Aya Ueno

The role of the dorsolateral prefrontal cortex in deception when remembering neutral and emotional events

We used functional magnetic resonance imaging (fMRI) to investigate the neural correlates of deception while remembering neutral events and emotional events. Before fMRI, subjects were presented with a series of neutral and emotional pictures and were asked to rate each picture for arousal. During fMRI, subjects were presented with the studied and nonstudied pictures and were asked to make an honest recognition judgment in response to half of the pictures and a dishonest response to the remaining half. We found that deception pertaining to the memory of neutral pictures was associated with increased activity in the bilateral dorsolateral prefrontal cortex, the left ventrolateral prefrontal cortex, and the left orbitofrontal cortex. We also found that deception while remembering emotional pictures was associated with increased activity in the bilateral dorsolateral prefrontal cortex. An overlapping activation between the two types of deception was found in the bilateral dorsolateral prefrontal cortex. Our results indicate that the dorsolateral prefrontal cortex is associated with the executive aspects of deception, regardless of the emotional valence of memory content.

Effects of emotion and reward motivation on neural correlates of episodic memory encoding: A PET study

It is known that emotion and reward motivation promote long-term memory formation. It remains unclear, however, how and where emotion and reward are integrated during episodic memory encoding. In the present study, subjects were engaged in intentional encoding of photographs under four different conditions that were made by combining two factors (emotional valence, negative or neutral; and monetary reward value, high or low for subsequent successful recognition) during H2 15O positron emission tomography (PET) scanning. As for recognition performance, we found significant main effects of emotional valence (negative>neutral) and reward value (high value>low value), without an interaction between the two factors. Imaging data showed that the left amygdala was activated during the encoding conditions of negative pictures relative to neutral pictures, and the left orbitofrontal cortex was activated during the encoding conditions of high reward pictures relative to low reward pictures. In addition, conjunction analysis of these two main effects detected right hippocampal activation. Although we could not find correlations between recognition performance and activity of these three regions, we speculate that the right hippocampus may integrate the effects of emotion (processed in the amygdala) and monetary reward (processed in the orbitofrontal cortex) on episodic memory encoding.

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.

Reactivation of medial temporal lobe and occipital lobe during the retrieval of color information: A positron emission tomography study.

It is widely accepted that memory traces of an event include various types of information about the content of the event and about the circumstances in which the individual experienced it. However, how these various types of information are stored and later retrieved is poorly understood. One hypothesis postulates that the retrieval of specific event information reactivates regions that were active during the encoding of this information, with the aid of binding functions of the medial temporal lobe (MTL) structures. We used positron emission tomography to identify the brain regions related to the encoding and retrieval of color information. Specifically, we assessed whether overlapping activity was found in both the MTL structures and color-related cortical regions during the encoding and retrieval of color information attached with meaningless shapes. During the study, subjects were asked to encode colored (red or green) and achromatic random shapes. At subsequent testing, subjects were presented with only achromatic shapes, which had been presented with or without colors during encoding, and were engaged in retrieval tasks of shapes and colors. Overlapping activity was found in the MTL and occipital lobe (the lingual and inferior occipital gyri) in the right hemisphere during the encoding and retrieval of meaningless shapes with color information compared with those without color information. Although there are some limitations to be considered, the present findings seem to support the view that the retrieval of specific event information is associated with reactivation of both the MTL structures and the regions involved during encoding of the information.

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.

Changing the criteria for old/new recognition judgments can modulate activity in the anterior hippocampus

Numerous functional magnetic resonance imaging (fMRI) studies have reported that the medial temporal lobe (MTL) is activated to a greater extent when subjects encounter novel items as compared with familiar ones. However, it remains unclear whether the novelty signals in the MTL are modulated by the criteria for old/new recognition judgments. In this study, we used fMRI to test our hypothesis that when subjects encounter items similar to previously encountered ones, the novelty signals in the MTL will differ depending on whether the subjects focus on the perceptual features or the semantic aspects of the items. The subjects studied a series of photographs and were later asked to make a recognition judgment of (a) Same items (items identical to those seen during encoding), (b) Similar items (items similar to but not identical to those seen during encoding), and (c) New items (unstudied items) in two types of tasks: Perceptual and Semantic. The subjects judged whether the items were perceptually identical to those seen during encoding in the Perceptual task and whether the items were semantically identical to those seen during encoding in the Semantic task. The left anterior hippocampus was activated when subjects were presented with New items relative to Same items in both tasks. In addition, the hippocampal activity in response to the Similar items was increased only in the Perceptual, but not the Semantic task. Our results indicate that the novelty signals in the hippocampus can be modulated by criteria for old/new recognition judgments.

Dissociable neural systems for moral judgment of anti- and pro-social lying.

Pro-social lying, which serves to benefit listeners, is considered more socially and morally acceptable than anti-social lying, which serves to harm listeners. However, it is still unclear whether the neural mechanisms underlying the moral judgment of pro-social lying differ from those underlying the moral judgment of anti-social lying. We used functional magnetic resonance imaging (fMRI) to examine the neural activities associated with moral judgment in anti- and pro-social lying. During fMRI scanning, subjects were provided with scenarios describing a protagonists anti- and pro-social lying and were then asked to judge whether the protagonists act was morally appropriate. The behavioral data showed that anti-social lying was mostly judged to be morally inappropriate and that pro-social lying was mainly judged to be morally appropriate. The functional imaging data revealed dissociable neural systems for moral judgment in anti- and pro-social lying. The anti-social lying, which was judged to be morally inappropriate, was associated with increased activity in the right ventromedial prefrontal cortex, right middle frontal gyrus, right precuneus/posterior cingulate gyrus, left posterior cingulate gyrus, and bilateral temporoparietal junction when compared with the control condition. The pro-social lying, which was judged to be morally appropriate, was associated with increased activity in the right middle temporal gyrus, right supramarginal gyrus, and the left middle cingulate gyrus when compared with the control condition. No overlapping activity was observed during the moral judgment of anti- and pro-social lying. Our data suggest that cognitive and neural processes for the moral judgment of lying are modulated by whether the lie serves to harm or benefit listeners.

Hippocampal activation associated with successful external source monitoring.

Studies demonstrating hippocampal activation associated with memories for persons from whom information is acquired (external source monitoring) are lacking. In this study, we used functional magnetic resonance imaging (fMRI) to investigate whether the medial temporal lobe (MTL), especially the hippocampus, is activated during the retrieval of external source information as well as during the retrieval of the items themselves. Before the fMRI, subjects intentionally studied photographs with names that were presented by either a woman or a man in a videotape. During the fMRI, subjects were asked to judge whether each photograph was new or old and, if they judged it as old, to indicate which person had presented the photograph during the study phase according to a confidence rating (high or low). The results showed that successful retrieval of a source with high confidence was associated with increased activity in the hippocampus and that correct item recognition with failed source retrieval and low confidence for a source (i.e., item-only hits) was associated with decreased activity in the perirhinal cortex. Further analysis revealed that the hippocampus was also associated with familiarity/novelty distinction for the items themselves. The present study is the first to provide evidence that hippocampal activation is associated with external source monitoring. The results also support existing models suggesting that the hippocampus is associated with recollection-based recognition and the perirhinal cortex with familiarity-based recognition, with the possibility that the hippocampus plays roles in both recognition processes.

Reactivation of medial temporal lobe and human V5/MT+ during the retrieval of motion information: a PET study.

Recent neuroimaging evidence suggests that the retrieval of a prior episode reactivates sensory-processing brain regions that were active when the episode was encoded. However, with regard to reactivation of the medial temporal lobe (MTL), the results remain controversial. In the present study, we used positron emission tomography (PET) to identify the brain regions associated with the encoding and retrieval of motion information. Specifically, we assessed whether overlapping activity was found in both the MTL structures and motion-related cortical regions during the encoding and retrieval of motion information attached to meaningless shapes. During the study, subjects were asked to encode moving (rotating to the right or left) and static meaningless shapes. At subsequent testing, subjects were presented with only static shapes, which had been presented with or without motion during encoding, and were engaged in retrieval tasks of shapes and motion. Overlapping activity was found in the right middle temporal gyrus (V5/MT+) and the left MTL (hippocampus) during the encoding and retrieval of shapes with motion compared with those without motion. These results support the view that the retrieval of specific event information is associated with reactivation of both the MTL and the regions involved during the encoding of that information.

Neural activity associated with enhanced facial attractiveness by cosmetics use

Previous psychological studies have shown that make-up enhances facial attractiveness. Although neuroimaging evidence indicates that the orbitofrontal cortex (OFC) shows greater activity for faces of attractive people than for those of unattractive people, there is no direct evidence that the OFC also shows greater activity for the face of an individual wearing make-up than for the same face without make-up. Using functional magnetic resonance imaging (fMRI), we investigated neural activity while subjects viewed 144 photographs of the same faces with and without make-up (48 with make-up, 48 without make-up, and 48 scrambled photographs) and assigned these faces an attractiveness rating. The behavioral data showed that the faces with make-up were rated as more attractive than those without make-up. The imaging data revealed that the left OFC and the right hippocampus showed greater activity for faces with make-up than for those without make-up. Furthermore, the activities of the right anterior cingulate cortex, left hippocampus, and left OFC increased with increasing facial attractiveness resulting from cosmetics use. These results provide direct evidence of the neural underpinnings of cosmetically enhanced facial attractiveness.