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Task Paradigms (task + paradigm)

Distribution by Scientific Domains

Medical Sciences	42%
Psychology	28%

Selected Abstracts

Evidence for implicit sequence learning in dyslexia

DYSLEXIA, Issue 1 2002
Steve W. Kelly
Abstract Nicolson and Fawcett (Cognition 1990; 35: 159,182) have suggested that a deficit in the automatization of skill learning could account for the general impairments found in dyslexia. Much of the evidence for their claims has been collected via a dual task paradigm, which might allow for alternative explanations of the data. The present study examines automatic skill learning in a single task paradigm and extends previous studies by independently examining the contribution of stimulus-based and response-based learning. The task replicates Mayr's (J. Exp. Psychol.: Learning Memory Cognition 1996; 22: 350,364) methodology in the Serial Reaction Time task by exposing participants to two structured displays, simultaneously. Learning is measured by comparing RT to the learned sequence against RT to a random display. This study demonstrates learning for both dyslexic and control groups for a spatial sequence which was observed and a concurrent non-spatial sequence which was responded to via a keypress. Learning of the sequence did not seem to depend on awareness of the sequence structure. These results suggest that automatic skill learning is intact in dyslexic individuals. Copyright © 2002 John Wiley & Sons, Ltd. [source]

Volitional control of attention and brain activation in dual task performance

HUMAN BRAIN MAPPING, Issue 2 2007
Sharlene D. Newman
Abstract This study used functional MRI (fMRI) to examine the neural effects of willfully allocating one's attention to one of two ongoing tasks. In a dual task paradigm, participants were instructed to focus either on auditory sentence comprehension, mental rotation, or both. One of the major findings is that the distribution of brain activation was amenable to strategic control, such that the amount of activation per task was systematically related to the attention-dividing instructions. The activation in language processing regions was lower when attending to mental rotation than when attending to the sentences, and the activation in visuospatial processing regions was lower when attending to sentences than when attending to mental rotations. Additionally, the activation was found to be underadditive, with the dual-task condition eliciting less activation than the sum of the attend sentence and attend rotation conditions. We also observed a laterality shift across conditions within language-processing regions, with the attend sentence condition showing bilateral activation, while the dual task condition showed a left hemispheric dominance. This shift suggests multiple language-processing modes and may explain the underadditivity in activation observed in the current and previous studies. Hum. Brain Mapp, 2007. © 2006 Wiley-Liss, Inc. [source]

Effect of external cueing on gait in Huntington's disease

MOVEMENT DISORDERS, Issue 10 2008
Arnaud Delval MD
Abstract In Huntington's disease (HD) patients, gait is characterized by a timing disorder with marked intraindividual variability in temporal gait parameters (caused by the presence of both hyperkinetic and hypokinetic features). We sought to determine the influence of use of a metronome on gait parameters in patients simultaneously performing motor or cognitive tasks that required attentional resources. The objective is to evaluate the influence of rhythmic cues on gait interference during self-regulated walking and a dual task paradigm in HD. Fifteen HD patients and 15 paired controls were asked to walk and simultaneously perform another motor task (carrying a tray with four full glasses) or a cognitive task (counting backwards). We evaluated the effect of a metronome (set at 100% and 120% of the subject's self-determined cadence) in three different task conditions (gait alone, gait + motor task, gait + cognitive task). The use of auditory cues during free gait and dual tasks did not improve kinematic parameters in HD patients, in contrast to the situation for control subjects (improvement in gait speed and cadence but not stride length when the metronome was set at 120% in all conditions). HD patients have difficulty in synchronizing their footsteps with a metronome, mainly due to attentional deficits. © 2008 Movement Disorder Society [source]

Effect of chronic treatment of carvedilol on oxidative stress in an intracerebroventricular streptozotocin induced model of dementia in rats

JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 12 2009
Atish Kumar Prakash
Abstract Objectives Oxidative stress is emerging as an important issue in the pathogenesis of dementia. This study was conducted to investigate the possible neuroprotective effects of carvedilol against streptozotocin induced behavioural alterations and oxidative damage in rats. Methods An intracerbroventricular cannula was implanted in the lateral ventricles of male Wistar rats. Various behavioural (locomotor activity, Morris water maze task) and biochemical parameters (lipid peroxidation, nitrate concentration, catalase, acetylcholinesterase, reduced glutathione and protein) were assessed. Key findings Intracerebroventricular administration of streptozotocin caused a significant memory deficit as evaluated in the Morris water maze task paradigms, and caused marked oxidative damage as indicated by significant increases in malondialdehyde and nitrite levels, and depletion of superoxide dismutase, catalase and reduced glutathione levels. It also caused a significant increase in acetylcholinesterase activity. Chronic administration of carvedilol (1 and 2 mg/kg, i.p.) for a period of 25 days starting 4 days before streptozotocin administration resulted in an improvement in memory retention, and attenuation of oxidative damage and acetylcholinesterase activity. Conclusions This study demonstrates the effectiveness of carvedilol in preventing cognitive deficits as well as the oxidative stress caused by intracerbroventicular administration of streptozotocin in rats. Carvedilol may have potential in the treatment of neurodegenerative diseases. [source]

Syntactic Priming Effects in Comprehension: A Critical Review

LINGUISTICS & LANGUAGE COMPASS (ELECTRONIC), Issue 10 2010
Kristen M. Tooley
Syntactic priming occurs when processing of a target sentence is facilitated following processing of a prime sentence that has the same syntactic structure (Bock, 1986 Cognitive Psychology, 18. 355,387). Syntactic priming has been widely investigated in production (Bock, 1986 Cognitive Psychology, 18. 355,387; Bock and Griffin, 2000 General. 129(2). 177,192; Cleland and Pickering, 2003. Journal of Memory and Language, 49. 214,230; Cleland and Pickering 2006. Journal of Memory and Language, 54. 185,198; Pickering and Branigan, 1998. Journal of Memory and Language, 39. 633,651; and others), but only relatively recently in comprehension (Arai et al. 2007. Cognitive Psychology, 54(3). 218,250; Ledoux et al., 2007. Psychological Science. 18(2). 135,143; and others). This article reviews the current literature on syntactic priming in comprehension and contrasts these findings to those in production. Critically, syntactic priming effects in comprehension are observed more often when prime and target sentences share a content word, whereas in production, these effects are often observed when there are no shared content words between the primes and targets. Possible explanations for the differing degrees of lexical dependency between syntactic priming effects in production and in comprehension are posed and include differences in task paradigms and stimuli, differences in time course and syntactic processing between the two modalities, and mechanistic differences. Implications from the reviewed literature are then considered in attempts at determining the most likely mechanistic explanation for syntactic priming effects in both comprehension and production. A residual activation account (Pickering and Branigan, 1998. Journal of Memory and Language, 39. 633,651), an implicit learning account (Bock and Griffin, 2000 General. 129(2). 177,192; Chang et al. 2006. Psychological Review, 113(2). 234,272), and a dual mechanism account (Tooley, 2009. Is Syntactic Priming in Sentence Comprehension Really Just Implicit Learning? Paper presented to the 22nd Annual CUNY Conference on Human Sentence Processing, Davis, March 26,28) are outlined. The dual mechanism account may prove more consistent with a wider range of the reviewed research findings. [source]

Source memory for the color of pictures: Event-related brain potentials (ERPs) reveal sensory-specific retrieval-related activity

PSYCHOPHYSIOLOGY, Issue 3 2003
Yael M. Cycowicz
Abstract Remembering the context (i.e., source) in which an event occurred reveals episodic memory effects (EM) in the event-related brain potentials (ERP). In some verbal source memory experiments, a late prefrontal EM effect has been observed. In a different, pictorial source memory paradigm, a late, parieto-occipital EM effect was recorded. To assess whether these two EM effects stemmed from differences in task paradigms or from source-attribute differences, ERPs were recorded during source memory retrieval for object colors in two tasks. In the sequential task, old/new judgments were followed by source judgments (i.e., color). In the exclusion task, source memory judgments coincided with recognition judgments. For both tasks, late, parietao-occipital EM effects were observed. These findings suggest that it is not the nature of the task, but rather the perceptual characteristics of the source that lead to the presence of the parieto-occipital EM effect. The data further imply that memories for perceptual attributes such as color are stored in and retrieved from sensory-specific cortical areas. [source]

Effect of N -Acetyl Cysteine against Aluminium-induced Cognitive Dysfunction and Oxidative Damage in Rats

BASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 2 2009
Atish Prakash
Chronic aluminium exposure induces oxidative stress and increases amyloid beta levels in vivo. The role of oxidative stress has been well-suggested in these cognitive problems. Therefore, the present study was designed to explore the possible role of N -acetyl cysteine against aluminium mediating cognitive dysfunction and oxidative stress in rats. Aluminium chloride (100 mg/kg, p.o.) was given to rats daily for 6 weeks. N -acetyl cysteine (per se; 50 and 100 mg/kg, i.p.) pre-treatment was given 30 min. before aluminium daily for 6 weeks. On the third (21st day) and sixth week (42nd day) of the study, various behavioural tests (Morris water maze and elevated plus maze task paradigms) and locomotion (photoactometer) were done to evaluate cognitive tasks. The rats were killed on the 43rd day following the last behavioural test, and various biochemical tests were performed to assess the extent of oxidative damage. Chronic aluminium chloride administration resulted in poor retention of memory in Morris water maze, elevated plus maze task paradigms and caused marked oxidative damage. It also caused a significant increase in the acetylcholinesterase activity. Chronic administration of N -acetyl cysteine significantly improved memory retention in tasks, attenuated oxidative damage and acetylcholinesterase activity in aluminium-treated rats. The study suggests a neuroprotective effect of N -acetyl cysteine against aluminium-induced cognitive dysfunction and oxidative damage. [source]