Neuroanatomical correlates of malingered memory impairment: event-related fMRI of deception on a recognition memory task

Meta-analytic connectivity modelling of deception-related brain regions

Brain-based deception research began only two decades ago and has since included a wide variety of contexts and response modalities for deception paradigms. Investigations of this sort serve to better our neuroscientific and legal knowledge of the ways in which individuals deceive others. To this end, we conducted activation likelihood estimation (ALE) and meta-analytic connectivity modelling (MACM) using BrainMap software to examine 45 task-based fMRI brain activation studies on deception. An activation likelihood estimation comparing activations during deceptive versus honest behavior revealed 7 significant peak activation clusters (bilateral insula, left superior frontal gyrus, bilateral supramarginal gyrus, and bilateral medial frontal gyrus). Meta-analytic connectivity modelling revealed an interconnected network amongst the 7 regions comprising both unidirectional and bidirectional connections. Together with subsequent behavioral and paradigm decoding, these findings implicate the supramarginal gyrus as a key component for the sociocognitive process of deception.

What Deception Tasks Used in the Lab Really Do: Systematic Review and Meta-analysis of Ecological Validity of fMRI Deception Tasks

Interpretation of the neural findings of deception without considering the ecological validity of the experimental tasks could lead to biased conclusions. In this study we classified the experimental tasks according to their inclusion of three essential components required for ecological validity: intention to lie, social interaction and motivation. First, we carried out a systematic review to categorize fMRI deception tasks and to weigh the degree of ecological validity of each one. Second, we performed a meta-analysis to identify if each type of task involves a different neural substrate and to distinguish the neurocognitive contribution of each component of ecological validity essential to deception. We detected six categories of deception tasks. Intention to lie was the component least frequently included, followed by social interaction. Monetary reward was the most frequent motivator. The results of the meta-analysis, including 59 contrasts, revealed that intention to lie is associated with activation in the left lateral occipital cortex (superior division) whereas the left angular gyrus and right inferior frontal gyrus (IFG) are engaged during lying under instructions. Additionally, the right IFG appears to participate in the social aspect of lying including simulated and real interactions. We found no effect of monetary reward in our analysis. Finally, tasks with high ecological validity recruited fewer brain areas (right insular cortex and bilateral anterior cingulate cortex (ACC)) compared to less ecological tasks, perhaps because they are more natural and realistic, and engage a wide network of brain mechanisms, as opposed to specific tasks that demand more centralized processes.

Electrophysiological markers of working memory usage as an index for truth-based lies

People prefer to lie using altered truthful events from memory, perhaps because doing so can increase their credibility while reducing cognitive and working memory (WM) load. One possible way to counter such deceptive behavior is to track WM usage, since fabricating coherent lies or managing between truth and lies is likely to involve heavy WM load. In this study, participants memorized a list of words in the study session and used these old words to provide deceptive answers when cued later, in the testing session. Our behavioral results showed that people needed more time to make a deceptive response during the execution stage, and this prolonged deceptive reaction time (RT) was negatively correlated with each participant's WM capacity. Event-related potential findings showed a more negative-going frontal amplitude between the lie and truth conditions during the preparation stage, suggesting that WM preparatory processes can be detected long before a deceptive response is verbalized. Furthermore, we observed a larger positive frontal-central amplitude during the execution stage, which was negatively correlated with participants' lie-truth RT differences, suggesting that participants' efficiency in producing deceptive responses can be readily traced electrophysiologically. Together, these findings suggest that WM capacity and preparation are crucial to efficient lying and that their related electrophysiological signatures can potentially be used to uncover deceptive behaviors.

Lie Detection Using fNIRS Monitoring of Inhibition-Related Brain Regions Discriminates Infrequent but not Frequent Liars

Functional near-infrared spectroscopy (fNIRS) was used to test whether monitoring inhibition-related brain regions is a feasible method for detecting both infrequent liars and frequent liars. Thirty-two participants were divided into two groups: the deceptive group (liars) and the non-deceptive group (ND group, innocents). All the participants were required to undergo a simulated interrogation by a computer. The participants from the deceptive group were instructed to tell a mix of lies and truths and those of the ND group were instructed always to tell the truth. Based on the number of deceptions, the participants of the deceptive group were further divided into a infrequently deceptive group (IFD group, infrequent liars) and a frequently deceptive group (FD group, frequent liars). The infrequent liars exhibited greater neural activities than the frequent liars and the innocents in the left middle frontal gyrus (MFG) when performing the deception detection tasks. While performing deception detection tasks, infrequent liars showed significantly greater neural activation in the left MFG than the baseline, but frequent liars and innocents did not exhibit this pattern of neural activation in any area of inhibition-related brain regions. The results of individual analysis showed an acceptable accuracy of detecting infrequent liars, but an unacceptable accuracy of detecting frequent liars. These results suggest that using fNIRS monitoring of inhibition-related brain regions is feasible for detecting infrequent liars, for whom deception may be more effortful and therefore more physiologically marked, but not frequent liars.

Using functional near-infrared spectroscopy (fNIRS) to detect the prefrontal cortical responses to deception under different motivations

In this study, functional near-infrared spectroscopy (fNIRS) was adopted to investigate the prefrontal cortical responses to deception under different motivations. By using a feigned memory impairment paradigm, 19 healthy adults were asked to deceive under the two different motivations: to obtain rewards and to avoid punishments. Results indicated that when deceiving for obtaining rewards, there was greater neural activation in the right inferior frontal gyrus (IFG) than the control condition. When deceiving for avoiding punishments, there was greater activation in the right inferior frontal gyrus (IFG) and the left middle frontal gyrus (MFG) than the control condition. In addition, deceiving for avoiding punishments led to greater neural activation in the left MFG than when deceiving for obtaining rewards. Furthermore, the results showed a moderate hit rate in detecting deception under either motivation. These results demonstrated that deception with different motivations led to distinct responses in the prefrontal cortex. fNIRS could provide a useful technique for the detection of deception with strategy of feigning memory impairment under different motivations.

Can individuals with schizophrenia be instructed to deliberately feign memory deficits?

INTRODUCTION

Neuropsychological tests are increasingly applied in research studies and clinical practice in psychiatry. In this context, the detection of poor effort is crucial to adequately interpret data. We measured schizophrenia patients' performance on a memory test designed to detect excessive malingering (the "21-Item Test"), before examining whether a second group of schizophrenia patients would excessively malinger on this test when given an incentive to feign memory impairment.

METHODS

Two independent studies including respectively 49 schizophrenia patients and 100 controls (study 1) and 25 schizophrenia patients and 25 controls (study 2) were conducted. In study 1, participants were asked to complete the 21-Item Test to the best of their ability. In study 2, participants were given a hypothetical scenario in which having a memory impairment would be financially advantageous for them, before completing the 21-Item Test.

RESULTS

In study 1, no participant scored at levels indicative of excessive malingering. In study 2, 84% of controls but only 36% of patients scored at excessive levels of malingering, and these patients had higher executive functioning than patients who did not excessively malinger, although it should be noted that a significantly greater proportion of patients excessively malingered in study 2 compared to study 1.

CONCLUSIONS

These results indicate that schizophrenia patients do not normally feign excessive memory impairment during psychological testing. Furthermore, they are less able and/or less inclined to excessively malinger than controls in situations where a memory impairment would be advantageous, perhaps indicating a better ability to malinger without detection. Potential clinical implications are discussed.

Effort, symptom validity testing, performance validity testing and traumatic brain injury

BACKGROUND

To understand the neurocognitive effects of brain injury, valid neuropsychological test findings are paramount.

REVIEW

This review examines the research on what has been referred to a symptom validity testing (SVT). Above a designated cut-score signifies a 'passing' SVT performance which is likely the best indicator of valid neuropsychological test findings. Likewise, substantially below cut-point performance that nears chance or is at chance signifies invalid test performance. Significantly below chance is the sine qua non neuropsychological indicator for malingering. However, the interpretative problems with SVT performance below the cut-point yet far above chance are substantial, as pointed out in this review. This intermediate, border-zone performance on SVT measures is where substantial interpretative challenges exist. Case studies are used to highlight the many areas where additional research is needed. Historical perspectives are reviewed along with the neurobiology of effort. Reasons why performance validity testing (PVT) may be better than the SVT term are reviewed.

CONCLUSIONS

Advances in neuroimaging techniques may be key in better understanding the meaning of border zone SVT failure. The review demonstrates the problems with rigidity in interpretation with established cut-scores. A better understanding of how certain types of neurological, neuropsychiatric and/or even test conditions may affect SVT performance is needed.

The neural basis of dishonest decisions that serve to harm or help the target

We conducted a functional magnetic resonance imaging (fMRI) study to elucidate the neurocognitive mechanisms of harmful and helpful dishonest decisions. During scanning, the subjects read scenarios concerning events that could occur in real-life situations and were asked to decide whether to tell a lie as though they were experiencing those events. Half of the scenarios consisted of harmful stories in which the dishonest decisions could be regarded as bad lies, and the other half consisted of helpful stories in which the dishonest decisions could be regarded as good lies. In contrast to the control decision-making task, we found that the decision-making tasks that involved honesty or dishonesty recruited a network of brain regions that included the left dorsolateral prefrontal cortex. In the harmful stories, the right temporoparietal junction and the right medial frontal cortex were activated when the subjects made dishonest decisions compared with honest decisions. No region discriminated between the honest and dishonest decisions made in the helpful stories. These preliminary findings suggest that the neural basis of dishonest decisions is modulated by whether the lying serves to harm or help the target.

Performance on the Green Word Memory Test following Operation Enduring Freedom/Operation Iraqi Freedom-era military service: Test failure is related to evaluation context

This study investigates prior reports of high neuropsychological symptom validity test (SVT) failure rates in post-deployed Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) active and veteran military personnel, using a large, multi-site sample (N = 214) drawn from three levels of the Department of Defense/Department of Veterans Affairs (VA) Polytrauma System of Care. The sample failure rate and its relationship to research versus dual research/clinical context of evaluation were examined, in addition to secondary variables explored in prior studies. Results yielded an overall failure rate of 25%, lower than prior reports describing OEF/OIF active-duty and veteran military personnel. Findings also supported the hypothesis that SVT failure rates would differ by context (dual > research). Participants with traumatic brain injury (TBI) failed more frequently than those without TBI in the dual context but not in the research context. Secondary analyses revealed that failure rates increased in the presence of depression, posttraumatic stress disorder, and male sex but were unrelated to active versus veteran military status, service connection (SC) or percentage of SC, age, education, or ethnicity. Further research is required to elucidate the underpinnings of these findings in light of the limited literature and variability between OEF/OIF-related SVT studies, as well as the substantial diagnostic and treatment implications for VA.

Memory and self-neuroscientific landscapes

Relations between memory and the self are framed from a number of perspectives-developmental aspects, forms of memory, interrelations between memory and the brain, and interactions between the environment and memory. The self is seen as dividable into more rudimentary and more advanced aspects. Special emphasis is laid on memory systems and within them on episodic autobiographical memory which is seen as a pure human form of memory that is dependent on a proper ontogenetic development and shaped by the social environment, including culture. Self and episodic autobiographical memory are seen as interlocked in their development and later manifestation. Aside from content-based aspects of memory, time-based aspects are seen along two lines-the division between short-term and long-term memory and anterograde-future-oriented-and retrograde-past-oriented memory. The state dependency of episodic autobiographical is stressed and implications of it-for example, with respect to the occurrence of false memories and forensic aspects-are outlined. For the brain level, structural networks for encoding, consolidation, storage, and retrieval are discussed both by referring to patient data and to data obtained in normal participants with functional brain imaging methods. It is elaborated why descriptions from patients with functional or dissociative amnesia are particularly apt to demonstrate the facets in which memory, self, and personal temporality are interwoven.

Symptom validity testing, effort, and neuropsychological assessment

Symptom validity testing (SVT) has become a major theme of contemporary neuropsychological research. However, many issues about the meaning and interpretation of SVT findings will require the best in research design and methods to more precisely characterize what SVT tasks measure and how SVT test findings are to be used in neuropsychological assessment. Major clinical and research issues are overviewed including the use of the “effort” term to connote validity of SVT performance, the use of cut-scores, the absence of lesion-localization studies in SVT research, neuropsychiatric status and SVT performance and the rigor of SVT research designs. Case studies that demonstrate critical issues involving SVT interpretation are presented.

Neural correlates of feigned memory impairment are distinguishable from answering randomly and answering incorrectly: an fMRI and behavioral study

Previous functional magnetic resonance imaging (fMRI) studies have identified activation in the prefrontal-parietal-sub-cortical circuit during feigned memory impairment when comparing with truthful telling. Here, we used fMRI to determine whether neural activity can differentiate between answering correctly, answering randomly, answering incorrectly, and feigned memory impairment. In this study, 12 healthy subjects underwent block-design fMRI while they performed digit task of forced-choice format under four conditions: answering correctly, answering randomly, answering incorrectly, and simulated feigned memory impairment. There were three main results. First, six areas, including the left prefrontal cortex, the left superior temporal lobe, the right postcentral gyrus, the right superior parietal cortex, the right superior occipital cortex, and the right putamen, were significantly modulated by condition type. Second, for some areas, including the right superior parietal cortex, the right postcentral gyrus, the right superior occipital cortex, and the right putamen, brain activity was significantly greater in feigned memory impairment than answering randomly. Third, for the areas including the left prefrontal cortex and the right putamen, brain activity was significantly greater in feigned memory impairment than answering incorrectly. In contrast, for the left superior temporal lobe, brain activity was significantly greater in answering incorrectly than feigned memory impairment. The results suggest that neural correlates of feigned memory impairment are distinguishable from answering randomly and answering incorrectly in healthy subjects.

The contribution of the dorsolateral prefrontal cortex to the preparation for deception and truth-telling

Recent neuroimaging evidence suggests that the dorsolateral prefrontal cortex is associated with creating deceptive responses. However, the neural basis of the preparatory processes that create deception has yet to be explored. Previous neuroimaging studies have demonstrated that the preparation for a certain task activates brain areas relevant to the execution of that task, leading to the question of whether dorsolateral prefrontal activity is observed during the preparation for deception. In the present study, we used functional magnetic resonance imaging (fMRI) to determine whether dorsolateral prefrontal activity, which increases during the execution of deception compared with the execution of truth-telling, also increases during the preparation for deception compared with the preparation for truth-telling. Our data show that the execution of deception was associated with increased activity in several brain regions, including the left dorsolateral prefrontal cortex, compared with truth-telling, confirming the contribution of this region to the production of deceptive responses. The results also reveal that the preparations for both deception and truth-telling were associated with increased activity in certain brain regions, including the left dorsolateral prefrontal cortex. These findings suggest that the preparations for truth-telling and deception make similar demands on the brain and that the dorsolateral prefrontal activity identified in the preparation phase is associated with general preparatory processes, regardless of whether one is telling a lie or the truth.

How the brain shapes deception: an integrated review of the literature

How do people tell a lie? One useful approach to addressing this question is to elucidate the neural substrates for deception. Recent conceptual and technical advances in functional neuroimaging have enabled exploration of the psychology of deception more precisely in terms of the specific neuroanatomical mechanisms involved. A growing body of evidence suggests that the prefrontal cortex plays a key role in deception, and some researchers have recently emphasized the importance of other brain regions, such as those responsible for emotion and reward. However, it is still unclear how these regions play a role in making effective decisions to tell a lie. To provide a framework for considering this issue, the present article reviews current accomplishments in the study of the neural basis of deception. First, evolutionary and developmental perspectives are provided to better understand how and when people can make use of deception. The ensuing section introduces several findings on pathological lying and its neural correlate. Next, recent findings in the cognitive neuroscience of deception based on functional neuroimaging and loss-of-function studies are summarized, and possible neural mechanisms underlying deception are proposed. Finally, the priority areas of future neuroscience research-human honesty and dishonesty-are discussed.

The neurobiology of deception: evidence from neuroimaging and loss-of-function studies

PURPOSE OF REVIEW

Visualization of how the brain generates a lie is now possible because of recent conceptual and technical advances in functional neuroimaging; this has led to a rapid increase in studies related to the cognitive neuroscience of deception. The present review summarizes recent work on the neural substrates that underlie human deceptive behavior.

RECENT FINDINGS

Functional neuroimaging studies in healthy individuals have revealed that the prefrontal cortex plays a predominant role in deception. In addition, recent evidence obtained from loss-of-function studies with neuropsychological investigation and transcranial direct current stimulation has demonstrated the functional contribution of the prefrontal cortex to deception. Other research into the relationship between deception and the brain has focused on the potential use of functional MRI for lie detection, neural correlates of pathological lying, and brain mechanisms underlying inference of deceit by others.

SUMMARY

Converging evidence from multiple sources suggests that the prefrontal cortex organizes the processes of inhibiting true responses and making deceptive responses. The neural mechanisms underlying various other aspects of deception are also gradually being delineated, although the findings are diverse, and further study is needed. These studies represent an important step toward a neural explanation of complex human deceptive behavior.

Do parkinsonian patients have trouble telling lies? The neurobiological basis of deceptive behaviour

Parkinson's disease is a common neurodegenerative disorder with both motor symptoms and cognitive deficits such as executive dysfunction. Over the past 100 years, a growing body of literature has suggested that patients with Parkinson's disease have characteristic personality traits such as industriousness, seriousness and inflexibility. They have also been described as 'honest', indicating that they have a tendency not to deceive others. However, these personality traits may actually be associated with dysfunction of specific brain regions affected by the disease. In the present study, we show that patients with Parkinson's disease are indeed 'honest', and that this personality trait might be derived from dysfunction of the prefrontal cortex. Using a novel cognitive task, we confirmed that patients with Parkinson's disease (n = 32) had difficulty making deceptive responses relative to healthy controls (n = 20). Also, using resting-state (18)F-fluorodeoxyglucose PET, we showed that this difficulty was significantly correlated with prefrontal hypometabolism. Our results are the first to demonstrate that the ostensible honesty found in patients with Parkinson's disease has a neurobiological basis, and they provide direct neuropsychological evidence of the brain mechanisms crucial for human deceptive behaviour.