Selective attention and the auditory vertex potential. 2: Effects of signal intensity and masking noise

A randomized sequence of tone bursts was delivered to subjects at short inter-stimulus intervals with the tones originating from one of three spatially and frequency specific channels. The subject's task was to count the tones in one of the three channels at a time, ignoring the other two, and press a button after each tenth tone. In different conditions, tones were given at high and low intensities and with or without a background white noise to mask the tones. The N sub 1 component of the auditory vertex potential was found to be larger in response to attended channel tones in relation to unattended tones. This selective enhancement of N sub 1 was minimal for loud tones presented without noise and increased markedly for the lower tone intensity and in noise added conditions

Selective attention and the auditory vertex potential. 1: Effects of stimulus delivery rate

Enhancement of the auditory vertex potentials with selective attention to dichotically presented tone pips was found to be critically sensitive to the range of inter-stimulus intervals in use. Only at the shortest intervals was a clear-cut enhancement of the latency component to stimuli observed for the attended ear

Vertex evoked potentials in a rating-scale detection task: Relation to signal probability

Vertex evoked potentials were recorded from human subjects performing in an auditory detection task with rating scale responses. Three values of a priori probability of signal presentation were tested. The amplitudes of the N1 and P3 components of the vertex potential associated with correct detections of the signal were found to be systematically related to the strictness of the response criterion and independent of variations in a priori signal probability. No similar evoked potential components were found associated with signal absent judgements (misses and correct rejections) regardless of the confidence level of the judgement or signal probability. These results strongly support the contention that the form of the vertex evoked response is closely correlated with the subject's psychophysical decision regarding the presence or absence of a threshold level signal

Effects of dried distillers grains with solubles on sow carcass fat quality

A pilot experiment was conducted to determine the effects of feeding nonpregnant (open) sows a diet containing 50% dried distillers grains with solubles (DDGS) on growth and carcass fat quality. A total of 8 open sows were allotted to 1 of 2 diets by parity and BW. One diet was a standard corn-soybean meal-based gestation diet; the second diet was a corn-soybean meal-based diet that contained 50% DDGS. All sows were fed 5 lb/d of feed in a single feeding for 92 d. All sows were harvested on d 92 at the Kansas State University Meat Laboratory for determination of carcass fat quality. As expected, no differences in BW or backfat change were found (P \u3e 0.62) for the feeding period. Additionally, no differences (P \u3e 0.23) in lipid oxidation as measured by 2-thiobarbituric acid reactive substances (TBARS) assay were reported either initially or after 5 d of retail display for sows fed 50% DDGS compared with controls. Lipid oxidation increased (P \u3c 0.003) as measured by TBARS assay for both treatments from d 1 to 5 as expected. Jowl fatty acid analysis revealed an increase in linoleic acid (P \u3c 0.01), total polyunsaturated fatty acids (P \u3c 0.01), and the ratio of polyunsaturated fatty acids to saturated fatty acids (P \u3c 0.03). Also, there was a trend for increased jowl iodine value (P \u3c 0.08) for sows fed 50% DDGS compared with the controls. In summary, feeding 50% DDGS to open sows for 92 d did not significantly affect BW, backfat, and lipid oxidation compared with controls. However, feeding 50% DDGS increased the concentration of linoleic acid and total polyunsaturated fatty acids and tended to increase jowl iodine value compared with controls.; Swine Day, 2008, Kansas State University, Manhattan, KS, 200

Representing environmental harm and resistance on Twitter: The case of the TAP pipeline

This research explores a new methodological path for doing green cultural criminological research via social media. It provides original case-study data and aims to stimulate further empirical and theoretical debate. In particular, the study explores how Twitter users have represented the harms related to an ongoing pipeline project in Italy (referred to as TAP), and the resistance to those harms. To these ends, it offers a virtual and visual ethnography of Twitter posts and posted images

‘As a woman…’; ‘As a Muslim…’: Subjects, positions and counter-terrorism powers in the United Kingdom

This article presents findings from original focus group research on the importance of identity claims within public understandings of counter-terrorism across the UK. Following a review of existing literature on the terrorism/counter-terrorism/identity nexus, the article introduces four prominent subject positions inhabited within public articulations of counter-terrorism powers: the ‘Muslim’, the ‘target’, the ‘woman’ and the ‘unaffected’. Positions such as these, we argue, both enable and inhibit particular normative, political and anecdotal claims about counter-terrorism frameworks and their impact upon the body politic. This, we suggest, is demonstrative of the co-constitutive role between counter-terrorism and identity claims. Thus, on the one hand, counter-terrorism initiatives work to position individuals socially, politically, and culturally: (re)producing various religious, ethnic and other identities. Yet, at the same time, specific subject positions are integral to the articulation of people’s attitudes toward developments in counter-terrorism. The article concludes by thinking through some of the implications of this, including for resistance toward securitising moves and for citizenship more generally

The N2cc component as an electrophysiological marker of space-based and feature-based attentional target selection processes in touch

An electrophysiological correlate of attentional target selection processes in touch (N2cc component) has recently been discovered in lateralized tactile working memory experiments. This tactile N2cc emerges at the same time as the visual N2pc component, but has a different modality-specific topography over central somatosensory areas. Here, we investigated links between N2cc components and the space-based versus feature-based attentional selection of task-relevant tactile stimuli. On each trial, a pair of tactile items was presented simultaneously to one finger on the left and right hand. Target stimuli were defined by their location (e.g., left index finger; Spatial Attention Task), by a non-spatial feature (continuous versus pulsed; Feature-based Attention Task), or by a combination of spatial and non-spatial features (Conjunction Task). Reliable N2cc components were observed in all three tasks. They emerged considerably earlier in the Spatial Attention Task than in the Feature-based Attention Task, suggesting that space-based selection mechanisms in touch operate faster than feature-guided mechanisms. The temporal pattern of N2cc components observed in the Conjunction Task revealed that space-based and feature-based attention both contributed to target selection, which was initially driven primarily by spatial location. Overall, these findings establish the N2cc component as a new electrophysiological marker of the selective attentional processing of task-relevant stimuli in touch

Selective Processing of Multiple Features in the Human Brain: Effects of Feature Type and Salience

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

Imaging cortical activity following affective stimulation with a high temporal and spatial resolution

Keil J, Adenauer H, Catani C, Neuner F. Imaging cortical activity following affective stimulation with a high temporal and spatial resolution. BMC Neuroscience. 2009;10(1):83.Background:The affective and motivational relevance of a stimulus has a distinct impact on cortical processing, particularly in sensory areas. However, the spatial and temporal dynamics of this affective modulation of brain activities remains unclear. The purpose of the present study was the development of a paradigm to investigate the affective modulation of cortical networks with a high temporal and spatial resolution. We assessed cortical activity with MEG using a visual steady-state paradigm with affective pictures. A combination of a complex demodulation procedure with a minimum norm estimation was applied to assess the temporal variation of the topography of cortical activity. Results: Statistical permutation analyses of the results of the complex demodulation procedure revealed increased steady-state visual evoked field amplitudes over occipital areas following presentation of affective pictures compared to neutral pictures. This differentiation shifted in the time course from occipital regions to parietal and temporal regions. Conclusion: It can be shown that stimulation with affective pictures leads to an enhanced activity in occipital region as compared to neutral pictures. However, the focus of differentiation is not stable over time but shifts into temporal and parietal regions within four seconds of stimulation. Thus, it can be crucial to carefully choose regions of interests and time intervals when analyzing the affective modulation of cortical activity