More information on the nature of stereotyped body-rocking

Automated detection of stereotypical motor movements

To overcome problems with traditional methods for measuring stereotypical motor movements in persons with Autism Spectrum Disorders (ASD), we evaluated the use of wireless three-axis accelerometers and pattern recognition algorithms to automatically detect body rocking and hand flapping in children with ASD. Findings revealed that, on average, pattern recognition algorithms correctly identified approximately 90% of stereotypical motor movements repeatedly observed in both laboratory and classroom settings. Precise and efficient recording of stereotypical motor movements could enable researchers and clinicians to systematically study what functional relations exist between these behaviors and specific antecedents and consequences. These measures could also facilitate efficacy studies of behavioral and pharmacologic interventions intended to replace or decrease the incidence or severity of stereotypical motor movements.

Indirect basal ganglia pathway mediation of repetitive behavior: attenuation by adenosine receptor agonists

Repetitive behaviors are diagnostic for autism and common in related neurodevelopmental disorders. Despite their clinical importance, underlying mechanisms associated with the expression of these behaviors remain poorly understood. Our lab has previously shown that the rates of spontaneous stereotypy in deer mice (Peromyscus maniculatus) were negatively correlated with enkephalin content, a marker of striatopallidal but not striatonigral neurons. To investigate further the role of the indirect basal ganglia pathway, we examined neuronal activation of the subthalamic nucleus (STN) using cytochrome oxidase (CO) histochemistry in high- and low-stereotypy mice. CO activity in STN was significantly lower in high-stereotypy mice and negatively correlated with the frequency of stereotypy. In addition, exposure to environmental enrichment, which attenuated stereotypy, normalized the activity of STN. Co-administration of the adenosine A(2A) receptor agonist CGS21680 and the A(1) receptor agonist CPA attenuated stereotypy dose-dependently. The significant reduction associated with the lowest dose of the drug combination tested was due to its effects on mice with lower baseline levels of stereotypy. Higher doses of the drug combination were required to show robust behavioral effects, and presumably requisite activation of the indirect pathway, in high-stereotypy mice. These findings support that decreased indirect pathway activity is linked to the expression of high levels of stereotypy in deer mice and that striatal A(1) and A(2A) receptors may provide promising therapeutic targets for the treatment of repetitive behaviors in neurodevelopmental disorders.

A case study in the misrepresentation of applied behavior analysis in autism: the gernsbacher lectures

I know that most men, including those at ease with problems of the greatest complexity, can seldom accept the simplest and most obvious truth if it be such as would oblige them to admit the falsity of conclusions which they have proudly taught to others, and which they have woven, thread by thread, into the fabrics of their life. (Tolstoy, 1894)This article presents a case study in the misrepresentation of applied behavior analysis for autism based on Morton Ann Gernsbacher's presentation of a lecture titled "The Science of Autism: Beyond the Myths and Misconceptions." Her misrepresentations involve the characterization of applied behavior analysis, descriptions of practice guidelines, reviews of the treatment literature, presentations of the clinical trials research, and conclusions about those trials (e.g., children's improvements are due to development, not applied behavior analysis). The article also reviews applied behavior analysis' professional endorsements and research support, and addresses issues in professional conduct. It ends by noting the deleterious effects that misrepresenting any research on autism (e.g., biological, developmental, behavioral) have on our understanding and treating it in a transdisciplinary context.

What is the function of nail biting: an analog assessment study

OBJECTIVE

To compare the frequency of nail biting in 4 settings (interventions) designed to elicit the functions of nail biting and to compare the results with a self-report questionnaire about the functions of nail biting.

DESIGN

Randomised allocation of participants to order of conditions.

SETTING

University Psychology Department.

SUBJECTS

Forty undergraduates who reported biting their nails.

INTERVENTIONS

Left alone (boredom), solving maths problems (frustration), reprimanded for nail biting (contingent attention), continuous conversation (noncontingent attention).

MAIN OUTCOME MEASURES

Number of times the undergraduates bit their nails.

RESULTS

Nail biting occurred most often in two conditions, boredom and frustration.

CONCLUSION

Nail biting in young adults occurs as a result of boredom or working on difficult problems, which may reflect a particular emotional state. It occurs least often when people are engaged in social interaction or when they are reprimanded for the behavior.

Behavior-related alterations of striatal neurochemistry in a mouse model of stereotyped movement disorder

Motor stereotypy is a common component of several developmental, genetic, and neuropsychiatric disorders. In animals, these behaviors can be induced or attenuated via pharmacological manipulation of specific neural loci comprising cortico basal ganglia-cortical feedback circuits, including the striatum. The present study employed the deer mouse model of spontaneous and persistent stereotypy to assess the involvement of several endogenous neurotransmitters and neuromodulators in mediating the expression of the stereotypic behaviors (i.e., repetitive hindlimb jumping) exhibited by these mice. This was accomplished by employing a microdialysis sampling system coupled on-line to capillary electrophoresis with laser-induced fluorescence (CE-LIF) detection apparatus. Given the 13-s temporal resolution for analyte measurement afforded by this system, discrete behavior-related alterations in striatal neurochemical concentrations were detected. Rearing behavior was found to be associated with significant and selective elevations of striatal glutamate (Glu) and aspartate (Asp) concentrations. Moreover, rearing was found to most frequently precede repetitive jumping. The results also indicated that alterations in striatal serine (Ser) concentrations were involved in the modulation of locomotor activity. The present findings support a role of the striatal glutamatergic system in the mediation of spontaneous stereotypic behavior and suggest a potential neuronal mechanism by which transition to stereotypy occurs in these mice. Moreover, the present findings demonstrate the usefulness of the microdialysis system employed in studying the neurochemical substrates of rapidly transitioning behavior.

Effects of intrastriatal administration of selective dopaminergic ligands on spontaneous stereotypy in mice

Abnormal repetitive behaviors are often associated with specific developmental, genetic, and neuropsychiatric disorders. Repetitive motor behaviors, often referred to as stereotypies, have been studied extensively as they can be readily induced by certain drugs (e.g., amphetamine). Recent work has shown, however, that such drug-induced models of stereotypy may not accurately reflect the neurobiological perturbations responsible for the spontaneous manifestation of these behaviors. The present study employed the deer mouse model of spontaneous and persistent stereotypy to evaluate the capacity of several selective dopaminergic agonists (apomorphine, SKF81297, and quinpirole) to exacerbate levels of spontaneously emitted stereotypic topographies when administered intrastriatally. Additionally, the effects of intrastriatal administration of the D(2)R antagonist raclopride on the expression of spontaneous stereotypic jumping were evaluated. No induction or exacerbation of stereotypy was observed following administration of the selective D(1)- or D(2)- receptor agonists, and the mixed agonist apomorphine induced hyperlocomotion and excessive grooming but failed to exacerbate spontaneous stereotypy. Thus, a dissociation was observed between spontaneously emitted and drug-induced stereotypy, suggesting significant limitations to the use of dopamine agonist-induced stereotypy as a model of clinical stereotyped movement disorder. Furthermore, an unexpected and statistically significant (P<.05) potentiation of locomotor activity was observed following intrastriatal raclopride administration, suggesting major alterations to the modulatory characteristics of the striatal dopaminergic system in these spontaneously stereotypic animals.

Selective blockade of spontaneous motor stereotypy via intrastriatal pharmacological manipulation

Abnormal repetitive behavior, including stereotypy, is often observed in conjunction with developmental, neuropsychiatric, and genetic disorders. The present work employed the deer mouse model of spontaneous and persistent stereotypy to identify basal ganglia involvement in the mediation of these abnormal behaviors. To evaluate the hypothesis that stereotypy is expressed in these mice due to alterations in the activity of cortico-basal ganglia motor circuits, intrastriatal pharmacological manipulations aimed at attenuating the spontaneously emitted stereotypy were performed. Bilateral striatal infusion of the NMDA or dopamine D(1) receptor antagonists MK-801 or SCH23390, respectively, produced a substantial reduction in levels of stereotypic jumping without inhibiting nonstereotypic motor behavior. These findings support the hypothesis that environmentally related stereotypy is expressed as a consequence of elevated feedback activity occurring along motor circuits of the basal ganglia.