Standard Oddball Task Research Articles

Do Rare Stimuli Evoke Large P3s by Being Unexpected? A Comparison of Oddball Effects Between Standard-Oddball and Prediction-Oddball Tasks.

The P3 component of event-related potentials increases when stimuli are rarely presented. It has been assumed that this oddball effect (rare-frequent difference) reflects the unexpectedness of rare stimuli. The assumption of unexpectedness and its link to P3 amplitude were tested here. A standard- oddball task requiring alternative key-press responses to frequent and rare stimuli was compared with an oddball-prediction task where stimuli had to be first predicted and then confirmed by key-pressing. Oddball effects in the prediction task depended on whether the frequent or the rare stimulus had been predicted. Oddball effects on P3 amplitudes and error rates in the standard oddball task closely resembled effects after frequent predictions. This corroborates the notion that these effects occur because frequent stimuli are expected and rare stimuli are unexpected. However, a closer look at the prediction task put this notion into doubt because the modifications of oddball effects on P3 by expectancies were entirely due to effects on frequent stimuli, whereas the large P3 amplitudes evoked by rare stimuli were insensitive to predictions (unlike response times and error rates). Therefore, rare stimuli cannot be said to evoke large P3 amplitudes because they are unexpected. We discuss these diverging effects of frequency and expectancy, as well as general differences between tasks, with respect to concepts and hypotheses about P3b’s function and conclude that each discussed concept or hypothesis encounters some problems, with a conception in terms of subjective relevance assigned to stimuli offering the most consistent account of these basic effects.

Measurement of Fronto-limbic Activity Using an Emotional Oddball Task in Children with Familial High Risk for Schizophrenia.

Adolescence is a critical developmental period where the early symptoms of schizophrenia frequently emerge. First-degree relatives of people with schizophrenia who are at familial high risk (FHR) may show similar cognitive and emotional changes. However, the neurological changes underlying the emergence of these symptoms remain unclear. This study sought to identify differences in frontal, striatal, and limbic regions in children and adolescents with FHR using functional magnetic resonance imaging. Groups of 21 children and adolescents at FHR and 21 healthy controls completed an emotional oddball task that relied on selective attention and the suppression of task-irrelevant emotional information. The standard oddball task was modified to include aversive and neutral distractors in order to examine potential group differences in both emotional and executive processing. This task was designed specifically to allow for children and adolescents to complete by keeping the difficulty and emotional image content age-appropriate. Furthermore, we demonstrate a technique for suitable fMRI registration for children and adolescent participants. This paradigm may also be applied in future studies to measure changes in neural activity in other populations with hypothesized developmental changes in executive and emotional processing.

P300 Correlates of Cognitive Dysfunctions in Schizophrenia

Introduction P300 is an event-related potential (ERP) thought to reflect attention, working memory and context integration and has been shown to be consistently reduced in patients with Schizophrenia. Despite a possible relation between P300 components and cognitive deficits in Schizophrenia has been hypothesized, few studies addressed this hypothesis. Objectives In the context of a multicenter study of the Italian Network for Research on Psychoses, our study focused on the investigation of auditory P300 component in relation to clinical and cognitive domains in patients with Schizophrenia. Methods ERPs were recorded in 64 chronic, stabilized patients with Schizophrenia during a standard oddball task. N1 and P3b latency and amplitude were assessed at Fz and Pz, respectively. State of art instruments was used for clinical assessment. Cognitive indices (from the seven cognitive domains of the Measurement and Treatment of Cognition in Schizophrenia, MATRICS) were expressed as Z-scores from an Italian normative sample. Results Correlation analysis revealed associations of P3b latency with age, education, PANSS-DIS, processing speed, working memory, St. Hans parkinsonism subscale. In a multiple linear regression model, processing speed was an independent significant predictor of P3b latency. Conclusion For the first time, a strong relation between P3b latency and processing speed impairment was shown in Schizophrenia. Processing speed is considered a central factor in the relation between cognitive deficits and functional outcome in chronic schizophrenia. The association with P3b latency might shed lights in the neural basis of this complex construct.

Event-Related Potentials and Plasma Levels of Monoamine Metabolites in Normal Subjects

We examined the relationships between the ERP measurements and concentrations of plasma monoamine metabolites in 20 healthy volunteers. Event-related potentials were recorded within the framework of two auditory paradigms, a standard oddball task and a novelty oddball task. The plasma concentrations of homovanillic acid (HVA, a metabolite of dopamine) and 3-methoxy-4-hydroxyphenylglycol (MHPG, a metabolite of noradrenaline) were analyzed. Some of the N100 measurements correlated with the MHPG concentration and the severity of anxiety. No significant correlations were found between the P300 measurements and concentrations of monoamine metabolites. The P300 latency and plasma HVA concentration were associated with the psychoticism estimate of EPQ. These findings indicate that modulation of the N100 component might be associated with the activity of the noradrenergic system, and that P300 latency and the HVA concentration might be associated with a tendency toward psychosis.

Autonomic and cortical reactivity in acute and chronic posttraumatic stress

This study investigated attention (P300 amplitude) and orienting (skin conductance amplitude) to auditory tones in a standard oddball task in early trauma-exposed groups (Acute Stress Disorder: ASD) (n=12) or no ASD (n=13), compared to individuals with chronic posttraumatic stress disorder (PTSD) (n=17) and non-trauma-exposed controls (n=17). Individuals with ASD displayed significantly higher SCR and P3 amplitudes to target tones than individuals with PTSD, non-traumatized controls, and traumatized controls. These findings suggest that attention and orienting responses are greater to neutral, task-relevant target tones in ASD than PTSD and traumatized and non-traumatized controls.

Auditory and visual cortical activity during selective attention in fragile X syndrome: A cascade of processing deficiencies

ObjectiveThis study examined whether attention deficits in fragile X syndrome (FXS) can be traced back to abnormalities in basic information processing. MethodSixteen males with FXS and 22 age-matched control participants (mean age 29years) performed a standard oddball task to examine selective attention in both auditory and visual modalities. Five FXS males were excluded from analysis because they performed below chance level on the auditory task. ERPs were recorded to investigate the N1, P2, N2b, and P3b components. ResultsN1 and N2b components were significantly enhanced in FXS males to both auditory and visual stimuli. Interestingly, in FXS males, the P3b to auditory stimuli was significantly reduced relative to visual stimuli. These modality differences in information processing corresponded to behavioral results, showing more errors on the auditory than on the visual task. ConclusionsThe current findings suggest that attentional impairments in FXS at the behavioral level can be traced back to abnormalities in event-related cortical activity. These information processing abnormalities in FXS may hinder the allocation of attentional resources needed for optimal processing at higher-levels. SignificanceThese findings demonstrate that auditory information processing in FXS males is critically impaired relative to visual information processing.

Effective connectivity in target stimulus processing: A dynamic causal modeling study of visual oddball task

PurposeTo investigate the fundamental connectivity architecture of neural structures involved in the goal-directed processing of target events. MethodsTwenty healthy volunteers underwent event-related functional magnetic resonance imaging (fMRI) while performing a standard oddball task. In the task, two types of visual stimuli – rare (target) and frequent – were randomly presented, and subjects were instructed to mentally count the target stimuli. Dynamic causal modeling (DCM), in combination with Bayes factors was used to compare competing neurophysiological models with different intrinsic connectivity structures and input regions within the network of brain regions underlying target stimulus processing. ResultsConventional analysis of fMRI data revealed significantly greater activation in response to the target stimuli (in comparison to the frequent stimuli) in several brain regions, including the intraparietal sulci and supramarginal gyri, the anterior and posterior cingulate gyri, the inferior and middle frontal gyri, the superior temporal sulcus, the precuneus/cuneus, and the subcortical grey matter (caudate and thalamus). The most extensive cortical activations were found in the right intraparietal sulcus (IPS), the anterior cingulate cortex (ACC), and the right lateral prefrontal cortex (PFC). These three regions were entered into the DCM. A comparison on a group level revealed that the dynamic causal models in which the ACC and alternatively the IPS served as input regions were superior to a model in which the PFC was assumed to receive external inputs. No significant difference was observed between the fully connected models with ACC and IPS as input regions. Subsequent analysis of the intrinsic connectivity within two investigated models (IPS and ACC) disclosed significant parallel forward connections from the IPS to the frontal areas and from the ACC to the PFC and the IPS. ConclusionOur findings indicate that during target stimulus processing there is a bidirectional frontoparietal information flow, very likely reflecting parallel activation of two distinct but partially overlapping attentional or attentional/event-encoding neural systems. Additionally, a simple hierarchy within the right frontal lobe is suggested with the ACC exerting influence over the PFC.

Effects of Self-Evaluation on the P300 Event-Related Potential

The effects of self evaluation on the P300 event-related potential (ERP) were explored with 56 participants (16 men, 40 women; M age = 23.4 yr., SD = 1.2) across three conditions. The conditions included (1) a standard ERP auditory oddball discrimination between a random target (15% occurrence) and standard stimuli (85% occurrence), (2) the oddball task followed by the additional cognitive task of maintaining a mental count of the target tones, and (3) the oddball task followed by the additional cognitive task of self-evaluating whether they felt surprised by the current occurrence of the target tone. The added cognitive requirements for Conditions 2 and 3 required the subjects to maintain a cognitive readiness for the secondary stimulus-related task during their sensory discrimination response for the standard oddball task. During the self-evaluation condition, the P300 amplitude was significantly larger across all recording locations than the regular oddball condition and the cognitive count condition.

P300 amplitude over temporal regions in schizophrenia

To examine the left temporal scalp area reductions of P300 amplitude, event-related potentials (ERPs) during a standard oddball task were recorded in 57 schizophrenic patients and 33 normal controls. The P300 amplitude at T3 was not significantly smaller than that at T4 in schizophrenic patients. In the ANOVA analysis of P300 peak amplitude, significant lateral topographical differences in P300 were not present between patients and controls. However, in schizophrenia, patients in the low T3 P300 group have relatively low P300 amplitudes and significantly delayed P300 latency, compared with those in the high T3 P300 group. These findings suggested that the reduction of left temporal P300 amplitude may be associated with the severity of the disease process and/or impairment of cognitive function.

P300 amplitude over temporal regions in schizophrenia

To examine the left temporal scalp area reductions of P300 amplitude, event-related potentials (ERPs) during a standard oddball task were recorded in 57 schizophrenic patients and 33 normal controls. The P300 amplitude at T3 was not significantly smaller than that at T4 in schizophrenic patients. In the ANOVA analysis of the P300 peak amplitude and PCA factor scores, significant lateral topographical differences in P300 were not present between patients and controls. However, in schizophrenia, patients in the low T3 P300 group were older and consuming higher doses of antipsychotic medicine than those in the high T3 P300 group, and they had relatively low P300 amplitudes and significantly delayed P300 latency, compared with those in the high T3 P300 group. These findings suggested that although the reduction in the left temporal P300 amplitude did not necessarily exist in schizophrenic patients, it may be associated with the severity of the disease process and/or impairment of cognitive function.

Event-related potentials and thought disorder in schizophrenia

We examined the relationship between event-related potentials and thought disorder in schizophrenia. The subjects were 29 chronic schizophrenic patients. Thought disorder was assessed using the Comprehensive Index of Positive Thought Disorder developed by Harrow and colleagues ( Harrow and Quinlan, 1985; Marengo et al., 1986). Auditory event-related potentials were recorded during a standard oddball task. The P300 amplitude correlated negatively with the severity of the thought disorder. The P300 amplitude in the patients with thought disorder was significantly smaller than in the patients without thought disorder. These results suggest that a reduction in P300 amplitude is associated with a fundamental impairment of information processing in schizophrenic patients.

Opposite patterns of P300 asymmetry in schizophrenia are syndrome related

In schizophrenia reduction of the P300 amplitude is a robust statistical finding but with inconsistent evidence of symptom correlates and of lateral asymmetry. Here relations were examined with active and withdrawn syndromes which in other cognitive and electrophysiological measurement modalities have been associated with opposite functional asymmetries. A standard oddball detection task was used to elicit auditory evoked potentials from dextral DSM-IV schizophrenic patients. On clinical ratings blind to the psychophysiology, eight were classified as withdrawn and 12 had a predominance of active syndrome features. Both patient groups had congruent P300 maxima at Pz or P4, attesting to their application to the detection task. Syndromes were differentiated by opposite asymmetries in P300, N200–P300 and N100 amplitudes at the posterior temporal sites: a reduction in P300 and N200–P300 amplitudes on the left in the active patients, and a reduction on the right in the withdrawn patients, with the opposite asymmetries in N100 amplitudes. The syndrome-related asymmetries in P300, also manifested in earlier attentional (N100) components are interpreted in terms of thalamo-cortical arousal systems having generalised, internalised influences, rather than in terms of later cognitive processes underpinning the P300. The findings endorse a syndromal approach to laterality research in schizophrenia.

P300 under standard and surprise conditions in self-reported impulsive aggression

1. 1. The purpose of the present study was to determine the cognitive psychophysiological correlates of impulsive aggression in a “high” functioning sample: college students. 2. 2. Visual P300 was measured during a standard oddball task and a surprise task that included unexpected low probability stimuli. 3. 3. Results indicated significantly reduced P300 amplitude and prolonged latency for impulsive aggressive subjects to target stimuli on the standard task. Target amplitude differences where further augmented under conditions involving unexpected stimuli although no significant latency differences were observed. The topography of P300 amplitude to unexpected stimuli differed from that of the target. 4. 4. Topographic group differences found for unexpected stimuli are suggestive of cognitive processing deficits previously demonstrated using neuropsychological techniques in impulsive aggressive individuals.

P300 and disability of daily life in schizophrenia

1. 1. The relationship between the P300 component of event-related potentials and disability of daily life was examined in schizophrenia. The subjects were 26 chronic schizophrenic patients. 2. 2. Disability of daily life was assessed by using the Life Assessment Scale for Mental illness (LASMI). 3. 3. Auditory event-related potentials were recorded during a standard oddball task. 4. 3. P300 amplitude correlated negatively with general psychopathology scale of PANSS ( r = − 0.416) and Work of LASMI ( r = − 0.417). P300 latency did not correlate with any of PANSS or LASMI score. 5. 4. These results indicat that P300 amplitude can be an index for disability of daily life in schizophrenia.

P3a of event-related potential in chronic methamphetamine dependence.

To investigate the psychophysiological features of methamphetamine (MAP) dependence, we recorded auditory event-related potentials (ERPs) in 15 patients with MAP dependence and in 15 age-matched normal controls. ERPs were recorded during a standard oddball task and a read task similar to those employed by Squires et al. (Squires NK, Squires KC, Hillyard SA [1975] Two varieties of long-latency positive waves evoked by unpredictable auditory stimuli in man. Electroenceph Clin Neurophysiol 38:387-401). The patients with MAP dependence showed reduced P3a amplitude and area in the read task and delayed P3b latency with normal P3b amplitude and area in the oddball task. These results suggest that central noradrenergic dysregulation may persist after the remission of acute psychotic symptoms in MAP psychosis and that chronic MAP dependence would produce impairment of the frontal cortex.

Auditory P300 and self-reported impulsive aggression

1. 1. The purpose of the present study was to determine the cognitive psychophysiological correlates of impulsive aggression in a population considered “normal” by societal standards: college students. 2. 2. Auditory event-related potentials were acquired on all subjects during a standard oddball task. The stimuli consisted of a random sequence of two tones, a frequent 1,000 Hz tone and a rare 2,000 Hz tone. Tones were presented in a ratio of 80 20 . 3. 3. Results of the study demonstrated that impulsive aggressive subjects show significantly lower P300 amplitude at frontal electrode sites when compared to nonaggressive controls. 4. 4. These findings are consistent with the psychophysiological findings in impulsive aggressive incarcerated criminals and support the notion of a specific behavioral syndrome associated with spontaneous aggressive outbursts.

On the dependence of P300 latency on stimulus evaluation processes.

ABSTRACTMcCarthy and Donchin (1981) found that the latency of a late positive component of the event‐related potential (ERP) was influenced by the presence of noise in a stimulus matrix but not by the compatibility between the stimulus presented and the response required. They concluded that this component is a P300 and that its latency was influenced by stimulus evaluation but not by response selection processes. The present experiments were designed to confirm that the component identified by McCarthy and Donchin was indeed a P300 and to determine if its latency varies systematically with increases in stimulus evaluation time produced by graded changes in noise level.In Experiment 1, subjects performed a standard oddball task in which they were required to count the rarer of two stimuli (the words RIGHT or LEFT) which were, or were not, embedded in a noise matrix (characters from the alphabet). The positive component of the ERP, whose amplitude was larger for rare target stimuli, was labeled a P300, and the latency of this component was longer when the stimuli were embedded in noise. In Experiment 2, subjects performed a choice reaction time task. Following the procedures used by McCarthy and Donchin, stimulus words RIGHT and LEFT required right or left hand responses depending on the presence of a cue word SAME or OPPOSITE which preceded the stimulus. Stimulus words were presented in four different degrees of noise, the levels of which were manipulated by varying the set size of the alphabetic characters which could surround the stimulus words. Reaction time increased both with noise (by 325 ms) and as a function of stimulus‐response incompatibility (by 127 ms). In contrast, P300 latency increased substantially with noise (by 200 ms) but, to a much lesser extent (by 14 ms), with response incompatibility. These results indicate that the P300 is sensitive to the ease with which a target stimulus can be discriminated from noise. They confirm that P300 latency can be used as a measure of the timing of stimulus evaluation processes that is relatively independent of response selection and execution.