Age Differences In Behavior Research Articles

Insular cortex dopamine 1 and 2 receptors in methamphetamine conditioned place preference and aversion: Age and sex differences

Rodent studies have proposed that adolescent susceptibility to substance use is at least partly due to adolescents experiencing reduced aversive effects of drugs compared to adults. We thus investigated methamphetamine (meth) conditioned place preference/aversion (CPP/CPA) in adolescent and adult mice in both sexes using a high dose of meth (3 mg/kg) or saline as controls. Mice tagged with green-fluorescent protein (GFP) at Drd1a or Drd2 were used so that dopamine receptor 1 (D1) and 2 (D2) expression within the insular cortex (insula) could be quantified. There are sex differences in how the density of D1+ and D2+ cells in the insula changes across adolescence that may be related to drug-seeking behaviors. Immunohistochemistry followed by stereology were used to quantify the density of cells with c-Fos and/or GFP in the insula. Unexpectedly, mice showed huge variability in behaviors including CPA, CPP, or no preference or aversion. Females were less likely to show CPP compared to males, but no age differences in behavior were observed. Conditioning with meth increased the number of D2 + cells co-labelled with c-Fos in adults but not in adolescents. D1:D2 ratio also sex- and age-dependently changed due to meth compared to saline. These findings suggest that reduced aversion to meth is unlikely an explanation for adolescent vulnerability to meth use. Sex- and age-specific expressions of insula D1 and D2 are changed by meth injections, which has implications for subsequent meth use.

Shaky scaffolding: Age differences in cerebellar activation revealed through activation likelihood estimation meta-analysis.

Cognitive neuroscience research has provided foundational insights into aging, but has focused primarily on the cerebral cortex. However, the cerebellum is subject to the effects of aging. Given the importance of this structure in the performance of motor and cognitive tasks, cerebellar differences stand to provide critical insights into age differences in behavior. However, our understanding of cerebellar functional activation in aging is limited. Thus, we completed a meta‐analysis of neuroimaging studies across task domains. Unlike in the cortex where an increase in bilateral activation is seen during cognitive task performance with advanced age, there is less overlap in cerebellar activation across tasks in older adults (OAs) relative to young. Conversely, we see an increase in activation overlap in OAs during motor tasks. We propose that this is due to inputs for comparator processing in the context of control theory (cortical and spinal) that may be differentially impacted in aging. These findings advance our understanding of the aging mind and brain.

The Orofacial Formalin Test in Mice Revisited—Effects of Formalin Concentration, Age, Morphine and Analysis Method

The orofacial formalin test is established in rats and was recently transferred to mice. The aim of this study was to determine the ideal formalin concentration for testing analgesic drugs, to examine alternatives for the assessment of nociceptive and non-nociceptive behavior as well as the effects of morphine and age on formalin-induced nociception. Formalin (.5, 1, 2.5, 5, 7.5, 10, and 15%) was injected into the vibrissa of mice. The cumulative nociceptive behavior was measured as well as nociceptive and non-nociceptive behavior based on a score that was recorded over a 5-second observation period once per minute. We also examined the effects of morphine on the nociceptive response induced by 2.5% formalin. Age-dependent differences were tested in the third part of the experiment. NONMEM was used to model the pharmacodynamic effects of formalin and morphine. Injection of formalin lead to a concentration-dependent increase in cumulative nociceptive behavior ratings as well as the specific nociceptive behavior 3 of scratching injection site with hindpaw (score 3). The formalin concentrations that lead to 50% of the maximum effect were 2.6 and 3.3%, respectively, for the continuous rating method and the scoring method. Morphine dose dependently suppressed the nociceptive behavior and the number of score 3 ratings of the nociceptive behavior. Age differences in behavior could not be detected by either analytic method. Perspective To improve the existing behavioral nociceptive assay for pain processed by the trigeminal system, we determined an ideal formalin concentration for the orofacial formalin test in mice, evaluated alternative timesaving analysis approaches, and investigated effects of morphine and age on formalin-induced nociception.

Age differences in big five behavior averages and variabilities across the adult life span: Moving beyond retrospective, global summary accounts of personality.

In 3 intensive cross-sectional studies, age differences in behavior averages and variabilities were examined. Three questions were posed: Does variability differ among age groups? Does the sizable variability in young adulthood persist throughout the life span? Do past conclusions about trait development, based on trait questionnaires, hold up when actual behavior is examined? Three groups participated: young adults (18-23 years), middle-aged adults (35-55 years), and older adults (65-81 years). In 2 experience-sampling studies, participants reported their current behavior multiple times per day for 1- or 2-week spans. In a 3rd study, participants interacted in standardized laboratory activities on 8 occasions. First, results revealed a sizable amount of intraindividual variability in behavior for all adult groups, with average within-person standard deviations ranging from about half a point to well over 1 point on 6-point scales. Second, older adults were most variable in Openness, whereas young adults were most variable in Agreeableness and Emotional Stability. Third, most specific patterns of maturation-related age differences in actual behavior were more greatly pronounced and differently patterned than those revealed by the trait questionnaire method. When participants interacted in standardized situations, personality differences between young adults and middle-aged adults were larger, and older adults exhibited a more positive personality profile than they exhibited in their everyday lives.

Snake Species Discrimination by Wild Bonnet Macaques (Macaca radiata)

AbstractWild bonnet macaques (Macaca radiata) were studied in southern India to assess their ability to discriminate non‐venomous, venomous and predatory snakes. Realistic snake models were presented to eight troops of bonnet macaques at feeding stations and their behavior was video‐recorded 3 min before and 3 min after snake exposure. Snakes presented were: (1) venomous Indian cobra (Naja naja) displaying an open hood with ‘eyespots’; (2) venomous common Indian krait (Bungarus caeruleus); (3) non‐venomous green keelback (Macropisthodan plumbicolor); (4) non‐venomous rat snake (Ptyas mucosus); and (5) Indian python (Python molurus) which preys on macaques. Latencies to detect and react to the snakes were evaluated to determine initial responsiveness. Longer‐term assessment was measured as the percentage of time individuals looked at the snakes and monitored the activity of nearby individuals before and after snake detection. All snake models engendered caution and maintenance of a safe distance. Alarm calling occurred only during python presentations. The cobra engendered a startle response or running in the largest percentage of individuals after its detection, whereas the rat snake and python elicited bipedal standing or ambulating to monitor the snakes. We also examined the influence of age on snake recognition. Juveniles and subadults looked at the cobra, krait, and python for a larger percentage of time than adults did; albeit, adults looked at the python substantially longer than at the other snakes. Age differences in behavior suggest that, with the exception of the python, repeated experience with snakes in the wild moderates excitability, consistent with the likely threat of envenomation.

Strain and age differences in behaviour, fear response and pecking tendency in laying hens

1. Behaviours associated with a high or low tendency to feather peck could be used as predictors of feather pecking behaviour in selective breeding programmes. This study investigated how strain and age at testing influenced responses in behavioural tests. 2. Four layer-type strains (ISA Brown, Columbian Blacktail, Ixworth and a high feather pecking (HP) and a low feather pecking (LP) line of White Leghorn) were reared in 6 same-strain/line pens of 8 birds from one day old. Birds in half the pens were given an open field test, a novel object test and a test with loose feather bundles between 4 and 12 weeks of age and a tonic immobility (TI) test at 13 weeks of age. All pens were tested with fixed feather bundles at 26 weeks, and undisturbed behaviour in the home pens was videoed at 1 and 27 weeks of age. Daily records of plumage damage were used as an indicator of feather pecking activity in the home pens. 3. Strain did not influence novel object test, open field test or loose feather test behaviour, although age effects in all three tests indicated a reduction in fearfulness and/or an increase in exploratory behaviour with increasing age. 4. White Leghorns showed longer TI durations than the other strains but less pecking at fixed feather bundles than ISA Browns and Columbian Blacktails. 5. There were few associations between behaviour in the 5 different tests, indicating that birds did not have overall behavioural traits that were consistent across different contexts. This suggests hens cannot easily be categorised into different behavioural 'types', based on their test responses and casts doubt on the usefulness of tests as predictors of feather pecking.

Strain and age differences in behaviour, fear response and pecking tendency in laying hens

Strain and age differences in behaviour, fear response and pecking tendency in laying hens

Age-related impairment in the 250-millisecond delay eyeblink classical conditioning procedure in C57BL/6 mice.

In this study we tested 4-, 9-, 12-, and 18-month-old C57BL/6 mice in the 250-msec delay eyeblink classical conditioning procedure to study age-related changes in a form of associative learning. The short life expectancy of mice, complete knowledge about the mouse genome, and the availability of transgenic and knock-out mouse models of age-related impairments make the mouse an excellent species for expanding knowledge on the neurobiologically and behaviorally well-characterized eyeblink classical conditioning paradigm. Based on previous research with delay eyeblink conditioning in rabbits and humans, we predicted that mice would be impaired on this cerebellar-dependent associative learning task in middle-age, at ~9 months. To fully examine age differences in behavior in mice, we used a battery of additional behavioral measures with which to compare young and older mice. These behaviors included the acoustic startle response, prepulse inhibition, rotorod, and the Morris water maze. Mice began to show impairment in cerebellar-dependent tasks such as rotorod and eyeblink conditioning at 9 to 12 months of age. Performance in hippocampally dependent tasks was not impaired in any group, including 18-month-old mice. These results in mice support results in other species, indicating that cerebellar-dependent tasks show age-related deficits earlier in adulthood than do hippocampally dependent tasks.

The social and behavioral ecology of mixed-age and same-age preschool classrooms: A natural experiment

Social interaction and task behavior of preschool children in mixed-age (MA) and same-age (SA) groups were studied longitudinally in this natural experiment, which capitalized on one preschool's transition from two SA (separate 3, 4) classrooms to two MA (combined 3/4) classrooms. In contrast to previous research examining MA and SA grouping, which has typically lacked appropriate comparison groups, the present study was essentially able to hold teachers, curriculum, location, teaching philosophy, and participant population constant. A total of 7887 naturalistic, time-sampled, classroom observations on 47 children attending the two classes were conducted over the course of 18 months. Children's goal-directed activity, sustained attention, social affiliation, inappropriate behavior, and affect were reliably recorded using a checklist instrument. Significant age differences in behavior between the 3- and 4-year-olds in SA classrooms were typically eliminated in the context of MA classrooms such that the 3-year-olds in MA classes in several ways were more like 4-year-olds in SA classrooms, and 4-year-olds in MA classes behaved more like 3-year-olds in SA classrooms. The social and behavioral ecology of the MA preschool classrooms changed significantly over time as children became more familiar with one another. Several of the social affiliation advantages of MA grouping that were found (i.e., age and gender desegregation) wore off over time as the school year progressed. The effects of MA grouping on children's social and behavioral development appear complicated. Developmental benefits that MA grouping may provide appear to come with some costs, especially for the older children in the classroom.

Swimming behavior of larval Medaka fish under microgravity

Fish exhibit looping and rolling behaviors when subjected to short periods of microgravity during parabolic flight. Strain-differences in the behavioral response of adult Medaka fish ( Oryzias latipes) were reported previously, however, there have been few studies of larval fish behavior under microgravity. In the present study, we investigated whether microgravity affects the swimming behavior of larvae at various ages (0 to 20 days after hatching), using different strains: HNI-II, HO5, ha strain, and variety of different strains (variety). The preliminary experiments were done in the ground laboratory: the development of eyesight was examined using optokinetic response for the different strains. The visual acuity of larvae improved drastically during 20 days after hatching. Strain differences of response were noted for the development of their visual acuity. In microgravity, the results were significantly different from those of adult Medaka. The larval fish appeared to maintain their orientation, except that a few of them exhibited looping and rolling behavior. Further, most larvae swam normally with their backs turning toward the light source (dorsal light response, DLR), and the rest of them stayed with their abdomen touching the surface of the container (ventral substrate response, VSR). For larval stages, strain-differences and age-differences in behavior were observed, but less pronounced than with adult fish under microgravity. Our observations suggest that adaptability of larval fish to the gravitational change and the mechanism of their postural control in microgravity are more variable than in adult fish.

Age differences in behavior and PET activation reveal differences in interference resolution in verbal working memory.

Older adults were tested on a verbal working memory task that used the item-recognition paradigm. On some trials of this task, response-conflict was created by presenting test-items that were familiar but were not members of a current set of items stored in memory. These items required a negative response, but their familiarity biased subjects toward a positive response. Younger subjects show an interference effect on such trials, and this interference is accompanied by activation of a region of left lateral prefrontal cortex. However, there has been no evidence that the activation in this region is causally related to the interference that the subjects exhibit. In the present study, we demonstrate that older adults show more behavioral interference than younger subjects on this task, and they also show no reliable activation at the same lateral prefrontal site. This leads to the conclusion that this prefrontal site is functionally involved in mediating resolution among conflicting responses or among conflicting representations in working memory.

Effects of prenatal testosterone on sex and age differences in behavior elicited by stimulus pups in the rat.

From Days 14 to 19, pregnant Wistar rats were treated with either 2 mg of testosterone propionate (TP) or vehicle. Thirty-, 60-, and 90-day-old offspring were tested individually during 15 min daily on 4 days with a stimulus litter, and pup-oriented and non-pup-oriented behaviors were recorded. Sex differences in pup-oriented behaviors observed in oil groups were eliminated by TP treatment, which affected mainly females. Additionally, TP treatment increased the frequency of self-grooming and decreased the time spent near the pups and the frequency of sniffing and pawing only at 90-days of age. Hiding behavior only occurred at 30 days of age, while pawing near the pups and lying-down behavior was observed mainly in adults. Results show that sex differences in behavior are present before subjects become sensitized to show evident maternal behavior, and suggest that prenatal androgens play an important role in the manifestation of these sex differences and that its effects depend on developmental factors.

Age Differences in Behaviors Leading to Completed Suicide

Age Differences in Behaviors Leading to Completed Suicide

Age Differences in Behaviors Leading to Completed Suicide

The authors described retrospectively the premorbid self destructive behaviors of suicide victims to determine whether these behaviors differ with age. One hundred forty one suicide victims, age 21-92 years, were studied by psychological autopsy. Older age was significantly associated with more determined and planful self-destructive acts, less violent methods, and fewer warnings of suicidal intent. Age differences in the behaviors leading to suicide indicate that intervention in the midst of a suicidal crisis may be less effective in elderly persons than in younger people. Primary prevention should be the focus of efforts to decrease suicide rates in late life.

Behavioral and Ecological Correlates of Interference Competition among Some Hawaiian Drepanidinae

Abstract Interference interactions were studied on the island of Maui among four species of drepanidines that fed on canopy flowers of the ohia tree (Metrosideros collina). The birds had a size-related dominance hierarchy, with ranking (most to least dominant, by location in dominance matrix) as follows: Crested Honeycreeper (Palmeria dolei), Iiwi (Vestiaria coccinea), Apapane (Himatione sanguinea), and Common Amakihi (Hemignathus virens). Immatures were subordinate to conspecific adults. Crested Honeycreepers and Iiwis defended tree-canopy territories, Apapanes were nomadic flock foragers, and Common Amakihis were secretive foragers. Dominance by Iiwis was indicated by a lack of reversals in the dominance matrix. For the top-ranked Crested Honeycreeper dominance was also reflected in greater chase or greater resulting retreat distances or both. Age-related differences in interference behavior by dominants appeared to be due to inexperience, as indicated by shorter chase distances for immatures. Among subordinates both experience and plumage could be responsible for age differences in behavior. Immatures were chased equal distances (despite closer spacing) but less often than adults, and they chose safer retreat sites. Apapanes fed in flocks in a dominant's tree. This increased a dominant's territorial costs, reduced chase frequencies, increased Apapane foraging times, and let Apapanes forage in trees from which they otherwise were excluded. Comparisons with the assemblage on the island of Hawaii suggested similar structure among the three species the two islands have in common. On Maui the bottom-ranked Common Amakihi may be more affected by interference competition, perhaps undergoing a niche shift toward greater insectivory because of an additional dominant.

Prosocial Behavior between Friends in Middle Childhood and Early Adolescence

Fourth, sixth, and eighth graders were paired either with a close friend or with a classmate whom they neither strongly liked nor strongly disliked. The pairs of children were observed as they did two tasks that provided them with opportunities for generous or helpful behavior toward each other. On one task, children distributed rewards to themselves and to their partner. On the second task, children were allowed to help their partner get rewards when the partner had been placed at a disadvantage. The results showed an increase with age in the differences between friends' and classmates' behavior. Eighth graders were more generous and more helpful toward friends than toward other classmates, but sixth and fourth graders treated friends and classmates similarly. After doing the tasks, eighth graders also reported that they thought their friends less often competed with them and more often tried for equality in rewards than other classmates. Attributions about the partner's motives were similar for friends and classmates at sixth and fourth grade. The age differences in behavior and motives are compared with current theories of the development of friendship.

Exploration of Developmental Variables by Manipulation and Simulation of Age Differences in Behavior

It is argued that developmental research should be oriented towards the explication of age changes by the manipulation of variables hypothesized to be associated with age. A number of strategies are discussed which permit short-term manipulation (simulation) of ontogenic change (age functions) in laboratory or controlled settings. These strategies are explored regarding their power in isolating the major variables whose effects are age (or time)-related and in providing information about the key developmental antecedents of age differences as they exist in natura. Although it was argued that such simulation strategies can supply suggestive evidence on key developmental variables, a number of caveats are added, primarily regarding the question of isomorphy between simulated and biotic developmental change. The consideration of these strategies, however, also focuses attention on the inherently descriptive nature of research designs which involve the use of age as an independent variable, further clarifies the role of chronological age in developmental theories, and highlights the potential importance of variables whose effects are manifested over time (or are age-related) but are not directly apparent when conventional cross-sectional or longitudinal methods of data collection are used.

Age Differences in Behavior at the Nursery School Level

Age Differences in Behavior at the Nursery School Level