The superior frontal gyrus (SFG) is thought to contribute to higher cognitive functions and particularly to working memory (WM), although the nature of its involvement remains a matter of debate. To resolve this issue, methodological tools such as lesion studies are needed to complement the functional imaging approach. We have conducted the first lesion study to investigate the role of the SFG in WM and address the following questions: do lesions of the SFG impair WM and, if so, what is the nature of the WM impairment? To answer these questions, we compared the performance of eight patients with a left prefrontal lesion restricted to the SFG with that of a group of 11 healthy control subjects and two groups of patients with focal brain lesions [prefrontal lesions sparing the SFG (n = 5) and right parietal lesions (n = 4)] in a series of WM tasks. The WM tasks (derived from the classical n-back paradigm) allowed us to study the impact of the SFG lesions on domain (verbal, spatial, face) and complexity (1-, 2- and 3-back) processing within WM. As expected, patients with a left SFG lesion exhibited a WM deficit when compared with all control groups, and the impairment increased with the complexity of the tasks. This complexity effect was significantly more marked for the spatial domain. Voxel-to-voxel mapping of each subject's performance showed that the lateral and posterior portion of the SFG (mostly Brodmann area 8, rostral to the frontal eye field) was the subregion that contributed the most to the WM impairment. These data led us to conclude that (i) the lateral and posterior portion of the left SFG is a key component of the neural network of WM; (ii) the participation of this region in WM is triggered by the highest level of executive processing; (iii) the left SFG is also involved in spatially oriented processing. Our findings support a hybrid model of the anatomical and functional organization of the lateral SFG for WM, according to which this region is involved in higher levels of WM processing (monitoring and manipulation) but remains oriented towards spatial cognition, although the domain specificity is not exclusive and is overridden by an increase in executive demand, regardless of the domain being processed. From a clinical perspective, this study provides new information on the impact of left SFG lesions on cognition that will be of use to neurologists and neurosurgeons.

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Clinical observations suggest early self-consciousness disturbances in schizophrenia. A double mirror combining the images of two individuals sitting on each side of the mirror was used to study self–other differentiation in 12 individuals with early onset schizophrenia (EOS) and 15 individuals with adult onset schizophrenia (AOS) compared to 27 typically developing controls (TDC) matched on age and sex. The effects of intermodal sensory perception (visual–tactile and visual–kinesthetic) on self–other recognition were also studied. The results showed that EOS and AOS individuals, independently of age and schizophrenia severity, were centered on their own image compared to TDC, with both significant earlier self-recognition and delayed other-recognition during the visual recognition task. In addition, there was no significant effect of intermodal sensory stimulation on self–other recognition in EOS and AOS patients, whereas self-centered functioning was significantly increased by visual–tactile stimulation and decreased by visual–kinesthetic stimulation in TDC. The findings suggest that self–other recognition impairments might be a possible endophenotypic trait of schizophrenia.

A historical review of the concepts of self-consciousness is presented, highlighting the important role of the body (particularly, body perception but also body action), and the social other in the construction of self-consciousness. More precisely, body perception, especially intermodal sensory perception including kinesthetic perception, is involved in the construction of a sense of self allowing self-other differentiation. Furthermore, the social other , through very early social and emotional interactions, provides meaning to the infant’s perception and contributes to the development of his/her symbolization capacities. This is a necessary condition for body image representation and awareness of a permanent self in a time-space continuum (invariant over time and space). Self-image recognition impairments in the mirror are also discussed regarding a comprehensive developmental theory of self-consciousness. Then, a neuropsychological and neurophysiological approach to self-consciousness reviews the role of complex brain activation/integration pathways and the mirror neuron system in self-consciousness. Finally, this article offers new perspectives on self-consciousness evaluation using a double mirror paradigm to study self- and other- image and body recognition.

BACKGROUND: Awake brain surgery allows extensive intraoperative monitoring of not only motor and sensory functions and language but also executive functions. OBJECTIVE: To administer the Stroop test intraoperatively to avoid dramatic side effects such as akinetic mutism and to monitor executive functions in an attempt to optimize the benefit/risk balance of surgery. METHODS: A series of 9 adult patients with frontal glioma were operated on for gross tumor resection under local anesthesia. All procedures involved the anterior cingulate cortex (ACC). RESULTS: Three types of response to the Stroop test were observed: 3 patients had a Stroop effect only for stimulation of the contralateral ACC; 3 patients had a Stroop effect for stimulation of the ipsilateral ACC; and 3 patients had no Stroop effect. Preoperative and postoperative neuropsychological and surgical results are presented and discussed. Stimulation sites eliciting a Stroop effect are compared with published image-based data, and insight provided by these surgical data regarding ACC function and plasticity is discussed. No operative complication related to intraoperative administration of the Stroop test was observed. CONCLUSION: Administration of the Stroop test during resection of gliomas involving the ACC in adult patients is an option for intraoperative monitoring of executive functions during awake surgery. Globally, these results suggest functional compensation, mediated by plasticity mechanisms, by contralateral homologous regions of the ACC in adult patients with frontal glioma.

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