular activity of 121 neurons was recorded while a robot passively placed the limb in 18 positions within a cubic workspace (3x3x3 cm). In order to characterize the relationship between spatial locations and Purkinje cell activity we performed a backward stepwise regression starting from a model with three independent variables representing the antero-posterior, the medial-lateral and the vertical axes of workspace. Regression analysis showed that the firing of most cells was modulated exclusively along the antero-posterior (25%) or the medial-lateral (38%) axis, while a small portion was related only to the vertical axis (8%), indicating a generalized nonuniform sensitivity of Purkinje cells to limb displacement in 3D space.     

Sensitizing properties of spectral lights in 4-month-old human infants

Previous studies of infant attention, learning, and memory have revealed that certain stimulus properties may increase an infant's arousal or excitation level, thereby increasing responsiveness and facilitating the encoding and processing of information. In a series of experiments aimed at identifying stimulus determinants of sensitization, we examined visual responses from 4-month-old infants to spectral lights. Habituation data were obtained from 92 full-term infants separated into one of five groups. Each group viewed either a broadband white light (correlated color temperature ≃ 2800 K) or one of four different spectral lights (λ_d = 470, 510, 570, or 650 nm) approximately corresponding to the elemental hues blue, green, yellow and red, respectively, for adults with normal trichromatic vision. Stimuli were equated in luminous efficiency for a standard infant observer. Stimulus fixation was recorded for twelve 10-s presentations, each separated by 10-s interstimulus intervals (ISIs). The results show that mean fixation times to the red and green lights were significantly greater than those for the blue and white light. Mean fixation time for the yellow light was also reduced (significantly) to the red but not the green light. These results suggest that the chromatic properties of red and green spectral lights may be more sensitizing to infants than those of the blue, yellow, or white lights. © 1997 John Wiley & Sons, Inc. Dev Psychobiol 30: 275–281, 1997     

Spatial orientation of attention and obstacle avoidance following concussion

Re-injury to the brain during recovery from an initial concussion leads to increased probability of permanent brain damage or death. Recovery from concussion has been proposed to be ongoing even up to a month post-injury. The goal of the current study was to investigate the relationship between the visuospatial orientation of attention and obstacle avoidance during gait in individuals that have recently suffered a concussion (mTBI) over a month post-injury. MTBI subjects and matched control subjects performed the attentional network test (ANT), designed to isolate several different components of attention. Obstacle crossing during gait with and without a concurrent attention dividing task was also performed. Reaction times from the ANT and obstacle clearance measurements were the main dependent variables. We observed that concussed individuals had statistically more obstacle contacts than controls. The ability to orient attention in space was also statistically deficient immediately after a concussion, and this was correlated with lower obstacle clearances of the leading foot. Similar correlations could also be found between both leading and trailing foot avoidance and spatial orientation of attention in participants with concussion when attention was divided during obstacle crossing, and these relationships gradually weakened as recovery progressed. By contrast, spatial attention and obstacle clearance were not significantly correlated in control subjects. These findings indicate that patients with mTBI who display greater spatial attention deficits cross over the obstacle with a lower clearance than patients with less or without spatial attention deficits, leading to an increased probability of obstacle contact.     

促红细胞生成素在早产儿贫血中的防治作用

目的观察重组人类促红细胞生成素（recombinant human erythropoietin,r h-EPO）在早产儿贫血中的防治作用。方法将早产后在我科住院的胎龄小于34w,体重低于2000g的新生儿50例,按入院顺序随机分成两组,治疗组25例,对照组25例。两组患儿入院后常规给予保暖,维持体温、血糖、血压等内环境稳定,营养支持等处理,必要时输血。治疗组于生后第7天开始给予重组人类促红细胞生成素200IU/kg.d,皮下注射,每周3次,共4w。对照组仅用常规治疗。分别于生后第1、2、3、4、5w抽取外周静脉血,检测并比较不同时间两组早产儿的血红蛋白（haemoglobin,HB）、网织红细胞（reticulocyte,Ret）和血细胞比容（hematocrit,HCT）。结果两组早产儿出生后血红蛋白均下降,但治疗组下降缓慢,治疗结束后两组差异非常显著（P〈0.01）;治疗组治疗后网织红细胞计数和血细胞比容较对照组明显升高（P〈0.01）;治疗结束后两组网织红细胞计数差异缩小（P〉0.05）,但血细胞比容差别仍显著（P〈0.01）;治疗组的输血率（8%）较对照组的输血率（32%）明显减少（P〈0.05）。结论重组人类促红细胞生成素可以有效的防治早产儿贫血,减少输血。     

Effect of delay interval on classical eyeblink conditioning in 5-month-old human infants

Associative learning was evaluated in human infants with simple delay classical eyeblink conditioning. A tone conditioned stimulus (CS) was paired with an airpuff unconditioned stimulus (US) at three different delay intervals (250, 650, and 1,250 ms). Independent groups of healthy, full-term 5-month-old human infants were assigned to these three paired conditions and received two identical training sessions 1 week apart. The two longer delays resulted in associative conditioning, as confirmed by comparison with unpaired control groups. However, only at the 650-ms delay were associative eyeblinks adaptively timed to avoid the airpuff. The delay function at 5 months of age appears much sharper than is observed in adults. Together with the findings of A. H. Little, L. P. Lipsitt, and C. Rovee-Collier (1984), the present study suggests a downward shift in the optimal delay interval for associative eyeblink conditioning between 1 and 6 months of age. However, this delay remains longer than what is typically reported in adults.     

Proximodistal structure of early reaching in human infants

Nine infants were tested, at the age of onset of reaching, seated on their parent’s lap and reaching for a small plastic toy. Kinematic analysis revealed that infants largely used shoulder and torso rotation to move their hands to the toy. Many changes in hand direction were observed during reaching, with later direction changes correcting for earlier directional errors. Approximately half of the infants started many reaches by bringing their hands backward or upward to a starting location that was similar across reaches. Individual infants often achieved highly similar peak speeds across their reaches. These results support the hypothesis that infants reduce the complexity of movement by using a limited number of degrees-of-freedom, which could simplify and accelerate the learning process. The proximodistal direction of maturation of the neural and muscular systems appears to restrict arm and hand movement in a way that simplifies learning to reach. Received: 27 July 1998 / Accepted: 26 March 1999     

Activation and deactivation in response to visual stimulation in the occipital cortex of 6-month-old human infants

In an infant's developing cortex, the explanation for the mechanisms underlying the activations and deactivations in response to visual stimuli remains controversial. While previous near-infrared spectroscopy (NIRS) studies in awake infants have demonstrated cortical activations in response to meaningful/attractive visual stimuli, functional magnetic resonance imaging (fMRI) studies performed on sleeping infants showed negative blood oxygenation level-dependent (BOLD) responses to high-luminance unpatterned stimulations, such as a photic stimulation. To examine the effect of the characteristics of visual stimuli on cortical processing in awake infants, we measured cortical hemodynamic responses in 6-month-old infants during the presentation of a high-luminance unpatterned stimulus by using a NIRS system with 94 measurement channels. Results from 35 infants showed dissociated cortical responses between the occipital region and the other parts of the cortex, including the temporal and prefrontal regions. Although the visual stimulus produced sustained increases in oxygenated hemoglobin (oxy-Hb) signals in the temporal and prefrontal regions, it produced a transient increase in oxy-Hb signals followed by a salient decrease in oxy-Hb signals during a trial in a focal region of the occipital visual region. This suggests that the deactivation of the occipital visual region in response to visual stimulation is not a phenomenon that occurs only in the sleeping state, but that a high-luminance unpatterned stimulus can induce deactivation even in the awake infants.     

新生儿晚期黄疸人巨细胞病毒gB基因分型研究

目的了解引起新生儿晚期黄疸患者人巨细胞病毒（HCMV）gB基因型的分布,探讨HCMVgB基因多态性与黄疸之间的关系。结论采用荧光定量PCR法检测本院新生儿科98例晚期黄疸新生儿标本HCMV-DNA含量,巢式聚合酶链反应扩增阳性标本HCMVgB基因,并进行DNA测序,绘制种系进化树。利用HinfⅠ和RsaⅠ对gB基因进行限制性片段长度多态性（RFLP）分析。结果 30例晚期黄疸新生儿HCMV荧光定量PCR检测阳性,阳性率为30.6%。种系进化树分析结果显示gB基因分为4个基因型,gB1型15株（50%）,gB2型5株（16.7%）,gB3型9株（30.0%）,gB1/3混合型1株（3.3%）。以HCMV实验室标准株AD169作为参考,将序列进行同源性比较,gB1型同源性为94.7%～95.0%,gB2型同源性93.1%～93.4%,gB3型同源性94.7%,gB1/3型同源性93.7%。RFLP分析将gB基因分为4个基因型,分型结果与种系进化树分型一致。结论 HCMV感染是导致新生儿晚期黄疸的原因之一;gB基因的DNA序列比较保守,但仍存在一定的多态性,晚期黄疸新生儿中HCMV感染以gB1、gB3型为主。     

人乳与早产儿配方乳喂养对早产儿生长的Meta分析

目的对单纯人乳、强化人乳和早产儿配方乳喂养早产儿的生长进行评价。方法检索PubMed、ScienceDirect、EBSCOHost、EMBASE、OVID、Cochrane图书馆、维普中文科技期刊数据库和中国期刊全文数据库,并手工检索会议记录和专题论文集等,收集关于单纯人乳、强化人乳与早产儿配方乳喂养早产儿的RCT研究,进行文献筛选和质量评价,采用RevMan5.0.18软件进行Meta分析,计量资料采用加权均数差（WMD）及其95%CI表示。无法进行合并分析的资料进行描述性分析。结果共纳入7篇文献,文献质量评价5篇为B级,2篇为C级。Meta分析结果显示：①对近期生长的影响：单纯人乳喂养组新生儿期体重增加速度（WMD=-6.03,95%CI：-9.58～-2.47,P=0.0009）、身长增长速度（WMD=-1.96,95%CI：-2.77～-1.16,P〈0.00001）及头围增长速度（WMD=-2.04,95%CI：-3.71～-0.37,P=0.02）均显著慢于早产儿配方乳喂养组;强化人乳喂养组新生儿期体重、身长和头围的增长速度与早产儿配方乳喂养组差异均无统计学意义。②...更多对远期生长的影响：单纯人乳喂养组与早产儿配方乳喂养组随访至9和18个月,以及7.5～8岁时的体重、身长（高）和头围的差异均无统计学意义。结论现有证据提示,强化人乳喂养可促进早产儿生后近期内生长,单纯人乳和强化人乳对早产儿远期生长的影响仍需进一步研究。     

Detection of geometric, but not topological, spatial transformations in 6- to 12-month-old infants in a visual exploration paradigm

Several theories of spatial orientation propose that the geometry of an environment plays a privileged role in reorientation, relative to relations between individual landmarks. Infants (N = 90) in three age groups (6, 8 1/2, and 12 months) experienced three conditions: topological, geometric, and control. A round room contained four distinctive objects in a rectangular arrangement on the inside periphery. Infants were familiarized to the array prior to a 2-min test period. In the topological condition, two objects were switched. In the geometric condition, the objects were moved to form an irregular quadrilateral. In the control condition, the array remained unchanged. Infants of 8 1/2 months and over visually explored significantly more in the geometric condition only. An initial study with adults found greater visual exploration in both geometric and topological conditions. These results are discussed in the context of current theories of spatial orientation.     

Respiratory variability in preterm and term infants: Effect of sleep state, position and age

The influence of sleep state and position on respiratory variability (RV) was studied in 13 preterm infants (PTIs) and 19 term infants (TIs). Temporally matched epochs of nasal pressure and oxygen saturation (Sp_O2)$(\text{S}{\text{p}}_{{\text{O}}_2})$ data were extracted from nap polysomnography. Inspiratory onset times (I) were determined, and variability measures of the I–I   interval compared in quiet sleep and active sleep, prone and supine and with age. Sleep state influenced respiratory variability (RV) in PTI and TI but Sp_O2$\text{S}{\text{p}}_{{\text{O}}_2}$ only varied with sleep state in PTI (p = 0.03). Position had no effect on RV in TI but influenced the standard deviation of ventilatory frequency (SDf) in PTI (p = 0.04). Age did not influence RV in PTI but SDf and the coefficient of variation of ventilatory frequency (CVf) decreased in TI from birth to 3 months. These data confirm sleep state as the predominant influence on RV in healthy term and convalescent preterm infants, with horizontal prone positioning having little effect when sleep state is controlled for.     

Probiotics for prevention of atopic diseases in infants: systematic review and meta‐analysis

Growing evidence underlines the pivotal role of infant gut colonization in the development of the immune system. The possibility to modify gut colonization through probiotic supplementation in childhood might prevent atopic diseases. The aim of the present systematic review and meta‐analysis was to evaluate the effect of probiotic supplementation during pregnancy and early infancy in preventing atopic diseases. PubMed, Embase and Cochrane Library were searched for randomized controlled trials evaluating the use of probiotics during pregnancy or early infancy for prevention of allergic diseases. Fixed‐effect models were used, and random‐effects models where significant heterogeneity was present. Results were expressed as risk ratio (RR) with 95% confidence interval (CI). Seventeen studies, reporting data from 4755 children (2381 in the probiotic group and 2374 in the control group), were included in the meta‐analysis. Infants treated with probiotics had a significantly lower RR for eczema compared to controls (RR 0.78 [95% CI: 0.69–0.89], P = 0.0003), especially those supplemented with a mixture of probiotics (RR 0.54 [95% CI: 0.43–0.68], P < 0.00001). No significant difference in terms of prevention of asthma (RR 0.99 [95% CI: 0.77–1.27], P = 0.95), wheezing (RR 1.02 [95% CI: 0.89–1.17], P = 0.76) or rhinoconjunctivitis (RR 0.91 [95% CI: 0.67–1.23], P = 0.53) was documented. The results of the present meta‐analysis show that probiotic supplementation prevents infantile eczema, thus suggesting a new potential indication for probiotic use in pregnancy and infancy.     

Reinstatement maintains a memory in human infants for 1(1/2) years

This study tested the proposition of Campbell and Jaynes (1966) that reinstatement is the mechanism by which early memories are maintained over a significant period of development. In four progressive replications, 6-month-old human infants learned to move a miniature train around a track by lever-pressing. They received a brief reinstatement at 7, 8, 9, 12, and 18 months of age and a final retention test at 2 years of age. Although 6-month-olds usually remember this task for only 2 weeks, after five reinstatements they exhibited significant retention 1(1/2) years later. Untrained yoked controls that received the same reinstatement regimen exhibited no retention after any delay. These findings reveal that the immaturity of the brain at the time of encoding is not the rate-limiting step in whether infants remember over the long term. Rather, as long as infants periodically encounter a nonverbal reminder, they can maintain early memories over a significant period of development.     

早产极低出生体重儿的病因和防治探讨

目的探讨早产极低出生体重儿发生的病因和防治。方法分析1993-2004年我院住院早产极低体重儿109 例临床资料。结果早产极低体重儿发生的主要原因为妊娠高血压综合征、双胎妊娠、胎膜早破,孕母疾病。早产极低出生体重儿的主要种并症依次为硬肿症、出生时窒息、感染性疾病、肺透明膜病、呼吸暂停、早产儿贫血、先天畸形等。109 例早产极低体重儿的死亡率为23．85％,胎龄≤30w组高,与胎龄>30w织相比有统计学差异P<0．05)。早产极低体重儿死因构成以肺透明膜病居首,窒息和畸形居次。结论加强围产期保健、及时治疗高危妊娠,防治早产、肺透明膜病和窒息,客观认真地评判Apgar评分和有效复苏是优生优育的重要环节。