Pre-attentive Change Detection Research Articles

Can the Mismatch Negativity Really Be Elicited by Abstract Linguistic Contrasts?

Abstract The mismatch negativity (MMN) is an event-related potential component that reflects pre-attentive change detection in the brain. As an electrophysiological index of processing that responds to differences in incoming consecutive stimuli, the MMN can be elicited through, for example, the presentation of two different categories of sounds in an oddball paradigm where sounds from the “standard” category occur frequently and sounds from the “deviant” category occur rarely. The specificity of what can elicit the MMN is yet to be fully defined. Here we test whether the MMN can be generated by an abstract linguistic contrast with no reliable acoustic cue. Previous studies have shown that the way in which an acoustic cue is used to elicit MMN is influenced by linguistic knowledge, but have not shown that a nonacoustic, abstract linguistic contrast can itself elicit MMN. In this study, we test the strongest interpretation of the claim that the MMN can be generated through a purely linguistic contrast by contrasting tenses in ablauting irregular English verbs (where there is no reliable acoustic cue for tense). We find that this contrast elicits a negativity, as do other linguistic contrasts previously shown to elicit MMN (a contrast between phonologically voiced and phonologically voiceless segments and a purely acoustic contrast between aspirated and unaspirated segments). The findings provide evidence that the MMN is indeed sensitive to purely abstract linguistic categories.

Magnetoencephalography reveals impaired sensory gating and change detection in older adults in the somatosensory system

Brain electrophysiological responses can provide information about age-related decline in sensory-cognitive functions with high temporal accuracy. Studies have revealed impairments in early sensory gating and pre-attentive change detection mechanisms in older adults, but no magnetoencephalographic (MEG) studies have been undertaken into both non-attentive and attentive somatosensory functions and their relationship to ageing. Magnetoencephalography was utilized to record cortical somatosensory brain responses in young (20–28 yrs), middle-aged (46–56 yrs), and older adults (64–78 yrs) under active and passive somatosensory oddball conditions. A repeated standard stimulus was occasionally replaced by a deviant stimulus (p = .1), which was an electrical pulse on a different finger. We examined the amplitudes of M50 and M100 responses reflecting sensory gating, and later components reflecting change detection and attention shifting (M190 and M250 for the passive condition, and M200 and M350 for the active condition, respectively). Spatiotemporal cluster-based permutation tests revealed that older adults had significantly larger M100 component amplitudes than young adults for task-irrelevant stimuli in both passive and active condition. Older adults also showed a reduced M250 component and an altered M350 in response to deviant stimuli. The responses of middle-aged adults did not differ from those of younger adults, but this study should be repeated with a larger sample size. By demonstrating changes in both somatosensory gating and attentional shifting mechanisms, our findings extend previous research on the effects of ageing on pre-attentive and attentive brain functions.

Detecting Emotional Prosody in Real Words: Electrophysiological Evidence From a Modified Multifeature Oddball Paradigm.

Emotional voice conveys important social cues that demand listeners' attention and timely processing. This event-related potential study investigated the feasibility of a multifeature oddball paradigm to examine adult listeners' neural responses to detecting emotional prosody changes in nonrepeating naturally spoken words. Thirty-three adult listeners completed the experiment by passively listening to the words in neutral and three alternating emotions while watching a silent movie. Previous research documented preattentive change-detection electrophysiological responses (e.g., mismatch negativity [MMN], P3a) to emotions carried by fixed syllables or words. Given that the MMN and P3a have also been shown to reflect extraction of abstract regularities over repetitive acoustic patterns, this study employed a multifeature oddball paradigm to compare listeners' MMN and P3a to emotional prosody change from neutral to angry, happy, and sad emotions delivered with hundreds of nonrepeating words in a single recording session. Both MMN and P3a were successfully elicited by the emotional prosodic change over the varying linguistic context. Angry prosody elicited the strongest MMN compared with happy and sad prosodies. Happy prosody elicited the strongest P3a in the centro-frontal electrodes, and angry prosody elicited the smallest P3a. The results demonstrated that listeners were able to extract the acoustic patterns for each emotional prosody category over constantly changing spoken words. The findings confirm the feasibility of the multifeature oddball paradigm in investigating emotional speech processing beyond simple acoustic change detection, which may potentially be applied to pediatric and clinical populations.

Frontotemporal network in automatic / pre-attentive detection of abstract change: An event-related optical signal (EROS) study

The human brain constantly monitors the environment for unexpected changes. Under the prediction violation account, the Inferior Frontal Cortex (IFC) is involved in prediction-related processes for deviance detection processes in the Superior Temporal Cortex (STC). Consistent with this account, previous studies revealed an IFC-to-STC-followed-by-IFC mismatch response pattern to physical changes using event-related optical signals (EROS). However, detecting physical changes can be achieved by direct comparison of physical features between stimuli without making predictions, thus direct evidence supporting the prediction nature of the IFC-STC network in pre-attentive change detection was lacking. To address this issue, this study examined the EROS mismatch responses of the IFC-STC network when detecting the violation of an abstract rule. The rule “the higher the frequency of a tone, the stronger the intensity” established by standards was violated by deviants of 12 deviance levels. When deviants were preceded by a short train of standards, early IFC, STC, and late IFC EROS mismatch responses linearly increased with the deviance levels. When deviants were preceded by a longer train of standards, the STC but not the early or late IFC EROS mismatch responses were elicited by all the deviants without modulation by deviance levels. These results demonstrate a functional role of the IFC in the abstract change detection when insufficient rule-conforming information could be extracted from the preceding standards and are consistent with the predictive violation account of pre-attentive change detection.

Fronto-occipital mismatch responses in pre-attentive detection of visual changes: Implication on a generic brain network underlying Mismatch Negativity (MMN)

Current theories of pre-attentive change detection suggest a regularity or prediction violation mechanism involving a frontotemporal network. Modulations of the early inferior frontal cortex (IFC) mismatch response representing the effort in comparing a stimulus to the prediction, the superior temporal cortex (STC) response indicating deviance detection, and the late IFC response representing prediction model updating were consistently demonstrated in auditory change detection using event-related optical signal (EROS). If the prediction violation hypothesis is universal, a generic neural mechanism should be found in all sensory modalities. We postulated a generic fronto-sensory cortical network underlying the prediction violation mechanism: the IFC is responsible for non-modality-specific prediction processes while the sensory cortices are responsible for modality-specific error signal generation process. This study examined the involvement of the IFC-occipital cortex (OC) network in visual pre-attentive change detection. The EROS mismatch responses to deviant bar arrays violating a fixed orientation regularity (low in regularity abstractness) were compared to that of deviant violating a rotational orientation regularity (high in abstractness) while the information available for establishing the prediction model was manipulated by varying the number of standards preceding the deviants. Modulations of the IFCOC mismatch response patterns by abstractness and train length reflected the processing demands on the prediction processes and were similar to that of the IFC-STC network in auditory change detection. These findings demonstrated that the fronto-sensory cortical network is not unique to auditory pre-attentive change detection and provided supports for a universal neural mechanism across sensory modalities as suggested by the prediction violation hypothesis.

Processing neutral tone under the non-attentional condition: a mismatch negativity study.

The neutral tone is a unique tone form in Mandarin as it distinguishes from four canonical tones or full tones on the one hand and integrates phonetic, morphological, syntactical and prosodic information on the other hand. Research to date has been focusing on its unique and variant acoustic features. However, little is known about how native Mandarin speakers process such a unique tone. In the present study, the mismatch negativity was used to explore the comparison-based pre-attentive change detection of Mandarin neutral tone. The mismatch negativity at the time window of 400-800 ms post-first-tone onset was obtained by subtracting event-related potentials to standard neutral tone from event-related potentials to a deviant natural tone. The source analysis of mismatch negativity showed the cortex generator was located at the left temporal lobe. The data suggest that Chinese native speakers process neutral tone automatically under non-attentional conditions, as revealed by the mismatch negativity data aligned with a neutral tone, and that neutral tone does exist as an automatically recognizable one in native Mandarin speakers' tone system.

The critical role of the inferior frontal cortex in establishing a prediction model for generating subsequent mismatch negativity (MMN): A TMS-EEG study

BackgroundThe prediction violation account of automatic or pre-attentive change detection assumed that the inferior frontal cortex (IFC) is involved in establishing a prediction model for detecting unexpected changes. Evidence supporting the IFC’s contribution to prediction model is mainly based on the Mismatch Negativity (MMN) to deviants violating predictions that are established based on the frequently presented standard events. However, deviant detection involves processes, such as events comparison, other than prediction model establishment. ObjectiveThe current study investigated the critical role of the IFC in establishing a prediction model during standards processing for subsequent deviant detection. MethodsTranscranial Magnetic Stimulation (TMS) was applied at the IFC to disrupt the processing of the initial 2 or 5 standards of a 3-, 6-, or 9-standard train, while the MMN responses to pitch deviant presented after the standard trains were recorded and compared. ResultsAn abolishment of MMN was only observed when TMS was delivered to the IFC at the initial 2 standards of the 3-standard train, but not at the initial 5 standards, or when TMS at the vertex or TMS sound recording was applied. The MMNs were also preserved when IFC TMS, vertex TMS, or TMS sound recording was applied at the initial 2 or 5 standards of longer trains. ConclusionThe IFC plays a critical role in processing the initial standards of a short standard train for subsequent deviant detection. This result is consistent with the prediction violation account that the IFC is important for establishing the prediction model.

Dysfunctional frontal activation of mismatch negativity in panic disorder: A magnetoencephalographic study

BackgroundMismatch negativity (MMN) or its magnetic counterpart (MMNm) is a neurophysiological signal to reflect the automatic change-detection ability. However, MMN studies in patients with panic disorder (PD) showed contrasting results using electroencephalographic (EEG) recordings. The present study attempted to overcome the limitations of EEG methodology by means of a whole-head magnetoencephalography (MEG) combined with the depth-weighted minimum norm estimate method to conduct an in-depth investigation on the MMNm at the cortical level in patients with PD. MethodsWe recruited 22 healthy controls (HC) and 20 patients with PD to perform auditory oddball paradigm during MEG recordings. The cortical MMNm amplitudes and latencies in the superior temporal gyrus, inferior parietal lobule, and inferior frontal gyrus (IFG) were compared between the HC and PD groups. The correlations between MMNm responses and clinical measurement were also examined. ResultsCompared with the HC group, the PD group demonstrated significantly reduced MMNm amplitudes in the IFG. Furthermore, higher trait scores of the State-Trait Anxiety Inventory were associated with lower MMNm amplitudes of the right IFG among patients with PD. LimitationsGeneralization of the current results to other settings or samples should be made cautiously due to the use of different medication regimens and presence of comorbidities in our patients. ConclusionsOur data suggest dysfunctional pre-attentive change-detection ability in patients with PD, particularly in the IFG.

Acute But Not Chronic Aerobic Exercise Enhances Attention And The Neuroelectric Mismatch Negativity Among Fatigued Individuals

PURPOSE: Symptoms of fatigue are a public health burden, comorbid with both cardiovascular disease and cancer. While exercise requires considerable energy expenditure, both acute and chronic aerobic exercise reduce feelings of fatigue. However, the brain mechanisms underlying this effect are not well-understood. To explore the neural mechanisms of this effect, we examined EEG correlates of attention before and after acute and chronic aerobic exercise. We hypothesized that the lo-intensity acute and chronic effects of exercise would produce increased attentiveness. METHODS: In this pilot study, 13 students, ages 18-36, with elevated levels of fatigue, were randomly assigned to: lo-intensity, hi-intensity, and a no exercise control. Each participant was evaluated pre- and post-exercise three times (e.g., baseline, week 3, and post-intervention) during the 6-week study. At each session participants were outfitted with hi-density EEG and completed an auditory odd-ball task that resulted in a mismatch negativity (MMN). The MMN is an index of pre-attentive change detection, and its amplitude decreases with fatigue. EEG was analyzed via established guidelines including ICA algorithms for artifact-removal. To extract the MMN, the N1 was located in each recording and a difference wave was calculated by subtracting the electrocortical activity to the standards minus targets, in the 100ms after the N1 (120-220ms). RESULTS: A repeated-measures, mixed model ANOVA (3 Group (lo-intensity, hi-intensity, control) x 2 Time (pre/post intervention) x 3 Week (baseline, week 3, post-intervention)) revealed a marginally significant interaction between Group, Time, and Week [F(4,16)=2.79, p=0.06, η2=0.41] such that the MMN was reduced after hi-intensity exercise at the final session. In addition, the 2-way interaction between Group and Time [F2,8)=4.05, p=0.06, η2= 0.50] revealed a marginally significant interaction such that the lo-intensity group showed an increased MMN amplitude post exercise, the hi-intensity group showed a decrease, and the control group showed no change. No other effects were significant (all p>0.24, η2<0.29). DISCUSSION: Our data suggest that automatic pre-attentive change detection is only altered after lo-intensity acute aerobic exercise among our sample of fatigued individuals.

The preattentive change detection in preschool children with attention deficit hyperactivity disorder: a mismatch negativity study.

To investigate the preattentive change detection in preschool children with attention deficit hyperactivity disorder (ADHD), we compared the mismatch negativity (MMN) and P3a of event-related potentials (ERPs) between preschool ADHD and normal children using three-stimulus oddball paradigm. Analyzing MMN and P3a components, we found that MMN elicited by deviants and P3a elicited by novelty were significantly reduced in patients than in controls. In addition, the P3a amplitude was positive correlated to IQ and negatively correlated to hyperactivity, antagonistic defiance and conduct problems in Swanson, Nolan, and Pelham IV Rating Scale, parent version. These data provided new neurophysiological evidence for the dysfunction of preattentive change detection and attentional shift in ADHD children.

Functional connectivity of the frontotemporal network in preattentive detection of abstract changes: Perturbs and observes with transcranial magnetic stimulation and event-related optical signal.

Current theories of automatic or preattentive change detection suggest a regularity or prediction violation mechanism involving functional connectivity between the inferior frontal cortex (IFC) and the superior temporal cortex (STC). By disrupting the IFC function with transcranial magnetic stimulation (TMS) and recording the later STC mismatch response with event‐related optical signal (EROS), previous study demonstrated a causal IFC‐to‐STC functional connection in detecting a pitch or physical change. However, physical change detection can be achieved by memory comparison of the physical features and may not necessarily involve regularity/rule extraction and prediction. The current study investigated the IFC–STC functional connectivity in detecting rule violation (i.e., an abstract change). Frequent standard tone pairs with a constant relative pitch difference, but varying pitches, were presented to establish a pitch interval rule. This abstract rule was violated by deviants with reduced relative pitch intervals. The EROS STC mismatch response to the deviants was abolished by the TMS applied at the IFC 80 ms after deviance onset, but preserved in the spatial (TMS on vertex), auditory (TMS sound), and temporal (200 ms after deviance onset) control conditions. These results demonstrate the IFC–STC connection in preattentive abstract change detection and support the regularity or prediction violation account.

Pre-attentive Mismatch Response and Involuntary Attention Switching to a Deviance in an Earlier-Than-Usual Auditory Stimulus: An ERP Study.

An acoustic stimulus elicits an electroencephalographic response called auditory event-related potential (ERP). When some members of a stream of standard auditory stimuli are replaced randomly by a deviant stimulus and this stream is presented to a subject who ignores the stimuli, two different ERPs to deviant and standard stimuli are recorded. If the ERP to standard stimuli is subtracted from the ERP to deviant stimuli, the difference potential (DP) waveform typically exhibits a series of negative-positive-negative deflections called mismatch negativity (MMN), P3a, and reorienting negativity (RON), which are associated with pre-attentive change detection, involuntary attention switching, and reorienting of attention, respectively. The aim of the present study was to investigate how these pre-attentive processes are affected if the change occurs earlier than its usual timing implied by isochronous standard stimuli. In the MMN paradigm employed, 15% of the standards were randomly replaced by deviant stimuli which differed either in their pitch, their earlier onset time, or in both. Event-related responses to these three deviants [timely pitch change (RTP), earlier onset (REO), earlier pitch change (REP)] and to standards (RS) were recorded from 10 reading subjects. To maintain identical stimulation histories for the responses subtracted from each other, “deviant-standard” difference potentials (DP) for “timely” and “early” pitch deviances were derived as follows: DPTP = RTP − RS and DPEP = REP − REO. Interestingly, the MMN components of the DPs to timely and early pitch deviances had similar amplitudes, indicating that regularity of stimulus timing does not provide any benefit for the pre-attentive auditory change detection mechanism. However, different scalp current density (SCD) dynamics of the MMN/P3a complexes, elicited by timely and early pitch deviances, suggested that an auditory change in a stimulus occurring earlier-than-usual initiates a faster and more effective call-for-attention and causes stronger attention switching than a timely change. SCD results also indicated that the temporal, frontal, and parietal MMN components are simultaneously present rather than emerging sequentially in time, supporting the MMN models based on parallel deviance processing in the respective cortices. Similarity of the RONs to timely and early pitch deviances indicated that reorienting of attention is of the same strength in two cases.

Does changes in mismatch negativity after tinnitus retraining therapy using tinnitus pitch as deviant stimulus, reflect subjective improvement in tinnitus handicap?

Objective: The objective of this research was to study the ability of Mismatch Negativity response parameters to assess the habituation after Tinnitus Retraining Therapy through comparing MMN parameters before and after TRT and comparing MMN in tinnitus patients to non-tinnitus patients, and correlating MMN parameters to subjective measures of tinnitus.Methodology: This research included two groups: a tinnitus group of 30 tinnitus patients who were compared with a control group that consisted of well-matched 10 normal adult subjects. All participants were subjected to full history taking, audiological examination, and MMN test. Tinnitus patients were further assessed for tinnitus severity using the Tinnitus Handicap Inventory (THI), tinnitus analyses including pitch and loudness matching, with the PMF as the deviant stimulus for the MMN test.Results: The MMN latencies were significantly shorter and the MMN amplitudes were significantly greater in the tinnitus group before TRT than the control group. The MMN amplitude after TRT has significantly decreased and the MMN latency has significantly been prolonged in both ears after TRT compared with before TRT. The MMN amplitude improvement matched the subjective improvement measured subjectively by the THI.Conclusion: Tinnitus patients showed abnormality in central auditory processing mechanisms involved in pre-attentive change detection of tinnitus-related neuronal activity. This MMN abnormality showed improvement after habituation using TRT. So, we recommend adding the MMN test in evaluating tinnitus patients objectively before and after TRT for monitoring the treatment progress, together with the usual subjective measures for assessment of the degree of tinnitus severity.

Establishing the functional connectivity of the frontotemporal network in pre-attentive change detection with Transcranial Magnetic Stimulation and event-related optical signal

Current theories of pre-attentive deviant detection postulate that before the Superior Temporal Cortex (STC) detects a change, the Inferior Frontal Cortex (IFC) engages in stimulus analysis, which is particularly critical for ambiguous deviations (e.g., deviant preceded by a short train of standards). These theories rest on the assumption that IFC and STC are functionally connected, which has only been supported by correlational brain imaging studies. We examined this functional connectivity assumption by applying Transcranial Magnetic Stimulation (TMS) to disrupt IFC function, while measuring the later STC mismatch response with the event-related optical signal (EROS). EROS can localize brain activity in both spatial and temporal dimensions via measurement of optical property changes associated with neuronal activity, and is inert to the electromagnetic interference produced by TMS. Specifically, the STC mismatch response at 120–180 ms elicited by a deviant preceded by a short standard train when IFC TMS was applied at 80 ms was compared with the STC mismatch responses in temporal control (TMS with 200 ms delay), spatial control (sham TMS at vertex), auditory control (TMS pulse noise only), and cognitive control (deviant preceded by a long standard train) conditions. The STC mismatch response to deviants preceded by the short train was abolished by TMS of the IFC at 80 ms, while the STC responses remained intact in all other control conditions. These results confirm the involvement of the IFC in the STC mismatch response and support a functional connection between IFC and STC.

Influence of mental workload on detecting information varieties revealed by mismatch negativity during flight simulation

Behavioral and physiological measures indexed by frontal mismatch negativity (MMN), temporal MMN and eye blink rate derived from electrooculogram (EOG) were used to assess the mental workload related to flight simulation tasks. A total of 14 healthy flying cadets carried out flight simulation tasks under high and low mental workload conditions respectively. The mental workload conditions were manipulated by the complexity of abnormal attitude identification task presented on the head-up display (HUD) during the cruise phase. In this experiment, the increasing mental workload was associated with decreased accuracy rate of detecting abnormal information and longer reaction time. The frontal MMN was enhanced under the high mental workload condition whereas the temporal MMN was decreased, reflecting different information processing mechanisms. In addition, the eye blink rate, an additional assessment of mental workload, also showed high sensitivity and decreased significantly with the increase of mental workload. These results suggested that high mental workload might influence operator's pre-attentive change detection.

Neurophysiological differentiation between preattentive and attentive processing of emotional expressions on French vowels

The present electrophysiological study investigated the processing of emotional prosody by minimizing as much as possible the effect of emotional information conveyed by the lexical-semantic context. Emotionally colored French vowels (i.e., happiness, sadness, fear, and neutral) were presented in a mismatch negativity (MMN) oddball paradigm. Both the MMN, i.e., an event-related potential (ERP) component thought to reflect preattentive change detection, and the P3a, i.e., an ERP marker of involuntary orientation of attention toward deviant stimuli, were significantly modulated by the emotional deviants compared to the neutral ones. Critically, the largest amplitude (MMN, P3a) and the shortest peak latency (MMN) were observed for fear deviants, all other things being equal. Taken together, the present findings lend support to a sequential neurocognitive model of emotion processing (Scherer, 2001) which postulates, among other checks, a first stage of automatic emotion detection (MMN) followed by a second stage of subjective evaluation of the stimulus or event (P3a). Consistently with previous studies, our data suggest that among the six universal emotions, fear could have a special status probably because of its adaptive role in the evolution of the human species.

Effect of mental fatigue on nonattention: a visual mismatch negativity study.

Individuals experience mental fatigue during or after prolonged periods of cognitive activity. The aim of the present study was to investigate the effect of mental fatigue on detection of changes at the preattentive stage in the visual system by recording visual mismatch negativity of event-related potential components. Twenty-four students who volunteered for the study were divided randomly into either a mental fatigue group or a control group. Participants in the mental fatigue group were asked to perform an AX continued practice test for 2.5 h while the control group rested in the lab for 2.5 h. Then, subjective fatigue and mood state were measured by the Subjective Fatigue Symptom Questionnaire and the Profile of Mood States, respectively. Preattentive processing was evaluated as well by assessing the duration of the passive oddball task both before and after manipulation. In participants who performed the AX continued practice test, we observed a significant increase in feelings of fatigue and tiredness, and negative emotion. In these same participants, we observed a significant decrease in attention and positive emotion. This indicates that continuous cognitive operation induces mental fatigue. In addition, we found that the visual mismatch negativity amplitude was significantly reduced in participants with mental fatigue, implying that visual deviant/change detection is affected by mental fatigue. These results suggest that preattentive change detection and automatic processing decline as a result of mental fatigue.

Study on pre-attentive change detection indexed by auditory MMN in undergraduate students with major depressive disorder

Objective To explore pre-attentive information processing in undergraduate students with major depressive disorder(MDD) indexed by auditory mismatch negativity (MMN) and provide scientific theory basis for the diagnosis of MDD. Methods In the deviant-standard reverse oddball paradigm with deviant stimulus presentation probability of 20%, duration auditory MMN was obtained in 17 MDD university students and 17 gender-/age- matched healthy undergraduate students. All data were analyzed by statistics means of repeated measurement of F test. Results The amplitudes of 150 ms MMN over the frontal-central area were smaller in MDD undergraduate students((-0.34±1.24) μV) than those in healthy undergraduate students ((-1.07±1.55) μV, F=24.318, P=0.000). The 50 ms MMN did not differ between MDD students((-1.96±1.14)μV) and healthy undergraduate students ((-1.23±1.97)μV, F=0.089, P=0.767). Conclusion Pre-attentive auditory information processing is impaired in MDD undergraduate students. Key words: Major depressive disorder; Undergraduate students; Pre-attentive processing; Mismatch negativity

Neural correlates of cigarette health warning avoidance among smokers

BackgroundEye-tracking technology has indicated that daily smokers actively avoid pictorial cigarette package health warnings. Avoidance may be due to a pre-cognitive perceptual bias or a higher order cognitive bias, such as reduced emotional processing. Using electroencephalography (EEG), this study aimed to identify the temporal point at which smokers’ responses to health warnings begin to differ. MethodNon-smokers (n=20) and daily smokers (n=20) viewed pictorial cigarette package health warnings and neutral control stimuli. These elicited Event Related Potentials reflecting early perceptual processing (visual P1), pre-attentive change detection (visual Mismatch Negativity), selective attentional orientation (P3) and a measure of emotional processing, the Late Positive Potential (LPP). ResultsThere was no evidence for a difference in P1 responses between smokers and non-smokers. There was no difference in vMMN and P3 amplitude but some evidence for a delay in vMMN latency amongst smokers. There was strong evidence for delayed and reduced LPP to health warning stimuli amongst smokers compared to non-smokers. ConclusionWe find no evidence for an early perceptual bias in smokers’ visual perception of health warnings but strong evidence that smokers are less sensitive to the emotional content of cigarette health warnings. Future health warning development should focus on increasing the emotional salience of pictorial health warning content amongst smokers.

Fluid Intelligence and Automatic Neural Processes in Facial Expression Perception: An Event-Related Potential Study.

The relationship between human fluid intelligence and social-emotional abilities has been a topic of considerable interest. The current study investigated whether adolescents with different intellectual levels had different automatic neural processing of facial expressions. Two groups of adolescent males were enrolled: a high IQ group and an average IQ group. Age and parental socioeconomic status were matched between the two groups. Participants counted the numbers of the central cross changes while paired facial expressions were presented bilaterally in an oddball paradigm. There were two experimental conditions: a happy condition, in which neutral expressions were standard stimuli (p = 0.8) and happy expressions were deviant stimuli (p = 0.2), and a fearful condition, in which neutral expressions were standard stimuli (p = 0.8) and fearful expressions were deviant stimuli (p = 0.2). Participants were required to concentrate on the primary task of counting the central cross changes and to ignore the expressions to ensure that facial expression processing was automatic. Event-related potentials (ERPs) were obtained during the tasks. The visual mismatch negativity (vMMN) components were analyzed to index the automatic neural processing of facial expressions. For the early vMMN (50–130 ms), the high IQ group showed more negative vMMN amplitudes than the average IQ group in the happy condition. For the late vMMN (320–450 ms), the high IQ group had greater vMMN responses than the average IQ group over frontal and occipito-temporal areas in the fearful condition, and the average IQ group evoked larger vMMN amplitudes than the high IQ group over occipito-temporal areas in the happy condition. The present study elucidated the close relationships between fluid intelligence and pre-attentive change detection on social-emotional information.