Amphetamine-induced rotation in normal cats

Childrens' left-turning preference is not modulated by magical ideation

The literature on human turning preferences is inconsistent. While the few studies with children below 14 years of age uniformly describe an overall left-turning (counterclockwise) tendency, a recent Internet study with more than 1500 adults found a right-sided (clockwise) bias. We set out to investigate spontaneous turning behaviour in children age 5-3 years and, based on neuropsychiatric work in adults, also explored a potential association with magical thinking. Findings indicated a clear left-turning preference, independent of a participant's sex and handedness. Whether a child responded a question about the existence of extrasensory communication in the affirmative or not was unrelated to direction and size of turning bias and lateral preference. Our results are consistent with a left-sided turning preference reported for children, but in opposition to the clockwise bias recently described in a large-scale study with adults. Whether they point to a maturational gradient in the preferred direction of spontaneous whole-body rotation or rather to a lack of comparability between measures used in observational versus Internet-based studies remains to be further investigated. Regarding a purported association between body turns and magical thinking, our study is preliminary, as only one single question was used to probe the latter.

Genetic analysis of the role of protein kinase C signaling pathways in behaviors by direct gene transfer with HSV-1 vectors

A genetic intervention strategy is described to elucidate the specific biochemical pathways in identified types of neurons that underlie behavioral adaptations. This strategy contains three parts: A Herpes simplex virus (HSV-1) vector is used to obtain localized gene transfer, a cell type-specific promoter is used to target expression to a particular type of neuron, and a constitutively active signal transduction enzyme is expressed to alter neuronal physiology. To enable this approach, a constitutively active protein kinase C (PKC) was developed which causes a long-lasting, activation-dependent increase in neurotransmitter release from cultured sympathetic neurons. This genetic intervention strategy was tested using the nigrostriatal system: Microinjection of HSV-1 vectors that contain the tyrosine hydroxylase promoter targeted expression to dopaminergic nigrostriatal neurons. Expression of the constitutively active PKC in a small percentage of nigrostriatal neurons (approximately 0.1-2%) produced a long-term (> or = 1 month) change in apomorphine-induced rotational behavior, the amount of rotational behavior correlated with the number of affected nigrostriatal neurons, and D2-like dopamine receptor levels were elevated in the striatal regions innervated by the affected nigrostriatal neurons. The strengths and limitations of this genetic intervention strategy are discussed.

Modulation of rat rotational behavior by direct gene transfer of constitutively active protein kinase C into nigrostriatal neurons

The modulation of motor behavior by protein kinase C (PKC) signaling pathways in nigrostriatal neurons was examined by using a genetic intervention approach. Herpes simplex virus type 1 (HSV-1) vectors that encode a catalytic domain of rat PKCbetaII (PkcDelta) were developed. PkcDelta exhibited a constitutively active protein kinase activity with a substrate specificity similar to that of rat brain PKC. As demonstrated in cultured sympathetic neurons, PkcDelta caused a long-lasting, activation-dependent increase in neurotransmitter release. In the rat brain, microinjection of HSV-1 vectors that contain the tyrosine hydroxylase promoter targeted expression to dopaminergic nigrostriatal neurons. Expression of pkcDelta in a small percentage of nigrostriatal neurons (approximately 0.1-2%) was sufficient to produce a long-term (>/=1 month) change in apomorphine-induced rotational behavior. Nigrostriatal neurons were the only catecholaminergic neurons that contained PkcDelta, and the amount of rotational behavior was correlated with the number of affected nigrostriatal neurons. The change in apomorphine-induced rotational behavior was blocked by a dopamine receptor antagonist (fluphenazine). D2-like dopamine receptor density was increased in those regions of the striatum innervated by the affected nigrostriatal neurons. Therefore, this strategy enabled the demonstration that a PKC pathway or PKC pathways in nigrostriatal neurons modulate apomorphine-induced rotational behavior, and altered dopaminergic transmission from nigrostriatal neurons appears to be the affected neuronal physiology responsible for the change in rotational behavior.

A sex difference in turning bias in humans

A large body of literature has documented the existence of individual preferences in turning direction among rodents which appear to be dependent on striatal dopaminergic mechanisms. Recent work has indicated that humans also demonstrate individual turning preferences, and that these preferences may also be related to the nigrostriatal dopamine system. We describe here a new method for measuring turning preferences in humans and report a sex difference in the magnitude of the directional preference. While both males and females tended to turn towards the right, this tendency was significantly stronger among females. Analyses of test-retest reliability across two sessions (1-2 weeks apart) indicated that, in general, the rotation task elicited consistent turning biases. However, the turning biases of males and of females using oral contraceptives were significantly more consistent than those of regularly cycling females. These results are compatible with the animal literature and provide indirect evidence that ovarian hormones may modulate the mechanism(s) underlying this motor asymmetry.

Delayed emergence of striatal dopaminergic hyperactivity after anterolateral ischemic cortical lesions in humans; evidence from turning behavior

To test the hypothesis that striatal dopaminergic hyperactivity in humans may be an aftermath of anterior cortical ischemic insults, we utilized earlier observations that in several species, including humans with hemiparkinson's disease, asymmetric striatal dopaminergic activity results in spontaneous asymmetric turning away from the hemisphere with higher dopaminergic activity. In this study, electronic monitoring showed that, compared to normal controls, outpatients with old frontal and inferior-parietal cortical strokes exhibit a marked tendency to turn away from the side of the lesion. This delayed ipsilateral neglect suggests a delayed emergence of lasting ipsilateral striatal dopaminergic hyperactivity after unilateral anterolateral cortical insult in humans. Old ischemic insults to anterolateral cortical areas could be one etiological mechanism in human brain disorders that are associated with cortical dysfunction and delayed subcortical dopamine hyperactivity.

What can asymmetry and laterality in EMG tell us about the face and brain?

This paper will review the use of the electromyographic (EMG) technique for studying asymmetry and laterality in facial behavior. My discussion will include several issues: (1) a review of the neurology of facial expression with respect to asymmetry/laterality; (2) a compendium of models of cerebral hemispheric participation in emotion and in facial motor control that imply asymmetry-laterality in facial behavior; (3) a summary of facial asymmetry-laterality findings to date; and (4) uses and abuses of EMG techniques in inferring asymmetry-laterality in facial behavior. I conclude with (5) recommendations for future facial asymmetry-laterality research in general.

Asymmetric rotational (circling) behavior, a dopamine-related asymmetry: preliminary findings in unmedicated and never-medicated schizophrenic patients

Circling behavior is one of the best understood behaviors in animals. It is, for the most part, dopaminergically mediated and related to asymmetry in dopaminergic activity between the left and right basal ganglia or left and right frontal cortex. As a rule, animals rotate toward the hemisphere with lower striatal dopaminergic activity. A direct technique to find human analogs of circling behavior was not available. We have developed an automated rotometer with which we can apply the circling rodent model to humans. Left-prone circling behavior (neglect of right-sided turning) was found in 10 unmedicated schizophrenic patients, whereas 85 normal controls demonstrated almost equal right and left turning. These preliminary results may suggest the presence of a dopaminergic asymmetry in some unmedicated schizophrenic patients; that is, right anterior subcortical or cortical structures of the brain may manifest a relative dopaminergic overactivity compared to left anterior structures in at least some unmedicated patients with schizophrenia.

Rotational movement (circling) in normal humans: sex difference and relationship to hand, foot and eye preference

An endogenous asymmetry in striatal dopaminergic function has been identified in rats, and related to spontaneous and drug-induced circling (rotation, turning). We have developed an electronic device for measuring in humans the same kinds of rotational movements observed in rats. Our data indicate that, without being aware of the type of information being obtained, normal men and women rotate preferentially to the left or to the right during a routine day. Women had higher average rates of rotation than men. Males that were consistently right-sided (left-hemisphere dominant) for hand, foot and eye dominance rotated more to the right than to the left, whereas left-hemisphere dominant females rotated more to the left than to the right. Subjects tested on two occasions, 6 weeks apart, exhibited consistent (significantly correlated) rotational preferences--this was much more evident in left-hemisphere dominant than in mixed dominance individuals. In view of similar animal data, the device used in this study may become a useful and objective means for obtaining quantitative information regarding the status of basal ganglia function in humans.

Spontaneous asymmetric circling behavior in hemi-parkinsonism; a human equivalent of the lesioned-circling rodent behavior

When induced experimentally in rodents, hemispheric asymmetry in basal ganglia dopamine results in spontaneous asymmetric circling toward the hemisphere with the lower level of dopamine. A similar asymmetry has long been thought to exist in the brains of hemi-Parkinsonian patients. Using an electronic turn counter, we demonstrated that, like unilaterally lesioned rats, and without being aware of it, five ambulating outpatients with hemi-Parkinson's disease exhibit spontaneous rotation toward the hemisphere containing less striatal dopaminergic activity.

Amphetamine-elicited perseverative and rotational behavior: evaluation of directional preference

Four experiments examined the effects of d-amphetamine on lateralized direction preference, circling behavior, and perseveration. The nature as well as the magnitude of the behavioral response to amphetamine was dependent upon the testing situation. Whereas 5.0-10.0 mg/kg of the drug induced a robust circling behavior in a circular alleyway, it required 10.0 mg/kg of amphetamine to produce a significant turn preference in an open field exploratory situation. In a symmetrical Y-maze, mice displayed spontaneous alternation behavior characterized by an exploratory pattern involving different arm sequences. After amphetamine administration, spontaneous alternation was reduced and pronounced perseverative patterns of exploration were evident at dose levels similar to those that induced rotational behavior. Directional preferences could not account for the exploratory patterns in the Y-maze of animals in the undrugged state, or under the influence of amphetamine regardless of dose. Since lateralized motor asymmetries after amphetamine were limited by the behavioral context in which the effects of the drug were evaluated, it was argued that rotational behavior cannot be considered to be a simple mechanistic behavior. Rather, in addition to the expression of a side preference, it involves a drug-induced perseverative tendency. On the basis of these data, it was suggested that evaluation of the direction of turning in an open field is a less biased measure of spatial preference following amphetamine administration. It was further argued that perseverative behavior is a prepotent response to amphetamine and the possibility of lateralized attentional asymmetries was discussed.