Temporal dynamics of selective attention and conflict resolution during cross-dimensional go-nogo decisions

<p>Abstract</p> <p>Background</p> <p>Decision-making is a fundamental capacity which is crucial to many higher-order psychological functions. We recorded event-related potentials (ERPs) during a visual target-identification task that required go-nogo choices. Targets were identified on the basis of cross-dimensional conjunctions of particular colors and forms. Color discriminability was manipulated in three conditions to determine the effects of color distinctiveness on component processes of decision-making.</p> <p>Results</p> <p>Target identification was accompanied by the emergence of prefrontal P2a and P3b. Selection negativity (SN) revealed that target-compatible features captured attention more than target-incompatible features, suggesting that intra-dimensional attentional capture was goal-contingent. No changes of cross-dimensional selection priorities were measurable when color discriminability was altered. Peak latencies of the color-related SN provided a chronometric measure of the duration of attention-related neural processing. ERPs recorded over the frontocentral scalp (N2c, P3a) revealed that color-overlap distractors, more than form-overlap distractors, required additional late selection. The need for additional response selection induced by color-overlap distractors was severely reduced when color discriminability decreased.</p> <p>Conclusion</p> <p>We propose a simple model of cross-dimensional perceptual decision-making. The temporal synchrony of separate color-related and form-related choices determines whether or not distractor processing includes post-perceptual stages. ERP measures contribute to a comprehensive explanation of the temporal dynamics of component processes of perceptual decision-making.</p

Predicting Continued Dizziness After an Acute Peripheral Vestibular Disorder

Heinrichs N, Edler C, Eskens S, Mielczarek MM, Moschner C. Predicting Continued Dizziness After an Acute Peripheral Vestibular Disorder. Psychosomatic Medicine. 2007;69(7):700-707.Objective: To identify individuals at risk of developing ongoing dizziness 3 months after an acute peripheral vestibular disorder episode, which is usually functionally compensated or even healed within a few weeks. Methods: In a prospective longitudinal study, we assessed fear of bodily sensations and cognitions related to anxiety at the time of hospital admission and 3 months later in 43 patients with an episode of vestibular neuritis (VN) or benign paroxysmal positional vertigo (BPPV). All participants were assessed for mental disorders using a structured clinical interview. Results: Only the interaction between fear of bodily sensations within the first 2 weeks after admission and the type of vestibular disorder predicted the extent of dizzy complaints 3 months later; this accounts for 21% of the variance in a multiple regression analysis. Specifically, the prediction was valid only in patients with VN but not in patients with BPPV. Further analysis demonstrated that the interaction was not due to the peripheral vestibular disorder per se but rather determined by the initial severity of dizziness, which was significantly different in BPPV and VN patients. Conclusions: The present study demonstrates that, for the development of persistent psychogenic dizziness after a peripheral vestibular disorder, the fear of bodily sensations is only relevant in interaction with the initial severity of dizziness experienced during the acute organic episode. To prevent development of persistent psychogenic dizziness, we feel that our results indicate the need to screen patients with vestibular disorders for at-risk status and offer them psychological support to deal with their symptoms. VN = vestibular neuritis; BPPV = benign paroxysmal positional vertigo; ACQ = Anxiety Cognitions Questionnaire; BSQ = Body Sensation Questionnaire; BAI = Beck Anxiety Inventory; MI = Mobility Inventory; BDI = Beck Depression Inventory; SCL-90-R GSI = Symptom Checklist Revised Global Severity Index; RC = (at least partially) recovered group; CC = continuously complaining group

Deficits of smooth pursuit initiation in patients with degenerative cerebellar lesions.

It is well known that cerebellar dysfunction can lead to an impairment of eye velocity during sustained pursuit tracking of continuously moving visual target. We have now studied the initiation of smooth pursuit eye movements towards predictable and randomized visual step-ramp stimuli in six patients with degenerative cerebellar lesions and six age-matched healthy controls using the magnetic scleral search-coil technique. In comparison with the control subjects, the cerebellar patients showed a significant delay of pursuit onset, and their initial eye acceleration was significantly decreased. These cerebellar deficits of pursuit initiation were similarly found in response to both randomized and predictable step-ramps, suggesting that predictive input does not compensate for cerebellar deficits in the initiation period of smooth pursuit. When we compared initial saccades during smooth tracking of foveofugal and foveopetal step-ramps, the absolute position error of these saccades did not significantly differ between patients and controls. In fact, none of the patients showed any bias of the saccadic position error that was related to the direction or velocity of the ongoing target motion. This work presents further evidence that the effect of cerebellar degeneration is not limited to the impaired velocity gain of steady-state smooth pursuit. Instead, it prolongs the processing time required to initiate smooth pursuit and impairs the initial eye acceleration. These two deficits were not associated with an abnormal assessment of target velocity and they were not modified by predictive control mechanisms, suggesting that cerebellar deficits of smooth initiation are not primarily caused by abnormal information on target motion being relayed to the cerebellum

Temporal dynamics of selective attention and conflict resolution during cross-dimensional go-nogo decisions-4

<p><b>Copyright information:</b></p><p>Taken from "Temporal dynamics of selective attention and conflict resolution during cross-dimensional go-nogo decisions"</p><p>http://www.biomedcentral.com/1471-2202/8/68</p><p>BMC Neuroscience 2007;8():68-68.</p><p>Published online 17 Aug 2007</p><p>PMCID:PMC2045106.</p><p></p>ering (see Methods) at posterior electrodes (P7, O1, O2, P8)

Temporal dynamics of selective attention and conflict resolution during cross-dimensional go-nogo decisions-0

<p><b>Copyright information:</b></p><p>Taken from "Temporal dynamics of selective attention and conflict resolution during cross-dimensional go-nogo decisions"</p><p>http://www.biomedcentral.com/1471-2202/8/68</p><p>BMC Neuroscience 2007;8():68-68.</p><p>Published online 17 Aug 2007</p><p>PMCID:PMC2045106.</p><p></p>ue ellipse is the form-overlap distractor, C-F+, and the blue rectangle serves as standard distractor, C-F-. () When the blue ellipse is the target, C+F+, the blue rectangle is the color-overlap distractor, C+F-, the red ellipse is the form-overlap distractor, C-F+, and the red rectangle serves as standard distractor, C-F-. () When the red rectangle is the target, C+F+, the red ellipse is the color-overlap distractor, C+F-, the blue rectangle is the form-overlap distractor, C-F+, and the blue ellipse serves as standard distractor, C-F-. () When the blue rectangle is the target, C+F+, the blue ellipse is the color-overlap distractor, C+F-, the red rectangle is the form-overlap distractor, C-F+, and the red ellipse serves as standard distractor, C-F-

Proof Development with ΩMEGA

The ΩMEGA proof development system [2] is the core of several related and well integrated..