Miskovic V.,Attention |
Keil A.,Attention |
Keil A.,University of Florida
Psychophysiology | Year: 2012
The capacity to associate neutral stimuli with affective value is an important survival strategy that can be accomplished by cell assemblies obeying Hebbian learning principles. In the neuroscience laboratory, classical fear conditioning has been extensively used as a model to study learning-related changes in neural structure and function. Here, we review the effects of classical fear conditioning on electromagnetic brain activity in humans, focusing on how sensory systems adapt to changing fear-related contingencies. By considering spatiotemporal patterns of mass neuronal activity, we illustrate a range of cortical changes related to a retuning of neuronal sensitivity to amplify signals consistent with fear-associated stimuli at the cost of other sensory information. Putative mechanisms that may underlie fear-associated plasticity at the level of the sensory cortices are briefly considered, and several avenues for future work are outlined. © 2012 Society for Psychophysiological Research.
Lang P.J.,Attention |
Mcteague L.M.,Medical University of South Carolina |
Psychophysiology | Year: 2016
Evidence is presented supporting a dimension of defensive reactivity that varies across the anxiety disorder spectrum and is defined by physiological responses during threat-imagery challenges that covary with objective measures of psychopathology. Previous imagery studies of anxiety disorders are reviewed, highlighting that, regardless of contemporary diagnostic convention, reliable psychophysiological patterns emerge for patients diagnosed with circumscribed fear compared to those diagnosed with pervasive anxious-misery disorders. Based on the heuristic outlined by the Research Domain Criteria (RDoC) initiative, an exploratory transdiagnostic analysis is presented, based on a sample of 425 treatment-seeking patients from across the spectrum of DSM-IV anxiety diagnoses. Using a composite index of startle reflex and heart rate reactivity during idiographic fear imagery for each patient, a defensive dimension was defined by ranking patients from most defensively reactive to least reactive and then creating five groups of equivalent size (quintile; N=85). Subsequent analyses showed significant parallel trends of diminishing reactivity in both electrodermal and facial electromyographic reactions across this defensive dimension. Negative affectivity, defined by questionnaire and extent of functional interference, however, showed consistent, inverse trends with defensive reactivity-as reports of distress increased, defensive reactivity was increasingly attenuated. Notably, representatives of each principal diagnosis appeared in each quintile, underscoring the reality of pronounced within-diagnosis heterogeneity in defensive reactivity. In concluding, we describe our new RDoC research project, focusing on the assessment of brain circuit function as it determines hypo/hyperreactivity to challenge-somatic and autonomic-and may relate to patients' stress history and genetic inheritance. © 2016 Society for Psychophysiological Research.
Attention, Perception, and Psychophysics | Year: 2014
Visual working memory is a volatile, limited-capacity memory that appears to play an important role in our impression of a visual world that is continuous in time. It also mediates between the contents of the mind and the contents of that visual world. Research on visual working memory has become increasingly prominent in recent years. The articles in this special issue of Attention, Perception, & Psychophysics describe new empirical findings and theoretical understandings of the topic. © 2014, The Psychonomic Society, Inc.
Henderson R.R.,Attention |
Bradley M.M.,Attention |
Psychophysiology | Year: 2014
An initial reflexive constriction of the pupil to stimulation-the light reflex-is primarily modulated by brightness, but is attenuated when participants are under threat of shock (i.e., fear-inhibited light reflex). The present study assessed whether the light reflex is similarly attenuated when viewing emotional pictures. Pupil diameter was recorded while participants viewed erotic, violent, and neutral scenes that were matched in brightness; scrambled versions identical in brightness were also presented as an additional control. Compared to viewing neutral scenes, the light reflex was reliably modulated by hedonic content, with significant attenuation both when viewing unpleasant as well as pleasant pictures. No differences in the light reflex were found among scrambled versions. Thus, emotional modulation of the initial light reflex is not confined to a context of fear and is not indicative of brightness differences when viewing pictures of natural scenes. © 2014 Society for Psychophysiological Research.
Song I.,Attention |
Psychophysiology | Year: 2014
Neutral cues, after being reliably paired with noxious events, prompt defensive engagement and amplified sensory responses. To examine the neurophysiology underlying these adaptive changes, we quantified the contrast-response function of visual cortical population activity during differential aversive conditioning. Steady-state visual evoked potentials (ssVEPs) were recorded while participants discriminated the orientation of rapidly flickering grating stimuli. During each trial, luminance contrast of the gratings was slowly increased and then decreased. Right-tilted gratings (CS+) were paired with loud white noise but left-tilted gratings (CS-) were not. The contrast-following waveform envelope of ssVEPs showed selective amplification of the CS+ only during the high-contrast stage of the viewing epoch. Findings support the notion that motivational relevance, learned in a time frame of minutes, affects vision through a response gain mechanism. © 2014 Society for Psychophysiological Research.
Aging Health | Year: 2011
As the worlds population continues to age, the issues of age-related memory impairment become increasingly important and relevant to individual health and quality of life, as well as an increasing public health and societal concern. The concept of mild cognitive impairment (MCI) has emerged as a response to the desire and need to identify an indolent clinical condition that would reliably predict progression to dementia, particularly Alzheimers disease (AD). As a result of decades of research in the field of neurodegeneration, it is becoming increasingly evident that neurodegenerative diseases begin years before the onset of clinical symptoms, and that standard clinical practice may be relatively insensitive at identifying early neurodegenerative states. The MCI concept was developed to identify the clinical parameters that define the earliest stages of the neurodegenerative process. The essence of the MCI classification is that of mild but measurable cognitive changes indicating a predisposition to progression to dementia, prior to the onset of functional decline. MCI and, more specifically, amnestic MCI were initially proposed as pathological transitional states that ultimately progress to full blown AD. However, after more than a decade of observations, it has been found that MCI subjects do not uniformly progress to dementia or AD and may revert back to normal cognitive states. While the concept of MCI may represent a valid model for characterization of the earliest stages of dementia and for delineation of risk factors, the operational definition may not adequately convey the intended concepts, and as such should be viewed with caution. Additional modifications to the concept and its operationalization are suggested in order to better identify patients with incipient AD and to guide clinical and research practices. © 2011 Future Medicine Ltd.
Ayeni O.R.,McMaster University |
Alradwan H.,McMaster University |
de Sa D.,McMaster University |
Knee Surgery, Sports Traumatology, Arthroscopy | Year: 2014
Purpose: With further understanding of the function and the importance of the hip labrum, greater attention has been paid to preserve and repair the damaged labrum. Hip labrum reconstruction has been described to optimize hip preservation when the labrum is deficient. This systematic review aimed to explore and identify the reported indications and outcomes in patients who undergo labral reconstruction of the hip joint. Methods: The electronic databases EMBASE, MEDLINE, and PubMed were searched for all available dates up to July 2013. Further hand search of the reference sections of the included studies was done. Two reviewers searched, screened, and evaluated the included studies for data quality using the Methodological Index for Non-Randomized Studies (MINORS) Scale. Data were also abstracted in duplicate, and agreement and descriptive statistics are presented. Results: There were 5 eligible studies (3 case series, 1 prospective cohort, and 1 retrospective chart review) with a total of 128 patients, and an average 11/16 quality on the MINORS score included in this review. All patients were diagnosed with femoroacetabular impingement and underwent labral reconstruction. Ninety-four patients were assessed at follow-up (73.4 % survivorship) between a reported mean range of 10 and 49 months. There was variability between the studies with regard to the graft types utilized (ilio-tibial band, Gracilis tendon, Ligamentum teres), surgical approaches [open (18.7 %) vs. arthroscopic (81.3 %)], and the reported outcome measures. Overall, improvement was observed in the patient-reported outcomes and functional scores (mHHS, HOS, UCLA, NASH, and SF-12). The failure rate or conversion to THA rate in all available patients was 20 %. The most common indication for labrum reconstruction was a young, active patient with minimal arthritis and non-salvageable or deficient labrum. Other indications included instability, pain, and hypotrophic dysfunctional labrum. Conclusion: Based on the current available evidence, hip labrum reconstruction is a new technique that shows short-term improvement in patient-reported outcomes and functional scores post-operatively. The main indication for reconstruction was a deficient labrum due to previous surgical excision or irreparable tears in young patients with no significant arthritis. Long-term follow-up results with higher quality studies are still lacking based on this review. Level of evidence: II. © 2013 Springer-Verlag Berlin Heidelberg.
McGinnis E.M.,Attention |
PLoS ONE | Year: 2011
Identifying targets in a stream of items at a given constant spatial location relies on selection of aspects such as color, shape, or texture. Such attended (target) features of a stimulus elicit a negative-going event-related brain potential (ERP), termed Selection Negativity (SN), which has been used as an index of selective feature processing. In two experiments, participants viewed a series of Gabor patches in which targets were defined as a specific combination of color, orientation, and shape. Distracters were composed of different combinations of color, orientation, and shape of the target stimulus. This design allows comparisons of items with and without specific target features. Consistent with previous ERP research, SN deflections extended between 160-300 ms. Data from the subsequent P3 component (300-450 ms post-stimulus) were also examined, and were regarded as an index of target processing. In Experiment A, predominant effects of target color on SN and P3 amplitudes were found, along with smaller ERP differences in response to variations of orientation and shape. Manipulating color to be less salient while enhancing the saliency of the orientation of the Gabor patch (Experiment B) led to delayed color selection and enhanced orientation selection. Topographical analyses suggested that the location of SN on the scalp reliably varies with the nature of the to-be-attended feature. No interference of non-target features on the SN was observed. These results suggest that target feature selection operates by means of electrocortical facilitation of feature-specific sensory processes, and that selective electrocortical facilitation is more effective when stimulus saliency is heightened. © 2011 McGinnis and Keil.
McTeague L.M.,Attention |
Depression and Anxiety | Year: 2012
Guided by the diagnostic nosology, anxiety patients are expected to show defensive hyperarousal during affective challenge, irrespective of the principal phenotype. In the current study, patients representing the whole spectrum of anxiety disorders (i.e., specific phobia, social phobia, panic disorder with or without agoraphobia, obsessive-compulsive disorder, generalized anxiety disorder (GAD), posttraumatic stress disorder(PTSD)), and healthy community control participants, completed an imagery-based fear elicitation paradigm paralleling conventional intervention techniques. Participants imagined threatening and neutral narratives as physiological responses were recorded. Clear evidence emerged for exaggerated reactivity to clinically relevant imagery-most pronounced in startle reflex responding. However, defensive propensity varied across principal anxiety disorders. Disorders characterized by focal fear and impairment (e.g., specific phobia) showed robust fear potentiation. Conversely, for disorders of long-enduring, pervasive apprehension and avoidance with broad anxiety and depression comorbidity (e.g., PTSDsecondary to cumulative trauma, GAD), startle responses were paradoxically diminished to all aversive contents. Patients whose expressed symptom profiles were intermediate between focal fearfulness and broad anxious-misery in both severity and chronicity exhibited a still heightened but more generalized physiological propensity to respond defensively. Importantly, this defensive physiological gradient-the inverse of self-reported distress-was evident not only between but also within disorders. These results highlight that fear circuitry could be dysregulated in chronic, pervasive anxiety, and preliminary functional neuroimaging findings suggest that deficient amygdala recruitment could underlie attenuated reflex responding. In summary, adaptive defensive engagement during imagery may be compromised by long-term dysphoria and stress-a phenomenon with implications for prognosis and treatment planning. © 2012 Wiley Periodicals, Inc.
News Article | December 20, 2016
SMS Gateways are used heavily in high availability environments, as an interface to system and network monitoring applications. They provide a backup to Internet-based notifications, for those situations when the Internet is not available. SMS Gateways communicate directly with the cellular network, providing an alternate path to message delivery. The Attention! SMS Gateway is also used as an alternative to Cloud-based short code solutions. When implemented with the required number of SMS channels, the Attention! SMS Gateway allows organizations to send, and receive, SMS text messages to a large number of users, for a fixed monthly cost. By eliminating the need for a short code, and the per-message charge assessed by Cloud providers, organizations using the Attention! SMS Gateway can save thousands—and sometimes tens of thousands of dollars per year. “We have had many customers asking for CDMA support,” said Bob Lueth, President of Attention Software. “So many companies are dedicated Verizon shops, but were required to make a trip to the AT&T store to get SIM chips to support the Attention! SMS Gateway hardware. With full support for CDMA, they can now just order the required number of data plans from their Verizon representative, and they are up and running. They also like the fact that SMS transmissions are being sent, and received, on their own network.” The Attention! 4G/LTE SMS Gateway supports up to 4,096 channels of outbound, and inbound SMS communication. When users reply to messages sent by the Attention! SMS Gateway, their response is archived for later review. In addition, the Attention! SMS Gateway supports automated, programmatic responses to all replies, in real-time. This capability is often used to verify acknowledgement of the message, or provide updates to help desk and management systems. About Attention Software Since 1993, Attention Software, Inc. of Colorado Springs, CO. has provided alerting, alarm management and web-based messaging systems to organizations around the world. For more information on Attention Software, visit http://www.attentionsoftware.com. Attention® is a registered trademark of Attention Software, Inc. Other products mentioned herein may be trademarks and/or registered trademarks of their respective owners.