Some parameters of behavioral contrast and allocation of interim behavior in rats

Two experiments examined the effects of baseline reinforcement rate and component duration on behavioral contrast and on re-allocation of interim behavior in rats. Positive behavioral contrast occurred during multiple variable-interval 10-second extinction (VI 10 EXT) after a multiple VI 10 VI 10 baseline condition, but not during multiple VI 60 EXT following multiple VI 60 VI 60 baseline. Component duration had no significant effect on contrast. These results differed from those found in studies of pigeons' key pecking. Contrast was accompanied by an increased rate of drinking in the changed component, but drinking in the constant component did not decrease. These results are not consistent with the competition theory of contrast, but are consistent with the predictions based on the matching law. However, no current theory seems to account for all instances of behavioral contrast.     

An age-related deficit in prefrontal cortical function associated with refreshing information

Older adults are slower than young adults to think of an item they just saw, that is, to engage or execute (or both) the simple reflective operation of refreshing just-activated information. In addition, they derive less long-term memory benefit from refreshing information. Using functional magnetic resonance imaging (fMRI), we found that relative to young adults, older adults showed reduced refresh-related activity in an area of dorsolateral prefrontal cortex (left middle frontal gyrus, Brodmann's Area 9), but not in other refresh-related areas. This provides strong evidence that a frontal component of the circuit that subserves this basic cognitive process is especially vulnerable to aging. Such a refresh deficit could contribute to poorer performance of older than young adults on a wide range of cognitive tasks.     

Conditioned behavioral and physiological changes associated with injections of a narcotic antagonist in morphine-dependent monkeys

Environmental stimuli which are repeatedly associated with the nalorphine-induced withdrawal syndrome in morphine-dependent monkeys acquire the ability to produce a variety of conditioned behavioral and physiological responses. Morphine-dependent rhesus monkeys were studied under a fixed-ratio schedule where every tenth lever press produced a food pellet. After several pairings of a stimulus (light or tone) with intravenous injection of a dose of nalorphine which produced an immediate and severe withdrawal syndrome, onset of the stimulus alone produced conditioned suppression of lever pressing, heartrate decrease, vomiting and salivation. Conditioned suppression of responding and conditioned heart-rate changes persisted in post-dependent monkeys for one to four months after termination of chronic morphine treatment. No conditioned electrocardiogram, respiration or temperature changes were ever seen. A second group of morphine-dependent rhesus monkeys was studied under a schedule where every lever press produced an intravenous injection of morphine. After 10 pairings of a light with the intravenous injection of a dose of nalorphine which produced marked withdrawal signs and increased responding for morphine, presentation of the light and injection of sahne produced conditioned increases in responding for morphine. A third group of morphine-dependent rhesus monkeys was studied under a schedule where every nth lever press (n = 1 to 10) terminated a stimulus light associated with periodic injections of nalorphine or naloxone; lever-press responding was engendered and subsequently maintained. Thus, stimuli associated with the nalorphineor naloxone-induced withdrawal syndrome can either suppress, enhance or maintain behavior depending on the schedule conditions.     

Brain weights correlate with behavioral parameters in individual inbred mice housed in a common and enriched environment

Fifty 8-week-old Balb/c mice were individually identified and housed together in a large and enriched environment for 5 months. Maze and open field exploration, response to an aversive noise, swimming, and induced grooming tests were applied to each mouse in an initial search for possible relationships between brain morphology and spontaneous behavior in isogenic individuals living in a complex social and physical environment. The tasks generated 39 quantitative behavioral indices which include locomotion, rearing, still, and grooming bout frequencies, latencies, total, and mean bout durations. At the end of the tests, the 7-month-old mice were sacrificed and the fresh weights of their whole brain, cerebellum, brain stem, diencephalon, telencephalon, and prosencephalon were rapidly obtained. Behavioral data have wide variations and do not adjust to normal population distributions. Means of the same parameter differ between tests. A Spearman correlation matrix of all data yielded many significant correlations between indices of the same task which can be interpreted in terms of time budget and sequence probability. Significant correlations between indices of different tests suggest diverse emotionalities, exploratory strategies, and motor skills. The correlations between body and brain weights and among separate brain regions were not significant. There were several low but significant correlations between brain weights and behavioral indices. Such correlations, the resulting factors, and significant behavioral differences between mice with large and small brains suggest that mice displaying low motor activity in novel environments have larger brains and forebrain/hindbrain ratios than mice with high activity, and that animals with high scores of some specific behaviors have larger brain areas physiologically related to such behaviors.(ABSTRACT TRUNCATED AT 250 WORDS)     

Preoperative enrichment and behavioral recovery in rats with septal lesions

To assess the behavioral effects of preoperative differential housing male rats were placed in either enriched or isolated environments at weaning prior to receiving either sham operations or septal lesions when 57 days of age. Rats with septal lesions showed reduced habituation of ambulation and initially made fewer rears in an empty open field but made more object-contacts coupled with a lack of habituation in the object-filled field. Septal rats also showed severe impairments when tested in a 12-arm radial maze with 7 arms baited and 5 arms unbaited. Preoperative enrichment did not significantly affect these lesion-induced changes. Nevertheless, enrichment significantly lowered ambulation (but did not affect habituation) in the open field and increased the number of manipulatory relative to nonmanipulatory contacts. However, preoperatively enriched septal rats showed a deficit in spontaneous alternation (45%) in contrast to the high levels (83%) shown by intact enriched rats, whereas both intact and septal isolated rats showed similar levels of spontaneous alternation (68%). These results conflict with earlier reports that preoperative enrichment "protects" rats against the deficits produced by septal lesions.     

Sequential evaluation of behavioral treatments and methylphenidate dosage for children with attention deficit hyperactivity disorder

We used a sequential approach to evaluate the relative and combined effects of different types of behavioral treatments, as well as dosage of methylphenidate (MPH), on the disruptive behavior of 3 students who had been diagnosed with attention deficit hyperactivity disorder. Results showed that individualized behavioral treatments produced decreases in disruptive behavior equivalent to MPH for all 3 participants and demonstrated the need to evaluate behavioral treatments and medication dosage on an individual basis.     

儿童行为抑制性与心理障碍关联的认知神经过程

行为抑制型儿童相较于普通儿童更容易在童年中期和青春期出现心理障碍, 具有更高的发展风险性。此类儿童比非抑制型儿童表现出更多的退缩动机、更长的预期过程与前注意过程、更少的注意控制、对负性信息更多的注意偏向、异常活跃的反应监控过程和更慢的习惯化过程。这些与心理障碍患者相似的认知神经过程是儿童行为抑制性与心理障碍间的重要联系途径, 并能作为预测指标筛选有更高发展风险性的个体。除儿童本身的特质外, 环境因素也能通过塑造认知神经过程, 进而影响儿童的发展结果。因此在未来的研究中, 可以考虑不同文化背景下的儿童行为抑制性与心理障碍关联的认知神经过程差异。进而从个体特质和环境因素两方面寻找行为抑制型儿童发展的保护性因素。     

Cytokine-purine interactions in behavioral depression in rats

This paper reviews recent findings from our laboratories concerning metabolic and immune mediators of behavioral depression in rats. Specifically, a single injection of 6 mg/kg of reserpine substantially increases behavioral depression, as evidenced by an increase in the amount of time spent floating by independent groups of rats tested for swim performance at various times during the next week. The behavioral impairment consists of two components. An early component emerges one hour after reserpine treatment and persists for about 24 hours. The deficit is not reversed by intracranial ventricular infusion of the receptor antagonist for interleukin-1β (IL-1β). A second, late-component deficit appears approximately 48 hours after reserpine treatment and recovers within a week. Late-component depression is reversed by central infusion of the IL-1β receptor antagonist, and is mimicked by central infusion of the proinflammatory cytokine. Importantly, both early and late components of reserpine-induced depression and IL-1β induced depression are reversed by a systemic injection of the highly selective A_2A adenosine receptor antagonist 8-(3-Chlorostyryl) caffeine. These data are discussed in terms of the overlap in the conservation-withdrawal reaction during sickness, traumatic stress, and major depression and the regional contribution of purines and cytokines to the organization of this reaction in the brain.     

Attachment in foster children associated with caregivers' sensitivity and behavioral problems

This study focused on attachment of foster children by examining factors associated with attachment relationships of children raised from birth by the same parents. The sample included 61 children between 26 to 88 months of age and their foster caregivers. Attachment security and caregiver sensitivity were coded on the basis of, respectively, a home‐observation (Attachment Q‐Set) and a laboratory procedure (Three boxes). Other measures included caregiver reports of child externalizing and internalizing behavior problems and symptoms of attachment disorder, including inhibited and disinhibited attachment as well as secure base distortions. For a subsample of children, teacher ratings of behavior problems also were available. Foster parent sensitivity was positively associated with attachment security, but only if symptoms of disordered attachment were partialled out. Symptoms of inhibited and disinhibited attachment as well as secure base distortions were positively related to parent reports of externalizing and internalizing behavior problems whereas attachment security was negatively related to teacher reports of externalizing behavior problems. Attachment theoretical tenets appeared valid with foster parent–child relationships, except for children with symptoms of attachment disorder.     

Family factors associated with attention deficit hyperactivity disorder and emotional disorders in children

Few well-controlled studies have identified psychosocial profiles of families of boys with ADHD and boys with emotional disorders compared with normal controls. However, the clinical and theoretical literature pinpoints four domains in which distinctive profiles would be expected to occur. In this study, twenty-two mothers and thirteen fathers of twenty-two boys with ADHD; twenty mothers and fifteen fathers of twenty boys with a mood or anxiety disorder; and twenty-six mothers and sixteen fathers of twenty-seven normal controls were compared on: (1) stress, support and quality of life; (2) current family functioning; (3) parenting style and satisfaction in the family of origin and current family; and (4) current and past parental functioning. The two clinical groups showed higher levels of stress and lower levels of both social support and quality of life than did normal controls. Both clinical groups showed deficits in current family functioning, but contrary to expectations the ADHD and emotional disorder group did not show distinctly different profiles. Parents of ADHD children reported higher levels of authoritarian parenting styles, and parents from both clinical groups reported less parenting satisfaction than did normal controls in both their current families and their families of origin. Parents of children with ADHD and emotional disorders reported greater parenting satisfaction in their families of origin than in their current families. This discrepancy was greatest for parents of ADHD children. Parents of children with ADHD and emotional disorders reported greater psychological health problems and more childhood ADHD symptomatology than did normal controls. Parents of children with ADHD and emotional disorders have significant psychosocial difficulties in family and personal functioning. Family intervention is highly appropriate for families with children who are referred for help with both types of difficulties.     

Ibuprofen effects on behavioral thermoregulation with microwave radiation in albino rats

This study determined whether ibuprofen causes a disruptive behavior pattern similar to aspirin yet contrary to acetaminophen regarding thermoregulatory effects. 8 Sprague-Dawley rats (3 males and 5 females) were drawn from a population of rats which had been conditioned to press a lever for food reinforcement in an undergraduate course in operant conditioning. Animals were conditioned in a refrigerated Skinner Box on a fixed-interval 2-min. (FI-2 min.) schedule of microwave radiation (5 sec. of radiation per exposure occasion) in a repeated-measures reversal (within-subjects) design. The rats were injected intraperitoneally with doses of ibuprofen in amounts of 10-50 mg/kg or methyl-cellulose control vehicle of equal volume over 8-hr. daily sessions. A multivariate analysis of variance showed significant differences due to doses (mg/kg) of ibuprofen for number of microwave heat reinforcers per hour and rate of responding (ns) both measures of which were significantly higher during the first 2 hours of the session. Comparative differences in behavioral thermoregulation in humans reflect the likelihood of underlying biochemical mechanisms based on research by Murphy, Badia, Myers, Boecker, and Wright in 1994.     

Histamine reverses a memory deficit induced in rats by early postnatal maternal deprivation

Early partial maternal deprivation causes long-lasting neurochemical, behavioral and brain structural effects. In rats, it causes a deficit in memory consolidation visible in adult life. Some of these deficits can be reversed by donepezil and galantamine, which suggests that they may result from an impairment of brain cholinergic transmission. One such deficit, representative of all others, is an impairment of memory consolidation, clearly observable in a one-trial inhibitory avoidance task. Recent data suggest a role of brain histaminergic systems in the regulation of behavior, particularly inhibitory avoidance learning. Here we investigate whether histamine itself, its analog SKF-91844, or various receptor-selective histamine agonists and antagonists given into the CA1 region of the hippocampus immediately post-training can affect retention of one-trial inhibitory avoidance in rats submitted to early postnatal maternal deprivation. We found that histamine, SKF-91844 and the H2 receptor agonist, dimaprit enhance consolidation on their own and reverse the consolidation deficit induced by maternal deprivation. The enhancing effect of histamine was blocked by the H2 receptor antagonist, ranitidine, but not by the H1 receptor antagonist pyrilamine or by the H3 antagonist thioperamide given into CA1 at doses known to have other behavioral actions, without altering locomotor and exploratory activity or the anxiety state of the animals. The present results suggest that the memory deficit induced by early postnatal maternal deprivation in rats may in part be due to an impairment of histamine mediated mechanisms in the CA1 region of the rat hippocampus.     

Molecular and behavioral changes associated with adult hippocampus-specific SynGAP1 knockout

The synaptic Ras/Rap-GTPase-activating protein (SynGAP1) plays a unique role in regulating specific downstream intracellular events in response to N-methyl-D-aspartate receptor (NMDAR) activation. Constitutive heterozygous loss of SynGAP1 disrupts NMDAR-mediated physiological and behavioral processes, but the disruptions might be of developmental origin. Therefore, the precise role of SynGAP1 in the adult brain, including its relative functional significance within specific brain regions, remains unexplored. The present study constitutes the first attempt in achieving adult hippocampal-specific SynGAP1 knockout using the Cre/loxP approach. Here, we report that this manipulation led to a significant numerical increase in both small and large GluA1 and NR1 immunoreactive clusters, many of which were non-opposed to presynaptic terminals. In parallel, the observed marked decline in the amplitude of spontaneous excitatory currents (sEPSCs) and inter-event intervals supported the impression that SynGAP1 loss might facilitate the accumulation of extrasynaptic glutamatergic receptors. In addition, SynGAP1-mediated signaling appears to be critical for the proper integration and survival of newborn neurons. The manipulation impaired reversal learning in the probe test of the water maze and induced a delay-dependent impairment in spatial recognition memory. It did not significantly affect anxiety or reference memory acquisition but induced a substantial elevation in spontaneous locomotor activity in the open field test. Thus, the present study demonstrates the functional significance of SynGAP1 signaling in the adult brain by capturing several changes that are dependent on NMDAR and hippocampal integrity.     

Acetaminophen effects on behavioral thermoregulation in albino rats

Acetaminophen (N-Acetyl-p-aminophenol) was administered intraperitoneally to 15 Sprague-Dawley rats partitioned into 3 studies (5 rats per study) using a within subjects, repeated-measures reversal design. Behavioral thermoregulation was assessed in a cold Skinner Box using 5-sec. exposures of microwave radiation [Specific Absorption Rate = 0.34 Watts/kg/(mW/cm2)] as reinforcing stimuli under a fixed-interval 2-min. schedule of positive reinforcement. Doses of 10, 20, 30, 40, and 50 mg/kg (in solutions of 1%, 2%, 3%, 4%, and 5%) acetaminophen showed stable rates of operant responding for heat compared with significant changes in rates for comparable doses of aspirin in a 1993 study by Vitulli, et al. Weight reductions and temperature increases varied significantly with before-session and after-session measures, respectively. 1994-95 biochemical data of Murphy, et al. from humans following aspirin or acetaminophen ingestion which affect thermoregulation and sleep patterns are discussed in conjunction with behavioral data from rats.     

Some determinants of behavioral contrast in pigeons and rats

In Expt. 1, pigeons trained on a multiple variable interval, extinction schedule, showed a positive contrast effect by comparison with control groups trained with S+ only, provided that the interval between stimulus presentations was short (10 sec), but not when it was long (60 sec). Positive contrast also occurred more readily with an easier discrimination, and its appearance was highly correlated with the temporary appearance of transient contrast effects. Although a longer interval between trials produced an overall increase in rate of responding in subjects trained only with S+, it was suggested that this at best represented a different type of contrast effect. In Expt. 2, rats showed positive contrast to S+ when S− was correlated with a lower frequency of reinforcement, but not when it was correlated with a reduced magnitude of reinforcement. The results were discussed in terms of frustration theory.