The Orienting Response in Healthy Aging: Novelty P3 Indicates No General Decline but Reduced Efficacy for Fast Stimulation Rates.

Automatic orienting to unexpected changes in the environment is a pre-requisite for adaptive behavior. One prominent mechanism of automatic attentional control is the Orienting Response (OR). Despite the fundamental significance of the OR in everyday life, only little is known about how the OR is affected by healthy aging. We tested this question in two age groups (19-38 and 55-72 years) and measured skin-conductance responses (SCRs) and event-related brain potentials (ERPs) to novels (i.e., short environmental sounds presented only once in the experiment; 10% of the trials) compared to standard sounds (600 Hz sinusoidal tones with 200 ms duration; 90% of the trials). Novel and standard stimuli were presented in four conditions differing in the inter-stimulus interval (ISI) with a mean ISI of either 10, 3, 1, or 0.5 s (blocked presentation). In both age groups, pronounced SCRs were elicited by novels in the 10 s ISI condition, suggesting the elicitation of stable ORs. These effects were accompanied by pronounced N1 and frontal P3 amplitudes in the ERP, suggesting that automatic novelty processing and orientation of attention are effective in both age groups. Furthermore, the SCR and ERP effects declined with decreasing ISI length. In addition, differences between the two groups were observable with the fastest presentation rates (i.e., 1 and 0.5 s ISI length). The most prominent difference was a shift of the peak of the frontal positivity from around 300 to 200 ms in the 19-38 years group while in the 55-72 years group the amplitude of the frontal P3 decreased linearly with decreasing ISI length. Taken together, this pattern of results does not suggest a general decline in processing efficacy with healthy aging. At least with very rare changes (here, the novels in the 10 s ISI condition) the OR is as effective in healthy older adults as in younger adults. With faster presentation rates, however, the efficacy of the OR decreases. This seems to result in a switch from novelty to deviant processing in younger adults, but less so in the group of older adults.

Memory detection using fMRI - does the encoding context matter?

Recent research revealed that the presentation of crime related details during the Concealed Information Test (CIT) reliably activates a network of bilateral inferior frontal, right medial frontal and right temporal-parietal brain regions. However, the ecological validity of these findings as well as the influence of the encoding context are still unclear. To tackle these questions, three different groups of subjects participated in the current study. Two groups of guilty subjects encoded critical details either only by planning (guilty intention group) or by really enacting (guilty action group) a complex, realistic mock crime. In addition, a group of informed innocent subjects encoded half of the relevant details in a neutral context. Univariate analyses showed robust activation differences between known relevant compared to neutral details in the previously identified ventral frontal-parietal network with no differences between experimental groups. Moreover, validity estimates for average changes in neural activity were similar between groups when focusing on the known details and did not differ substantially from the validity of electrodermal recordings. Additional multivariate analyses provided evidence for differential patterns of activity in the ventral fronto-parietal network between the guilty action and the informed innocent group and yielded higher validity coefficients for the detection of crime related knowledge when relying on whole brain data. Together, these findings demonstrate that an fMRI-based CIT enables the accurate detection of concealed crime related memories, largely independent of encoding context. On the one hand, this indicates that even persons who planned a (mock) crime could be validly identified as having specific crime related knowledge. On the other hand, innocents with such knowledge have a high risk of failing the test, at least when considering univariate changes of neural activation.

Effects of emotional context on memory for details: the role of attention.

It was repeatedly demonstrated that a negative emotional context enhances memory for central details while impairing memory for peripheral information. This trade-off effect is assumed to result from attentional processes: a negative context seems to narrow attention to central information at the expense of more peripheral details, thus causing the differential effects in memory. However, this explanation has rarely been tested and previous findings were partly inconclusive. For the present experiment 13 negative and 13 neutral naturalistic, thematically driven picture stories were constructed to test the trade-off effect in an ecologically more valid setting as compared to previous studies. During an incidental encoding phase, eye movements were recorded as an index of overt attention. In a subsequent recognition phase, memory for central and peripheral details occurring in the picture stories was tested. Explicit affective ratings and autonomic responses validated the induction of emotion during encoding. Consistent with the emotional trade-off effect on memory, encoding context differentially affected recognition of central and peripheral details. However, contrary to the common assumption, the emotional trade-off effect on memory was not mediated by attentional processes. By contrast, results suggest that the relevance of attentional processing for later recognition memory depends on the centrality of information and the emotional context but not their interaction. Thus, central information was remembered well even when fixated very briefly whereas memory for peripheral information depended more on overt attention at encoding. Moreover, the influence of overt attention on memory for central and peripheral details seems to be much lower for an arousing as compared to a neutral context.

Depersonalization disorder: disconnection of cognitive evaluation from autonomic responses to emotional stimuli.

BACKGROUND: Patients with depersonalization disorder (DPD) typically complain about emotional detachment. Previous studies found reduced autonomic responsiveness to emotional stimuli for DPD patients as compared to patients with anxiety disorders. We aimed to investigate autonomic responsiveness to emotional auditory stimuli of DPD patients as compared to patient controls. Furthermore, we examined the modulatory effect of mindful breathing on these responses as well as on depersonalization intensity. METHODS: 22 DPD patients and 15 patient controls balanced for severity of depression and anxiety, age, sex and education, were compared regarding 1) electrodermal and heart rate data during a resting period, and 2) autonomic responses and cognitive appraisal of standardized acoustic affective stimuli in two conditions (normal listening and mindful breathing). RESULTS: DPD patients rated the emotional sounds as significantly more neutral as compared to patient controls and standardized norm ratings. At the same time, however, they responded more strongly to acoustic emotional stimuli and their electrodermal response pattern was more modulated by valence and arousal as compared to patient controls. Mindful breathing reduced severity of depersonalization in DPD patients and increased the arousal modulation of electrodermal responses in the whole sample. Finally, DPD patients showed an increased electrodermal lability in the rest period as compared to patient controls. CONCLUSIONS: These findings demonstrated that the cognitive evaluation of emotional sounds in DPD patients is disconnected from their autonomic responses to those emotional stimuli. The increased electrodermal lability in DPD may reflect increased introversion and cognitive control of emotional impulses. The findings have important psychotherapeutic implications.

fMRI-activation patterns in the detection of concealed information rely on memory-related effects.

Recent research on potential applications of fMRI in the detection of concealed knowledge primarily ascribed the reported differences in hemodynamic response patterns to deception. This interpretation is challenged by the results of the present study. Participants were required to memorize probe and target items (a banknote and a playing card, each). Subsequently, these items were repeatedly presented along with eight irrelevant items in a modified Guilty Knowledge Test design and participants were instructed to simply acknowledge item presentation by pressing one button after each stimulus. Despite the absence of response monitoring demands and thus overt response conflicts, the experiment revealed a differential physiological response pattern as a function of item type. First, probes elicited the largest skin conductance responses. Second, differential hemodynamic responses were observed in bilateral inferior frontal regions, the right supramarginal gyrus and the supplementary motor area as a function of item type. Probes and targets were accompanied by a larger signal increase than irrelevant items in these regions. Moreover, the responses to probes differed substantially from targets. The observed neural response pattern seems to rely on retrieval processes that depend on the depth of processing in the encoding situation.

Emotional arousal modulates the encoding of crime-related details and corresponding physiological responses in the Concealed Information Test.

Previous studies demonstrated that concealed crime-related memories can be validly identified using the Concealed Information Test (CIT). However, its field applicability is still debated, and it is specifically unknown how emotional arousal during a crime would influence CIT results. In the current study, emotional arousal during a mock crime and the time delay between mock crime and CIT examination were manipulated. At the immediate and the delayed CIT occasion, central crime details were better remembered than peripheral ones and enhanced emotional arousal further reduced memory for peripheral information. Electrodermal, respiratory, and cardiovascular responses to central crime details were strong and CIT validity was unaffected by delaying the test when arousal was induced during the mock crime. These findings indicate that emotional arousal might facilitate the detection of concealed information some time after a crime occurred.

Strength of memory encoding affects physiological responses in the Guilty Actions Test.

The Guilty Actions Test (GAT) is a valid and scientifically sound technique of forensic psychophysiology that allows for the detection of concealed memories. However, its application has been challenged because the results might be affected by the culprit's forgetting of crime details as well as the leakage of information to innocents. In the current study, these aspects were examined by varying the amount of time between a mock crime and the subsequent GAT, as well as by contrasting culprits with informed innocents. It turned out that culprits specifically forgot peripheral crime details during a period of 2 weeks whereas informed innocents showed similar forgetting for all details. As a consequence, GAT validity based on electrodermal, respiratory and heart rate measures remained temporally stable for culprits whereas the amount of false positive errors for informed innocents decreased as a function of time. These results indicate that the process of memory encoding and consolidation has significant effects on the physiological response pattern in the GAT.

Combining physiological measures in the detection of concealed information.

Meta-analytic research has confirmed that skin conductance response (SCR) measures have high validity for the detection of concealed information. Furthermore, cumulating research has provided evidence for the validity of two other autonomic measures: Heart rate (HR) and Respiration Line Length (RLL). In the present report, we compared SCR detection efficiency with HR and RLL, and investigated whether HR and RLL provide incremental validity to electrodermal responses. Analyses were based on data from 7 different samples covering 275 guilty and 53 innocent examinees. Results revealed that the area under the ROC curve was significantly higher for SCR than for HR and RLL. A weighted combination of these measures using a logistic regression model yielded slightly larger validity coefficients than the best single measure. These results proved to be stable across different protocols and various samples.

Electrodermal and phasic heart rate responses in the Guilty Actions Test: comparing guilty examinees to informed and uninformed innocents.

The present mock-crime study concentrated on the validity of the Guilty Actions Test (GAT) and the role of the orienting response (OR) for differential autonomic responding. N=105 female subjects were assigned to one of three groups: a guilty group, members of which committed a mock-theft; an innocent-aware group, members of which witnessed the theft; and an innocent-unaware group. A GAT consisting of ten question sets was administered while measuring electrodermal and heart rate (HR) responses. For informed participants (guilty and innocent-aware), relevant items were accompanied by larger skin conductance responses and heart rate decelerations whereas irrelevant items elicited HR accelerations. Uninformed participants showed a non-systematic response pattern. The differential electrodermal responses of informed participants declined across the test. With respect to the HR data, however, no habituation was observed. Findings suggest that GAT results could not exclusively be interpreted by referring to the OR.

Covariations among fMRI, skin conductance, and behavioral data during processing of concealed information.

Imaging techniques have been used to elucidate the neural correlates that underlie deception. The scientifically best understood paradigm for the detection of deception, however, the guilty knowledge test (GKT), was rarely used in imaging studies. By transferring a GKT-paradigm to a functional magnetic resonance imaging (fMRI) study, while additionally quantifying reaction times and skin conductance responses (SCRs), this study aimed at identifying the neural correlates of the behavioral and electrodermal response pattern typically found in GKT examinations. Prior to MR scanning, subjects viewed two specific items (probes) and were instructed to hide their knowledge of these. Two other specific items were designated as targets and required a different behavioral response during the experiment and eight items served as irrelevant stimuli. Reaction times and SCR amplitudes differed significantly between all three item types. The neuroimaging data revealed that right inferior frontal and mid-cingulate regions were more active for probe and target trials compared to irrelevants. Moreover, the differential activation in the right inferior frontal region was modulated by stimulus conflicts. These results were interpreted as an increased top-down influence on the stimulus-response-mapping for concealed and task-relevant items. Additionally, the influence of working memory and retrieval processes on this activation pattern is discussed. Using parametric analyses, reaction times and SCR amplitudes were found to be linearly related to activity in the cerebellum, the right inferior frontal cortex, and the supplementary motor area. This result provides a first link between behavioral measures, sympathetic arousal, and neural activation patterns during a GKT examination.

Psychophysiological and vocal measures in the detection of guilty knowledge.

The Guilty Knowledge Test (GKT) and its variant, the Guilty Actions Test (GAT), are both psychophysiological questioning techniques aiming to detect guilty knowledge of suspects or witnesses in criminal and forensic cases. Using a GAT, this study examined the validity of various physiological and vocal measures for the identification of guilty and innocent participants in a mock crime paradigm. Electrodermal, respiratory, and cardiovascular measures successfully differentiated between the two groups. A logistic regression model based on these variables achieved hit rates of above 90%. In contrast to these results, the vocal measures provided by the computerized voice stress analysis system TrusterPro were shown to be invalid for the detection of guilty knowledge.