Circumscribed low grade astrocytomas in the dominant opercular and insular region: A pilot study

Summary Intraoperative mapping techniques allow a reliable identification or exclusion of eloquent brain areas and are well tolerated by the patients. In dominant opercular tumours radical surgery can only be achieved without lasting deficits with intraoperative histological examination of the resection line and mapping. If an early post-operative MRI shows residual opercular tumour in non-eloquent areas re-operation is recommended.In large dominant insular or opercular-insular tumours only biopsy is recommended, because only an incomplete removal can be accomplished, because the trial of radical removal carries a high risk of postoperative deficits due to possible vascular damage of the lenticulo-striate arteries or internal capsule. Because subtotal removal of low grade gliomas does not increase the progression free interval, we would not recommend surgery in these cases, as they carry a significant risk of a further deficit.     

Keeping the body in mind: Insula functional organization and functional connectivity integrate interoceptive,exteroceptive, and emotional awareness

Relatively discrete experimental literatures have grown to support the insula's role in the domains of interoception, focal exteroceptive attention and cognitive control, and the experience of anxiety, even as theoretical accounts have asserted that the insula is a critical zone for integrating across these domains. Here we provide the first experimental demonstration that there exists a functional topography across the insula, with distinct regions in the same participants responding in a highly selective fashion for interoceptive, exteroceptive, and affective processing. Although each insular region is associated with areas of differential resting state functional connectivity relative to the other regions, overall their functional connectivity profiles are quite similar, thereby providing a map of how interoceptive, exteroceptive, and emotional awareness are integrated within the insular cortex. Hum Brain Mapp 34:2944–2958, 2013. © 2012 Wiley Periodicals, Inc.     

Somatosensory Thalamic Activity Modulation by Posterior Insular Stimulation: Cues to Clinical Application Based on Comparison of Frequencies in a Cat Model

BackgroundThe posterior insula (PI) has been proposed as a potential neurostimulation target for neuropathic pain relief as it represents a key-structure in pain processing. However, currently available data remain inconclusive as to efficient stimulation parameters.ObjectivesAs frequency was shown to be the most correlated parameter to pain relief, this study aims to evaluate the potential modulatory effects of low frequency (LF-IS, 50 Hz) and high-frequency (HF-IS, 150 Hz) posterior insular stimulation on the activity of somatosensory thalamic nuclei.Materials and MethodsEpidural bipolar electrodes were placed over the PI of healthy adult cats, and extracellular single-unit activities of nociceptive (NS), nonnociceptive (NN), and wide dynamic range (WDR) thalamic cells were recorded within the ventral posterolateral nucleus and the medial division of the thalamic posterior complex. Mean discharge frequency and burst firing mode were analyzed before and after either LF-IS or HF-IS.ResultsLF-IS showed a significant thalamic modulatory effects increasing the firing rate of NN cells (p ≤ 0.03) and decreasing the burst firing of NS cells (p ≤ 0.03), independently of the thalamic nucleus. Conversely, HF-IS did not induce any change in firing properties of the three recorded cell types.ConclusionThese data indicate that 50 Hz IS could be a better candidate to control neuropathic pain.     

Language disturbances associated to insular and entorhinal damage: study of a patient affected by herpetic encephalitis

The herpes simplex encephalitis (HSE) patient reported in this study presented a left hemisphere lesion limited to the left insula and to the left anterior parahippocampal region. The patient was followed longitudinally, focusing on the aphasia type, the language recovery, and the integrity of semantic representations. The language deficit was of fluent type, without phonological impairment, and showed a good but incomplete recovery after four months. A semantic impairment was possible at the onset, but recovered quickly and did not present a disproportionate impairment of living categories.     

Questioning the role of amygdala and insula in an attentional capture by emotional stimuli task

Our senses are constantly monitoring the environment for emotionally salient stimuli that are potentially relevant for survival. Because of our limited cognitive resources, emotionally salient distractors prolong reaction times (RTs) as compared to neutral distractors. In addition, many studies have reported fMRI blood oxygen level‐dependent (BOLD) activation of both the amygdala and the anterior insula for similar valence contrasts. However, a direct correlation of trail‐by‐trial BOLD activity with RTs has not been shown, yet, which would be a crucial piece of evidence to relate the two observations. To investigate the role of the above two regions in the context of emotional distractor effects, we study here the correlation between BOLD activity and RTs for a simple attentional capture by emotional stimuli (ACES) choice reaction time task using a general linear subject‐level model with a parametric RT regressor. We found significant regression coefficients in the anterior insula, supplementary motor cortex, medial precentral regions, sensory‐motor areas and others, but not in the amygdala, despite activation of both insula and amygdala in the traditional valence contrast across trials (i.e., negative vs. neutral pictures). In addition, we found that subjects that exhibit a stronger RT distractor effect across trials also show a stronger BOLD valence contrast in the right anterior insula but not in the amygdala. Our results indicate that the current neuroimaging‐based evidence for the involvement of the amygdala in RT slowing is limited. We advocate that models of emotional capture should incorporate both the amygdala and the anterior insula as separate entities.     

Neural correlates of self-focused attention in social anxiety

Socially anxious individuals tend to shift their attention away from external socially threatening cues and instead become highly self-focused. Such heightened self-focused attention has been suggested to be involved in the development and maintenance of social anxiety disorder. This study used functional magnetic resonance imaging to investigate the neural correlates of self-focused attention in 16 high socially anxious (HSA) and 16 low socially anxious (LSA) individuals. Participants were instructed to focus their attention either inwardly or outwardly during a simulated social situation. Results indicate hyperactivation of medial prefrontal cortex (mPFC), temporo-parietal junction (TPJ) and temporal pole during inward vs outward attention in HSA compared with LSA participants. Furthermore, activation of mPFC, right anterior insula, TPJ and posterior cingulate cortex was positively correlated with the trait of self-focused attention in HSA subjects. Results highlight the prominent role of the mPFC and other cortical structures in abnormal self-focused attention in social anxiety. Finally, findings for the insula suggest increased processing of bodily states that is related to the amount of habitual self-focused attention in social anxiety.