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Objective. To systematically assess previous findings on the orbitofrontal sulcogyral pattern in psychiatric disorders and to address the utility of this pattern as a transdiagnostic trait marker of early neurodevelopment in the social brain. Methods. An online literature search was conducted using the PubMed database from inception to August 2019. Studies included in this review were based on the Chiavaras’s original classification method of this H-shaped sulcus (type I, II, and III), intermediate orbital sulcus (IOS), and posterior orbital sulcus (POS). Results. Twenty-six studies were included in the review. Sixteen studies (62%) focused on schizophrenia spectrum (Sz) disorders, and the remaining studies focused on autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), history of extremely preterm and extremely low birth weight, bipolar disorder (BD), panic disorder, obsessive-compulsive disorder, cannabis users, and pathological gambling. In Sz, compared with healthy controls, the orbitofrontal sulcogyral pattern was decreased in type I, increased in type II and III, and there were fewer numbers of IOS and POS reported, although specificity in sex and hemispheric dominance was not consistent. BD and neurodevelopmental disorders in ASD and ADHD showed a similar pattern of alteration to that observed in the Sz. Conclusions.The present review of the orbitofrontal sulcogyral pattern indicated that type I expression might reflect a neurodevelopmental protective marker, and type II and III expressions, as well as fewer numbers of IOS and POS, might reflect neurodevelopmental risk markers. These trait markers may be transdiagnostic among socially disabling diseases.

The electrical activity in the electroencephalogram (EEG) and the event-related potentials extracted from the EEG provide the greatest temporal resolution for examining brain function. When coupled with the high spatial resolution of structural magnetic resonance imaging (sMRI), the combined techniques provide a powerful tool for neuroscience in the examination of brain abnormalities in major psychiatric illnesses. Over the last 20 years, our work has examined brain structure and function in schizophrenia. Both EEG and MRI measures have indicated profound abnormalities in schizophrenia within the temporal lobe, particularly marked over the left hemisphere. Our studies of patients first hospitalized due to psychosis revealed the early course of the disease to be characterized by progressive impairment and cortical gray matter reduction, most intense near the time of first hospitalization. Knowledge of those locations and brain signals affected early should help understand the basic physiological defect underlying this progression, with potential implications for new therapeutic interventions.

We have reported the presence of continuous gamma (30–150 Hz) activity in the human medial temporal lobe (MTL). Since the MTL is involved in learning and memory, we speculated that MTL gamma activity is related to such higher brain functions. It is thus of interest to learn how this activity changes during different states of consciousness. In this study, we recorded electrocorticographic (ECoG) activity directly from the surface of the MTL after various doses of sevoflurane anesthesia. Five epileptic patients underwent electrode placement operations in which electrodes were attached to the surfaces of the MTL and the basal temporal lobe (BTL). Immediately following the operation ECoG was recorded from each patient under four concentrations of sevoflurane anesthesia (1.5, 2.0, 2.5 and 3.0). Fast Fourier Transform (FFT) analysis was performed on the MTL ECoGs. Under the lowest sevoflurane concentration, MTL gamma activity was observed in all patients. However, gamma activity was progressively suppressed by increased concentrations of sevoflurane, in a dose-dependent manner. Sevoflurane has been known to reduce neuronal excitability in the rat hippocampus in vitro, probably by changing GABAergic inhibition. The reduction of MTL gamma in the present study may be the result of such a mechanism. Although memory function was not tested in this study, the amount of MTL gamma activity may be related to residual memory function during anesthesia.

Cooperation enhances interpersonal communication and nurtures society. However, efforts to socially cooperate may often evoke conflict. Individuals may selfishly pursue a greater reward or success by exploiting the efforts of other individuals or taking unnecessary risk to oneself. Such a cooperation dilemma is highly prevalent in real life; thus, it has been studied in various disciplines. Although published functional magnetic resonance imaging studies have shown the involvement of the right temporoparietal junction (TPJ) in resolving a dilemma through cooperation, a causal relationship between the two has rarely been explored. Hence, we investigated this issue by combining repetitive transcranial magnetic stimulation with a priority game task (modified snowdrift game). In this game task, participants and opponent players jointly faced a problem whereby their collaboration was anticipated to defuse the situation. This conflicted with a choice in the participant's self-interest that was more rewarding but risky. We further included conditions with and without explicit social cues using figures describing elderly/pregnant passengers in the game opponent's car, and measured participants' prosocial traits to examine any cue-induced effect as well as the personality-cooperation relationship, respectively. The cooperation ratio was not statistically different in both the no-cue and with-cue conditions between the sham stimulation and inhibitory continuous theta burst stimulation (cTBS). However, after cTBS, in the no-cue condition, the strength of the association between cooperation ratio and empathy traits decreased significantly. These results add to our knowledge about the right TPJ's role in social cognition, which may be extraordinarily complex. This topic is deserving of further examination.