Stereotyped Motor Patterns Research Articles

An animal model of autism: behavioural studies in the GS guinea-pig

Autism is a human behavioural pathology marked by major difficulties in abnormal socialization, language comprehension and stereotypic motor patterns. These behavioural abnormalities have been associated with corticocerebral and cerebellar abnormalities in autistic patients, particularly in vermal folia VI and VII. Progress in understanding this disease has been hindered by the absence of a non-primate animal model. GS guinea-pigs are a partially inbred, non-ataxic guinea-pig strain with cerebellar and corticocerebral abnormalities similar to those reported to exist in human patients with autism. In order to determine if GS guinea-pigs represent an animal model of autism, their behaviour was compared with that of Hartley strain guinea-pigs. GS animals learned a motor task significantly more rapidly than Hartley guinea-pigs, but performed it in a more stereotypic manner and were less influenced by environmental stimuli than Hartleys. GS animals exhibited significantly less exploratory behaviour in a novel environment and were significantly less responsive to 50–95 dBA pure tones than Hartley guinea-pigs. In a social interaction assay, GS guinea-pigs interacted significantly less frequently with each other or with Hartley guinea-pigs than Hartleys did under the same conditions. GS behaviour thus exhibits autistic-like behaviour patterns: motor stereotypy, lack of exploration and response to environment and poor social interaction. Coupled with the neuropathological findings, this abnormal behaviour suggests that GS guinea-pigs could be a useful animal model of autism.

An animal model of autism: behavioural studies in the GS guinea-pig.

Autism is a human behavioural pathology marked by major difficulties in abnormal socialization, language comprehension and stereotypic motor patterns. These behavioural abnormalities have been associated with corticocerebral and cerebellar abnormalities in autistic patients, particularly in vermal folia VI and VII. Progress in understanding this disease has been hindered by the absence of a non-primate animal model. GS guinea-pigs are a partially inbred, non-ataxic guinea-pig strain with cerebellar and corticocerebral abnormalities similar to those reported to exist in human patients with autism. In order to determine if GS guinea-pigs represent an animal model of autism, their behaviour was compared with that of Hartley strain guinea-pigs. GS animals learned a motor task significantly more rapidly than Hartley guinea-pigs, but performed it in a more stereotypic manner and were less influenced by environmental stimuli than Hartleys. GS animals exhibited significantly less exploratory behaviour in a novel environment and were significantly less responsive to 50-95 dBA pure tones than Hartley guinea-pigs. In a social interaction assay, GS guinea-pigs interacted significantly less frequently with each other or with Hartley guinea-pigs than Hartleys did under the same conditions. GS behaviour thus exhibits autistic-like behaviour patterns: motor stereotypy, lack of exploration and response to environment and poor social interaction. Coupled with the neuropathological findings, this abnormal behaviour suggests that GS guinea-pigs could be a useful animal model of autism.

Coordination of side-to-side head movements and walking in amphetamine-treated rats: a stereotyped motor pattern as a stable equilibrium in a dynamical system.

Rats injected with 5.0 mg/kg (+)-amphetamine perform, at one stage of the drug's influence, rhythmic side-to-side head movements while walking. This makes them an interesting preparation for investigating how stereotyped motor patterns emerge from the coordination of periodic movements. We report here such a pattern we have isolated: the left foreleg and the right hindleg land on the ground as the head reaches the peak of its movement to the right, and vice versa (contra-lateral pattern). We show that this pattern can be explained as a stable equilibrium in a simple, nonlinear dynamical model, similar to models developed for tapping with both hands in human subjects. The model also accounts for sequences of behavior that are not in the contra-lateral pattern, explaining them as a flow of the system back towards the stable equilibrium after a disturbance. Motor patterns that constitute the building blocks of unconstrained behavior are often defined as fixed phase relations between movements of the parts of the body. This study applies the paradigm of Dynamic Pattern Generation to free (unconstrained) behavior: motor patterns are defined as stable equilibria in dynamical systems, assembled by mutual influence of concurrent movements. Our findings suggest that this definition is more powerful for the description of free behavior. The amphetamine-treated rat is a useful preparation for investigating this notion in an unconstrained animal whose behavior is still not as complex and variable as that of the normal animal.

Coordination of side-to-side head movements and walking in amphetamine-treated rats: a stereotyped motor pattern as a stable equilibrium in a dynamical system

Coordination of side-to-side head movements and walking in amphetamine-treated rats: a stereotyped motor pattern as a stable equilibrium in a dynamical system

Motor stereotypy and diversity in songs of mimic thrushes

The relationship between the motor and acoustic similarity of song was examined in brown thrashers (Toxostoma rufum) and grey catbirds (Dumetella carolinensis) (family Mimidae), which have very large song repertoires and sometimes mimic other species. Motor similarity was assessed by cross correlation of syringeal airflows and air sac pressures that accompany sound production. Although most syllables were sung only once in the song analyzed, some were repeated, either immediately forming a couplet, or after a period of intervening song, as a distant repetition. Both couplets and distant repetitions are produced by distinctive, stereotyped motor patterns. Their motor similarity does not decrease as the time interval between repetitions increases, suggesting that repeated syllables are stored in memory as fixed motor programs. The acoustic similarity between nonrepeated syllables, as indicated by correlation of their spectrograms, has a significant positive correlation with their motor similarity. This correlation is weak, however, suggesting that there is no simple linear relationship between motor action and acoustic output and that similar sounds may sometimes be produced by different motor mechanisms. When compared without regard to the sequence in which they are sung, syllables paired for maximum spectral similarity form a continuum with repeated syllables in terms of their acoustic and motor similarity. The prominence of couplets in the “syntax” of normal song is enhanced by the dissimilarity of successive nonrepeated syllables that make up the remainder of the song. © 1996 John Wiley & Sons, Inc.

Lateralization and motor stereotypy of song production in the brown-headed cowbird.

Song production in adult brown-headed cowbirds (Molothrus ater ater) is lateralized, with a slight right syringeal dominance. The left side of the syrinx produces low-frequency (200-2000 Hz) notes within the introductory note clusters, while the right side produces the higher-frequency (1500-6000 Hz) introductory notes, the interphrase unit (10-12 kHz), and the final high-frequency whistle (5-13 kHz). Cross-correlation analyses reveal that individual cowbirds produce each of their four to seven song types with a distinct stereotyped motor pattern--as judged by the patterns of syringeal airflow and subsyringeal pressure. The acoustic differences across song types are reflected in the differences in the bronchial airflow and air sac pressure patterns associated with song production. These motor differences are particularly striking within the second and third introductory note clusters where there is a rapid switching back and forth between the two sides of the syrinx in the production of notes. These motor skills may be especially important in producing behaviorally effective song.

Stiff man syndrome: clinical and laboratory findings in eight patients.

The clinical, biochemical, neuroimaging and neurophysiological findings of eight patients with stiff man syndromes (SMS) [four of six being tested with autoantibodies against glutamic acid decarboxylase (GAD)] are presented. In two patients (one GAD-positive, one GAD-negative), transient oculomotor disturbances suggested progressive encephalomyelitis with rigidity and myoclonus (PERM) as differential diagnosis. The catalogue of characteristic clinical symptoms of SMS is extended by three new symptoms: (1) an aura-like feeling reported by five patients to precede spontaneous spasmodic attacks; (2) a stereotyped motor pattern seen in seven patients during spasmodic jerks, consisting of brief opisthotonos, stiffening of the slightly abducted legs and inversion of the plantar-flexed feet; (3) a paroxysmal fear when crossing a free space unaided, or even thinking of it. Clinical findings did not enable us to discriminate between patients tested GAD-positive or GAD-negative. Cerebrospinal fluid contained elevated immunoglobulin levels or cell counts, or both, in the majority of patients. Autopsy of one patient revealed scattered lymphocyte cuffs around leptomeningeal, intracerebral and particularly intraspinal vessels, suggesting a mild inflammatory process. Whether SMS and PERM are closely related is discussed; they are possibly both manifestations of a spectrum of encephalomyelopathies having autoimmunity against GABAergic neurons in common.

Visual information processing in the fly's landing system

When approaching a landing site flies (Musca domestica) extend their legs in order to prevent crash-landing. Pattern expansion in front of a tethered fly can mimic an approach towards a landing site. Under these conditions landing is a rather stereotyped motor pattern. Only the latency of the onset of the landing response varies with the stimulus strength. Quantitative studies of the stimulus-latency relationship led to the formulation of a simple model which describes the way movement information at the fly's retina is processed in order to trigger landing. We propose that the output of local directionally selective movement detectors are spatially pooled and subsequently integrated in time. Whenever the level of this integrated signal reaches a fixed threshold landing is released.

The Bullsnake as an Excavator

ABSTRACr. The bullsnake (Pituophis melanoleucus sayi) exhibits head morphology and stereotyped motor patterns adapted to excavating. Spading actions by the snout are followed by scooping a load of sand in a head-neck flexure, moving posterior, and dumping the load away from the excavation at varying distances. An excavating bullsnake can move as much as 3400 cm3/h. This behavior was seen in adults of both sexes and in a juvenile and may function for obtaining food (especially pocket gophers), digging a nest or a retreat. Bullsnakes respond positively to the soil from pocket gopher mounds.

Modulatory multiplicity in the functional repertoire of the feeding mechanism in cichlid fishes. I. Piscivores.

Among piscivorous cichlids consistent differences have been recorded between ambush and pursuit hunters with respect to electromyographic, kinematic, pressure and behavioral profiles during prey capture by high speed inertial suction. Piscivorous cichlids possess a repertoire of at least two patterns of prey capture, each of which is characterized by an extreme regularity of the kinematic, pressure, electromyographic and behavioral profiles. The nature and locomotory behavior of the prey, visually analyzed by the predator during the prestrike stalk, determine which of the two preprogrammed patterns is recruited. Agile and elusive prey invariably will elicit a preprogrammed motor output (stereotyped motor pattern) that produces the greatest suction velocities in both ambush and pursuit hunters. The greater the kinematic and suction velocities, the greater the overlap of the firing sequences of antagonistic muscle complexes. The opercular and branchiostegal apparati function as an exceedingly effective anti-backwash device, damping potential fluid oscillations within the oropharynx. Mastication occurs by triphasic movements and actions of muscles of the upper and lower pharyngeal jaws in both ambush and pursuit hunters. The lower pharyngeal jaw is acted upon by a force couple of which the fourth levator externus on one hand and the pharyngocleithralis externus and pharyngohyoideus on the other hand are the antagonistic components. Furthermore, the lower pharyngeal jaw is suspended by a muscular sling, the tension of which can be modified continuously. It is postulated that the switch from insectivorous to piscivorous feeding regimes (and perhaps vice versa) is accomplished by very minor structural and functional modifications, because the modulatory multiplicity and total range of repertories of the feeding machinery of the two trophic groups overlap significantly. Piscivorous cichlids may not have arisen by orthoselection in gradually-changing lineages, but represent the differential success of subsets from a random pool of speciation events. Adaptive features identified as characteristic for piscivory could have evolved in multiple and independent lineages at a punctuational mode and tempo.

Relative role of catecholamines in head-shaking of infant rats

The relative contribution of catecholaminergic mechanisms in head-shaking (H-S) of infant rats was explored by comparing the H-S inducing effects of apomorphine and amphetamine in rats from 4–14 days old, and the blocking effect of neuroleptic drugs (chlorpromazine and haloperidol) and more specific α- and β-adrenergic receptor antagonists (phenoxybenzamine and propranolol), on amphetamine induced head-shaking. As apomorphine, but not amphetamine, may induce H-S in four-day-old rats, and the latter drug potentiates apomorphine induced H-S, even in days in which, if injected alone it has no effect, it is suggested that both dopaminergic and noradrenergic mechanisms are involved in H-S, thus differentiating this motor item from other motor patterns included in stereotyped behaviour. This suggestion is further supported by the demonstration that while D-amphetamine induced H-S is blocked by phenoxybenzamine, other stereotyped motor patterns continue unimpaired.

Relationship of rats' spatial preferences effects of d-amphetamine on timing behavior

Rats were trained to bar-press on a differential reinforcement of low rate 16 sec (DRL 16) schedule for water reinforcement. On alternate days, rats were tested in the presence or absence of a light which signaled the availability of reinforcement. Rats were allowed to bar-press on either of two levers (left and right). All rats show consistent side preferences. Doses (0.5–2.0 mg/kg) of d-amphetamine differentially affected performance under signaled and nonsignaled conditions. Performance during the nonsignaled condition was much more sensitive to a drug-induced rate increment and timing impairment than performance during the signaled condition. With increasing drug dosage, under both conditions, side preferences reliably increased, decreased or remained unchanged depending upon the particular pattern of paw usage and the relationship between paw and side preferences. For the nonsignaled condition but not for the signaled condition, baseline rates were related to the strength of side preferences; lower rates and better timing performance were significantly correlated with greater preferences. Observations of bar-pressing behavior suggested that stereotyped motor patterns associated with side preferences might be related to mechanisms involved in timing behavior and perhaps, in behavior controlled by internal stimuli generally.

The Strut Display of Male Sage Grouse: a "Fixed" Action Pattern

AbstractThe Strut display of male Sage Grouse, Centrocercus urophasianus, exemplifies a complex "fixed" action pattern. The display results in the inflation of the male's large esophageal sac, which is then used to produce a strange sound that includes two sharp snaps 0.19 seconds apart. Measurements of the durations of an individual's displays usually yielded a coefficient of variation (C.V.) less than 4%; the most accurate measurements had C.V.'s less than 1%. The intervals between Struts, in contrast, had much higher variability. No geographic differences were detected among three populations in Wyoming and Montana. Nor did the slight differences in the displays of individual adult males have a consistent relation to their successes in mating. First-year males performed their Struts with faster tempo but not with greater variability. The temporal stereotypy in the Strut display approximates or exceeds the stereotypy in passerine songs. Stereotyped motor patterns in vertebrates often subserve communication at long range or between individuals in brief, but biologically crucial, contact with each other. The Strut display exemplifies both of these functions in communication. Stereotyped, complex signals incorporate more redundancy and/or more efficient encoding; they thus enhance the receiver's chances of detecting and correctly interpreting the signal. Reafference that depends on the harmonic properties of moving structures might help to explain both the developmental and physiological stability of this stereotyped motor coordination. Because year-old males' displays show no greater variability than those of older males, the peculiarities of young males' performances probably are not the result of incompletely crystallized neural mechanisms.

Effects of apomorphine on exploration

An attempt is made to analyse those effects of apomorphine usually described as stereotyped motor patterns, including, in rats, sniffing. Following a suggestion that this could reflect a raised reactivity rather than a mere motor disturbance, an experiment is presented which indicates that apomorphine induces heightened and prolonged exploration.

THE NEST‐BUILDING BEHAVIOUR OF DOMESTICATED CANARIES

SUMMARY The nest‐building behaviour of domesticated canaries was studied. The principal activities, or groups of activities, studied were inspecting, gathering, carrying and sitting (building). The latter includes a number of stereotyped motor patterns functioning in shaping the cup. The nest‐site is selected by the female as or before building begins. Building activity reaches its peak three or four days before the laying of the first egg, and slightly before the peak of copulation. The temporal relations between building and egg‐laying are highly variable between individuals. The male plays only a small part in nest‐building. The total times spent gathering, carrying and sitting per watch are positively correlated. Since the change‐over from one activity to the next does not depend solely on external stimuli, this suggests that these activities share internal causal factors.Two characteristics of building behaviour (total time building per watch and number of placings per watch) are not fully correlated with each other, and there are differences between the relations of the total times spent gathering, carrying and sitting with each of these characteristics (Figs. 3 and 4). The concept of a nest‐building drive is thus not useful, for the selection of criteria whereby it could be quantified is arbitrary.The median bout lengths of gathering, carrying and sitting first increase and then decrease with increase in the number of placings per watch (Figs. 5 and 6) and there are correlations between the bout lengths of the different activities in each nest‐building sequence. Each activity can be interrupted by the activity which functionally follows it before it own motivation has fallen to the normal threshold.The appetitive/consummatory behaviour dichotomy is not useful in analysing the relationships between gathering, carrying and sitting, but these can be understood in terms of concepts such as common causal factors, threshold differences, and self‐suppressing effects consequent upon performance. The stereotyped movements of nest‐building differ in frequency between individuals “Scrabbling” is influenced by the size of the nest. The decrease in nest‐building activity around the time of egg‐laying is due partially to internal changes, and partially to stimuli from the nest. The length of sitting bouts is influenced by stimuli from the nest‐pan as well as internal factors. The change‐over from building with grass to building with feathers which occurs shortly before egg‐laying is due partially to internal changes and partially to stimuli from the nest. Canaries reared without material show a number of bizarre patterns of behaviour which are established by learning during deprivation. The mere performance of nest‐building movements has some reinforcing value. Many of the constituent patterns of nest‐building behaviour occur in naive birds, but their integration is partially dependent on learning.