232 research outputs found
Giving subjects the eye and showing them the finger: socio-biological cues and saccade generation in the anti-saccade task.
Pointing with the eyes or the finger occurs frequently in social interaction to indicate
direction of attention and one's intentions. Research with a voluntary saccade task (where saccade
direction is instructed by the colour of a fixation point) suggested that gaze cues automatically
activate the oculomotor system, but non-biological cues, like arrows, do not. However, other work
has failed to support the claim that gaze cues are special. In the current research we introduced
biological and non-biological cues into the anti-saccade task, using a range of stimulus onset
asynchronies (SOAs). The anti-saccade task recruits both top ^ down and bottom^ up attentional
mechanisms, as occurs in naturalistic saccadic behaviour. In experiment 1 gaze, but not arrows,
facilitated saccadic reaction times (SRTs) in the opposite direction to the cues over all SOAs,
whereas in experiment 2 directional word cues had no effect on saccades. In experiment 3 finger
pointing cues caused reduced SRTs in the opposite direction to the cues at short SOAs. These
findings suggest that biological cues automatically recruit the oculomotor system whereas non-
biological cues do not. Furthermore, the anti-saccade task set appears to facilitate saccadic responses in the opposite direction to the cues
Application of the ex-Gaussian function to the effect of the word blindness suggestion on Stroop task performance suggests no word blindness
The aim of the present paper was to apply the ex-Gaussian function to data reported by Parris et al. (2012) given its utility in studies involving the Stroop task. Parris et al. showed an effect of the word blindness suggestion when Response-Stimulus Interval (RSI) was 500 ms but not when it was 3500 ms. Analysis revealed that: (1) The effect of the suggestion on interference is observed in μ, supporting converging evidence indicating the suggestion operates over response competition mechanisms; and, (2) Contrary to Parris et al. an effect of the suggestion was observed in μ when RSI was 3500 ms. The reanalysis of the data from Parris et al. (2012) supports the utility of ex-Gaussian analysis in revealing effects that might otherwise be thought of as absent. We suggest that word reading itself is not suppressed by the suggestion but instead that response conflict is dealt with more effectively. © 2013 Parris, Dienes and Hodgson
Temporal constraints of the word blindness posthypnotic suggestion on Stroop task performance
The present work investigated possible temporal constraints on the posthypnotic word blindness
suggestion effect. In a completely within-subjects and counterbalanced design 19 highly suggestible
individuals performed the Stroop task both with and without a posthypnotic suggestion that they
would be unable to read the word dimension of the Stroop stimulus, both when response–stimulus
interval (RSI) was short (500 ms) or equivalent to previous studies (3500 ms). The suggestion
reduced Stroop interference in the short RSI condition (54 vs. 6 ms) but not in the long RSI condition
(52 vs. 56 ms), and did not affect Stroop facilitation. Our results suggest that response to the
suggestion involves reactive top-down control processes that persist only if levels of activation can
be maintained
Facilitating goal-oriented behaviour in the Stroop task: when executive control is influenced by automatic processing.
A portion of Stroop interference is thought to arise from a failure to maintain goal-oriented behaviour (or goal neglect). The aim of the present study was to investigate whether goal- relevant primes could enhance goal maintenance and reduce the Stroop interference effect. Here it is shown that primes related to the goal of responding quickly in the Stroop task (e.g. fast, quick, hurry) substantially reduced Stroop interference by reducing reaction times to incongruent trials but increasing reaction times to congruent and neutral trials. No effects of the primes were observed on errors. The effects on incongruent, congruent and neutral trials are explained in terms of the influence of the primes on goal maintenance. The results show that goal priming can facilitate goal-oriented behaviour and indicate that automatic processing can modulate executive control
The neural basis of overall similarity and single-dimension sorting
Copyright © 2009 Elsevier. NOTICE: This is the author’s version of a work accepted for publication by Elsevier. Changes resulting from the publishing process, including peer review, editing, corrections, structural formatting and other quality control mechanisms, may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in NeuroImage, 2009, Vol. 46, pp. 319 – 326 DOI: http://dx.doi.org/10.1016/j.neuroimage.2009.01.043The ability to group stimuli into meaningful categories is fundamental to natural behavior. Raw perceptions would be useless without an ability to classify items as, for example, threat or food. Previous work suggests that people have a tendency to group stimuli either on the basis of a single dimension or by overall similarity (e.g., Milton, F.N., Longmore, C.A., and Wills, A.J. (2008). Processes of overall similarity sorting in free classification. J. Exp. Psychol. Hum. Percept. Perform, 34, 676-692.). It has recently been suggested that overall similarity sorting can engage similar rule-based processes to single-dimension sorting and, in addition, requires greater use of working memory (Milton, F.N., and Wills, A.J. (2004). The influences of stimulus properties on category construction. J. Exp. Psychol. Learn. Mem. Cogn, 30, 407-415.). These predictions were tested in an event-related fMRI study of spontaneous categorization. Results showed a striking overlap of activation between overall similarity and single-dimension sorting indicating engagement of common neural processes. Furthermore, overall similarity sorting recruited additional activity in bilateral precuneus, right cuneus, left cerebellum, left postcentral gyrus, right thalamus and right ventrolateral frontal cortex (VLFC). Our findings suggest that overall similarity sorting can be the result of rule-based processes and highlight a potential role for right VLFC in integrating multi-dimensional sensory information to form conceptual categories
Act quickly, decide later: long latency visual processing underlies perceptual decisions but not reflexive behavior
Jolij J, Scholte H, Van Gaal S, Hodgson TL, Lamme VAF (2011) Act quickly, decide later: Long latency visual processing underlies perceptual decisions but not reflexive behavior. Journal of Cognitive Neuroscience 23(12), p 3734-3745
An fMRI investigation of moral cognition in healthcare decision making
This study used fMRI to investigate the neural substrates of moral cognition in
health resource allocation decision problems. In particular, it investigated the
cognitive and emotional processes that underpin utilitarian approaches to health
care rationing such as Quality Adjusted Life Years (QALYs). Participants viewed
hypothetical medical and nonmedical resource allocation scenarios which described
equal or unequal allocation of resources to different groups. In addition, participants
were assigned to 1 of 2 treatments in which they either did or did not receive
advanced instructions about the principles of utilitarianism. In all cases, participants
were asked to judged the proposed allocations as “fair” or “unfair.” More
brain activity was observed within the superior parietal lobe, angular gyrus, middle
temporal gyrus, and bilateral caudate nucleus when participants viewed scenarios
depicting equal divisions of resources. Conversely, unequal resource divisions were
associated with more activity in the inferior frontal gyrus and insula cortex.
Furthermore, instructions about the principles of utilitarianism led to significant
activation differences within the inferior frontal gyrus and the middle frontal gyrus.
Significant differences in activity were also found within the inferior frontal cortex
and anterior insula between medical and nonmedical scenarios. The implications
for cognitive control mechanisms and the cognitive and neural bases of utilitarian
ethical judgment are discussed
The role of the lateral prefrontal cortex and anterior cingulate in stimulus–response association reversals
Many complex tasks require us to flexibly switch between
behavioral rules, associations, and strategies. The prefrontal cerebral cortex is thought to be critical to the performance of such behaviors, although the relative contribution of different components of this structure and associated subcortical regions are not fully understood. We used functional magnetic resonance imaging to measure brain activity during a simple task which required repeated reversals of a rule linking a colored cue and a left/right motor response. Each trial comprised three discrete events separated by variable delay periods. A colored cue instructed which response was to be executed, followed by a go signal which told the subject to execute the response and a feedback instruction which indicated whether to ‘‘hold’’ or ‘‘f lip’’ the rule linking the colored cue and response. The design allowed us to determine which brain regions were recruited by the specific demands of
preparing a rule contingent motor response, executing such a
response, evaluating the significance of the feedback, and
reconfiguring stimulus–response (SR) associations. The results indicate that an increase in neural activity occurs within the anterior cingulate gyrus under conditions in which SR associations are labile. In contrast, lateral frontal regions are activated by unlikely/unexpected perceptual events regardless of their significance for behavior. A network of subcortical structures, including the mediodorsal nucleus of the thalamus and striatum were the only regions showing activity that was exclusively correlated with the neurocognitive demands of reversing SR associations. We conclude that lateral frontal regions act to evaluate the behavioral significance of perceptual
events, whereas medial frontal–thalamic circuits are involved in monitoring and reconfiguring SR associations when necessary
Practical, appropriate, empirically-validated guidelines for designing educational games
There has recently been a great deal of interest in the
potential of computer games to function as innovative
educational tools. However, there is very little evidence of
games fulfilling that potential. Indeed, the process of
merging the disparate goals of education and games design
appears problematic, and there are currently no practical
guidelines for how to do so in a coherent manner. In this
paper, we describe the successful, empirically validated
teaching methods developed by behavioural psychologists
and point out how they are uniquely suited to take
advantage of the benefits that games offer to education. We
conclude by proposing some practical steps for designing
educational games, based on the techniques of Applied
Behaviour Analysis. It is intended that this paper can both
focus educational games designers on the features of games
that are genuinely useful for education, and also introduce a
successful form of teaching that this audience may not yet
be familiar with
The role of the dominant versus the non-dominant hemisphere: an fMRI study of Aphasia recovery following stroke
Background: Speech production is one of the most frequently affected cognitive functions following stroke; however, the neural mechanisms underlying the recovery of speech function are still incompletely understood.
Aims: The current study aims to address the differential contributions of the dominant and non-dominant hemispheres in recovery from aphasia following stroke by comparing data from four stroke patients and 12 control participants to assess the patterns of activation during speech production tasks during functional magnetic resonance imaging (fMRI) scanning.
Methods & Procedures: Four chronic stroke patients (three left-hemisphere lesion and one right-hemisphere lesion) diagnosed with Broca’s aphasia at the acute phase, but now recovered to near normal speech ability, were tested on speech production tasks (phonemic fluency, categorical fluency and picture naming) whilst undergoing fMRI. These patients were compared with 12 healthy controls undergoing the same procedure.
Outcomes & Results: Individual subject analysis showed activation peaks in perilesional areas in three out of four patients. This included one patient with right-hemisphere lesion, who also showed predominant perilesional activation. Group analysis of control participants showed predominately left-hemisphere activation, but not exclusively so. Laterality indexes were calculated and showed predominant left-hemisphere lateralisation in the control group (LI = 0.4). Three out of the four patients showed speech lateralised to the same hemisphere as their lesion and the fourth patient showed speech lateralised to the opposite hemisphere to their lesion. Different speech production tasks resulted in varying lateralisation indices (LIs) within participants.
Conclusions: The data suggest that perilesional areas support recovery of speech in the chronic phase post-stroke regardless of the site of the lesion. The study has implications for the understanding of functional recovery as well as for the paradigms used in fMRI to localise speech production areas. Specifically, a variety of speech tasks are required to elicit activation that is representative of the range of cortical involvement in speech in healthy adults and that also allows for accurate reporting of the extent of recovery experienced in patients
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