[Show abstract][Hide abstract] ABSTRACT: Self-injurious behavior (SIB) is a chronic disorder that often begins in early childhood; however, few studies have examined the onset of SIB in young children. This preliminary study reports on the identification, assessment and observation of SIB in 32 children who had begun to engage in SIB within the previous 6 months. Participants were ages birth to 5 years and presented with or were at risk for intellectual and/or developmental disabilities. Assessment measures included parental interviews, developmental and language measures, standardized measures of problem behavior, and direct observations conducted in the home. Results indicated that for most children, SIB emerged prior to age 1 year, and multiple topographies of SIB and other problem behaviors developed in most children. Multiple measures were useful in identifying SIB and in characterizing the behavior by topography, frequency, and severity. Findings from the examination of child communication in relation to SIB were inconclusive. Results are discussed in relation to theories of SIB emergence, and previous observational studies of young children with SIB.
Journal of mental health research in intellectual disabilities. 07/2012; 5(3-4):260-285.
[Show abstract][Hide abstract] ABSTRACT: Anxiety is relatively common in depression and capable of modifying the severity and course of depression. Yet our understanding of how anxiety modulates frontal and limbic activation in depression is limited.
We used functional magnetic resonance imaging and two emotional information processing tasks to examine frontal and limbic activation in ten patients with major depression and comorbid with preceding generalized anxiety (MDD/GAD) and ten non-depressed controls.
Consistent with prior studies on depression, MDD/GAD patients showed hypoactivation in medial and middle frontal regions, as well as in the anterior cingulate, cingulate and insula. However, heightened anxiety in MDD/GAD patients was associated with increased activation in middle frontal regions and the insula and the effects varied with the type of emotional information presented.
Our findings highlight frontal and limbic hypoactivation in patients with depression and comorbid anxiety and indicate that anxiety level may modulate frontal and limbic activation depending upon the emotional context. One implication of this finding is that divergent findings reported in the imaging literature on depression could reflect modulation of activation by anxiety level in response to different types of emotional information.
Behavioral and Brain Functions 01/2012; 8:8. · 2.79 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Neuroimaging technology has afforded advances in our understanding of normal and pathological brain function and development in children and adolescents. However, noncompliance involving the inability to remain in the magnetic resonance imaging (MRI) scanner to complete tasks is one common and significant problem. Task noncompliance is an especially significant problem in pediatric functional magnetic resonance imaging (fMRI) research because increases in noncompliance produces a greater risk that a study sample will not be representative of the study population.
In this preliminary investigation, we describe the development and application of an approach for increasing the number of fMRI tasks children complete during neuroimaging. Twenty-eight healthy children ages 9-13 years participated. Generalization of the approach was examined in additional fMRI and event-related potential investigations with children at risk for depression, children with anxiety and children with depression (N=120). Essential features of the approach include a preference assessment for identifying multiple individualized rewards, increasing reinforcement rates during imaging by pairing tasks with chosen rewards and presenting a visual 'road map' listing tasks, rewards and current progress.
Our results showing a higher percentage of fMRI task completion by healthy children provides proof of concept data for the recommended tactics. Additional support was provided by results showing our approach generalized to several additional fMRI and event-related potential investigations and clinical populations.
We proposed that some forms of task noncompliance may emerge from less than optimal reward protocols. While our findings may not directly support the effectiveness of the multiple reward compliance protocol, increased attention to how rewards are selected and delivered may aid cooperation with completing fMRI tasks.
The proposed approach contributes to the pediatric neuroimaging literature by providing a useful way to conceptualize and measure task noncompliance and by providing simple cost effective tactics for improving the effectiveness of common reward-based protocols.
Behavioral and Brain Functions 01/2011; 7:10. · 2.79 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Attention-deficit/hyperactivity disorder (ADHD) is a developmental disorder that, by current definition, has onset prior to age 7 years. MRI studies have provided some insight into brain differences associated with ADHD, but thus far have almost exclusively focused on children ages 7 years and older. To better understand the neurobiological development of ADHD, cortical and subcortical brain development should be systematically examined in younger children presenting with symptoms of the disorder. High-resolution anatomical (MPRAGE) images, acquired on a 3.0T scanner, were analyzed in a total of 26 preschoolers, ages 4-5 years (13 with ADHD, 13 controls, matched on age and sex). The ADHD sample was diagnosed using DSM-IV criteria, and screened for language disorders. Cortical regions were delineated and measured using automated methods in Freesurfer; basal ganglia structures were manually delineated. Children with ADHD showed significantly reduced caudate volumes bilaterally; in contrast there were no significant group differences in cortical volume or thickness in this age range. After controlling for age and total cerebral volume, left caudate volume was a significant predictor of hyperactive/impulsive, but not inattentive symptom severity. Anomalous basal ganglia, particularly caudate, development appears to play an important role among children presenting with early onset symptoms of ADHD.
The Clinical Neuropsychologist 01/2011; 25(6):1009-28. · 1.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Many forms of psychopathology and substance abuse problems are characterized by chronic ritualized forms of avoidance and escape behavior that are designed to control or modify external or internal (i.e., thoughts, emotions, bodily sensations) threats. In this functional magnetic resonance imaging investigation, we examined amygdala reactivity to threatening cues when avoidance responding consistently prevented contact with an upcoming aversive event (money loss). In addition, we examined escape responding that terminated immediate escalating money loss and approach responding that produced a future money gain. Results showed cues prompting avoidance, escape and approach behavior recruited a similar fronto-striatal-parietal network. Within the amygdala, bilateral activation was observed to threatening avoidance and escape cues, even though money loss was consistently avoided, as well as to the reward cue. The magnitude of amygdala responses within subjects was relatively similar to avoidance, escape and approach cues, but considerable between-subject differences were found. The heightened amygdala response to avoidance and escape cues observed within a subset of subjects suggests threat-related responses can be maintained even when aversive events are consistently avoided, which may account for the persistence of avoidance-coping in various clinical disorders. Further assessment of the relation between amygdala reactivity and avoidance-escape behavior may prove useful in identifying individuals with or at risk for neuropsychiatric disorders.
[Show abstract][Hide abstract] ABSTRACT: Active avoidance involving controlling and modifying threatening situations characterizes many forms of clinical pathology, particularly childhood anxiety. Presently our understanding of the neural systems supporting human avoidance is largely based on nonhuman research. Establishing the generality of nonhuman findings to healthy children is a needed first step towards advancing developmental affective neuroscience research on avoidance in childhood anxiety. Accordingly, this investigation examined brain activation patterns to threatening cues that prompted avoidance in healthy youths. During functional magnetic resonance imaging, fifteen youths (ages 9-13) completed a task that alternately required approach or avoidance behaviors. On each trial either a threatening 'Snake' cue or a 'Reward' cue advanced towards a bank containing earned points. Directional buttons enabled subjects to move cues away from (Avoidance) or towards the bank (Approach). Avoidance cues elicited activation in regions hypothesized to support avoidance in nonhumans (amygdala, insula, striatum and thalamus). Results also highlighted that avoidance response rates were positively correlated with amygdala activation and negatively correlated with insula and anterior cingulate activation. Moreover, increased amygdala activity was associated with decreased insula and anterior cingulate activity. Our results suggest that nonhuman neurophysiological research findings on avoidance may generalize to neural systems associated with avoidance in childhood. Perhaps most importantly, the amygdala/insula activation observed suggests that threat-related responses can be maintained even when aversive events are consistently avoided, which may account for the persistence of avoidance-coping in childhood anxiety. The present approach may offer developmental affective neuroscience a conceptual and methodological framework for investigating avoidance in childhood anxiety.
[Show abstract][Hide abstract] ABSTRACT: In reinforcer-selective transfer, Pavlovian stimuli that are predictive of specific outcomes bias performance toward responses associated with those outcomes. Although this phenomenon has been extensively examined in rodents, recent assessments have extended to humans. Using a stock market paradigm adults were trained to associate particular symbols and responses with particular currencies. During the first test, individuals showed a preference for responding on actions associated with the same outcome as that predicted by the presented stimulus (i.e., a reinforcer-selective transfer effect). In the second test of the experiment, one of the currencies was devalued. We found it notable that this served to reduce responses to those stimuli associated with the devalued currency. This finding is in contrast to that typically observed in rodent studies, and suggests that participants in this task represented the sensory features that differentiate the reinforcers and their value during reinforcer-selective transfer. These results are discussed in terms of implications for understanding associative learning processes in humans and the ability of reward-paired cues to direct adaptive and maladaptive behavior.
[Show abstract][Hide abstract] ABSTRACT: Background: Autism is characterized by impairments in reciprocal social interactions and in social communication. Social interactions appear to be less rewarding for children with autism compared with typically developing (TD) children; deficient learning of social skills may result directly from deficits in responding to social rewards. Objectives: This study was designed to examine whether 8-10 year old boys with high functioning autism spectrum disorder (ASD) differ from typically developing boys (TD) in their preferences for activities embedded in a social or non-social context. Methods: Twenty boys with ASD and 20 TD boys engaged in three paired-choice stimulus preference assessments (SPAs): one consisting of 12 social activities, one consisting of 12 non-social activities, and a third preference assessment (combined SPA) consisting of 12 activities, made up of the top three social and non-social activities and the bottom three social and non-social activities identified from the single-class SPAs. A progressive-ratio (PR) analysis procedure, involving the individual presentation of each of the 12 activities from the combined SPA was also administered to assess whether boys with ASD (n=18) differ from TD boys (n=20) in the amount of work' they are willing to produce to gain access to social and non-social activities. Results: Analysis of variance revealed no significant group differences in the percentage of social and non-social activities selected during the combined SPA (all ps > .13). Examinations of relative rankings for social activities compared to non-social activities from the combined SPA revealed that boys with ASD prefer social stimuli to a similar extent as TD boys (Mann-Whitney U Tests, all ps > .46). Results from the PR analyses revealed no significant group differences in the break-points reflecting the amount of work participants were willing to produce to gain access to social and non-social activities (ANOVA, all ps > .35). Conclusions: Our findings suggest that boys with high functioning ASD may be similar to TD boys in their preferences for and in their responses to activities embedded in a social and non-social context. This research has implications for expanding our understanding about social and non-social rewards in autism.
International Meeting for Autism Research 2010; 05/2010
[Show abstract][Hide abstract] ABSTRACT: An essential component of cognition and language involves the formation of new conditional relations between stimuli based upon prior experiences. Results of investigations on transitive inference (TI) highlight a prominent role for the medial temporal lobe in maintaining associative relations among sequentially arranged stimuli (A > B > C > D > E). In this investigation, medial temporal lobe activity was assessed while subjects completed "Stimulus Equivalence" (SE) tests that required deriving conditional relations among stimuli within a class (A identical with B identical with C).
Stimuli consisted of six consonant-vowel-consonant triads divided into two classes (A1, B1, C1; A2, B2, C2). A simultaneous matching-to-sample task and differential reinforcement were employed during pretraining to establish the conditional relations A1:B1 and B1:C1 in class 1 and A2:B2 and B2:C2 in class 2. During functional neuroimaging, recombined stimulus pairs were presented and subjects judged (yes/no) whether stimuli were related. SE tests involved presenting three different types of within-class pairs: Symmetrical (B1 A1; C1 B1; B2 A2; C2 B2), and Transitive (A1 C1; A2 C2) and Equivalence (C1 A1; C2 A2) relations separated by a nodal stimulus. Cross-class 'Foils' consisting of unrelated stimuli (e.g., A1 C2) were also presented.
Relative to cross-class Foils, Transitive and Equivalence relations requiring inferential judgments elicited bilateral activation in the anterior hippocampus while Symmetrical relations elicited activation in the parahippocampus. Relative to each derived relation, Foils generally elicited bilateral activation in the parahippocampus, as well as in frontal and parietal lobe regions.
Activation observed in the hippocampus to nodal-dependent derived conditional relations (Transitive and Equivalence relations) highlights its involvement in maintaining relational structure and flexible memory expression among stimuli within a class (A identical with B identical with C).
Behavioral and Brain Functions 02/2008; 4:6. · 2.79 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Forming new knowledge based on knowledge established through prior learning is a central feature of higher cognition that is captured in research on stimulus equivalence (SE). Numerous SE investigations show that reinforcing behavior under control of distinct sets of arbitrary conditional relations gives rise to stimulus control by new, derived relations. This investigation examined whether frontal-subcortical and frontal-parietal networks known to support reinforced conditional relations also support derived conditional relations. Twelve adult subjects completed matching-to-sample (MTS) training with correct/wrong feedback to establish four trained conditional relations within two distinct, three-member stimulus classes: (1) A1-->B1, B1-->C1 and (2) A2-->B2, B2-->C2. Afterwards, functional neuroimaging was performed when MTS trials were presented involving matching two identical circles (a sensorimotor control condition), trained relations (A-->B, B-->C), and derived relations: symmetry (B-->A, C-->B), transitivity (A-->C), and equivalence (C-->A). Conditional responding to trained and derived relations was similarly correlated with bilateral activation in the targeted networks. Comparing trained to derived relations, however, highlighted greater activation in several prefrontal regions, the caudate, thalamus, and putamen, which may represent the effects of extended training or feedback present during imaging. Each derived relation also evidenced a unique activation pattern. Collectively, the findings extend the role of frontal-subcortical and frontal-parietal networks to derived conditional relations and suggest that regional involvement varies with the type of derived conditional relation.
Journal of the Experimental Analysis of Behavior 03/2007; 87(2):287-307. · 1.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Many human neuroimaging investigations on recognition memory employ verbal instructions to direct subject's attention to a stimulus attribute. But do the same or a similar neurophysiological process occur during nonverbal experiences, such as those involving contingency-shaped responses? Establishing the spatially distributed neural network underlying recognition memory for instructed stimuli and operant, contingency-shaped (i.e., discriminative) stimuli would extend the generality of contemporary domain-general views of recognition memory and clarify the involvement of declarative memory processes in human operant behavior.
Fifteen healthy adults received equivalent amounts of exposure to three different stimulus sets prior to neuroimaging. Encoding of one stimulus set was prompted using instructions that emphasized memorizing stimuli (Instructed). In contrast, encoding of two additional stimulus sets was prompted using a GO/NO-GO operant task, in which contingencies shaped appropriate GO and NO-GO responding. During BOLD functional MRI, subjects completed two recognition tasks. One required passive viewing of stimuli. The second task required recognizing whether a presented stimulus was a GO/NO-GO stimulus, an Instructed stimulus, or novel (NEW) stimulus. Retrieval success related to recognition memory was isolated by contrasting activation from each stimulus set to a novel stimulus (i.e., an OLD > NEW contrast). To explore differences potentially related to source memory, separate contrasts were performed between stimulus sets.
No regions reached supralevel thresholds during the passive viewing task. However, a relatively similar set of regions was activated during active recognition regardless of the methods and included dorsolateral and ventrolateral prefrontal cortex, right inferior and posterior parietal regions and the occipitoparietal region, precuneus, lingual, fusiform gyri and cerebellum. Results also showed the magnitude of the functional response in the occipitoparietal region was inversely correlated with reaction times (RTs), such that the largest functional response and slowest RTs occurred to Instructed stimuli and the smallest functional response and fastest RTs occurred to GO stimuli, with effects to NO-GO stimuli intermediate. The inverse relation was also present bilaterally in the parahippocampus and hippocampus. Comparisons between stimulus sets also revealed regional differences potentially related to source memory.
Recognition of stimuli previously associated with instructions and operant contingencies (i.e., discriminative stimuli) generally recruited similar inferior frontal and occipitoparietal regions and right posterior parietal cortex, with the right occipitoparietal region showing the largest effect. These findings suggest domain-general views of recognition memory may be applicable to understanding the neural correlates of control exerted by discriminative stimuli and suggest declarative memory processes are involved in human operant behavior.
Behavioral and Brain Functions 02/2007; 3:44. · 2.79 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Results of numerous human imaging studies and nonhuman neurophysiological studies on "reward" highlight a role for frontal, striatal, and thalamic regions in operant learning. By integrating operant and functional neuroimaging methodologies, the present investigation examined brain activation to two types of discriminative stimuli correlated with different contingencies. Prior to neuroimaging, 10 adult human subjects completed operant discrimination training in which money was delivered following button pressing (press-money contingency) in the presence of one set of discriminative stimuli, and termination of trials followed not responding (no response-next trial contingency) in the presence of a second set of discriminative stimuli. After operant training, subjects were instructed to memorize a third set of control stimuli unassociated with contingencies. Several hours after training, functional magnetic resonance imaging was performed while subjects viewed discriminative and control stimuli that were presented individually for 1,500 ms per trial, with stimulus presentations occurring, on average, every 6 s. Activation was found in frontal and striatal brain regions to both sets of discriminative stimuli relative to control stimuli. In addition, exploratory analyses highlighted activation differences between discriminative stimuli. The results demonstrate the utility of coupling operant and imaging technologies for investigating the neural substrates of operant learning in humans.
Journal of the Experimental Analysis of Behavior 12/2005; 84(3):505-19. · 1.07 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Functional magnetic resonance imaging (fMRI) is used to study brain function during behavioral tasks. The participation of pediatric subjects is problematic because reliable task performance and control of head movement are simultaneously required. Differential reinforcement decreased head motion and improved vigilance task performance in 4 children (2 with behavioral disorders) undergoing simulated fMRI scans. Results show that behavior analysis techniques can improve child cooperation during fMRI procedures.
[Show abstract][Hide abstract] ABSTRACT: Pediatric feeding disorders are estimated to occur in as many as one in every four infants and children, and when serious can require numerous, costly and sustained interventions. For over a decade research has cumulated evidence on the contributions of Behavior Analysis in understanding and remediating some types of pediatric feeding disorders. The systematic use of this body of evidence in conjunction with other approaches (medical, nutrition, occupational therapy, physical therapy, and so forth) is being carried out on an inpatient treatment unit at the Kennedy Krieger Institute. Key aspects are described here, including direct observation behavior assessment, approaches for increasing and decreasing feeding behavior, skill acquisition, transfer of treatment gains, and parent training. The results based on case studies and overall program evaluation indicate that medically complicated, severe feeding disorders can be treated successfully in a few months with a multidisciplinary approach which incorporates behavioral procedures.
[Show abstract][Hide abstract] ABSTRACT: Pediatric feeding disorders are estimated to occur in as many as one in every four infants and children, and when serious can require numerous, costly and sustained interventions. For over a decade research has cumulated evidence on the contributions of Behavior Analysis in understanding and remediating some types of pediatric feeding disorders. The systematic use of this body of evidence in conjunction with other approaches (medical, nutrition, occupational therapy, physical therapy, and so forth) is being carried out on an inpatient treatment unit at the Kennedy Krieger Institute. Key aspects are described here, including direct observation behavior assessment, approaches for increasing and decreasing feeding behavior, skill acquisition, transfer of treatment gains, and parent training. The results based on case studies and overall program evaluation indicate that medically complicated, severe feeding disorders can be treated successfully in a few months with a multidisciplinary approach which incorporates behavioral procedures. J Dev Behav Pediatr 15:278-291, 1994. Index terms: pediatric feeding disorders, food refusal, failure to thrive, tube dependence.
(C) Lippincott-Raven Publishers.
[Show abstract][Hide abstract] ABSTRACT: Continued problematic behavior in children and adolescents after brain trauma is a major barrier to medical care, rehabilitation, and eventual independent living. The present study demonstrates the application of already well-developed behavior analysis techniques to the early posttrauma expression of behavior problems during hospital recovery. To satisfy concerns regarding both cost and individualized treatment, interventions were carried out primarily by regular hospital staff (nurses and therapists), medical record data were used to document gains, and time series, within subject designs were used to show experimental control. Four patients (three male and one female) ranging in age from 10 to 16 years, received intervention based on behavior analysis techniques, which reduced disruption and increased cooperation with therapy and medical care. Behavior analysis techniques will be relevant to future rehabilitation research to the extent that the posttrauma patient's behavior is effected by environmental consequences as demonstrated here.
Archives of Physical Medicine and Rehabilitation 09/1993; 74(8):810-7. · 2.36 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Magnetic resonance imaging is a promising technological advance used for research and diagnosis of disease. The procedure has no risks, except when uncooperative patients require sedation. Four normal children participated in simulated scans to study the effects of (a) antecedent changes in the imaging environment and (b) operant conditioning of movement inhibition. Changing the environment can decrease movement, but operant contingencies were necessary to decrease movement to a level that, in most cases, would allow the procedure to occur without sedation.