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Stress during the prenatal and early postnatal periods (perinatal stress, PS) is known to impact offspring cognitive, behavioral, and physical development, but effects on skeletal growth are not clear. Our objective was to analyze effects of variable, mild, daily PS exposure on adult offspring long bone length. Twelve pregnant rat dams were randomly assigned to receive variable stress from gestational days 14-21 (Prenatal group), postpartum days 2-9 (Postnatal), both periods (Pre-Post), or no stress (Control). Differences in adult offspring tibia and femur length were analyzed among treatment groups. Mean tibia length differed among groups for males (P = 0.016) and females (P = 0.009), and differences for femur length approached significance for males (P = 0.051). Long bone length was shorter among PS-exposed offspring, especially those exposed to postnatal stress (Postnatal and Pre-Post groups). Results persisted when controlling for nose-tail length. These differences might reflect early stunting that is maintained in adulthood, or delayed growth among PS-exposed offspring. This study suggests that PS results in shorter long bones in adulthood, independently of effects on overall body size. Stunting and growth retardation are major global health burdens. Our study adds to a growing body of evidence suggesting that PS is a risk factor for poor linear growth.

The present study was designed to determine whether delayed recognition memory for visual stimuli was present at birth. It was hypothesized that: (1) newborns would demonstrate delayed recognition memory for both a rotating and stationary Maltese Cross (MC); (2) stimulus movement would influence retention; and (3) various patterns of habituation (c.f., Bornstein & Benasich, 1986) would be observed. Seventy-eight newborns were divided into five delay conditions (0 s, 30 s, 60 s, 90 s, 120 s). Half were habituated to a stationary MC and half to a rotating MC. Following habituation and the delay period, the "habituated" MC was re-presented for 3 trials. The MC was then modified (i.e., (i) direction of rotation was reversed; or (ii) from stationary to rotating) and presented for 3 trials. Measures of stimulus-directed looking and negative state were recorded. The results indicated that newborns in the 90 s and 120 s delay conditions displayed significant increases in looking during the first test trial, but not when looking was averaged across the three test trials. Stimulus movement did not influence retention. Newborns in all five delay conditions increased looking to the modified MC. Finally, the majority of newborns exhibited a fluctuating pattern of habituation, but the patterns did not influence retention. The findings indicate that newborns retain visual information for at least 120 s. However, retrieval appears to degrade after 60 s. Following the longer delay intervals, the first test trial appeared to prime the newborns' long-term memory, permitting successful matching of the "habituated" MC on subsequent trials. Thus, it was concluded that delayed recognition memory for visual stimuli is present at birth. It was argued that the information processing model provides the best explanation for the obtained findings. Behavioural fatigue was ruled out since newborn looking increased to novelty. Furthermore, variable patterns of looking during the habituation phase (i.e., fluctuating) which were present in some newborns was used to argue against a selective receptor model of newborn habituation. The failure to obtain the expected stimulus movement effects was discussed in terms of procedural considerations.Dept. of Psychology. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1996 .L36. Source: Dissertation Abstracts International, Volume: 57-07, Section: B, page: 4747. Adviser: R. Robert Orr. Thesis (Ph.D.)--University of Windsor (Canada), 1996.

Previous research has demonstrated that newborn infants are capable of discriminating stationary objects based on one stimulus dimension. The present study asked the following questions: can newborns process spatial orientation changes?; does stimulus movement influence spatial orientation processing?; can stimulus movement changes be processed?; and can changes to two dimensions of a stimulus be detected? Forty-eight, 2-day-old newborns were administered successive presentations of either stationary or moving, high contrast, black-and-white square wave gratings (stripes) and their level of visual fixation was recorded. The results indicated that newborns are capable of detecting spatial orientation changes in stationary and moving stimuli. Moreover, the findings indicated that newborn infants were capable of detecting direction of movement changes. It was demonstrated that newborn infants could detect changes to two dimensions of a stimulus concurrently. It was concluded that newborns are capable of processing more than one stimulus dimension simultaneously, demonstrating that their information processing capabilities are more sophisticated than previously thought. Finally, it was hypothesized that newborns encode stimulus dimension information separately, but can integrate these memories during object discrimination tasks.Dept. of Psychology. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1993 .L375. Source: Masters Abstracts International, Volume: 32-02, page: 0725. Adviser: Robert Orr. Thesis (M.A.)--University of Windsor (Canada), 1993.