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At least 1,549 records · Page 86Linked to original sources
PubMed2004

A waterborne behavioral cue for the actinotroch larva of Phoronis pallida (Phoronida) produced by Upogebia pugettensis (Decapoda: Thalassinidea).

Phoronis pallida (Phoronida) occurs as a commensal within the burrow of Upogebia pugettensis (Decapoda: Thalassinidea). Upogebia-conditioned seawater (UCSW) induced an exploratory swimming behavior in competent larvae of P. pallida in a dosage-dependent manner. This behavior included a significant increase in swimming speed that was directed downward, along with the repeated probing of the bottom with the sensory portion of the oral hood. The waterborne cue from the shrimp was present in the gut effluent, and the swimming behavior was not the result of the elevated ammonia concentration. Molecular weight separation of the UCSW estimated that the cue was between 10 and 50 kDa. Enzymatic treatments showed that the cue's activity could be eliminated by arginase and significantly reduced by lipase. Competent larvae were also induced to metamorphose when exposed to 20 mM CsCl for 30 min. Larvae did not respond to CsCl when cultured about 4 weeks past the onset of competence. Compared with actinotroch larvae of other phoronid species, P. pallida larvae exhibit greater behavioral specificity and neuronal differences within the hood sense organ. These anatomical and behavioral differences may have been maintained through a coevolutionary process among P. pallida and species of thalassinid shrimps that share Upogebia life-history characteristics.

Animals↗
PubMed2002

Visual search for high-level configural differences as well as low-level critical features is highly efficient early in childhood.

Visual search, or the ability to locate a single target from a field of distractors, is used as a means of assessing the capacity of the visual system with regard to the detection of low-level stimulus dimensions such as color, line orientation, and other specific perceptual features and higher level characteristics such as three-dimensional (3-D) orientation implied by pictorial cues to depth or occlusion. Target-distractor differences of importance to the visual system result in rapid (and possibly preattentive) target location while differences of lesser importance (or differences that are less salient) tend to elicit slower, less efficient search performance (search in this latter case may require attentional resources.) Adult abilities in this type of task have been tested extensively, but comparatively little is known about the development of these abilities. The present investigation was conducted to test, across a range of ages in childhood, the ability to detect visual search targets defined by a low-level critical feature (a texton; B. Julesz, 1981) and by static (pictorial) cues to depth. Children 2 to 9 years of age and adults were tested with each type of target. Previous data from infant studies predicted that the texton-defined differences would elicit highly efficient search performance, and this proved to be the case. When no texton difference was present, however, children's search was highly inefficient. Children between 4 to 9 years of age also proved to be quite efficient at locating a target, differing only by a pictorially rendered 3-D orientation from the distractors, but were much less efficient when the static cues to 3-D orientation were removed. These findings confirm previous reports that the basic processes underlying visual search are functional early in development, but suggest that children's search is less efficient than adult search when attention is required for object localization.

Child↗
PubMed1975

Influence of age and sex on the behavior of rats deprived of the rearing response.

Rearing on the hind legs, one component of "general activity" was restricted in male and female rats both before (25 days) and after (50 days) the development of this response. In contrast to previous restriction studies the animals were kept in groups and allowed free locomotor activity in the cage environment. After 8 weeks, open-field testing showed that selective restriction decreased the frequency of rearing behavior, particularly unsupported rearing which requires physical coordination and balance. Effects were greater for females (which usually rear more than males) and for animals restricted at weaning (25 days).

Age Factors↗
PubMed1977

Exploration and play with objects in domestic kittens.

The responses of 12 kittens to unfamiliar and familiar objects was tested. Four categories of behavior were measured: exploration, play-exploration, play, and non-manipulatory contact. The results indicated that exploration and play-exploration were used for longer durations with unfamiliar objects and play was used for longer durations with familiar objects. Rank-order correlations between the measures showed that objects explored were not correlated with objects played with or play-explored. Analyses of the rankings revealed that small size and mobility were important object properties of play. The results suggest that exploration involves learning about stimulus properties, play-exploration involves learning about perceptual-motor properties, and play involves learning to coordinate movements with those of moving objects.

Animals↗
PubMed2006

Behavioral correlates of the distributed coding of spatial context.

Hippocampal place cells respond heterogeneously to elemental changes of a compound spatial context, suggesting that they form a distributed code of context, whereby context information is shared across a population of neurons. The question arises as to what this distributed code might be useful for. The present study explored two possibilities: one, that it allows contexts with common elements to be disambiguated, and the other, that it allows a given context to be associated with more than one outcome. We used two naturalistic measures of context processing in rats, rearing and thigmotaxis (boundary-hugging), to explore how rats responded to contextual novelty and to relate this to the behavior of place cells. In experiment 1, rats showed dishabituation of rearing to a novel reconfiguration of familiar context elements, suggesting that they perceived the reconfiguration as novel, a behavior that parallels that of place cells in a similar situation. In experiment 2, rats were trained in a place preference task on an open-field arena. A change in the arena context triggered renewed thigmotaxis, and yet navigation continued unimpaired, indicating simultaneous representation of both the altered contextual and constant spatial cues. Place cells similarly exhibited a dual population of responses, consistent with the hypothesis that their activity underlies spatial behavior. Together, these experiments suggest that heterogeneous context encoding (or "partial remapping") by place cells may function to allow the flexible assignment of associations to contexts, a faculty that could be useful in episodic memory encoding.

Action Potentials↗
PubMed2005

High and low responders to novelty show differential effects in striatal glutamate.

The goal of this study was to determine whether there was a difference in glutamate within the dorsolateral striatum in mice exhibiting either a high (HR) or low (LR) locomotor response to a novel environment. The number of line crossings over a 30-min-period when the mice were placed in a novel environment was determined, and those mice for which the values were above the mean were in the HR group and those with the values below the mean were in the LR group. In vivo microdialysis was carried out to determine the basal extracellular level of striatal glutamate, and the contralateral striatum was taken to measure the density of glutamate immunolabeling within nerve terminals making an asymmetrical (excitatory) synaptic contact using quantitative immuno-gold electron microscopy. There was a statistically significant difference (35%) in the basal extracellular level of striatal glutamate between the HR and LR groups, with the HR group having a lower level, compared with that of the LR group. There was a 25% difference in the density of nerve terminal glutamate immuno-gold labeling associated with the synaptic vesicle pool in the HR, compared with that in the LR group, but this difference was not statistically significant. There was no change in the basal extracellular level of striatal dopamine between the two groups, but there was a statistically significant difference (73%) in the basal turnover ratio of striatal dopamine and its metabolites in the HR, compared with that in the LR group. The data suggests that the difference in extracellular striatal glutamate between the HR and LR groups is not due to an alteration in basal extracellular dopamine but could be due to an increase in dopamine turnover.

Animals↗
PubMed1998

The influence of a targeted deletion of the IFNgamma gene on emotional behaviors.

Evidence suggests that interferon-gamma (IFNgamma) plays an important role in CNS function and development. While the paucity of agents that selectively modify IFNgamma production or interaction with its receptors makes analyses of its potential behavioral relevance difficult, mice with null mutations of the IFNgamma gene have been used to investigate the potential role of IFNgamma in emotional behaviors. C57Bl/6 (B6) mice with null mutations of the IFNgamma gene (IFNgamma (-/-)) showed significantly increased emotionality compared to the wild-type (IFNgamma (+/+)) B6 mice. This was manifested in performance in the elevated plus maze as well as increased defecation scores and decreased locomotor activity both in novel environments and following a sonic stimulus. In contrast, the general level of emotionality of both IFNgamma (+/+) and (-/-) BALB/c (C) mice was substantially greater than that of either of the B6 mouse groups. While C IFNgamma (-/-) showed increased immobility in response to novelty, other indices of emotionality of C IFNgamma (-/-) mice were not significantly different from those of the C IFNgamma (+/+) mice. In summary, the lack of IFNgamma appears to contribute to increased emotionality, but the basal behaviors of the parental strain (e.g., BALBc) may overshadow the expression of this emotionality. While mice with null mutations of the IFNgamma gene may be useful tools for investigating the role of IFNgamma in brain function and behavior, the influence of the parent strain genome(s) on the behaviors in question must be taken into account.

Adaptation, Psychological↗
PubMed2000

Behavioural activity of (S)-3,5-DHPG, a selective agonist of group I metabotropic glutamate receptors.

The influence of intracerebroventricular (i.c.v.) injections of (S)-3,5-dihydroxyphenyl-glycine (S)-3,5-DHPG, a selective agonist of group I metabotropic glutamate receptors (mGluRs), on the activity of the central nervous system was examined in male rats. (S)-3,5-DHPG at doses of 25, 50 and 100 nmol significantly attenuated crossings of squares and rearings, but not bar approaches, in an 'open field' test and failed to change apomorphine-induced stereotypy. (S)-3,5-DHPG at the above doses, given immediately after the learning trial, significantly facilitated the consolidation process in a passive avoidance situation, but given before the learning trial and before the retention testing did not have any influence on acquisition and retrieval processes, respectively. Moreover, (S)-3,5-DHPG did not influence recognition memory evaluated in an object recognition test. These results may suggest that activation of group I mGluRs takes part in the consolidation process in affectively-motivated memory, but is probably not necessary for processing of recognition memory, and that (S)-3,5-DHPG memory facilitation seems to be independent of glutamatergic and dopaminergic interaction.

Animals↗
PubMed1985

Dopamine-sensitive alternation and collateral behaviour in a Y-maze: effects of d-amphetamine and haloperidol.

The degree of alternation of arm choice in a Y-maze was examined on 15-min tests over 4 days in rats treated (IP) with saline, amphetamine (0.5 or 2.0 mg/kg) or pretreated with haloperidol (0.08 mg/kg) in each condition prior to test. On day 1 amphetamine-treated animals chose arms at random, but from day 2-4 those receiving the higher dose perseverated their choice. Controls maintained alternation. These effects could be prevented by haloperidol pretreatment. Amphetamine treatment increased the frequency of rearing at the middle, choice-point of the maze more than at the end of an arm. The increase at the mid-point was suppressed by haloperidol pretreatment from day 1 and at the end of an arm from day 2. Amphetamine induced an increase in head-turning/"looking" that was suppressed by haloperidol from day 2. The effect of haloperidol in increasing the duration of an item of looking or rearing at the end of an arm also started later in testing. Two effects are postulated to have occurred: (i) a conflict on day 1 between novelty-controlled sensory or attentional effects that leads to an alternation of arm choice and amphetamine-induced dopaminergic activity that facilitates an alternation of behavioural responses. The result was random choice and increased rearing at the choice point. (ii) On days 2-4 the drug-induced effects on switching motor responses came to control behaviour.

Animals↗