More than skin deep: body representation beyond primary somatosensory cortex

The neural circuits underlying initial sensory processing of somatic information are relatively well understood. In contrast, the processes that go beyond primary somatosensation to create more abstract representations related to the body are less clear. In this review, we focus on two classes of higher-order processing beyond somatosensation. Somatoperception refers to the process of perceiving the body itself, and particularly of ensuring somatic perceptual constancy. We review three key elements of somatoperception: (a) remapping information from the body surface into an egocentric reference frame (b) exteroceptive perception of objects in the external world through their contact with the body and (c) interoceptive percepts about the nature and state of the body itself. Somatorepresentation, in contrast, refers to the essentially cognitive process of constructing semantic knowledge and attitudes about the body, including: (d) lexical-semantic knowledge about bodies generally and one’s own body specifically, (e) configural knowledge about the structure of bodies, (f) emotions and attitudes directed towards one’s own body, and (g) the link between physical body and psychological self. We review a wide range of neuropsychological, neuroimaging and neurophysiological data to explore the dissociation between these different aspects of higher somatosensory function

Contributions of episodic retrieval and mentalizing to autobiographical thought: Evidence from functional neuroimaging, resting-state connectivity, and fMRI meta-analyses

A growing number of studies suggest the brain's "default network" becomes engaged when individuals recall their personal past or simulate their future. Recent reports of heterogeneity within the network raise the possibility that these autobiographical processes comprised of multiple component processes, each supported by distinct functional-anatomic subsystems. We previously hypothesized that a medial temporal subsystem contributes to autobiographical memory and future thought by enabling individuals to retrieve prior information and bind this information into a mental scene. Conversely, a dorsal medial subsystem was proposed to support social-reflective aspects of autobiographical thought, allowing individuals to reflect on the mental states of one's self and others (i.e. "mentalizing"). To test these hypotheses, we first examined activity in the default network subsystems as participants performed two commonly employed tasks of episodic retrieval and mentalizing. In a subset of participants, relationships among task-evoked regions were examined at rest, in the absence of an overt task. Finally, large-scale fMRI meta-analyses were conducted to identify brain regions that most strongly predicted the presence of episodic retrieval and mentalizing, and these results were compared to meta-analyses of autobiographical tasks. Across studies, laboratory-based episodic retrieval tasks were preferentially linked to the medial temporal subsystem, while mentalizing tasks were preferentially linked to the dorsal medial subsystem. In turn, autobiographical tasks engaged aspects of both subsystems. These results suggest the default network is a heterogeneous brain system whose subsystems support distinct component processes of autobiographical thought

The neural correlates of academic self-concept in adolescence and the relation to makeing future-oriented academic choices

This study examined the role of brain regions involved in academic self-evaluation in relation to problems with study orientation. For this purpose, 48 participants between ages 14–20 years evaluated themselves on academic traits sentences in an fMRI session. In addition, participants completed an orientation to study choice questionnaire, evaluated the importance of academic traits, and completed a reading and shortened IQ test as an index of cognitive performance. Behavioral results showed that academic self-evaluations were a more important predictor for problems with study orientation compared to subjective academic importance or academic performance. On a neural level, we found that individual differences in the positivity of academic self-evaluations were reflected in increased precuneus activity. Moreover, precuneus activity mediated the relation between academic self positivity and problems with study orientation. Together, these findings support the importance of studying academic self-concept and its neural correlates in the educational decision-making process

The Self versus Others: Spatial Localization and Timing of Trait Judgments in the mPFC and PCC/Precuneus

Simulation theory (ST) states that people understand others through simulation, which counters the probabilistic reasoning view of theory theory (TT). When thinking about traits of a known other, people use self-referential thought. It is unclear which theory—ST or TT—best describes the method by which self-referential thoughts occur. A combination of event-related potential (ERP), event-related spectral perturbation (ERSP), source localization, and hidden semi-Markov model multivariate pattern analysis (HSMM-MVPA) techniques are hypothesized to disentangle self-vs-other information processing and distinguish competing theory of mind theories during a trait judgment task. EEG was recorded for 45 participants (30 females) ages 18-24 (M = 19.4) on resting and task measures, in which participants determined whether character and appearance words matched characteristics of the self and a close and distant other. Data analysis included repeated measures MANOVAs of reaction times, amplitudes and latencies generated from the parietal (PCC/precuneus) P300 and latter components of the frontal (mPFC) and parietal LSW. Time-frequency analysis included evoked and induced power through 100 Hz. ERP data was localized with MNE to verify location and timing assumptions for P300 and LSW. Lastly, HSMM-MVPA provided an alternative look at differences in number and duration of processing stages. The P300/LSW and source localization showed no differences between self, mother, and Fallon, which did not reflect prior BOLD activations. ERP data did not have the specificity to detect changes amid highly variable trials. Differences in self and mother were predicted by induced gamma ERSP, suggesting involvement of gamma in information integration or categorization. HSMM-MVPA models fit TT predictions and showed significant self-other differences in duration of processing and magnitude of peaks. Future research should clarify the role of the mPFC in self-referential thought and its relation to ST and TT with simultaneous fMRI and EEG and populations with impaired self-recognition such as ASD and schizophrenia