Brain composition and olfactory learning in honey bees

Correlations between brain or brain component size and behavioral measures are frequently studied by comparing different animal species, which sometimes introduces variables that complicate interpretation in terms of brain function. Here, we have analyzed the brain composition of honey bees (Apis mellifera) that have been individually tested in an olfactory learning paradigm. We found that the total brain size correlated with the bees’ learning performance. Among different brain components, only the mushroom body, a structure known to be involved in learning and memory, showed a positive correlation with learning performance. In contrast, visual neuropils were relatively smaller in bees that performed better in the olfactory learning task, suggesting modality-specific behavioral specialization of individual bees. This idea is also supported by inter-individual differences in brain composition. Some slight yet statistically significant differences in the brain composition of European and Africanized honey bees are reported. Larger bees had larger brains, and by comparing brains of different sizes, we report isometric correlations for all brain components except for a small structure, the central body.     

Behavioral correlates of learned aggression in male mice

The aims of this paper are to study the aggressive behavior in male mice with consecutive experience of victories in 2, 10, and 20 days (T2, T10, and T20 winners) of daily agonistic confrontations under the sensory contact model and to determine the most probable behavioral domains that should be used as animal models for learned aggression in humans. It has been shown that the structure of winners' behavior changes from test to test: the attacking behavior prevailed (81% of the total time) in the behavior of T2 winners. Attacks and diggings (herein: digging up and scattering the litter on the partner' territory) prevailed in the behavior of T10 winners (each approximately 40%). T20 winners demonstrated aggressive grooming half of the testing time and digging behavior 25% of the time. Correlational analysis revealed that the number of significant correlations between the behavioral domains (attacking, digging, aggressive grooming, self‐grooming, threats, rotations) and between different behavioral parameters (latency, number, total and average time) of one behavioral domain are growing from the second test to twentieth test, and the relationships between the behavioral domains change qualitatively. The following may be regarded as elements of learned aggression in male mice: (1) appearance of aggressive grooming instead of the intensive attacking behavior and (2) involvement of the digging behavior in the hostile behavior together with the threats and attacking behavior. Negative correlations between parameters of the behavioral domains may testify to the replacement of one behavioral pattern by another and reflect learned behavior. Positive correlations between certain behavioral domains may reflect the formation of a common motivational background for the winners' behavior. Aggr. Behav. 26:386–400, 2000. © 2000 Wiley‐Liss, Inc.     

Increased novelty-induced grooming in aged rats: a preliminary observation

Age-related changes in grooming activity in female Fischer-344 rats were observed in a home cage and in a novel testing chamber for 50 min. Compared to the home cage condition with brief handling treatment, excessive grooming was found in the novel situation. The amount of novelty-induced grooming of aged rats (26-28 months) was about two times that of young animals (6-8 months). This increase in novelty-induced grooming of aged animals was attributable to an increase in the number of grooming bouts, prolongation of each grooming bout, and a slight increase in the duration of licking elements. However, there were no age differences in the percentage of face washing and the duration of face-washing elements. These results are discussed in terms of behavioral aging and age-related changes in peptidergic pathways in the brain.     

Between-individual variability and interpretation of associations between neurophysiological and behavioral measures in aging populations: comment on Salthouse (2011)

Salthouse (2011) argued that (a) variance between individuals on cognitive test scores remains constant between 20 and 90 years of age and (b) widely recognized problems of deducing functional relationships from patterns of correlations between measurements become especially severe for neuropsychological indices, especially for gross indices of age-related brain changes (e.g., losses of brain volume or increases in white matter lesions). I argue that between-individual variability on cognitive tests does increase with age and provides useful information on causes of age-related cognitive decline. I suggest that problems of inference from correlations are just as difficult for behavioral as for neurophysiological indices and that inclusion, in analyses, of even gross measures of brain status such as loss of volume and white matter lesions can correct misinterpretations that occur when only behavioral data are examined.     

Antagonism of behavioral effects of bromocriptine by prolactin in female cats

The effects of the dopaminergic agonist bromocriptine (BC) and exogenously administered prolactin (PRL) on the spontaneous behavior of female cats were investigated. The objective was to test whether BC-induced behavioral effects may be antagonized by PRL. BC (6 mg/kg ip) administration induced abnormal behaviors such as limb flicks, abortive grooms, head/body shakes, and hallucinatory-like behavior/escape as well as excessive grooming. PRL (5 mg/kg ip) administration induced biphasic changes in grooming. The first change was an increase in grooming frequency averaging 256% of baseline control values and lasting for 1 h. This change was followed by reductions in grooming of 75 and 82.5% below baseline during Hours 2 and 3 postinjection, respectively. Combined BC and PRL treatment antagonized the frequency of BC-induced motor effects such as limb flicks, abortive grooms, and head/body shakes. Limb flicks occurred nine times more often 2 h after BC alone than after BC and PRL. The combined treatment also antagonized the excessive grooming observed after separate administrations of BC and PRL. The observed interactions between PRL and BC behavioral effects support the notion that PRL may be an important modulator of dopamine-dependent motor behavior in female cats.     

Impaired Learning and Motor Behavior in Heterozygous Pafah1b1 (Lis1) Mutant Mice

Heterozygous mutation or deletion of Pafah1b1 (LIS1) in humans is associated with syndromes with type 1 lissencephaly, a severe brain developmental disorder resulting from abnormal neuronal migration. We have created Lis1 heterozygous mutant mice by gene targeting. Heterozygous mutant mice are viable and fertile, but display global organizational brain defects as a result of impaired neuronal migration. To assess the functional impact of the mutation, Lis1 heterozygous mice and their wild-type littermates were evaluated on a wide variety of behavioral tests. Lis1 mutant mice displayed abnormal hindpaw clutching responses and were impaired on a rotarod test. Lis1 heterozygous mice were also impaired in the spatial learning version of the Morris water task. Impaired motor behavior and spatial learning and memory in Lis1 mutant mice indicates that impaired neuronal migration can have functional effects on complex behavioral responses. The behavioral findings also support the use of the Lis1 mutant mice as a model from human type 1 lissencephaly.     

Prevalence and correlates of pubic hair grooming among low-income Hispanic,Black, and White women

The purpose of this paper was to describe pubic hair grooming behaviors (shaving, waxing, trimming or dyeing) and the extent to which grooming was related to demographic characteristics and sexual history among low-income Hispanic, Black, and White women. Data were collected from 1677 women aged 16–40 years between July 2010 and August 2011 as part of a larger study. Participants completed a cross-sectional written survey. Multivariable analyses were used to identify correlates of pubic hair grooming. Being a current groomer was associated with being White, a younger age, under or normal weight, having a yearly household income >$30,000, and having 5 or more lifetime sexual partners. Overall, we discovered pubic hair grooming was extremely common among women of varying demographics. It is important for health and research professionals to understand pubic hair grooming practices so they can address behavioral and clinical concerns.     

The AXS battery and “neurological fingerprints”: Meeting the challenge of individual differences in human brain/behavior relations

A new test battery, the Auditory Cross-Section (AXS) Battery, offers a relatively inexpensive, noninvasive means of describing a “neurological fingerprint” for each individual. The battery’s “access to axes” combines physiological and behavioral measures so that a large set of dependent variables can be used to profile an individual and can serve as a context for additional anatomical, behavioral, and physiological data for the same subject. Physiological tests included in the battery described here include (1) otoacoustic emissions (OAEs); (2) the repeated evoked potentials version of the auditory brainstem response (REPs/ABR); and (3) quantitative electroencephalography (qEEG). Complementary behavioral tests were chosen to assess capabilities related to functional asymmetries, such as phonemic awareness and fine motor control, and/or to demonstrate temporal correlations that link behavioral and neural function. Applications of the AXS battery include (1) documentation of individual differences and similarities in neural organization that are related to specific behaviors, such as learning styles or clinical symptoms; (2) provision of contextual data for neuroimaging studies that aid in interpreting individually specific patterns of activation; and (3) development of a neurotypology of human brain/behavior relations, linking characteristics of neuroanatomy and neurophysiology with features of behavior, and general body health.     

Effects of acute administration of nicotine and lobeline on agonistic encounters in male mice

The effects of acute administration of two nicotinic ligands, (‐)‐nicotine and (‐)‐lobeline were examined on isolation‐induced aggression in mice. Individually housed male mice confronted anosmic “standard opponents” in a neutral arena 10 min after drug administration. Encounters were videotaped and evaluated using an ethologically based analysis facilitating estimation of time allocated to 11 broad behavioral categories. Nicotine did not have significant effects on threat or attack but significantly diminished time allocated to digging. The lowest dose of lobeline significantly diminished attack and induced a slight increase of immobility without significantly diminishing other behaviors with motor components. The intermediate and highest dose of lobeline reduced time allocated to all behaviors with motor components. It is concluded that these two nicotinic agonists produce different behavioral profiles during agonistic encounters in mice but that this test may not facilitate assessing the impact of such drugs on irritability. Aggr. Behav. 26:376–385, 2000. © 2000 Wiley‐Liss, Inc.     

Learning and memory in S100-beta transgenic mice: an analysis of impaired and preserved function

S100-beta, a calcium-binding astrocytic protein from chromosome 21, has been implicated in CNS function generally and the hippocampus in particular. Elevated levels of S100-beta have been observed reliably in the brains of patients with Alzheimer's Disease and Down Syndrome. Groups of transgenic mice, carrying multiple S100-beta gene copies, and nontransgenic controls were administered a series of behavioral tests (delayed spatial and nonspatial non-matching-to-sample, radial arm maze, socially acquired food preference) that assessed a wide range of cognitive functions. Consistent with the widespread presence of S100-beta throughout the brain, transgenic mice exhibited learning or memory impairment on all tasks. The dementia-like cognitive profile of S100-beta mice represents a promising model for studying comparable cognitive deficits associated with neurodegenerative diseases.     

Effects of posttraining ethanol on an appetitive task

The present study examined the effects of posttraining ethanol administration upon retention of an appetitive task using a variety of retention behaviors associated with the task. Male C57BL/6J mice were individually trained to find a cheese pellet placed in the corner of an open field. Five behavioral measures were used including locomotor activity counts, rearings, grooming episodes, approaches to the cheese pellet, and latency to consume the cheese pellet. Immediately after training, mice were injected intraperitoneally with saline or 2.0 g/kg of ethanol and then returned to their home cage in which four "intruder" mice were added for 2 h after training. On subsequent testing days (1, 6, 14, and 51 days posttraining), mice were returned to the original training environment and the five behaviors were measured. Both saline- and ethanol-treated mice habituated to the initially novel test environment at similar rates as indicated by decreased exploratory behavior (locomotor activity and rearings). In contrast, a divergence in the latency to consume the cheese pellet was observed: Saline-treated mice behaved as though the cheese was rewarding (decreased latency to eat the pellet), while the ethanol group behaved as though the cheese was aversive (increased latency to eat the pellet). Taken with previous studies, these results demonstrate that posttraining ethanol can have strikingly different effects on retention depending on the task, the measure of retention used, and the underlying neural structures involved.     

Are there pre-existing neural, cognitive, or motoric markers for musical ability?

Adult musician's brains show structural enlargements, but it is not known whether these are inborn or a consequence of long-term training. In addition, music training in childhood has been shown to have positive effects on visual-spatial and verbal outcomes. However, it is not known whether pre-existing advantages in these skills are found in children who choose to study a musical instrument nor is it known whether there are pre-existing associations between music and any of these outcome measures that could help explain the training effects. To answer these questions, we compared 5- to 7-year-olds beginning piano or string lessons (n=39) with 5- to 7-year-olds not beginning instrumental training (n=31). All children received a series of tests (visual-spatial, non-verbal reasoning, verbal, motor, and musical) and underwent magnetic resonance imaging. We found no pre-existing neural, cognitive, motor, or musical differences between groups and no correlations (after correction for multiple analyses) between music perceptual skills and any brain or visual-spatial measures. However, correlations were found between music perceptual skills and both non-verbal reasoning and phonemic awareness. Such pre-existing correlations suggest similarities in auditory and visual pattern recognition as well a sharing of the neural substrates for language and music processing, most likely due to innate abilities or implicit learning during early development. This baseline study lays the groundwork for an ongoing longitudinal study addressing the effects of intensive musical training on brain and cognitive development, and making it possible to look retroactively at the brain and cognitive development of those children who emerge showing exceptional musical talent.     

Midsagittal brain shape correlation with intelligence and cognitive performance

Brain shape might influence cognitive performance because of the relationships between functions, spatial organization, and differential volumetric development of cortical areas. Here we analyze the relationships between midsagittal brain shape variation and a set of basic psychological measures. Coordinates in 2D from 102 MRI-scanned young adult human brains were superimposed through a Procrustes approach, and the residual variation was regressed onto 21 cognitive tests performed by the same individuals. Most of the composite and specific variables (including general intelligence, working memory, attention, and executive functions) do not show meaningful correlations with midsagittal brain morphology. However, variables related to mental speed display subtle but consistent correlations with brain shape variation. Such correlations are small, suggesting that the influence of midsagittal brain geometry on individual cognitive performance is negligible. Nevertheless, this evidence can supply information on brain biology and evolution. Areas associated with the parietal cortex appear to be involved in relationships between brain geometry and mental speed. These areas have been associated with relevant endocranial differences between living and extinct humans, and are important as functional and structural components of brain organization. The limited correlation between brain geometry and mental speed among modern individuals might be more relevant when the large paleoneurological variation of the genus Homo is taken into account.     

NEURONAL CODING OF SERIAL ORDER:

Abstract— How does the brain create rule-governed sequences of behavior? An answer to this question may come from a surprising source: the neostriatum (caudate nucleus and putamen), Traditionally, the neostriatum has been considered pun of the brain's motor system, but its contribution to the preparation or execution of movement is recognized generally to concern high-level motor functions. Recent work implicates the neostriatum in disorders of sequential action and thought, as in the repetition of thoughts or habits in human obsessive-compulsive disorder and movements or speech in Tourette's syndrome. Yet there is no direct evidence to support the idea that the neostriatum controls sequences of behavior. Using ethological and neurophysiological techniques to study neural activity in the rat neoslriatum during syntactic grooming sequences, we found that neuronal activity in the anterolateral neostriatum depended on the execution of syntactic sequences of grooming actions. The individual grooming movements themselves did not activate the neoslriatum; activation was determined by the syntactic sequence in which grooming movements were performed. These data provide the first direct evidence that the neoslriatum coordinates the control of rule-governed behavioral sequences.     

Correlations between behavior of mice in Porsolt's swim test and in tests of anxiety, locomotion, and exploration

This study examined whether the behavior of male NIH Swiss mice in a putative animal model of depression, Porsolt's swim test, is related to that in other behavioral tests. The other tests were the plus-maze test of anxiety, the holeboard test of exploration and locomotor activity, and a test of seizure threshold to bicuculline. The immobility of the mice in the swim test did not correlate with their behavior in any of the other tests used. The only significant correlations found occurred between individual measures in the holeboard and plus-maze tests. The data suggest that immobility in the swim test is not related to behavior in the tests of anxiety, directed exploration, locomotor activity, or seizure threshold.     

The ecological assessment of an autistic child

The behavior of an autistic child was observed in his natural environment. Observations were made in three settings, over approximately 6 months. Sixteen behaviors of the child and six behaviors of adults and peers were recorded. A cluster analysis was performed to identify response classes within the behavioral structure of the child and to see if correlations existed between response and stimulus events. To examine intra- and intersetting changes, Spearman rank correlations and ttests were also computed. This autistic child exhibited a diversity of behavior over time in a given setting and across settings. He persistently ignored other nonautistic children, although he was responsive to adults. Response classes reflected an inverse correlation between the child's selfstimulatory behaviors and his attentiveness to the environment. Elevated levels of adult attention were consistently related to reduced levels in most self-stimulatory behaviors. Two response classes showed inverse relationships between self-stimulatory behaviors. Reducing the frequency of some self-stimulatory behaviors might cause increases in others.This study is based on a dissertation submitted by the first author to The University of Tennessee in partial fulfillment of the requirements for the Ph.D. degree. The research was conducted under the chairmanship of the second author. The authors wish to express their appreciation to Dr. Edward E. Cureton for his help with the statistical analyses.     

Exploration in outbred mice covaries with general learning abilities irrespective of stress reactivity, emotionality, and physical attributes

Across multiple learning tasks (that place different sensory, motor, and information processing demands on the animals), we have found that the performance of mice is commonly regulated by a single factor ("general learning") that accounts for 30-40% of the variance across individuals and tasks. Furthermore, individuals' general learning abilities were highly correlated with their propensity to engage in exploration in an open field, a behavior that is potentially stress-inducing. This relationship between exploration in the open field and general learning abilities suggests the possibility that variations in stress sensitivity/responsivity or related emotional responses might directly influence individuals' general learning abilities. Here, the relationship of sensory/motor skills and stress sensitivity/emotionality to animals' general learning abilities were assessed. Outbred (CD-1) mice were tested in a battery of six learning tasks as well as 21 tests of exploratory behavior, sensory/motor function and fitness, emotionality, and stress reactivity. The performances of individual mice were correlated across six learning tasks, and the performance measures of all learning tasks loaded heavily on a single factor (principal component analysis), accounting for 32% of the variability between animals and tasks. Open field exploration and seven additional exploratory behaviors (including those exhibited in an elevated plus maze) also loaded heavily on this same factor, although general activity, sensory/motor responses, physical characteristics, and direct measures of fear did not. In a separate experiment, serum corticosterone levels of mice were elevated in response to a mild environmental stressor (confinement on an elevated platform). Stress-induced corticosterone levels were correlated with behavioral fear responses, but were unsystematically related to individuals' propensity for exploration. In total, these results suggest that although general learning abilities are strongly related to individuals' propensity for exploration, this relationship is not attributable to variations in sensory/motor function or the individuals' physiological or behavioral sensitivity to conditions that promote stress or fear.     

Novel odors evoke risk assessment and suppress appetitive behaviors in mice

The effects of four novel odors on risk assessment by mice (i. e., flat back approach, stretched attention, immobility) and the suppression of appetitive behaviors were examined in two experiments. When novel odors were presented in a straight runway, subjects spent significantly less time in the odor compartment, relative to controls, when it contained sheep wool, chocolate, or citronella (but not cat fur) odors. Risk assessment behaviors occurred at similar levels among all groups and appetitive behaviors were not suppressed by the novel odors. When odorants were scattered over one half of the subjects' home cage floor in Experiment 2, all novel odors increased the duration of at least on e risk assessment measure and/or suppressed appetitive behaviors (i. e., eating, grooming, rearing). The results clearly reveal that a reasonably wide range of novel odors evoke at least some level of risk assessment which presumably reflects increased fearfulness. The odors of sheep wool and cat fur induced a wider range of such responses than did chocolate or cinnamon suggesting that mammalian odors may be particularly effective stimuli. If so, however, it is clear that predator odors are not uniquely effective in this regard. Experiment 1 also underscores the importance of the testing environment in assessing the behavioral effects of novel odors in mice. © 1993 Wiley-Liss, Inc.     

Estimates of the Validity and Utility of the Conners’ Continuous Performance Test in the Assessment of Inattentive and/or Hyperactive-Impulsive Behaviors in Children

This study evaluated the validity and classification utility of the Conners' Continuous Performance Test (CCPT) in the assessment of inattentive and hyperactive-impulsive behaviors in children. Significant, positive correlations between the CCPT parameters and behavioral ratings of ADHD behaviors were hypothesized. In addition, it was hypothesized that the CCPT parameters would perform better than a random test (chance) and show fair to moderate utility of classification across the different indices. Participants were 104 children between 6 and 12 years of age who were referred for evaluation of attention problems. The first hypothesis was not supported. There were no significant, positive correlations between the CCPT parameters and parent and teacher ratings of inattentive and hyperactive-impulsive behaviors. The second hypothesis was only partially supported. The CCPT Overall Index and the Omission Errors (84th percentile cutoff) performed better than a random test; however, the utility of the CCPT Overall Index only ranged from poor to slight. Receiver operating characteristic analyses showed the accuracy of the CCPT to be low. The implications and limitations of this study and future research directions are discussed.     

Sex-dependent habituation to novelty in rats

Male and female rats were familiarized with one-half of an exploration box for 30 or 60 minutes. When later tested, females showed higher preferences for the other novel half than males. Females also showed higher levels of rearing and ambulation. No sex differences were evident for grooming, freezing or defecation. The results were interpreted as females having habituated to the forced-exposure novelty of the familiar half of the apparatus more rapidly than males when the familiarization period was relatively short. With a longer period, males would have had more time to reach a similar level of habituation to that attained by females familiarized for 30 minutes. Relationships between novelty preferences and both rearing and ambulation as indices of exploration were also discussed in the light of significant correlations for males only.