Differential mastication kinematics of the rabbit in response to food and water: Implications for conditioned movement

Analysis of naturalistic chewing patterns may provide insight into mapping the neural substrates of jaw movement control systems, including their adaptive modification during the classically conditioned jaw movement (CJM) paradigm. Here, New Zealand White rabbits were administered food and water stimuli orally to evaluate the influence of stimulus consistency on masticatory pattern. Chewing patterns were recorded via video camera and movements were analyzed by computerized image analysis. The mandibular kinematics, specifically the extent of dorsal/ventral, medial/lateral, and rostral/caudal movement, were significantly larger in food-evoked than water-evoked chewing. Water-evoked chewing frequency, however, was significantly higher than that of food-evoked movements. In light of known cortical mastication modulatory centers, our findings implicate different neural substrates for the responses to food and water stimuli in the rabbit. A detailed delineation of jaw movement patterns and circuitry is essential to characterize the neural substrates of CJM.     

Timing and stiffness in speech motor control of stuttering and nonstuttering adults

Twelve stutterers and 12 nonstutterers were investigated in order to measure speech movements of the jaw. They spoke the nonsense word /papapas/ with stress on either the first or second syllable and with three speech rates (fast, moderate, and slow). During these trials, jaw movements were analyzed with a selspot-like optical tracking system. It was shown that stutters and nonstutterers applied the same strategies for realizing jaw movements of accented and unaccented syllables. The first strategy (stiffness variation) was used to achieve fast jaw movements while the second strategy (timing) was used in order to realize jaw movements for accented syllables. These results were taken as evidence for the assumption that, in general, stutterers and nonstutterers used the same control strategies when speaking fluently. However, it was also evident that stutterers produced lengthened jaw opening and closing durations as well as reduced peak velocities and maximal opening and closing displacements. This deviating movement pattern was supposed to reflect motor compensations necessary to achieve fluent speech rather than anomalies of the speech neuromotor system.     

Graze: A program to analyze recordings of the jaw movements of ruminants

Graze is a user friendly, Microsoft Windows 95/NT program for analyzing jaw movement recordings taken with the IGER Behavior Recorder. The program displays a plot of the jaw movement amplitude (vertical axis) against time (horizontal axis). Individual jaw movements can be automatically identified, using amplitude and frequency criteria specified by the user. Bouts of jaw movements can then be analyzed and are automatically identified as either grazing or ruminating. Behaviors other than grazing and ruminating (such as drinking or eating supplements) can also be identified and marked by the user. Identified jaw movements and bouts of behavior are superimposed on the jaw data display. Finally, the user can perform a bout analysis, which discriminates between bites and chews during eating and generates a summary file.     

Adults with probable developmental coordination disorder selectively process early visual,but not tactile information during action preparation. An electrophysiological study

Developmental coordination disorder (DCD) is a neurodevelopmental condition affecting motor coordination in children and adults. Here, EEG signals elicited by visual and tactile stimuli were recorded while adult participants with and without probable DCD (pDCD) performed a motor task. The task cued reaching movements towards a location in visible peripersonal space as well as an area of unseen personal space. Event-related potentials elicited by visual and tactile stimuli revealed that visual processing was strongly affected by movement preparation in the pDCD group, even more than in controls. However, in contrast to the controls, tactile processing in unseen space was unaffected by movement preparation in the pDCD group. The selective use of sensory information from vision and proprioception is fundamental for the adaptive control of movements, and these findings suggest that this is impaired in DCD. Additionally, the pDCD group showed attenuated motor rhythms (beta: 13–30 Hz) over sensorimotor regions following cues to prepare movements towards unseen personal space. The results reveal that individuals with pDCD exhibit differences in the neural mechanisms of spatial selection and action preparation compared to controls, which may underpin the sustained difficulties they experience. These findings provide new insights into the neural mechanisms potentially disrupted in this highly prevalent disorder.     

Dissecting the conditioned pecking response: an integrated system for the analysis of pecking response parameters.

The conventional pecking response key, although an excellent transducer of response rate, can provide minimal information on the topography, coordination, or localization of conditioned pecking. We describe the hardware and software components of a system that, in addition to recording response rates, permits simultaneous "on-line" monitoring of head acceleration, jaw movement, terminal peck location, and duration of pecking response. Head movements are monitored with a miniature accelerometer, jaw movements with a magnetosensitive transducer, and peck location with modified touch screen technology. Initial experiments with the system suggest that it will be useful in studies of response differentiation, acquisition and maintenance of complex discriminations, and interaction of conditioned and unconditioned stimuli in the control of pecking response probability and response topography.     

Age-related differences in the integration of sensory information during the execution of a bimanual coordination task

Young (n = 7) and elderly (n = 7) subjects performed bimanual coordination patterns in the transverse plane according to the in-phase or antiphase mode. Sensory information was manipulated through visual (with or without vision of the limbs) and proprioceptive input (with or without vibratory stimuli on one limb). Movement patterns with vibrations showed higher deviations from the intended relative phase than did those without vibrations. This finding suggests that the proprioceptive information induced by the vibrations and the movement interfered, leading to a disruption of the coordination patterns. In addition, as compared with the elderly, the young subjects performed more stable movements under normal circumstances but were more strongly affected by vibratory stimuli during the performance of in-phase movements. During antiphase movements, both age groups experienced a decrease of pattern stability. Furthermore, the absence or presence of visual feedback influenced the performance of the young subjects more than that of the elderly. The presence of vision led to stable in-phase movements, whereas a decrease of pattern stability was observed for antiphase movements. In general, these results demonstrate that manipulation of feedback sources affects young subjects more than elderly ones, and this can be related to a reduced sensory sensitivity as a function of aging.     

Differential recognition of pitch patterns in discrete and gliding stimuli in congenital amusia: evidence from Mandarin speakers

This study examined whether "melodic contour deafness" (insensitivity to the direction of pitch movement) in congenital amusia is associated with specific types of pitch patterns (discrete versus gliding pitches) or stimulus types (speech syllables versus complex tones). Thresholds for identification of pitch direction were obtained using discrete or gliding pitches in the syllable /ma/ or its complex tone analog, from nineteen amusics and nineteen controls, all healthy university students with Mandarin Chinese as their native language. Amusics, unlike controls, had more difficulty recognizing pitch direction in discrete than in gliding pitches, for both speech and non-speech stimuli. Also, amusic thresholds were not significantly affected by stimulus types (speech versus non-speech), whereas controls showed lower thresholds for tones than for speech. These findings help explain why amusics have greater difficulty with discrete musical pitch perception than with speech perception, in which continuously changing pitch movements are prevalent.     

EMG activities of facial and chewing muscles of human adults in response to taste stimuli

To evaluate facial expression patterns induced by different taste stimuli, electromyograms (EMG) of the facial and chewing muscles of 12 healthy university students, aged 20 to 23 years, were analyzed. Sucrose (sweet), NaCl (salty), citric acid (sour), quinine-HCl (bitter), monosodium glutamate (MSG; umami), homogentisic acid (harsh), tannic acid (astringent), and capsaicine (pungent) were the taste stimuli used. Rating scale tests were made to assess the hedonics (pleasantness) of the taste stimuli. EMG responses of the corrugator supercilii, venter frontalis, orbicularis oculi, depressor anguli, and digastricus muscles to capsaicine, tannic, acid, and citric acid showed larger amplitudes than to NaCl, MSG, homogentisic acid, and sucrose. Increases in EMG responses for most facial and chewing muscles for the taste solutions had significant negative correlations to the solutions' hedonic scale values. Most facial and chewing muscles of adult humans therefore showed greater responses to disliked than to preferred or less preferred tastes.     

Real and imagined body movement primes metaphor comprehension

We demonstrate in two experiments that real and imagined body movements appropriate to metaphorical phrases facilitate people's immediate comprehension of these phrases. Participants first learned to make different body movements given specific cues. In two reading time studies, people were faster to understand a metaphorical phrase, such as push the argument, when they had previously just made an appropriate body action (e.g., a push movement) (Experiment 1), or imagined making a specific body movement (Experiment 2), than when they first made a mismatching body action (e.g., a chewing movement) or no movement. These findings support the idea that appropriate body action, or even imagined action, enhances people's embodied, metaphorical construal of abstract concepts that are referred to in metaphorical phrases.     

Response Timing Accuracy as a Function of Movement Velocity and Distance

In two experiments, patterns of response error during a timing accuracy task were investigated. In Experiment 1, these patterns were examined across a full range of movement velocities, which provided a test of the hypothesis that as movement velocity increases, constant error (CE) shifts from a negative to a positive response bias, with the zero CE point occurring at approximately 50% of maximum movement velocity (Hancock & Newell, 1985). Additionally, by examining variable error (VE), timing error variability patterns over a full range of movement velocities were established. Subjects (N = 6) performed a series of forearm flexion movements requiring 19 different movement velocities. Results corroborated previous observations that variability of timing error primarily decreased as movement velocity increased from 6 to 42% of maximum velocity. Additionally, CE data across the velocity spectrum did not support the proposed timing error function. In Experiment 2, the effect(s) of responding at 3 movement distances with 6 movement velocities on response timing error were investigated. VE was significantly lower for the 3 high-velocity movements than for the 3 low-velocity movements. Additionally, when MT was mathematically factored out, VE was less at the long movement distance than at the short distance. As in Experiment 1, CE was unaffected by distance or velocity effects and the predicted CE timing error function was not evident.     

Use of a distracting task to obtain defensive head movements to looming visual stimuli by human adults in a laboratory setting.

Defensive responses to looming visual stimuli have been obtained in a wide variety of species, including human infants as young as one week. This phenomenon has not, however, been formally demonstrated for adults under laboratory conditions. In this paper it is reported that similar responses, namely avoidance movements of the head, can be obtained in most human adults provided that they are suitably distracted by playing a computer tracking game. Such behaviours were not obtained when subjects were not so distracted. The use of control conditions also ruled out the possibility that simple movement cues from stimuli presented on a noncollision trajectory are sufficient stimulus to obtain defensive responses. It is of interest to note that latencies for avoidance movements were significantly shorter than those for orienting movements in the same situation, but were no different from the latencies for orienting movements when subjects were not distracted. It is argued that these findings are consistent with the proposition that defensive head movements to looming stimuli, like orienting movements to novel peripheral stimuli, represent a basic visual competence that is normally suppressed (or subsumed) by higher competences. The decision to avoid is probably based on the computation of time to contact, and may reflect the operation of a subcortical system for elementary analysis of optic flow.     

Impact of contextual constraint on vocabulary acquisition in reading*

The current study investigated the influence of contextual constraint (strong versus moderate) on incidental vocabulary acquisition in reading, as eye movements of adult skilled readers were monitored. Surprise post-tests followed the reading session, and eye movement behaviour was directly connected to retention data. Longer and more frequent reading/rereading was associated with trials containing a novel target (rather than a known control), and unique patterns of connective rereading between constraint conditions were observed. For reading measures reflecting target word processing and connecting target with context, fixations were generally longer and more frequent for moderate constraint than for strong. The exception was in rereading of informative context, which was generally longer for strong constraint. More and longer fixations while connecting novel targets with informative context proved critical for novel word retention, significantly so for moderate constraint but not for strong, based on eye movement data associated with memory for novel word stimuli.     

Localisation of auditory targets during optokinetic nystagmus

Previous studies have shown that the perceived location of visual stimuli briefly flashed during smooth pursuit, saccades, or optokinetic nystagmus (OKN) is not veridical. We investigated whether these mislocalisations can also be observed for brief auditory stimuli presented during OKN. Experiments were carried out in a lightproof sound-attenuated chamber. Participants performed eye movements elicited by visual stimuli. An auditory target (white noise) was presented for 5 ms. Our data clearly indicate that auditory targets are mislocalised during reflexive eye movements. OKN induces a shift of perceived location in the direction of the slow eye movement and is modulated in the temporal vicinity of the fast phase. The mislocalisation is stronger for look- as compared to stare-nystagmus. The size and temporal pattern of the observed mislocalisation are different from that found for visual targets. This suggests that different neural mechanisms are at play to integrate oculomotor signals and information on the spatial location of visual as well as auditory stimuli.     

Stimulus generalization and the peak shift with movement stimuli

Stimulus generalization is suggested as an alternative method for examination of the "novelty" problem in motor learning. These experiments demonstrated that stimulus generalization occurs using simple movements as stimuli. The phenomenon of the "peak shift" in post-discrimination generalization gradients was also examined. The first experiment demonstrated that a peak shift occurred using linear movements as stimuli and that the magnitude of the peak shift increased as the difference between the training stimuli decreased. The second experiment showed similar results when the stimuli consisted of a range of movements rather than single movement length. The final experiment provided evidence that perception of movement length is influenced by the magnitude of an immediately preceding movement. The relevance of these studies to current motor-learning theory is discussed.     

Stimulus Generalization and the Peak Shift with Movement Stimuli

Stimulus generalization is suggested as an alternative method for examination of the “novelty? problem in motor learning. These experiments demonstrated that stimulus generalization occurs using simple movements as stimuli. The phenomenon of the “peak shift? in post-discrimination generalization gradients was also examined. The first experiment demonstrated that a peak shift occurred using linear movements as stimuli and that the magnitude of the peak shift increased as the difference between the training stimuli decreased. The second experiment showed similar results when the stimuli consisted of a range of movements rather than a single movement length. The final experiment provided evidence that perception of movement length is influenced by the magnitude of an immediately preceding movement. The relevance of these studies to current motor-learning theory is discussed.     

Comparing music- and food-evoked autobiographical memories in young and older adults: A diary study

Previous research has found that music brings back more vivid and emotional autobiographical memories than various other retrieval cues. However, such studies have often been low in ecological validity and constrained by relatively limited cue selection and predominantly young adult samples. Here, we compared music to food as cues for autobiographical memories in everyday life in young and older adults. In two separate four-day periods, 39 younger (ages 18–34) and 39 older (ages 60–77) adults recorded their music- and food-evoked autobiographical memories in paper diaries. Across both age groups, music triggered more frequent autobiographical memories, a greater proportion of involuntary memories, and memories rated as more personally important in comparison to food cues. Age differences impacted music- and food-evoked memories similarly, with older adults consistently recalling older and less specific memories, which they rated as more positive, vivid, and rehearsed. However, young and older adults did not differ in the number or involuntary nature of their recorded memories. This work represents an important step in understanding the phenomenology of naturally occurring music-evoked autobiographical memories across adulthood and provides new insights into how and why music may be a more effective trigger for personally valued memories than certain other everyday cues.     

Sucking patterns are not predictive of further feeding development in healthy preterm infants

Preterm infants are at risk of experiencing difficulties in their feeding development. For a possible early identification of these, we examined the association between sucking patterns, assisted spoon feeding, and chewing skills in 40 healthy preterm infants, and the role of experience in the acquisition of these skills in a prospective longitudinal study. Sucking patterns were evaluated at 34, 37, and 44 weeks postmenstrual age (PMA), assisted spoon feeding was evaluated at 6, 9, and 12 months PMA, and chewing was evaluated at 9, 12, and 24 months PMA. Sucking patterns were rated using the Neonatal Oral Motor Assessment Scale, assisted spoon feeding was rated using the Observation List Spoon Feeding, and chewing was evaluated using the Mastication Observation and Evaluation Instrument.All infants showed progression in their oral motor skills during the study period, but not all demonstrated a stable progression of skills. Quality of sucking patterns was not associated with skill level achievement of assisted spoon feeding or with chewing. Length of experience in sucking was significantly associated with duration of supplemental tube feeding but not with the quality of the sucking pattern. Length of chewing experience was significantly associated with chewing abilities at 9 and 12 months PMA. No clinical characteristics were sufficiently predictive of oral motor skill development. Results show that sucking patterns are not predictive of subsequent feeding development in healthy preterm infants. The food consistency offered and the length of feeding experience influenced the acquisition and quality of oral motor skills differently.     

Visual Feedback of Target Position Affects Accuracy of Sequential Movements at Even Spaces

The role of visual feedback during movement is attributed to its accuracy, but findings regarding the utilization of this information are inconsistent. We developed a novel dot-placing task to investigate the role of vision in arm movements. Participants conducted pointing-like movements between two target stimuli at even spaces. In Experiment 1, visual feedback of targets and response positions was manipulated. Although visual loss of target stimuli hindered accuracy of movements, the absence of the position of previously placed dots had little effect. In Experiment 2, the effect of movement time on accuracy was assessed, as the relationship between these has been traditionally understood as a speed/accuracy trade-off. Results revealed that duration of movement did not impact movement accuracy.     

A review on eye movement studies in childhood and adolescent psychiatry

The neural substrates of eye movement measures are largely known. Therefore, measurement of eye movements in psychiatric disorders may provide insight into the underlying neuropathology of these disorders. Visually guided saccades, antisaccades, memory guided saccades, and smooth pursuit eye movements will be reviewed in various childhood psychiatric disorders. The four aims of this review are (1) to give a thorough overview of eye movement studies in a wide array of psychiatric disorders occurring during childhood and adolescence (attention-deficit/hyperactivity disorder, oppositional deviant disorder and conduct disorder, autism spectrum disorders, reading disorder, childhood-onset schizophrenia, Tourette’s syndrome, obsessive compulsive disorder, and anxiety and depression), (2) to discuss the specificity and overlap of eye movement findings across disorders and paradigms, (3) to discuss the developmental aspects of eye movement abnormalities in childhood and adolescence psychiatric disorders, and (4) to present suggestions for future research. In order to make this review of interest to a broad audience, attention will be given to the clinical manifestation of the disorders and the theoretical background of the eye movement paradigms.     

A review on eye movement studies in childhood and adolescent psychiatry

The neural substrates of eye movement measures are largely known. Therefore, measurement of eye movements in psychiatric disorders may provide insight into the underlying neuropathology of these disorders. Visually guided saccades, antisaccades, memory guided saccades, and smooth pursuit eye movements will be reviewed in various childhood psychiatric disorders. The four aims of this review are (1) to give a thorough overview of eye movement studies in a wide array of psychiatric disorders occurring during childhood and adolescence (attention-deficit/hyperactivity disorder, oppositional deviant disorder and conduct disorder, autism spectrum disorders, reading disorder, childhood-onset schizophrenia, Tourette’s syndrome, obsessive compulsive disorder, and anxiety and depression), (2) to discuss the specificity and overlap of eye movement findings across disorders and paradigms, (3) to discuss the developmental aspects of eye movement abnormalities in childhood and adolescence psychiatric disorders, and (4) to present suggestions for future research. In order to make this review of interest to a broad audience, attention will be given to the clinical manifestation of the disorders and the theoretical background of the eye movement paradigms.