Habituation of Central and Electrodermal Responses to an Auditory Two-Stimulus Oddball Paradigm.

The orienting reaction (OR) towards a new stimulus is subject to habituation, i.e., progressively attenuates with stimulus repetition. The skin conductance responses (SCRs) are known to represent a reliable measure of OR at the peripheral level. Yet, it is still a matter of debate which of the P3 subcomponents is the most likely to represent the central counterpart of the OR. The aim of the present work was to study habituation, recovery, and dishabituation phenomena intrinsic to a two-stimulus auditory oddball paradigm, one of the most-used paradigms both in research and clinic, by simultaneously recording SCRs and P3 in twenty healthy volunteers. Our findings show that the target stimulus was capable of triggering a more marked OR, as indexed by both SCRs and P3, compared to the standard stimulus, that could be due to its affective saliency and relevance for task completion; the application of temporal principal components analysis (PCA) to the P3 complex allowed us to identify several subcomponents including both early and late P3a (eP3a; lP3a), P3b, novelty P3 (nP3), and both a positive and a negative Slow Wave (+SW; -SW). Particularly, lP3a and P3b subcomponents showed a similar behavior to that observed for SCRs , suggesting them as central counterparts of OR. Finally, the P3 evoked by the first standard stimulus after the target showed a significant dishabituation phenomenon which could represent a sign of the local stimulus change. However, it did not reach a sufficient level to trigger an SCR/OR since it did not represent a salient event in the context of the task.

Neural Signals Associated with Orienting Response and Arousal Inhibition in Concealed Information Test.

Recent theory suggests that both the orienting response and arousal inhibition play roles in the effect of the concealed information test (CIT). However, the neural signatures associated with these two processes remain unclear. To address this issue, participants were motivated to either conceal or reveal crime-related stimulus during CIT while EEG was recorded. By using a temporal principal component analysis, we found that crime-related stimuli produced a larger early P3 than crime-irrelevant stimuli in both the conceal condition and reveal condition. This result suggests that this early P3 reflects an orienting response. In addition, we found that crime-related stimuli elicited a larger frontal negative slow wave than crime-irrelevant stimuli in the conceal condition but not the reveal condition, which suggests that the frontal negative slow wave reflects the arousal inhibition process. These results provide crucial evidence for understanding the neural basis underlying CIT.

Influence of Perceptual Load on Attentional Orienting in Post-Stroke Fatigue: A Study of Auditory Evoked Potentials.

OBJECTIVE: Increasing perceptual load alters behavioral outcomes in post-stroke fatigue (PSF). While the effect of perceptual load on top-down attentional processing is known, here we investigate if increasing perceptual load modulates bottom-up attentional processing in a fatigue dependent manner. METHODS: In this cross-sectional observational study, in 29 first-time stroke survivors with no clinical depression, an auditory oddball task consisting of target, standard, and novel tones was performed in conditions of low and high perceptual load. Electroencephalography was used to measure auditory evoked potentials. Perceived effort was rated using the visual analog scale at regular intervals during the experiment. Fatigue was measured using the fatigue severity scale. The effect of fatigue and perceptual load on behavior (response time, accuracy, and effort rating) and auditory evoked potentials (amplitude and latency) was examined using mixed model ananlysis of variances (ANOVA). RESULTS: Response time was prolonged with greater perceptual load and fatigue. There was no effect of load or fatigue on accuracy. Greater effort was reported with higher perceptual load both in high and low fatigue. p300a amplitude of auditory evoked potentials (AEP) for novel stimuli was attenuated in high fatigue with increasing load when compared to low fatigue. Latency of p300a was longer in low fatigue with increasing load when compared to high fatigue. There were no effects on p300b components, with smaller N100 in high load conditions. INTERPRETATION: High fatigue specific modulation of p300a component of AEP with increasing load is indicative of distractor driven alteration in orienting response, suggestive of compromise in bottom-up selective attention in PSF.

Unlocking the symmetric transfer of irrelevant information: gene-environment interplay and enhanced interhemispheric cross-talk.

Hemispheric specialization influences stimulus processing and behavioural control, affecting responses to relevant stimuli. However, most sensory input is irrelevant and must be filtered out to prevent interference with task-relevant behaviour, a process known as habituation. Despite habituation's vital role, little is known about hemispheric specialization for this brain function. We conducted an experiment with domestic chicks, an elite animal model to study lateralization. They were exposed to distracting visual stimuli while feeding when using binocular or monocular vision. Switching the viewing eye after habituation, we examined if habituation was confined to the stimulated hemisphere or shared across hemispheres. We found that both hemispheres learned equally to ignore distracting stimuli. However, embryonic light stimulation, influencing hemispheric specialization, revealed an asymmetry in interhemispheric transfer of the irrelevant information discarded via habituation. Unstimulated chicks exhibited a directional bias, with the right hemisphere failing to transfer distracting stimulus information to the left hemisphere, while transfer from left to right was possible. Nevertheless, embryonic light stimulation counteracted this asymmetry, enhancing communication from the right to the left hemisphere and reducing the pre-existing imbalance. This sharing extends beyond hemisphere-specific functions and encompasses a broader representation of irrelevant events.

Alpha-band oscillations and emotion: A review of studies on picture perception.

Although alpha-band activity has long been a focus of psychophysiological research, its modulation by emotional value during picture perception has only recently been studied systematically. Here, we review these studies and report that the most consistent alpha oscillatory pattern indexing emotional processing is an enhanced desynchronization (ERD) over posterior sensors when viewing emotional compared with neutral pictures. This enhanced alpha ERD is not specific to unpleasant picture content, as previously proposed for other measures of affective response, but has also been observed for pleasant stimuli. Evidence suggests that this effect is not confined to the alpha band but that it also involves a desynchronization of the lower beta frequencies (8-20 Hz). The emotional modulation of alpha ERD occurs even after massive stimulus repetition and when emotional cues serve as task-irrelevant distractors, consistent with the hypothesis that evaluative processes are mandatory in emotional picture processing. A similar enhanced ERD has been observed for other significant cues (e.g., conditioned aversive stimuli, or in anticipation of a potential threat), suggesting that it reflects cortical excitability associated with the engagement of the motivational systems.

A new theoretical perspective on concealed information detection.

The concealed information test (CIT) was designed to detect concealed knowledge. It does so by measuring differential physiological and behavioral responses to concealed, compared to control, items - i.e., the CIT effect. Although the CIT has gained extensive empirical support in laboratory studies, scientific validity requires also a theoretical understanding of the method's underlying mechanisms. In this article, we present a new theoretical perspective. Specifically, we elaborate and clarify several features of Orienting Response (OR) theory, which has been the dominant theory in this domain. Importantly, we suggest for the first time that the voluntary (rather than the involuntary) OR modulates the CIT effect. Second, we argue that motivational-emotional accounts of the CIT effect are consistent with OR theory and cannot be considered as alternative approaches. Finally, we discuss some more recent developments which highlight the idea that different physiological measures reflect different underlying mechanisms - an idea dubbed as response fractionation.

Orienting versus inhibition: The theory behind the ocular-based Concealed Information Test.

When trying to conceal one's knowledge, various ocular changes occur. However, which cognitive mechanisms drive these changes? Do orienting or inhibition-two processes previously associated with autonomic changes-play a role? To answer this question, we used a Concealed Information Test (CIT) in which participants were either motivated to conceal (orienting + inhibition) or reveal (orienting only) their knowledge. While pupil size increased in both motivational conditions, the fixation and blink CIT effects were confined to the conceal condition. These results were mirrored in autonomic changes, with skin conductance increasing in both conditions while heart rate decreased solely under motivation to conceal. Thus, different cognitive mechanisms seem to drive ocular responses. Pupil size appears to be linked to the orienting of attention (akin to skin conductance changes), while fixations and blinks rather seem to reflect arousal inhibition (comparable to heart rate changes). This knowledge strengthens CIT theory and illuminates the relationship between ocular and autonomic activity.

Wireless Heart Sensor for Capturing Cardiac Orienting Response for Prediction of Neurodevelopmental Delay in Infants.

Early identification of infants at risk of neurodevelopmental delay is an essential public health aim. Such a diagnosis allows early interventions for infants that maximally take advantage of the neural plasticity in the developing brain. Using standardized physiological developmental tests, such as the assessment of neurophysiological response to environmental events using cardiac orienting responses (CORs), is a promising and effective approach for early recognition of neurodevelopmental delay. Previous CORs have been collected on children using large bulky equipment that would not be feasible for widespread screening in routine clinical visits. We developed a portable wireless electrocardiogram (ECG) system along with a custom application for IOS tablets that, in tandem, can extract CORs with sufficient physiologic and timing accuracy to reflect the well-characterized ECG response to both auditory and visual stimuli. The sensor described here serves as an initial step in determining the extent to which COR tools are cost-effective for the early screening of children to determine who is at risk of developing neurocognitive deficits and may benefit from early interventions. We demonstrated that our approach, based on a wireless heartbeat sensor system and a custom mobile application for stimulus display and data recording, is sufficient to capture CORs from infants. The COR monitoring approach described here with mobile technology is an example of a desired standardized physiologic assessment that is a cost-and-time efficient, scalable method for early recognition of neurodevelopmental delay.

The orienting response drives pseudoneglect-Evidence from an objective pupillometric method.

Spatial attention is generally slightly biased leftward ("pseudoneglect"), a phenomenon typically assessed with paper-and-pencil tasks, limited by the requirement of explicit responses and the inability to assess on a subsecond timescale. Pseudoneglect is often stable within experiments, but differs vastly between investigations and is sometimes directed to the left, sometimes to the right. To date, no exhaustive explanation to this phenomenon has been provided. Here, we objectively assessed lateralized attention over time, exploiting the phenomenon that changes in the pupil reflect the allocation of attention in space. Pupil sizes of 41 healthy participants fixating the center were influenced stronger by the differential background luminance of the left side compared to the right side of the visual display. These differences were mainly driven by visual information in the periphery. Differences in pupil sizes positively related with greyscales scores. Time-based analyses within trials show strongest effects early on. With increasing trial number (not time), the initial leftward bias shifted central in pupillometry-based and greyscales measures. This suggests that the orienting response determines the degree of attention bias. In our amplification hypothesis we pose that the quality of pseudoneglect (i.e., the direction) is determined by higher order factors such as hemispheric imbalances, whereas the quantity (i.e., the degree) is determined by the orienting network. This account might explain numerous-previously thought opposing-findings. We here show how pupil light responses reveal pseudoneglect, in a next step, this might allow clinical diagnosis of hemispatial neglect.

No evidence for auditory N1 dishabituation in healthy adults after presentation of rare novel distractors.

Previous studies were not able to show that presentation of change stimuli leads to dishabituation of the auditory evoked potential (AEP) component N1 for repeated stimuli. However, these change stimuli were usually themselves repeatedly presented. Here, we tested whether the presentation of non-repeating distractor stimuli ('novels') would lead to N1 dishabituation. The study sample consisted of 18 healthy participants who had to identify auditory target stimuli (´targets´) among repeated standard stimuli and rare novels. AEPs to standards were separately averaged, depending on the preceding stimulus (standards after standards, standards after targets, and standards after novels) and were compared by F statistics and Bayesian t-test. Moreover, N1 repetition effects within recording blocks were analyzed in single trial analyses. The analyses showed that targets elicited significantly larger N1 amplitudes than standards and standards elicited larger N1 amplitudes than novels. In contrast, the N1 amplitude to standards did not vary with the preceding stimulus. The single trial analyses revealed significant, but similar N1 amplitude decreases within the recording blocks for all standards. The current study revealed no evidence for N1 dishabituation, as the N1 amplitude for standards after novels was not increased as compared to the N1 for standards after standards. Thus, stimulus variation had no impact on the N1 of repeated standards, as also suggested by the single trial analyses. The lack of N1 dishabituation is at odds with the assumption that the N1 amplitude decrease after repeated stimulation results from habituation.

A psychophysiological approach to fear appeals. Autonomic, subjective and behavioral responses to health promotion messages / Un enfoque psicofisiológico de los mensajes de miedo. Respuestas autónomas, subjetivas y conductuales a los mensajes de promoción de la salud

A study was designed in order to analyze the effects of fear appeals on psychophysiological, subjective and behavioral responses on the target audience. Three messages on breast cancer, promoting regular mammography screening, elaborated in a similar way to those used by health promotion programs, were presented to ninety-eight women aged 49-50. Messages were of equal length, format and structure but varied in specific clues which distinguished their character (Threat, Surprise, and Standard/control). Psychophysiological reactions (heart rate and frequency of non- specific skin conductance responses) were recorded continuously during message exposure. Self-report measures and personality traits (STAI and EPQ-A) were obtained after viewing the stimulus. There were significant responses to the messages for all psychophysiological measures. The pattern of psychophysiological response, independent of the eliciting message, was significantly related to cancer preventive/detection behavior.(AU)

Se diseñó un estudio para analizar los efectos que tienen las apelaciones al miedo sobre las respuestas psicofisiológicas, subjetivas y conductuales en la población diana. Para ello, se presentaron, a 98 mujeres de 49-50 años de edad, tres mensajes sobre el cáncer de mama promoviendo la realización de mamografía regularmente. Los mensajes fueron elaborados de manera similar a los utilizados por los programas de promoción de la salud. Los tres tenían la misma longitud, formato y estructura, pero variaban en determinadas claves que diferenciaban su carácter (Amenaza, Sorpresa y Estándar/control). Durante la exposición a estos mensajes, se registraron, de manera continua, las respuestas psicofisiológicas (frecuencia cardíaca y frecuencia de respuestas electrodérmicas inespecíficas). Después de ver los estímulos, se tomaron medidas de autoinforme y de personalidad (STAI y EPQ-A). Se encontraron respuestas significativas a los mensajes para todas las medidas psicofisiológicas. Independientemente del mensaje presentado, el patrón de respuesta psicofisiológica se relacionó significativamente con la conducta preventiva de detección del cáncer.(AU)

Did you say my name? Congruency of 12-month-old infants' behavioral and cardiac responses to name.

Reduced orienting to name is an early behavioral risk marker for neurodevelopmental disorders. However, individual instances of infants' behavioral responses to name are limited in both reliability and predictive validity. Physiological responses such as heart rate (HR) deceleration may serve as more sensitive metrics than behavioral methods. As a first step toward validating HR deceleration as a candidate psychophysiological measure of name processing, we examined the congruency of behavioral and cardiac responses to name in 12-month-old typically developing infants. Infants exhibited greater median HR deceleration and spent a larger proportion of time in HR deceleration when they behaviorally oriented to their names than when they failed to do so; however, maximum HR deceleration was not related to behavioral responses. These findings provide preliminary evidence that specific HR deceleration metrics may be useful indices of infants' responses to name and may inform psychophysiological mechanisms underlying behavioral responses.

Different psychophysiological responses induced by a stimulus change during the orienting task and the Concealed Information Test.

The orienting response (OR) account of the Concealed Information Test (CIT) posits that physiological responses to CIT items are components of the OR. Physiological variations within a stimulus sequence were investigated in an OR task (Study 1) and the CIT (Study 2). In Study 1, an unexpected increase in tone intensity was introduced after repeated standard tone presentations. The deviant tone elicited a large skin conductance response (SCR), heightened vascular tone, and self-reported surprise and also increased skin conductance level, self-reported arousal, and sustained vascular tone thereafter. In Study 2, the deviant relevant item presentation elicited a larger SCR and greater surprise compared with the frequent irrelevant item presentation, whereas vascular tone and self-reported arousal dropped after presentation of the relevant item. These results indicate that although phasic responses to a deviant stimulus were similar in both tasks, tonic variations following the stimulus change differed. Possible implications are discussed.

Development of a Classical Conditioning Task for Humans Examining Phasic Heart Rate Responses to Signaled Appetitive Stimuli: A Pilot Study.

Cardiac responses to appetitive stimuli have been studied as indices of motivational states and attentional processes, the former being associated with cardiac acceleration and latter deceleration. Very few studies have examined heart rate changes in appetitive classical conditioning in humans. The current study describes the development and pilot testing of a classical conditioning task to assess cardiac responses to appetitive stimuli and cues that reliably precede them. Data from 18 adults were examined. They were shown initially neutral visual stimuli (putative CS) on a computer screen followed by pictures of high-caloric food (US). Phasic cardiac deceleration to food images was observed, consistent with an orienting response to motivationally significant stimuli. Similar responses were observed to non-appetitive stimuli when they were preceded by the cue associated with the food images, suggesting that attentional processes were engaged by conditioned stimuli. These autonomic changes provide significant information about classical conditioning effects in humans.

Brain-based concealed memory detection is driven mainly by orientation to salient items.

In the pursuit of new methods for concealed memory detection, event-related potential components (ERP) have been placed at the forefront of research. No method, however, is scientifically complete without a theory and the present study therefore aimed to unravel the cognitive processes underlying these ERPs (i.e., orienting and arousal inhibition). This was accomplished by using a Concealed Information Test (CIT) in which participants were once motivated to conceal and once motivated to reveal their identity. The results showed a similarly strong P3 CIT effect in the two motivational conditions, which was enhanced for high salience compared to low salience identity items. Similar results were observed when using a multivariate machine-learning algorithm - suggesting that brain-based concealed memory detection is driven mainly by orientation to salient stimuli, rather than by arousal inhibition. In addition, the algorithm, trained and tested on the ERPs of different identity items, achieved detection rates exceeding those achieved by the P3. This implies that CIT researchers and practitioners could potentially rely on the entire ERP waveform instead of a-priori selecting separate components. Together these results enrich current understanding of the mechanisms underlying neurophysiological responding to concealed information and pave the way for novel and powerful algorithms which could be used in real-life forensic investigations.

Stimulus probability affects the visual N700 component of the event-related potential.

OBJECTIVE: To examine whether the occipito-temporal visual N700 component of the event-related potential is sensitive to stimulus probabilities. METHODS: P1, N1, P3, and, in particular, the occipito-temporal N700 component of the event-related potential were analysed in response to frequent and rare non-target letters of a continuous performance task in 200 healthy adolescents. Additionally, amplitude habituation with time was examined for the occipito-temporal N700 and N1 components. RESULTS: The visual P1, N1, and occipito-temporal N700 components were significantly larger in response to rare letters than to frequent letters, whereas the P3 component demonstrated no amplitude difference. Over time, the occipito-temporal N700 amplitude decreased in response to the rare letters, while the N1 amplitude increased, to both, frequent and rare letters. CONCLUSIONS: This study provides first evidence that the visual occipito-temporal N700 is sensitive to stimulus probabilities, suggesting an enhanced post-processing of rare stimuli in secondary visual areas. The distinct habituation patterns of occipito-temporal N700 and N1 amplitudes distinguish repetition effects on stimulus post-processing (N700) from those on perception (N1). SIGNIFICANCE: The enhanced N700 component to rare stimuli might reflect an orienting response and underlying attentional processes. The N700 sensitivity to stimulus probabilities should be examined in patient groups with attentional deficits.

Human Auditory Detection and Discrimination Measured with the Pupil Dilation Response.

In the standard Hughson-Westlake hearing tests (Carhart and Jerger 1959), patient responses like a button press, raised hand, or verbal response are used to assess detection of brief test signals such as tones of varying pitch and level. Because of its reliance on voluntary responses, Hughson-Westlake audiometry is not suitable for patients who cannot follow instructions reliably, such as pre-lingual infants (Northern and Downs 2002). As an alternative approach, we explored the use of the pupillary dilation response (PDR), a short-latency component of the orienting response evoked by novel stimuli, as an indicator of sound detection. The pupils of 31 adult participants (median age 24 years) were monitored with an infrared video camera during a standard hearing test in which they indicated by button press whether or not they heard narrowband noises centered at 1, 2, 4, and 8 kHz. Tests were conducted in a quiet, carpeted office. Pupil size was summed over the first 1750 ms after stimulus delivery, excluding later dilations linked to expenditure of cognitive effort (Kahneman and Beatty 1966; Kahneman et al. 1969). The PDR yielded thresholds comparable to the standard test at all center frequencies tested, suggesting that the PDR is as sensitive as traditional methods of assessing detection. We also tested the effects of repeating a stimulus on the habituation of the PDR. Results showed that habituation can be minimized by operating at near-threshold stimulus levels. At sound levels well above threshold, the PDR habituated but could be recovered by changing the frequency or sound level, suggesting that the PDR can also be used to test stimulus discrimination. Given these features, the PDR may be useful as an audiometric tool or as a means of assessing auditory discrimination in those who cannot produce a reliable voluntary response.

Hide or Seek? Physiological Responses Reflect Both the Decision and the Attempt to Conceal Information.

The process of information concealment is more relevant than ever in this day and age. Using a modified concealed-information test (CIT), we aimed to unmask this process by investigating both the decision and the attempt to conceal information in 38 students. The attempt to conceal (vs. reveal) information induced a differential physiological response pattern within subjects-whereas skin conductance increased in both conditions, respiration and heart rate were suppressed only in the conceal condition-confirming the idea that these measures reflect different underlying mechanisms. The decision to conceal (vs. reveal) information induced enhanced anticipatory skin conductance responses. To our knowledge, this is the first study that observed such anticipatory responses in an information-concealment paradigm. Together, these findings imply that our physiological responses reflect, to some degree, both the decision and the attempt to conceal information. In addition to strengthening CIT theory, this knowledge sheds novel light on anticipatory responding in decision making.

Role of the insula in top-down processing: an intracranial EEG study using a visual oddball detection paradigm.

Functional neuroimaging studies suggest that the insular cortex-and more especially the anterior insula (aI)-is involved in attentional processes and plays a crucial role in the "salience network". However, its specific role in attentional processing remains unclear, which is partly attributable to the low temporal resolution of non-invasive neuroimaging techniques. This study aims to examine the spatio-temporal dynamics of visual target processing using intracranial EEG recorded directly from the insula. Eight epileptic patients (four women, age 18-44 years) completed a three-stimulus visual oddball task during the extraoperative invasive intracranial EEG (iEEG) monitoring of their drug-resistant seizures. Depth electrodes were implanted in ten insular lobes (5 left and 5 right) and provided a total of 59 recording contacts in the insula. Event-related potentials (ERPs) and high-gamma-band responses (GBRs) were processed offline. Permutation analyses were performed to compare ERP signals across conditions during the P300 (225-400) interval, and modulations of GBRs (70-150 Hz) were computed for separate 100 ms time windows (from 0 to 1000 ms post-stimulus) and compared across conditions using non-parametric Wilcoxon test. Target stimuli were associated with a P300 (250-338 ms) component for 39% of contacts implanted in the aI, most probably reflecting voluntary attentional processing. Amplitude was significantly greater for target than for standard stimuli for all of these contacts, and was greater than for novel stimuli for 72%. In the posterior insula (pI), 16% of contacts showed preferential responses to target stimulus in the P300 interval. Increased GBRs in response to targets were observed in 53% of aI contacts (from ≈ 200 to 300 ms) and in 43% of pI contacts (from ≈ 400 to 500 ms). This study is the first to characterize the spatio-temporal dynamics of visual target processing in the insula using iEEG. Results suggest that visual targets elicit a P300 in the aI which corresponds in latency to the P3b component, suggesting that this region is involved in top-down processing of task-relevant information. GBRs to visual targets occur earlier in the aI than in the pI, further characterizing their respective roles in voluntary attentional processing.

Spontaneous blink rate as an index of attention and emotion during film clips viewing.

Spontaneous blinking is a non-invasive indicator known to reflect dopaminergic influence over frontal cortex and attention allocation in perceptual tasks. 38 participants watched eighteen short film clips (2 min), designed to elicit specific affective states, and arranged in six different emotional categories, while their eye movements were recorded from the vertical electroculogram. The largest blink rate inhibition, reflecting greater attention allocation to the movie, was observed during the presentation of Erotic clips, excerpts on wilderness depicting beautiful landscapes (Scenery), as well as clips showing crying characters (Compassion). Instead, the minimum blink rate inhibition was found for Fear clips, which induced a defensive response with stimulus rejection. Blink rate across time evidenced how Compassion clips elicited early inhibition while Sadness clips induced a slower, later inhibition. Correlation analyses also revealed a negative correlation (r < -0.40) between total blink rate recorded during Erotic and Compassion clips and self-reported interest. Overall, the main variable explaining blink rate was emotional Valence. Results suggest that blink modulation is related with the motivational relevance and biological significance of the stimuli, tracking their differential recruitment of attentional resources. Furthermore, they provide a solid background for studying the emotion-attention patterns and their deficits also in clinical samples (e.g., neurological and psychiatric patients) using spontaneous blinking as a not-interfering psychophysiological measure.