ISSN:0012-1630    

DOI:10.1002/dev.420090602

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

ISSN:0012-1630    

DOI:10.1002/dev.420090603

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe development of the electroencephalogram EEG and, especially, behavioral state‐specific EEG patterns was studied in white and black hooded rats of the Lister strain, aged 9‐30 days. Movements of the rat were recorded and the behavioral state was monitored by means of a push‐button device. The EEG was collected when the rat was in State 1 (regular respiration, absense of movements, and, after the 14th day when the rat eye opens, eyes closed, State 2 irregular respiration, continual occurrence of twitches, and, after the 14th day, eyes closed, and in State 4 irregular respiration, presence of gross body movements, and, after the 14th day, eyes opened).The EEG of rats on the 9th and 10th day did not reveal behavioral state‐specific patterns. The amplitudes of the EEG were low and only low frequencies occurred. Between the 10th and 13th day an EEG pattern specific for State 1 containing high amplitudes developed. From the 14th day onwards, spindles frequencies from 14‐18 Hz occurred in the EEG during State 1. From the 14th day onwards, the EEG from the visual cortex during State 2 showed a regular and continually occurring 5‐Hz rhythm. Bursts with 5‐Hz waves were recorded from the visual cortex only intermittently during State 4. The EEG frequencies during the bursts varied between 5 and 7 Hz from the 17th day onwards. Computer analysis of the amplitude distributions showed a considerable increase in the power after the 10th day. The analysis of the frequency spectra indicated that the power increase occurs especially in the higher frequencies of the EEG signal. Visual analysis as well as computer analysis of the EEG did not reveal systematic changes in the EEG after the 18th day when the EEG was similar to that recorded

ISSN:0012-1630    

DOI:10.1002/dev.420090604

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe psychological refractory period–the prolonged reaction time RT to the second of 2 closely‐spaced stimuli–was investigated in groups of 13 children and 13 adults. Subjects responded as fast as possible to the 2nd of 2 loud clicks that were presented after a soft click which served as a ready signal. The inter‐stimulus interval ISI, or time between loud clicks, was investigated as an independent variable. The results for ISIS of 50, 100, 250, and 500 msec confirmed the existence of an inverse relationship between RT and ISI. In accordance with the hypothesis investigated, RT was more prolonged in children than in adults as ISI decreased. Findings were consistent with the view that refractory period RP of aninformation‐processing element in the central processor is longer in children than in adults. A single‐channel model of information processing was proposed which could explain the inverse relationship between RT and ISI; could account for the slope differences between the RT vs ISI curves from children and adults; and could account, in part, for the overall longer RTs of children tha

ISSN:0012-1630    

DOI:10.1002/dev.420090605

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe growth‐retarded offspring of mother rats undernourished throughout pregnancy and lactation were fed ad libitum from weaning. Males were tested at 100 days of age, and ovariectomized females at 150 days. After 2 weeks of isolation, pairs of males consisting of 1 control C and 1 previously undernourished PU rat were observed for 10 min on each of 9 consecutive days. Similarly paired and treated female rats were tested a total of 8 times, the first 3 tests being separated from the last 5 by a 10‐day interval. The PU rats, whether male or female, performed more rearing responses and PU male rats ambulated more in the social situation than C rats. The PU males also performed more of the social responses allogroom, walk over, and mount than C males. Similarly, PU females performed more allogroom and crawl under than C females. In general, PU rats were more active than C rats and more socially respons

ISSN:0012-1630    

DOI:10.1002/dev.420090606

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractA technique for embryonic implantation and the subsequent recording of electrocortical, neck muscle, and ocular activity continously from the 20th day of incubation through hatching and the first few days thereafter is demonstrated. The embryonic maturation of the EEG, with a characteristic muscle burst pattern heralding hatching was found, supporting previous reports obtained with acute preparations. The technique for injection into the chorioallantoic membrane CAM vessels or direct deposition onto the CAM is also described. The usefulness of the embryonic neurophysiological implantation coupled with the injection at specific stages of development is discussed as an approach to the understanding of the parameters of the maturation of the sleep‐wakefulness cycle, neurochemistry, and behavio

ISSN:0012-1630    

DOI:10.1002/dev.420090607

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractPrevious work indicates that mice of different genotypes reared in enriched environments show differential increases in performance on a food‐seeking task. In this study 2 experiments examined the effects in selected mice strains of short exposures to such enrichment. Experiment 1 indicated that 48 hr of exposure to enriched cages was sufficient to produce results found previously when subjects were reared from birth in enriched cages. Experiment 2 indicated that as little as 6 hr of exposure to an enriched cage was sufficient to produce almost maximal enrichment effects in C57BL/10J mic

ISSN:0012-1630    

DOI:10.1002/dev.420090608

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractCyclophosphamide (CP), an antineoplastic agent, was administered subcutaneously to Swiss‐Webster mice on the day of birth and the mice were later tested for developmental or adult behavioral abnormalities. The CP dosages of 20, 30, or 45 mg/kg of body weight retarded maturation of swimming ability and 45 mg/kg retarded maturation of the righting reflex. At 7 weeks of age mice treated neonatally with 30 or 45 mg/kg of CP had reduced locomotor activity and were more emotionally reactive than controls in an open field. Mice treated with 30 but not 20 mg/kg of CP tended to avoid shock less often than controls and those treated with 20 mg/kg fell more frequently when crossing a rotating rod for food. Rotorod performance was improved by treatment with 45 but not 30 mg/kg of CP. All dosages examined decreased body weight gains but only 30 or 45 mg/kg resulted in gross body malformations. The results indicate that CP can functionally impair the development of mice and that some of these impairments are independent of gross body malformation

ISSN:0012-1630    

DOI:10.1002/dev.420090609

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractThe effects of tactile and kinesthetic stimulation on the neonatal development of 12 premature infants were investigated. Experimental infants received four 15‐min periods of tactile and kinesthetic stimulation daily for 10 days. The control infants received only standard, routine nursery care. Data were collected daily on 8 dependent measures: weight, number of feedings, amount of formula intake, body temperature, respiration, heart rate, frequency of voiding, and frequency of stooling. The data analyses revealed significant differences in amount of formula intake and in weight at the end of the treatment period in favor of the experimental infants. Additionally, the experimental infants required significantly fewer feedings during the stimulation period. All other dependent measures were nonsignifican

ISSN:0012-1630    

DOI:10.1002/dev.420090610

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY

摘要:

AbstractHighly inbred mice of 3 strains A/J, DBA/2J, and C57 BL/6J were tested in an open field at 14, 21, or 28 days of age. Ten minutes prior to testing, mice received treatment of saline, scopolamine .5 or 1.0 mg/kg of body weight, or d‐amphetamine (.5, 1.0, or 5.0 mg/kg). The d‐amphetamine 5.0 mg/kg increased activity in all strains at 14 days and 28 days of age, and at 21 days significantly increased activity in all except the C57BL/6. In contrast, increased activity with the scopolamine treatment was seen in DBA/2 at 21 days, but not in A and C57BL/6 until 28 days postnatally. The data support a caudal‐rostral gradient of brain development with the inhibitory cholinergic system developing more slowly than the excitatory catecholamine system. In addition, strain‐specific differences in activity levels are discussed in relation to the differential rates of cholinergic mat

ISSN:0012-1630    

DOI:10.1002/dev.420090611

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1976

数据来源: WILEY