First-Person Perspective Effects on Theory of Mind without Self-Reference

This study examined dissociations between brain networks involved in theory of mind, which is needed for guessing others' mental states, and the self, which might constitute the basis for theory of mind's development. We used event-related fMRI to compare a condition that required participants to guess the mental state of a subject featured in first-person perspective sentences (1stPP condition) with a third-person perspective sentence condition (3rdPP condition). The caudate nucleus was marginally more activated in the 1stPP than in the 3rdPP condition, while the left dorsolateral prefrontal cortex (DLPFC) was significantly more activated in the 3rdPP condition as compared to the 1stPP condition. Furthermore, we examined the correlation between activation (signal intensity) of the caudate nucleus and left DLPFC with that of the right DLPFC, which is thought to be closely connected with sense of self. We found a significant correlation between caudate nucleus and right DLPFC activation in the 1stPP condition, and between left and right DLPFC activation in the 3rdPP condition. Although theory of mind and the self both appear to recruit the right DLPFC, this region seems to be accessed through the left DLPFC during theory of mind tasks, but through the caudate nucleus when tasks require self reference

Visual imagery and false memory for pictures:a functional magnetic resonance imaging study in healthy participants

BACKGROUND: Visual mental imagery might be critical in the ability to discriminate imagined from perceived pictures. Our aim was to investigate the neural bases of this specific type of reality-monitoring process in individuals with high visual imagery abilities. METHODS: A reality-monitoring task was administered to twenty-six healthy participants using functional magnetic resonance imaging. During the encoding phase, 45 words designating common items, and 45 pictures of other common items, were presented in random order. During the recall phase, participants were required to remember whether a picture of the item had been presented, or only a word. Two subgroups of participants with a propensity for high vs. low visual imagery were contrasted. RESULTS: Activation of the amygdala, left inferior occipital gyrus, insula, and precuneus were observed when high visual imagers encoded words later remembered as pictures. At the recall phase, these same participants activated the middle frontal gyrus and inferior and superior parietal lobes when erroneously remembering pictures. CONCLUSIONS: The formation of visual mental images might activate visual brain areas as well as structures involved in emotional processing. High visual imagers demonstrate increased activation of a fronto-parietal source-monitoring network that enables distinction between imagined and perceived pictures

Autobiographical memory: a biocultural relais between subject and environment

Markowitsch HJ. Autobiographical memory: a biocultural relais between subject and environment. EUROPEAN ARCHIVES OF PSYCHIATRY AND CLINICAL NEUROSCIENCE. 2008;258(S5):98-103.Autobiographical memory is described as integrated part of a number of memory systems which serve different functions in human information processing. These systems are regarded to be build-up onto each other both phylo- and ontogenetically and are named 'procedural memory', 'priming', 'perceptual memory, semantic memory (or knowledge system)' and episodic-autobiographical memory (EAM)'. Of these, EAM requires an established self and autonoetic consciousness and processes events or personal episodes. On the brain level, EAM is based on the synchronous activation of cognitive fact-processing and emotional, evaluating structures (e.g., hippocampal formation, amygdaloid body). Retrieval from EAM requires the activation of fronto-temporal areas and of limbic regions, particularly of the right hemisphere. Damage to these structures or their functional disengagement due to traumatic, stressful events selectively blocks the retrieval of EAM, though that of facts remains unimpaired ('mnestic block syndrome'). Consequently, both brain tissue damage and an altered hormonal status can have the same consequences, namely severe retrograde amnesia, which is either named organic or dissociative amnesia