Spontaneous Movement Activity Research Articles

A novel two-body sensor system to study spontaneous movements in infants during caregiver physical contact

Spontaneous movements, which refer to repetitive limb movements in the absence of any external stimulus, have been found to be reflective of neurodevelopmental status during infancy. These movements are modulated by both individual and environmental factors, including physical contact (holding) with the caregiver. However, it is a challenge to measure spontaneous movements during physical contact because infant-generated movements become coupled with caregiver-generated movements in such contexts. Here, we propose the use of a novel two-body sensor system to distinguish infant-generated movements in the presence of physical contact with the caregiver. Data from seven typically developing infants and their caregivers were recorded during different simulated home activities, which involved different combinations of physical interaction, caregiver’s movement and infant positions. The two-body sensor system consisted of two wearable accelerometers – one placed on the infant’s arm and one on the caregiver’s arm, and we developed a Kalman-filter based algorithm to isolate the infant-generated movements. In addition, video was recorded for qualitative analysis. Results indicated that spontaneous movement activity was higher when there was no physical contact with caregiver. When there was physical contact, spontaneous movements were increased when the caregiver was still and when the infant was held horizontally. These results show that the novel two-body sensor system and the associated algorithms were able to isolate infant-generated movements during physical contact with the caregiver. This approach holds promise for the automated long-term tracking of spontaneous movements in infants, which may provide critical insight into developmental disorders.

P183 – 2406: Specific features of cerebral lesions in small premature infants at cytomegalovirus infection

Objective Study of specific features of CNS lesions in small premature infants at cytomegalovirus infection (CMVI). Methods Clinical-paraclinical (laboratory tests, neurosonography – NSG, brain MRI) examination of 518 infants with cytomegalovirus infection (CMVI) was performed. 197 children was born with extremely low birth weight and 221children – with very low birth weight (ELBW and VLBW). Results During first 7 days of life depression syndrome was observed in 85% of children with ELBW and in 69% – with VLBW: apnoe attacks, seizures, hard disorders of muscular tonus and spontaneous movement activity, absence of oral and spinal inborn reflexes, hypertensive and vegetovisceral and seizure syndromes were noted. NSG revealed echogenicity increase in periventricular area in 89% of children with ELBW and 74% – with VLBW; the necessity to differentiate manifestation of periventricular edema (PVE) with periventricular leukomalacia occurred. More often increased echogenicity of periventricular areas was observed in 94% of children with ELBW (76% – with VLBW). Hyperechoic inclusions in the brain parenchyma varied from single to multiple (picture of starry sky); often they were found in optic thalamus areas. Rarer gliosis of striatal vessels like crows feet which clinically manifested by syndrome of increased nervous-reflectory irritability. Hyperechoic inclusions in the brain parenchyma contained mineralized vasculopathy in the basal ganglia area were observed in 89% of children with ELBW and 74% – with VLBW. Pathologic neurosonographic signs in the isolated form were rare. Character of structural lesions was also confirmed by brain MRI; hyperechoic inclusions combined with PVE in 61% and 48% of children correspondingly; rarer they combined with ventriculomegaly, concomitant periventricular hemorrhage. Conclusion Neurosenography is available highly sensitive screening diagnostic method for determination of severe lesions of immature brain structures in small premature infants with CMVI.

L-dopa reverses behavioral deficits in the Pitx3 mouse fetus.

Studies of fetal rodents have provided evidence that early emerging behaviors, such as the suckling response, are dependent on the developing dopaminergic system. Although connections have been made between manipulations of dopamine and altered behavioral responses, the specific neural pathways involved have yet to be discovered. In this study, we examined the neurobehavioral output of the nigrostriatal pathway, using the Pitx3ak/2J mouse model (Pitx3). Used extensively in the study of Parkinson's disease, the Pitx3 mouse has very specific prenatal loss of dopaminergic neurons solely in the nigrostriatal pathway. Because of this specificity, we hypothesized that behavioral deficits specific to the nigrostriatal pathway would be reversed with administration of the dopamine precursor 3,4-dihydroxyphenylalanine (L-dopa). To test this hypothesis, homozygous mutant and heterozygous control fetal subjects were administered 1 of 4 doses (0, 25, 50, or 75 mg/kg) of L-dopa on the day before birth. Quantification of fetal behavior was scored from video recordings of behavioral observations. The behavioral measures used were (a) spontaneous movement activity; (b) state organization, from quantifications of high- and low-amplitude movements; (c) interlimb movement synchrony, a measure of limb coordination; and (d) oral grasp, similar to a newborn infant suckling response. Specific behavioral deficits observed in the Pitx3 mutants were reversed by L-dopa administration in a dose-dependent manner. However, different deficits required dissimilar doses for reversal, suggesting that some early emerging behaviors may be more sensitive to the administration of L-dopa. Taken together, this study provides valuable information about prenatal behaviors dependent on the nigrostriatal pathway.

Dopamine‐dependent and dopamine‐independent actions of cocaine as revealed by brain thermorecording in freely moving rats

Brain temperature fluctuates biphasically in response to repeated, intravenous (i.v.) cocaine injections, perhaps reflecting cocaine's inhibiting effect on both dopamine (DA) transporters and Na+ channels. By using a DA receptor blockade, one could separate these actions and determine the role of DA-dependent and DA-independent mechanisms in mediating this temperature fluctuation. Rats were chronically implanted with thermocouple probes in the brain, a non-locomotor head muscle and subcutaneously. Temperature fluctuations associated with ten repeated i.v. cocaine injections (1 mg/kg with 8-min inter-injection intervals) were examined after a combined, systemic administration of selective D1-like and D2-like receptor blockers (SCH-23390 and eticlopride) at doses that effectively inhibit DA transmission. In contrast to the initial temperature increases and subsequent biphasic fluctuations (decreases followed by increases) seen with repeated cocaine injections in saline-treated control, brain and muscle temperatures during DA receptor blockade decreased with each repeated cocaine injection. DA receptor blockade had no effects on skin temperature, which tonically decreased and biphasically fluctuated (decreases followed by increases) during repeated cocaine injections in both conditions. DA receptor blockade by itself slightly increased brain and muscle temperatures, with no evident effect on skin temperature. DA antagonists also strongly decreased spontaneous movement activity and completely blocked the locomotor activation normally induced by repeated cocaine injections. Although our data confirm that cocaine's inhibitory action on presynaptic DA uptake is essential for its ability to induce metabolic and behavioral activation, they also suggest that the physiological effects of this drug cannot be explained through this system alone. The continued hypothermic effect of cocaine points to its action on other central systems (particularly blockade of Na+ channels) that may be important for the development of cocaine abuse and adverse effects of this drug.

549 Lambda-cyhalothrin's influence on memory processes, movement co-ordination and spontaneous movement activity in mice exposed to transient oligemic brain hypoxia in BCCA model

Endosulfan is a widely used insecticide with immunosuppressive or immunopotentiating effects which alters the immune response of fish. The effects of the acute exposure to endosulfan on a series of parameters of the innate immune response (IIR) of Nile tilapia (Oreochromis niloticus) were investigated—phagocytosis, production of oxygen reactive species, lipoperoxidation as well as spleen cell viability, relative spleen weight and splenocyte concentration—to fully document the effects of this pesticide on Nile tilapia. Juvenile Nile tilapia were exposed in vivo and for 96 h to each one of nine concentrations of endosulfan in order to determine the pesticide's acute toxicity level and calculate the lethal concentration of endosulfan to these organisms (LC50 = 12,795 ppb). Functional assays showed that endosulfan, at a level equivalent to 1/2LC50, altered some parameters of the spleen macrophages of Nile tilapia. Phagocytosis, production of oxygen reactive species, and lipoperoxidation increased significantly in exposed fish. Spleen cell viability and relative spleen weight were lower in exposed organisms compared to non-exposed ones, without reaching statistical significance. Splenocyte concentration was not altered in the present experimental conditions. Thus, in vivo exposure (7 ppb) of juvenile organisms stimulated the phagocytic activity up to significant oxidative stress levels as indicated by the increased lipid peroxidation in plasma. It can be concluded that short exposure to low concentration of endosulfan stimulated macrophage activity but that there was no significant reduction in the structural parameters of the IIR.

Analysis of striopallidal interactions in the control of avoidance behavior.

The effects of chronic administration of phenamine (15 microg) into the neostriatum and bicucculline (5 microg) in the globus pallidus of rats on the performance of avoidance behavior in a shuttle box were studied. Agents were injected daily for three weeks, and control animals received physiological saline. Activation of the dopaminergic system of the neostriatum compensated for decreases in avoidance behavior due to surgical trauma, increased the intensity of spontaneous activity in the "open field," and induced motor stereotypy. Administration of bicucculline into the globus pallidus produced sharp worsening of conditioned reflex avoidance behavior throughout the treatment period (spontaneous movement activity showed no significant change), with recovery only occurring two weeks after the last microinjection. Simultaneous treatment with phenamine into the neostriatum and bicucculline into the globus pallidus resulted in compensation for the inhibitory effects of bicucculline. Several phases were observed in behavioral changes, apparently reflecting the dynamics of interactions between the neo- and paleostriatum. The significance of the coordination of intrastriatal functions for the regulatory activity of the basal ganglia is discussed.

Functional Properties of Presumed Doparmine-Containing and Other Ventral Tegmental Area Neurons in Conscious Rats

To elucidate the functional significance of mesolimbocortical dopamine (DA)-containing neurons in animal adaptive activity, the properties of single units in ventral tegmental area (VTA) and adjacent regions of the midbrain were studied in conscious rats with strictly fixed skull. Analysis of spontaneous firing activity, its changes during polymodal activating and aversive stimulations and their interrelations was performed in electrophysiologically-identified presumed DA-containing (D-type, 48 cells) and other (A-B and C-type, 47 and 29 cells accordingly) neurons found in this brain area. A common feature of all cells was the dependence of their discharge changes on the biological significance of the stimulation used and the strong correlation between these firing changes and stimulation-induced or spontaneous movement activity and blood pressure oscillations. Moreover, a significant correlation between the rate of firing and its dispersion and constancy of directions of neuronal changes during experimental stimulation in single cells were found. Presumed DA-containing neurons of D-type had a high variability of all properties and heterogeneity in the pattern of their discharges and in direction changes (prevalent activations). In presumed acetylcholine (ACh)-containing A-B type cells strong tonic-like activations and in presumed GABA- or ACh-containing interneurons of C-type depressions of firing both correlated with animal movement activity were found. Present data were discussed in relation with mediator specifity of studied cells and the differences of their participation in avoidance behavior forming in aversive environment.