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Behavioral Tasks (behavioral + task)
Selected AbstractsPrenatal Alcohol Exposure Affects Frontal,Striatal BOLD Response During Inhibitory ControlALCOHOLISM, Issue 8 2007Susanna L. Fryer Background: Prenatal alcohol exposure can lead to widespread cognitive impairment and behavioral dysregulation, including deficits in attention and response inhibition. This study characterized the neural substrates underlying the disinhibited behavioral profile of individuals with fetal alcohol spectrum disorders (FASD). Methods: Children and adolescents (ages 8,18) with (n=13) and without (n=9) histories of heavy prenatal alcohol exposure underwent functional magnetic resonance imaging while performing a response inhibition (go/no-go) task. Results: Despite similar task performance (mean response latency, performance accuracy, and signal detection), blood oxygen level-dependent (BOLD) response patterns differed by group. Region-of-interest analyses revealed that during portions of the behavioral task that required response inhibition, alcohol-exposed participants showed greater BOLD response across prefrontal cortical regions (including the left medial and right middle frontal gyri), while they showed less right caudate nucleus activation, compared with control participants. Conclusions: These data provide an account of response inhibition-related brain functioning in youth with FASD. Furthermore, results suggest that the frontal,striatal circuitry thought to mediate inhibitory control is sensitive to alcohol teratogenesis. [source] Designing mouse behavioral tasks relevant to autistic-like behaviors,DEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 4 2004Jacqueline N. Crawley Abstract The importance of genetic factors in autism has prompted the development of mutant mouse models to advance our understanding of biological mechanisms underlying autistic behaviors. Mouse models of human neuropsychiatric diseases are designed to optimize (1) face validity, i.e., resemblance to the human symptoms; (2) construct validity, i.e., similarity to the underlying causes of the disease; and (3) predictive validity, i.e., expected responses to treatments that are effective in the human disease. There is a growing need for mouse behavioral tasks with all three types of validity for modeling the symptoms of autism. We are in the process of designing a set of tasks with face validity for the defining features of autism: deficits in appropriate reciprocal social interactions, deficits in verbal social communication, and high levels of ritualistic repetitive behaviors. Social approach is tested in an automated three-chambered apparatus that offers the subject a choice between a familiar environment, a novel environment, and a novel environment containing a stranger mouse. Preference for social novelty is tested in the same apparatus, with a choice between the start chamber, the chamber containing a familiar mouse, and the chamber containing a stranger mouse. Social communication is evaluated by measuring the ultrasonic distress vocalizations emitted by infant mouse pups and the parental response of retrieving the pup to the nest. Resistance to change in ritualistic repetitive behaviors is modeled by forcing a change in habit, including reversal of the spatial location of a reinforcer in a T-maze task and in the Morris water maze. Mouse behavioral tasks that may model additional features of autism are discussed, including tasks relevant to anxiety, seizures, sleep disturbances, and sensory hypersensitivity. Applications of these tests include (1) behavioral phenotyping of transgenic and knockout mice with mutations in genes relevant to autism, (2) characterization of mutant mice derived from random chemical mutagenesis, (3) DNA microarray analyses of genes in inbred strains of mice that differ in social interaction, social communication and resistance to change in habit, and (4) evaluation of proposed therapeutics for the treatment of autism. Published 2004 Wiley-Liss, Inc. MRDD Research Reviews 2004;10:248,258. [source] Genetic reductions of ,-site amyloid precursor protein-cleaving enzyme 1 and amyloid-, ameliorate impairment of conditioned taste aversion memory in 5XFAD Alzheimer's disease model miceEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2010Latha Devi Abstract Although transgenic mouse models of Alzheimer's disease (AD) recapitulate amyloid-, (A,)-related pathologies and cognitive impairments, previous studies have mainly evaluated their hippocampus-dependent memory dysfunctions using behavioral tasks such as the water maze and fear conditioning. However, multiple memory systems become impaired in AD as the disease progresses and it is important to test whether other forms of memory are affected in AD models. This study was designed to use conditioned taste aversion (CTA) and contextual fear conditioning paradigms to compare the phenotypes of hippocampus-independent and -dependent memory functions, respectively, in 5XFAD amyloid precursor protein/presenilin-1 transgenic mice that harbor five familial AD mutations. Although both types of memory were significantly impaired in 5XFAD mice, the onset of CTA memory deficits (,9 months of age) was delayed compared with that of contextual memory deficits (,6 months of age). Furthermore, 5XFAD mice that were genetically engineered to have reduced levels of ,-site amyloid precursor protein-cleaving enzyme 1 (BACE1) (BACE1+/,·5XFAD) exhibited improved CTA memory, which was equivalent to the performance of wild-type controls. Importantly, elevated levels of cerebral ,-secretase-cleaved C-terminal fragment (C99) and A, peptides in 5XFAD mice were significantly reduced in BACE1+/,·5XFAD mice. Furthermore, A, deposition in the insular cortex and basolateral amygdala, two brain regions that are critically involved in CTA performance, was also reduced in BACE1+/,·5XFAD compared with 5XFAD mice. Our findings indicate that the CTA paradigm is useful for evaluating a hippocampus-independent form of memory defect in AD model mice, which is sensitive to rescue by partial reductions of the ,-secretase BACE1 and consequently of cerebral A,. [source] Ventral hippocampal involvement in temporal order, but not recognition, memory for spatial informationHIPPOCAMPUS, Issue 3 2008John G. Howland Abstract The hippocampus is critical for spatial memory. Recently, subregional differences in the function of hippocampus have been described in a number of behavioral tasks. The present experiments assessed the effects of reversibly lesioning either the dorsal (dHip) or ventral hippocampus (vHip) on spontaneous tests of spatial recognition and temporal order memory. We report that although the dHip is necessary for spatial recognition memory (RM) (distinguishing a novel from a familiar spatial location), the vHip is involved in temporal order memory (the capacity to distinguish between two spatial locations visited at different points in time), but not RM. These findings and others are consistent with the hypothesis that temporal order memory is supported by an integrated circuit of limbic areas including the vHip and the medial prefrontal cortex. © 2007 Wiley-Liss, Inc. [source] Differential involvement of the dorsal hippocampus in passive avoidance in C57bl/6J and DBA/2J miceHIPPOCAMPUS, Issue 1 2008Petra J.J. Baarendse Abstract The inferior performance of DBA/2 mice when compared to C57BL/6 mice in hippocampus-dependent behavioral tasks including contextual fear conditioning has been attributed to impaired hippocampal function. However, DBA/2J mice have been reported to perform similarly or even better than C57BL/6J mice in the passive avoidance (PA) task that most likely also depends on hippocampal function. The apparent discrepancy in PA versus fear conditioning performance in these two strains of mice was investigated using an automated PA system. The aim was to determine whether these two mouse strains utilize different strategies involving a different contribution of hippocampal mechanisms to encode PA. C57BL/6J mice exhibited significantly longer retention latencies than DBA/2J mice when tested 24 h after training irrespective of the circadian cycle. Dorsohippocampal NMDA receptor inhibition by local injection of the selective antagonist DL -2-amino-5-phosphonovaleric acid (AP5, 3.2 ,g/mouse) before training resulted in impaired PA retention in C57BL/6J but not in DBA/2J mice. Furthermore, nonreinforced pre-exposure to the PA system before training caused a latent inhibition-like reduction of retention latencies in C57BL/6J, whereas it improved PA retention in DBA/2J mice. These pre-exposure experiments facilitated the discrimination of hippocampal involvement without local pharmacological intervention. The results indicate differences in PA learning between these two strains based on a different NMDA receptor involvement in the dorsal hippocampus in this emotional learning task. We hypothesize that mouse strains can differ in their PA learning performance based on their relative ability to form associations on the basis of unisensory versus multisensory contextual/spatial cues that involve hippocampal processing. © 2007 Wiley-Liss, Inc. [source] Episodic memory,From brain to mindHIPPOCAMPUS, Issue 9 2006Janina Ferbinteanu Abstract Neuronal mechanisms of episodic memory, the conscious recollection of autobiographical events, are largely unknown because electrophysiological studies in humans are conducted only in exceptional circumstances. Unit recording studies in animals are thus crucial for understanding the neurophysiological substrate that enables people to remember their individual past. Two features of episodic memory,autonoetic consciousness, the self-aware ability to "travel through time", and one-trial learning, the acquisition of information in one occurrence of the event,raise important questions about the validity of animal models and the ability of unit recording studies to capture essential aspects of memory for episodes. We argue that autonoetic experience is a feature of human consciousness rather than an obligatory aspect of memory for episodes, and that episodic memory is reconstructive and thus its key features can be modeled in animal behavioral tasks that do not involve either autonoetic consciousness or one-trial learning. We propose that the most powerful strategy for investigating neurophysiological mechanisms of episodic memory entails recording unit activity in brain areas homologous to those required for episodic memory in humans (e.g., hippocampus and prefrontal cortex) as animals perform tasks with explicitly defined episodic-like aspects. Within this framework, empirical data suggest that the basic structure of episodic memory is a temporally extended representation that distinguishes the beginning from the end of an event. Future research is needed to fully understand how neural encodings of context, sequences of items/events, and goals are integrated within mnemonic representations of autobiographical events. © 2006 Wiley-Liss, Inc. [source] Impairment and recovery on a food foraging task following unilateral vestibular deafferentation in ratsHIPPOCAMPUS, Issue 4 2006Yiwen Zheng Abstract It has been suggested that the vestibular system may contribute to the development of higher cognitive function, especially spatial learning and memory that uses idiothetic cues (e.g., dead reckoning). However, few studies have been done using behavioral tasks that could potentially separate the animals' ability for dead reckoning from piloting. The food foraging task requires the animal to continuously monitor and integrate self-movement cues and generate an accurate return path. It has been shown that bilateral vestibular-lesioned rats were impaired on this task. The present study used the same task to further examine the contribution of vestibular information to spatial navigation by comparing unilateral and bilateral lesions and by testing the animals at different time points following the lesion. The results demonstrated that animals with unilateral vestibular deafferentation were impaired in performing the task in the dark at 3 months after the lesion, and this impairment disappeared at 6 months after the lesion. This supports the notion that vestibular information contributes to dead reckoning and suggests possible recovery of function over time after the lesion. Animals with bilateral vestibular deafferentation were not able to be tested on the foraging task because they exhibited behavior distinct from the unilateral-lesioned animals, with significant hesitation in leaving their home cage for as long as 6 months after the lesion. © 2005 Wiley-Liss, Inc. [source] Estimating readiness for change in anorexia nervosa: Comparing clients, clinicians, and research assessorsINTERNATIONAL JOURNAL OF EATING DISORDERS, Issue 3 2002Josie Geller Abstract Objective This research compared the relative ability of clients, clinicians, and research assessors in estimating readiness for change in individuals with anorexia nervosa. Method Fifty-six individuals with a current or past diagnosis of anorexia nervosa made ratings of the extent to which they perceived themselves to be ready for treatment and recovery. Clinicians and research assessors made the same ratings based on their impressions following clinical and research assessments, respectively. The outcome variables included questionnaire measures of change activities, assigned behavioral tasks, and clients' decision to accept intensive treatment. Results While research assessor and client ratings predicted questionnaire recovery activities, only research assessor ratings predicted completion of behavioral tasks and clients' decision to accept intensive treatment. Clinician ratings were not related to any of the questionnaire or behavioral recovery activity measures. Discussion Conditions favoring the accurate prediction of readiness for treatment and recovery are discussed, and implications for clinical practice are addressed. © 2002 by Wiley Periodicals, Inc. Int J Eat Disord 31: 251,260, 2002; DOI 10.1002/eat.10045 [source] New developments of brain imaging for Parkinson's disease and related disorders,MOVEMENT DISORDERS, Issue 12 2006Paola Piccini MD Abstract Parkinson's disease (PD) and related disorders are subcortical degenerations targeting the nigrostriatal dopaminergic system and basal ganglia. Traditionally, MRI has been used to detect structural and positron emission tomography and single emission computed tomography functional neurochemical and metabolic changes associated with these disorders. Recently, advances in diffusion-weighted MRI, ultrasonography, and radiotracer-based imaging have yielded greater sensitivity for revealing structural change and allowed detection of changes in brain dopamine levels after levodopa and during behavioral tasks. This review focuses on these recent advances in neuroimaging technology and their use for the diagnosis and assessment of PD and other parkinsonian disorders. © 2006 Movement Disorder Society [source] Socioeconomic status and hemodynamic recovery from mental stressPSYCHOPHYSIOLOGY, Issue 2 2003Andrew Steptoe Abstract We assessed the changes in cardiac index and total peripheral resistance underlying blood pressure reactions and recovery from acute mental stress, in relation to socioeconomic status. A sample of 200 men and women aged 47,59 years was divided on the basis of occupation into higher, intermediate, and lower socioeconomic status groups. Blood pressure was monitored using the Portapres, and hemodynamic measures were derived by Modelflow processing of the arterial pressure waveform. Blood pressure increases during two stressful behavioral tasks were sustained by increases in cardiac index and total peripheral resistance. During the 45-min posttask recovery period, cardiac index fell below baseline levels, whereas peripheral resistance remained elevated. Peripheral resistance changes during recovery varied with socioeconomic status and blood pressure stress reactivity, with particularly high levels in reactive low status participants. Results are consistent with the hypothesis that disturbances of stress-related autonomic processes are relevant to the social gradient in cardiovascular disease risk. [source] Longitudinal Study of Young Children's Responses to Challenging Achievement SituationsCHILD DEVELOPMENT, Issue 2 2001Dannah I. Ziegert Three studies were conducted to replicate and extend Dweck's findings regarding young children's responses to challenging achievement situations. Dweck's dichotomous helplessness classification system (i.e., task choice, task choice reason) was replicated with kindergartners, n= 235 (50% male), and first graders, n=70 (46% male). To test whether individual differences in young children's responses to challenging situations are stable over time, 1- and 5-year follow-ups of the kindergartners were conducted. On the basis of children's responses on age-appropriate behavioral tasks, a composite of cognitive, behavioral, and affective helplessness indices predicted helplessness at 1 and 5 years later, n= 114 (50% male), above and beyond kindergarten task ability and gender, p < .05. Kindergarten helplessness predicted teacher ratings of children's helplessness 5 years later as well, p < .05. The implications of these findings for early intervention are discussed. [source] | ||||||||||||||||