Lucile Rapin

What is that little voice inside my head? Inner speech phenomenology, its role in cognitive performance, and its relation to self-monitoring

The little voice inside our head, or inner speech, is a common everyday experience. It plays a central role in human consciousness at the interplay of language and thought. An impressive host of research works has been carried out on inner speech these last fifty years. Here we first describe the phenomenology of inner speech by examining five issues: common behavioural and cerebral correlates with overt speech, different types of inner speech (wilful verbal thought generation and verbal mind wandering), presence of inner speech in reading and in writing, inner signing and voice-hallucinations in deaf people. Secondly, we review the role of inner speech in cognitive performance (i.e., enhancement vs. perturbation). Finally, we consider agency in inner speech and how our inner voice is known to be self-generated and not produced by someone else.

Left-Dominant Temporal-Frontal Hypercoupling in Schizophrenia Patients With Hallucinations During Speech Perception

BACKGROUND Task-based functional neuroimaging studies of schizophrenia have not yet replicated the increased coordinated hyperactivity in speech-related brain regions that is reported with symptom-capture and resting-state studies of hallucinations. This may be due to suboptimal selection of cognitive tasks. METHODS In the current study, we used a task that allowed experimental manipulation of control over verbal material and compared brain activity between 23 schizophrenia patients (10 hallucinators, 13 nonhallucinators), 22 psychiatric (bipolar), and 27 healthy controls. Two conditions were presented, one involving inner verbal thought (in which control over verbal material was required) and another involving speech perception (SP; in which control verbal material was not required). RESULTS A functional connectivity analysis resulted in a left-dominant temporal-frontal network that included speech-related auditory and motor regions and showed hypercoupling in past-week hallucinating schizophrenia patients (relative to nonhallucinating patients) during SP only. CONCLUSIONS These findings replicate our previous work showing generalized speech-related functional network hypercoupling in schizophrenia during inner verbal thought and SP, but extend them by suggesting that hypercoupling is related to past-week hallucination severity scores during SP only, when control over verbal material is not required. This result opens the possibility that practicing control over inner verbal thought processes may decrease the likelihood or severity of hallucinations.

Hyperintensity of functional networks involving voice-selective cortical regions during silent thought in schizophrenia

An important aspect of schizophrenia symptomatology is inner-outer confusion, or blurring of ego boundaries, which is linked to symptoms such as hallucinations and Schneiderian delusions. Dysfunction in the cognitive processes involved in the generation of private thoughts may contribute to blurring of the ego boundaries through increased activation in functional networks including speech- and voice-selective cortical regions. In the present study, the neural underpinnings of silent verbal thought generation and speech perception were investigated using functional magnetic resonance imaging (fMRI). Functional connectivity analysis was performed using constrained principal component analysis for fMRI (fMRI-CPCA). Group differences were observable on two functional networks: one reflecting hyperactivity in speech- and voice-selective cortical regions (e.g., bilateral superior temporal gyri (STG)) during both speech perception and silent verbal thought generation, and another involving hyperactivity in a multiple demands (i.e., task-positive) network that included Wernickes area, during silent verbal thought generation. This set of preliminary results suggests that hyperintensity of functional networks involving voice-selective cortical regions may contribute to the blurring of ego boundaries characteristic of schizophrenia.

Atypical Activations of Fronto-Cerebellar Regions During Forethought in Parents of Children With ADHD

Objective: Although several studies suggest heritability of ADHD, only a few investigations of possible associations between people at risk and neural abnormalities in ADHD exist. In this study, we tested whether parents of children with ADHD would show atypical patterns of cerebral activations during forethought, a feature of working memory. Method: Using Functional Magnetic Resonance Imaging (fMRI), we compared 12 parents of children with ADHD and 9 parents of control children during a forethought task. Results: Parents of children with ADHD exhibited significantly increased neural activations in the posterior lobes of the cerebellum and in the left inferior frontal gyrus, relative to parents of control children. Conclusion: These findings are consistent with previous reports in children and suggest the fronto-cerebellar circuit’s abnormalities during forethought in parents of children with ADHD. Future studies of people at risk of ADHD are needed to fully understand the extent of the fronto-cerebellar heritability.

Forethought in Youth with Attention Deficit/Hyperactivity Disorder: An fMRI Study of Sex-Specific Differences

Objective. The majority of studies investigating neurocognitive processing in attention deficit/hyperactivity disorder (ADHD) have been conducted on male participants. Few studies evaluated females or examined sex differences. Among various cognitive anomalies in ADHD, deficit in forethought seems particularly important as children with ADHD often fail to adequately use previous information in order to prepare for responses. The main goal of this study was to assess sex-specific differences in behavioral and neural correlates of forethought in youth with ADHD. Methods. 21 typically developing (TD) youth and 23 youth with ADHD were asked to judge whether two pictures told a congruent or incongruent story. Reaction time, performance accuracy, and cerebral activations were recorded during functional magnetic resonance imaging (fMRI). Results. Significant sex-specific differences in cerebral activations appeared, despite equivalent performance. Relative to the boys TD participants, boys with ADHD had extensive bilateral frontal and parietal hypoactivations, while girls with ADHD demonstrated more scattered hypoactivations in the right cerebral regions. Conclusion. Present results revealed that youth with ADHD exhibit reduced cerebral activations during forethought. Nevertheless, the pattern of deficits differed between boys and girls, suggesting the use of a different neurocognitive strategy. This emphasizes the importance of including both genders in the investigations of ADHD.

Intergenerational transmission of fronto-parietal dysfunction during forethought in attention deficit/hyperactivity disorder: A pilot study

There are only a few published reports of neural abnormalities within the families of children with attention deficit/hyperactivity disorder (ADHD). Functional magnetic resonance imaging was used to compare cerebral activation of ADHD and control biological parent-child dyads during forethought, a prospective function of working memory. Reduced activations in ADHD dyads were found in the inferior frontal gyrus, right superior parietal lobule and left inferior parietal lobule. This suggests that fronto-parietal abnormalities are shared within ADHD families.