scholarly journals The Development of Infants’ Expectations for Event Timing

2019 ◽  
Vol 7 (3) ◽  
pp. 219-242 ◽  
Author(s):  
Kyle J. Comishen ◽  
Scott A. Adler
Keyword(s):  
Target Location ◽  
Temporal Information ◽  
Brain Maturation ◽  
Limiting Factor ◽  
Anticipatory Eye Movements ◽  
Event Timing ◽  
Temporal Cues ◽  
Temporal Events ◽  
The Right ◽  
Visual Expectation

The capacity to process and incorporate temporal information into behavioural decisions is an integral component for functioning in our environment. Whereas previous research has extended adults’ temporal processing capacity down the developmental timeline to infants, little research has examined infants’ capacity to use that temporal information in guiding their future behaviours and whether this capacity can detect event-timing differences on the order of milliseconds. The present study examined 3- and 6-month-old infants’ ability to process temporal durations of 700 and 1200 milliseconds by means of the Visual Expectation Cueing Paradigm in which the duration of a central stimulus predicted either a target appearing on the left or on the right of a screen. If 3- and 6-month-old infants could discriminate the milliseconds difference between the centrally-presented temporal cues, then they would correctly make anticipatory eye movements to the proper target location at a rate above chance. Results indicated that 6- but not 3-month-olds successfully discriminated and incorporated events’ temporal information into their visual expectations. Brain maturation and the perceptual capacity to discriminate the relative timing values of temporal events may account for these findings. This developmental limitation in processing and discriminating events on the scale of milliseconds, consequently, may be a limiting factor for attentional and cognitive development that has not previously been explored.

Biochemical and Histopathological Evaluation of the Radioprotective Effects of Melatonin Against Gamma Ray-Induced Skin Damage

2019 ◽  
Vol 12 (1) ◽  
pp. 72-81 ◽  
Author(s):  
Dheyauldeen Shabeeb ◽  
Masoud Najafi ◽  
Ahmed Eleojo Musa ◽  
Mansoor Keshavarz ◽  
Alireza Shirazi ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Histopathological Examination ◽  
Radical Scavenging ◽  
Limiting Factor ◽  
Skin Damage ◽  
Exposed Skin ◽  
Male Wistar Rats ◽  
Time Periods ◽  
Skin Damages ◽  
The Right

Background:Radiotherapy is one of the treatment methods for cancers using ionizing radiations. About 70% of cancer patients undergo radiotherapy. Radiation effect on the skin is one of the main complications of radiotherapy and dose limiting factor. To ameliorate this complication, we used melatonin as a radioprotective agent due to its antioxidant and anti-inflammatory effects, free radical scavenging, improving overall survival after irradiation as well as minimizing the degree of DNA damage and frequency of chromosomal abrasions.Methods:Sixty male Wistar rats were randomly assigned to 4 groups: control (C), melatonin (M), radiation (R) and melatonin + radiation (MR). A single dose of 30 Gy gamma radiation was exposed to the right hind legs of the rats while 40 mg/ml of melatonin was administered 30 minutes before irradiation and 2 mg/ml once daily in the afternoon for one month till the date of rat’s sacrifice. Five rats from each group were sacrificed 4, 12 and 20 weeks after irradiation. Afterwards, their exposed skin tissues were examined histologically and biochemically.Results:In biochemical analysis, we found that malondialdehyde (MDA) levels significantly increased in R group and decreased significantly in M and MR groups after 4, 12, and 20 weeks, whereas catalase (CAT) and superoxide dismutase (SOD) activities decreased in the R group and increased in M and MR groups during the same time periods compared with the C group (p<0.05). Histopathological examination found there were statistically significant differences between R group compared with the C and M groups for the three different time periods (p<0.005, p<0.004 and p<0.004) respectively, while R group differed significantly with MR group (p<0.013). No significant differences were observed between C and M compared with MR group (p>0.05) at 4 and 20 weeks except for inflammation and hair follicle atrophy, while there were significant effects at 12 weeks (p<0.05).Conclusion:Melatonin can be successfully used for the prevention and treatment of radiation-induced skin injury. We recommend the use of melatonin in optimal and safe doses. These doses should be administered over a long period of time for effective radioprotection and amelioration of skin damages as well as improving the therapeutic ratio of radiotherapy.

Foveal Attention Modulates Responses to Peripheral Stimuli

2000 ◽  
Vol 83 (4) ◽  
pp. 2443-2452 ◽  
Author(s):  
Simo Vanni ◽  
Kimmo Uutela
Keyword(s):  
Visual Field ◽  
Target Location ◽  
Peripheral Vision ◽  
Human Subjects ◽  
Stimulus Onset ◽  
Visual Object ◽  
Frontal Eye Field ◽  
L1 Norm ◽  
Luminance Stimulus ◽  
The Right

When attending to a visual object, peripheral stimuli must be monitored for appropriate redirection of attention and gaze. Earlier work has revealed precentral and posterior parietal activation when attention has been directed to peripheral vision. We wanted to find out whether similar cortical areas are active when stimuli are presented in nonattended regions of the visual field. The timing and distribution of neuromagnetic responses to a peripheral luminance stimulus were studied in human subjects with and without attention to fixation. Cortical current distribution was analyzed with a minimum L1-norm estimate. Attention enhanced responses 100–160 ms after the stimulus onset in the right precentral cortex, close to the known location of the right frontal eye field. In subjects whose right precentral region was not distinctly active before 160 ms, focused attention commonly enhanced right inferior parietal responses between 180 and 240 ms, whereas in the subjects with clear earlier precentral response no parietal enhancement was detected. In control studies both attended and nonattended stimuli in the peripheral visual field evoked the right precentral response, whereas during auditory attention the visual stimuli failed to evoke such response. These results show that during focused visual attention the right precentral cortex is sensitive to stimuli in all parts of the visual field. A rapid response suggests bypassing of elaborate analysis of stimulus features, possibly to encode target location for a saccade or redirection of attention. In addition, load for frontal and parietal nodi of the attentional network seem to vary between individuals.

scholarly journals The development of auditory temporal processing during the first year of life

2021 ◽  
Author(s):  
Laurianne Cabrera ◽  
Bonnie K. Lau
Keyword(s):  
Temporal Processing ◽  
Temporal Structure ◽  
Temporal Information ◽  
First Year ◽  
Auditory Temporal Processing ◽  
Speech Stimuli ◽  
Temporal Cues ◽  
Neurophysiological Studies ◽  
Psychophysical Studies ◽  
First Year Of Life

The processing of auditory temporal information is important for the extraction of voice pitch, linguistic information, as well as the overall temporal structure of speech. However, many aspects regarding its early development remains not well understood. This paper reviews the development of different aspects of auditory temporal processing during the first year of life when infants are acquiring their native language. First, potential mechanisms of neural immaturity are discussed in the context of neurophysiological studies. Next, what is known about infant auditory capabilities is considered with a focus on psychophysical studies involving non-speech stimuli to investigate the perception of temporal fine structure and envelope cues. This is followed by a review of studies involving speech stimuli, including those that present vocoded signals as a method of degrading the spectro-temporal information available to infant listeners. Finally, we highlight key findings from the cochlear implant literature that illustrate the importance of temporal cues in speech perception.

Components of Visual Orienting in Early Infancy: Contingency Learning, Anticipatory Looking, and Disengaging

1991 ◽  
Vol 3 (4) ◽  
pp. 335-344 ◽  
Author(s):  
Mark H. Johnson ◽  
Michael I. Posner ◽  
Mary K. Rothbart
Keyword(s):  
Age Of Onset ◽  
Age Groups ◽  
Spatial Location ◽  
Contingency Learning ◽  
Significant Evidence ◽  
Anticipatory Eye Movements ◽  
General Terms ◽  
Visual Orienting ◽  
The Right ◽  
Anticipatory Looking

Three aspects of the development of visual orienting in infants of 2, 3, and 4 months of age are examined in this paper. These are the age of onset and sequence of development of (1) the ability to readily disengage gaze from a stimulus, (2) the ability to consistently show “anticipatory” eye movements, and (3) the ability to use a central cue to predict the spatial location of a target. Results indicated that only the 4--month-old group was easily able to disengage from an attractive central stimulus to orient toward a simultaneously presented target. The 4--month-old group also showed more than double the percentage of “anticipatory” looks than did the other age groups. Finally, only the 4--month-old group showed significant evidence of being able to acquire the contingent relationship between a central cue and the spatial location (to the right or to the left) of a target. Measures of anticipatory looking and contingency learning were not correlated. These findings are, in general terms, consistent with the predictions of matura-tional accounts of the development of visual orienting.

Ch.7 Non-performance, s.4: Damages, Introduction to Section 7.4 of the PICC

2015 ◽  
Author(s):  
McKendrick Ewan
Keyword(s):  
United Nations ◽  
The Other ◽  
Limiting Factor ◽  
Notable Feature ◽  
United Nations Convention ◽  
The United Nations ◽  
International Sale Of Goods ◽  
The Right

Section 7.4 of the UNIDROIT Principles of International Commercial Contracts (PICC) is concerned with remedy of damages. It covers the right to recover damages in the event of non-performance as well as the measure of damages, particularly the use of foreseeability as a limiting factor on the recoverability of damages. A notable feature of Section 7.4 is that the entitlement to recover damages is not linked to any notion of fault, nor to any system of notification of the defaulting party. Instead, the right arises on non-performance by the other party to the contract unless the non-performance is excused. The articles in Section 7.4 build upon, and in places develop, the rules to be found in the United Nations Convention on Contracts for the International Sale of Goods (CISG).

scholarly journals Week-by-week changes in sleep EEG in healthy full-term newborns

SLEEP ◽  
2019 ◽  
Vol 43 (4) ◽  
Author(s):  
María Corsi-Cabrera ◽  
Lourdes Cubero-Rego ◽  
Josefina Ricardo-Garcell ◽  
Thalia Harmony
Keyword(s):  
Full Term ◽  
Sleep Eeg ◽  
Brain Maturation ◽  
Sleep Stages ◽  
Postnatal Life ◽  
Quiet Sleep ◽  
New Findings ◽  
Higher Power ◽  
Term Newborns ◽  
The Right

Abstract Spectral analysis of neonatal sleep is useful for studying brain maturation; however, most studies have analyzed conventional broad bands described for awake adults, so a distinct approach for EEG analysis may disclose new findings. Study Objectives To extract independent EEG broad bands using principal component analysis (PCA) and describe week-by-week EEG changes in quiet sleep (QS) and active sleep (AS) during the first 5 weeks of postnatal life in healthy, full-term newborns. Methods Polysomnography of spontaneous sleep was recorded in 60 newborns in 5 groups at 41, 42, 43, 44, and 45 weeks (n = 12 each) postconceptional age (POST-C). QS and AS stages were identified. Absolute power (AP) for 1 Hz bins between 1 and 30 Hz was subjected to PCA to extract independent broad bands. Results PCA rendered three independent broad bands distinct from conventional bands. They explained 82.8% of variance: 2–10 Hz, 10–16 Hz, and 17–30 Hz. ANOVAs (group × age × derivations) showed significant higher power at 2–10 Hz with greater age, higher power in QS than AS in all three bands, and significantly higher AP in the left central region, and in the right occipital and temporal areas, in both sleep stages. Conclusion A different method of analyzing sleep EEG generated new information on brain maturation. The Sigma frequencies identified suggest that sleep spindle maturation begins by at least 41 weeks of POST-C age. Interhemispheric asymmetries during sleep suggest earlier development of the central left region and the right occipital and temporal areas.

TMS entrainment of pre-stimulus oscillatory activity in tactile perception

2012 ◽  
Vol 25 (0) ◽  
pp. 152
Author(s):  
Manuela Ruzzoli ◽  
Salvador Soto-Faraco
Keyword(s):  
Parietal Cortex ◽  
Target Location ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Rhythmic Activity ◽  
Tactile Perception ◽  
Oscillatory Activity ◽  
Alpha Frequency ◽  
Specific Frequency ◽  
The Right ◽  
Beta Frequency

It is widely recognized that oscillatory activity plays an important functional role in neural systems. Decreases in alpha (∼10 Hz) EEG/MEG activity in the parietal cortex correlate with the deployment of spatial attention controlateral to target location in visual, auditory and tactile domains. Recently, repetitive Transcranial Magnetic Stimulation (rTMS) has been successfully applied to entrain a specific frequency at the parietal cortex (IPS) and the visual cortex. A short burst of 10 Hz rTMS impaired contralateral visual target detection and improved it ipsilaterally, compared to other control frequencies. This finding suggests a causal role of rhythmic activity in the alfa range in perception. The aim of the present study is to address whether entraining alpha frequency in the IPS plays a role in tactile orienting, indicating similarities between senses (vision and touch) in the communication between top-down (parietal) and primary sensory areas (V1 or S1). We applied rhythmic TMS at 10 and 20 Hz to the (right or left) IPS and S1, immediately before a masked vibrotactile target stimulus (present in 50% of the trials) to the left or right hand. Preliminary results lean towards the consequential effects of entraining alpha frequency into IPS for tactile detection such that it decreases tactile perception contralaterally and increases it ipsilaterally, compared to Beta frequency.

Temporal Averaging in Response to Change

2016 ◽  
Vol 4 (3) ◽  
pp. 223-247 ◽  
Author(s):  
Matthew S. Matell ◽  
Benjamin J. De Corte ◽  
Thomas Kerrigan ◽  
Christine M. DeLussey
Keyword(s):  
Information Sources ◽  
Weighted Average ◽  
Temporal Information ◽  
Recent Information ◽  
Temporal Cues ◽  
Timing System ◽  
Temporal Averaging ◽  
Response To Change ◽  
Reinforcement Availability

We have previously found that when rats are simultaneously presented with two different cues that signify possible reinforcement availability at two different times, they will respond as though they are timing an intermediate duration. We have interpreted this result as indicating that rats deal with conflicting temporal information by averaging these temporal expectations. In the present work, we show that rats update their temporal expectations when temporal cues change during a trial, producing a normally shaped, unimodal peak in responding at a time in between the reinforced times. These peaks are approximately scalar, suggesting that the rats are timing a single expectation. These data are consistent with a timing system that generates a weighted average of conflicting temporal expectancies, with greater weight given to more recent information sources.

scholarly journals Right-hemispheric dominance for visual remapping in humans

2011 ◽  
Vol 366 (1564) ◽  
pp. 572-585 ◽  
Author(s):  
L. Pisella ◽  
N. Alahyane ◽  
A. Blangero ◽  
F. Thery ◽  
S. Blanc ◽  
...  
Keyword(s):  
Posterior Parietal Cortex ◽  
Right Hemisphere ◽  
Target Location ◽  
Original Data ◽  
Hemispheric Dominance ◽  
Cortical Lesion ◽  
Constructional Apraxia ◽  
Posterior Parietal ◽  
The Right ◽  
Transfer Of Information

We review evidence showing a right-hemispheric dominance for visuo-spatial processing and representation in humans. Accordingly, visual disorganization symptoms (intuitively related to remapping impairments) are observed in both neglect and constructional apraxia. More specifically, we review findings from the intervening saccade paradigm in humans—and present additional original data—which suggest a specific role of the asymmetrical network at the temporo-parietal junction (TPJ) in the right hemisphere in visual remapping: following damage to the right dorsal posterior parietal cortex (PPC) as well as part of the corpus callosum connecting the PPC to the frontal lobes, patient OK in a double-step saccadic task exhibited an impairment when the second saccade had to be directed rightward . This singular and lateralized deficit cannot result solely from the patient's cortical lesion and, therefore, we propose that it is due to his callosal lesion that may specifically interrupt the interhemispheric transfer of information necessary to execute accurate rightward saccades towards a remapped target location. This suggests a specialized right-hemispheric network for visuo-spatial remapping that subsequently transfers target location information to downstream planning regions, which are symmetrically organized.

scholarly journals Mitotic Degradation of Human Thymidine Kinase 1 Is Dependent on the Anaphase-Promoting Complex/Cyclosome-Cdh1-Mediated Pathway

2004 ◽  
Vol 24 (2) ◽  
pp. 514-526 ◽  
Author(s):  
Po-Yuan Ke ◽  
Zee-Fen Chang
Keyword(s):  
Cell Cycle ◽  
Thymidine Kinase ◽  
Mammalian Cells ◽  
Mitotic Exit ◽  
Limiting Factor ◽  
Anaphase Promoting Complex ◽  
Thymidine Kinase 1 ◽  
Ubiquitin Proteasome ◽  
The Right

ABSTRACT The expression of human thymidine kinase 1 (hTK1) is highly dependent on the growth states and cell cycle stages in mammalian cells. The amount of hTK1 is significantly increased in the cells during progression to the S and M phases, and becomes barely detectable in the early G1 phase by a proteolytic control during mitotic exit. This tight regulation is important for providing the correct pool of dTTP for DNA synthesis at the right time in the cell cycle. Here, we investigated the mechanism responsible for mitotic degradation of hTK1. We show that hTK1 is degraded via a ubiquitin-proteasome pathway in mammalian cells and that anaphase-promoting complex/cyclosome (APC/C) activator Cdh1 is not only a necessary but also a rate-limiting factor for mitotic degradation of hTK1. Furthermore, a KEN box sequence located in the C-terminal region of hTK1 is required for its mitotic degradation and interaction capability with Cdh1. By in vitro ubiquitinylation assays, we demonstrated that hTK1 is targeted for degradation by the APC/C-Cdh1 ubiquitin ligase dependent on this KEN box motif. Taken together, we concluded that activation of the APC/C-Cdh1 complex during mitotic exit controls timing of hTK1 destruction, thus effectively minimizing dTTP formation from the salvage pathway in the early G1 phase of the cell cycle in mammalian cells.

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