Exploring Physical Lumbar Microvascular Geometry Through Endoscopy and Illustrations: Implications for Clinical Interpretation.

STUDY DESIGN: Retrospective Study. OBJECTIVES: Minimally invasive endoscopic spinal surgery is gaining popularity, but our understanding of the lumbar spine's microvascular geometry relies heavily on cadaver studies and textbook illustrations. Additionally, inconsistent nomenclature of vessels in the literature hampers effective communication among surgeons. This study aims to improve the clarity and comprehensibility of the lumbar spinal microvascular geometry under endoscopic view. METHODS: The study included 400 patients who underwent endoscopic spinal surgery for lumbar spinal canal stenosis and foraminal stenosis. The surgeries were performed by an experienced surgeon using either the interlaminar or transforaminal approach. Endoscopic video recordings were further analyzed to map the microvascular geometry and common bleeding foci. The observed results were cross-referenced with existing literature to reconstruct a comprehensive view of the vascular anatomy. RESULTS: The transforaminal approach commonly encounters bleeding foci originating from the major branches of the segmental lumbar artery and the emissary veins within the foramen. The interlaminar approach primarily encounters bleeding foci from the muscle vessels in the dorsal lamina, which are believed to be located near the ends of the three main branches. In the intracanal region, epidural vessels form a rotary loop above the disc, which can contribute to most of the bleeding during discectomy. CONCLUSIONS: This study provides a comprehensive understanding of the microvascular anatomy in the lumbar spine during endoscopic spinal surgery. Recognizing the geometry will help surgeons anticipate and control bleeding, reducing the risk of complications. The findings contribute to the improvement of surgical techniques and patient safety in endoscopic spinal surgery.

Effect and safety of C7 neurotomy at the intervertebral foramen in patients with chronic poststroke aphasia: a multicentre, randomised, controlled study protocol.

INTRODUCTION: Aphasia affects many stroke survivors; therefore, effective treatments are urgently needed. Preliminary clinical findings have suggested an association between contralateral C7-C7 cross nerve transfer and recovery from chronic aphasia. Randomised controlled trials supporting the efficacy of C7 neurotomy (NC7) are lacking. This study will explore the efficacy of NC7 at the intervertebral foramen for improving chronic poststroke aphasia. METHODS AND ANALYSIS: This study protocol reports a multicentre, randomised, assessor-blinded active-controlled trial. A total of 50 patients with chronic poststroke aphasia for over 1 year and with a aphasia quotient calculated by Western Aphasia Battery Aphasia Quotient (WAB-AQ) score below 93.8 will be recruited. Participants will be randomly assigned to 1 of 2 groups (25 individuals each) to receive NC7 plus intensive speech and language therapy (iSLT), or iSLT alone programme. The primary outcome is the change in Boston Naming Test score from baseline to the first follow-up after NC7 plus 3 weeks of iSLT or iSLT alone. The secondary outcomes include the changes in the WAB-AQ, Communication Activities of Daily Living-3, International Classification of Functioning, Disability and Health (ICF) speech language function, Barthel Index, Stroke Aphasic Depression Questionnaire-hospital version and sensorimotor assessments. The study will also collect functional imaging outcomes of naming and semantic violation tasks through functional MRI and electroencephalogram to evaluate the intervention-induced neuroplasticity. ETHICS AND DISSEMINATION: This study was approved by the institutional review boards of Huashan Hospital, Fudan University, and all participating institutions. The study findings will be disseminated through peer-reviewed publications and conference presentations. TRIAL REGISTRATION NUMBER: ChiCTR2200057180.

Representing linguistic communicative functions in the premotor cortex.

Linguistic communication is often regarded as an action that serves a function to convey the speaker's goal to the addressee. Here, with an functional magnetic resonance imaging (fMRI) study and a lesion study, we demonstrated that communicative functions are represented in the human premotor cortex. Participants read scripts involving 2 interlocutors. Each script contained a critical sentence said by the speaker with a communicative function of either making a Promise, a Request, or a Reply to the addressee's query. With various preceding contexts, the critical sentences were supposed to induce neural activities associated with communicative functions rather than specific actions literally described by these sentences. The fMRI results showed that the premotor cortex contained more information, as revealed by multivariate analyses, on communicative functions and relevant interlocutors' attitudes than the perisylvian language regions. The lesion study results showed that, relative to healthy controls, the understanding of communicative functions was impaired in patients with lesions in the premotor cortex, whereas no reliable difference was observed between the healthy controls and patients with lesions in other brain regions. These findings convergently suggest the crucial role of the premotor cortex in representing the functions of linguistic communications, supporting that linguistic communication can be seen as an action.

Neural segregation in left inferior frontal gyrus of semantic processes at different levels of syntactic hierarchy.

Humans are unique in their ability to parse hierarchical structures of sentences. Previous studies demonstrated that syntactic processes at different hierarchies are subserved by distinct subregions in left inferior frontal gyrus (LIFG), in which BA45 is mainly involved in processing lower-level syntactic structures and BA44 is mainly involved in processing higher-level syntactic structures. However, little is known about whether semantic processes at different syntactic hierarchies show similar dissociations in LIFG. In the present fMRI experiment, participants read sentences with the structure "subject noun + verb + numeral + classifier + object noun", in which the object noun is constrained by the classifier at the lower-level and by the verb at the higher-level. The object noun was manipulated to be either semantically congruent or incongruent with the classifier at the lower-level and/or with the verb at the higher-level. Both the whole brain contrasts and the region of interest (ROI) analyses showed that, in LIFG, the semantic process of integrating the object noun with the classifier induced stronger activation in BA45 whereas the semantic process of integrating the object noun with the verb induced stronger activation in BA44. This dissociation demonstrates a neural segregation for semantic processes at different syntactic hierarchies, with the lower-level process relying more on neural substrates for general semantic processes and the higher-level process relying more on neural substrates for processing structural hierarchies.

Reward expectation modulates multiple stages of auditory conflict control.

Although mounting evidence has shown that reward can improve conflict control in the visual domain, little is known about whether and how reward affects conflict processing in the auditory domain. In the present study, we adopted an auditory Stroop task in which the meaning of a sound word ('male' or 'female') could be either congruent or incongruent with the gender of the voice (male or female speaker), and the participants were asked to discriminate the gender of the voice (the phonetic task) or the meaning of the word (the semantic task). Importantly, an auditory cue signalling a potential reward or no-reward for the current trial was presented prior to the sound word. In both tasks, relative to the congruent sound word, response to the incongruent sound word was delayed, i.e., an auditory Stroop effect. However, this auditory Stroop effect was reduced following a reward cue relative to a no-reward cue. Event-related potentials (ERPs) showed a stronger contingent negativity variation (CNV, 1000-1500 ms) for the reward cue than for the no-reward cue. The conflict negativity Ninc (300-400 ms) was more negative-going for the incongruent word than for the congruent word, but this effect was significantly reduced in the reward condition. However, the late positive complex (LPC) showed at most a weak reward modulation. These findings suggest that reward expectation improves auditory conflict control by modulating different stages of conflict processing: promoting better attentional preparation for the upcoming target (CNV), and facilitating conflict detection (Ninc) on the presentation of the target.

Neural Dynamics of Reward-Induced Response Activation and Inhibition.

Reward-predictive stimuli can increase an automatic response tendency, which needs to be counteracted by effortful response inhibition when this tendency is inappropriate for the current task. Here we investigated how the human brain implements this dynamic process by adopting a reward-modulated Simon task while acquiring EEG and fMRI data in separate sessions. In the Simon task, a lateral target stimulus triggers an automatic response tendency of the spatially corresponding hand, which needs to be overcome if the activated hand is opposite to what the task requires, thereby delaying the response. We associated high or low reward with different targets, the location of which could be congruent or incongruent with the correct response hand. High-reward targets elicited larger Simon effects than low-reward targets, suggesting an increase in the automatic response tendency induced by the stimulus location. This tendency was accompanied by modulations of the lateralized readiness potential over the motor cortex, and was inhibited soon after if the high-reward targets were incongruent with the correct response hand. Moreover, this process was accompanied by enhanced theta oscillations in medial frontal cortex and enhanced activity in a frontobasal ganglia network. With dynamical causal modeling, we further demonstrated that the connection from presupplementary motor area (pre-SMA) to right inferior frontal cortex (rIFC) played a crucial role in modulating the reward-modulated response inhibition. Our results support a dynamic neural model of reward-induced response activation and inhibition, and shed light on the neural communication between reward and cognitive control in generating adaptive behaviors.

Reward enhances cross-modal conflict control in object categorization: Electrophysiological evidence.

Cross-modal conflict arises when information from different sensory modalities are incompatible with each other. Such conflict may influence the processing of stimuli in the task-relevant modality and call for cognitive control to resolve this conflict. Here, we investigate how reward modulates cross-modal conflict control during object categorization. Participants categorized pictures as representing animate or inanimate objects while ignoring auditory stimuli. We manipulated the audiovisual congruency and performance-dependent reward (reward vs. no-reward). Behavioral results showed a significant cross-modal interference effect only in the no-reward condition, not in the reward condition. Neurally, we found that the frontocentral N2and theta band oscillations were larger in the incongruent condition than in the congruent condition, but only when there was no reward for performance. The converging behavioral and electrophysiological evidence demonstrates that reward enhances cognitive control in a cross-modal context and reduces cross-modal conflict.