Auditory prediction errors in sound frequency and duration generated different cortical activation patterns in the human brain: an ECoG study.

Sound frequency and duration are essential auditory components. The brain perceives deviations from the preceding sound context as prediction errors, allowing efficient reactions to the environment. Additionally, prediction error response to duration change is reduced in the initial stages of psychotic disorders. To compare the spatiotemporal profiles of responses to prediction errors, we conducted a human electrocorticography study with special attention to high gamma power in 13 participants who completed both frequency and duration oddball tasks. Remarkable activation in the bilateral superior temporal gyri in both the frequency and duration oddball tasks were observed, suggesting their association with prediction errors. However, the response to deviant stimuli in duration oddball task exhibited a second peak, which resulted in a bimodal response. Furthermore, deviant stimuli in frequency oddball task elicited a significant response in the inferior frontal gyrus that was not observed in duration oddball task. These spatiotemporal differences within the Parasylvian cortical network could account for our efficient reactions to changes in sound properties. The findings of this study may contribute to unveiling auditory processing and elucidating the pathophysiology of psychiatric disorders.

Auditory prediction and prediction error responses evoked through a novel cascade roving paradigm: a human ECoG study.

Auditory sensory processing is assumed to occur in a hierarchical structure including the primary auditory cortex (A1), superior temporal gyrus, and frontal areas. These areas are postulated to generate predictions for incoming stimuli, creating an internal model of the surrounding environment. Previous studies on mismatch negativity have indicated the involvement of the superior temporal gyrus in this processing, whereas reports have been mixed regarding the contribution of the frontal cortex. We designed a novel auditory paradigm, the "cascade roving" paradigm, which incorporated complex structures (cascade sequences) into a roving paradigm. We analyzed electrocorticography data from six patients with refractory epilepsy who passively listened to this novel auditory paradigm and detected responses to deviants mainly in the superior temporal gyrus and inferior frontal gyrus. Notably, the inferior frontal gyrus exhibited broader distribution and sustained duration of deviant-elicited responses, seemingly differing in spatio-temporal characteristics from the prediction error responses observed in the superior temporal gyrus, compared with conventional oddball paradigms performed on the same participants. Moreover, we observed that the deviant responses were enhanced through stimulus repetition in the high-gamma range mainly in the superior temporal gyrus. These features of the novel paradigm may aid in our understanding of auditory predictive coding.

Paving the Way for Memory Enhancement: Development and Examination of a Neurofeedback System Targeting the Medial Temporal Lobe.

Neurofeedback (NF) shows promise in enhancing memory, but its application to the medial temporal lobe (MTL) still needs to be studied. Therefore, we aimed to develop an NF system for the memory function of the MTL and examine neural activity changes and memory task score changes through NF training. We created a memory NF system using intracranial electrodes to acquire and visualise the neural activity of the MTL during memory encoding. Twenty trials of a tug-of-war game per session were employed for NF and designed to control neural activity bidirectionally (Up/Down condition). NF training was conducted with three patients with drug-resistant epilepsy, and we observed an increasing difference in NF signal between conditions (Up-Down) as NF training progressed. Similarities and negative correlation tendencies between the transition of neural activity and the transition of memory function were also observed. Our findings demonstrate NF's potential to modulate MTL activity and memory encoding. Future research needs further improvements to the NF system to validate its effects on memory functions. Nonetheless, this study represents a crucial step in understanding NF's application to memory and provides valuable insights into developing more efficient memory enhancement strategies.

Intracranial Neurofeedback Modulating Neural Activity in the Mesial Temporal Lobe During Memory Encoding: A Pilot Study.

Removal of the mesial temporal lobe (MTL) is an established surgical procedure that leads to seizure freedom in patients with intractable MTL epilepsy; however, it carries the potential risk of memory damage. Neurofeedback (NF), which regulates brain function by converting brain activity into perceptible information and providing feedback, has attracted considerable attention in recent years for its potential as a novel complementary treatment for many neurological disorders. However, no research has attempted to artificially reorganize memory functions by applying NF before resective surgery to preserve memory functions. Thus, this study aimed (1) to construct a memory NF system that used intracranial electrodes to feedback neural activity on the language-dominant side of the MTL during memory encoding and (2) to verify whether neural activity and memory function in the MTL change with NF training. Two intractable epilepsy patients with implanted intracranial electrodes underwent at least five sessions of memory NF training to increase the theta power in the MTL. There was an increase in theta power and a decrease in fast beta and gamma powers in one of the patients in the late stage of memory NF sessions. NF signals were not correlated with memory function. Despite its limitations as a pilot study, to our best knowledge, this study is the first to report that intracranial NF may modulate neural activity in the MTL, which is involved in memory encoding. The findings provide important insights into the future development of NF systems for the artificial reorganization of memory functions.

Aneurysm Isolation is Associated with Complete Occlusion of Aneurysms After Flow Diverter Treatment.

PURPOSE: Some aneurysms remain patent after treatment with flow diverters (FD) due to residual blood flow in the aneurysm. Several studies have proposed that branches and residual flow are associated with delayed aneurysm occlusion. We propose that aneurysm isolation (i.e., the complete disconnection of the aneurysm from surrounding vessels) might be a possible factor facilitating aneurysm occlusion. This study aimed to determine if aneurysm isolation was a factor associated with aneurysm occlusion after FD treatment. METHODS: We reviewed 80 internal carotid artery (ICA) aneurysms treated with FDs between October 2014 and April 2021. Aneurysm isolation was assessed in high-resolution cone-beam computed tomograms at the end of each treatment. Aneurysms with incorporated branches and those with connections to other branches due to stent malapposition were deemed to be nonisolated. Other factors, such as patient age, sex, anticoagulant use, aneurysm size, adjunct coil use, and the presence of incorporated branches, were considered. The degree of aneurysm occlusion (complete or incomplete) was assessed by follow-up angiograms 12 months after treatment. RESULTS: Complete occlusion was achieved in 57 of 80 aneurysms (71%). Completely occluded aneurysms had a significantly higher ratio of isolation compared to incompletely occluded aneurysms (91.2% vs. 69.6%, P = 0.032). Multivariate logistic regression analysis showed that aneurysm isolation was the sole significant predictor of complete aneurysm occlusion (odds ratio, OR 19.38; 95% confidence interval, CI 2.280-164.657; P = 0.007). CONCLUSION: Aneurysm isolation is a significant factor contributing to complete occlusion after FD treatment.

Ventral Clival Branch of the Ascending Pharyngeal Artery as a Transosseous Feeder of an Arteriovenous Fistula Surrounding the Clival Lesions.

PURPOSE: Arteriovenous fistulas (AVFs) adjacent to the clivus, such as cavernous sinus dural AVFs (CSDAVFs) and condylar AVFs, sometimes have an intraosseous shunted pouch and recruit blood supply from transosseous feeders. Precise analysis of transosseous feeders regarding the clival lesion has not yet been performed. Therefore, this study aimed to clarify the characteristics and identity of transosseous feeders in clival lesions. METHODS: Patients with CSDAVFs and condylar AVFs, who underwent high-resolution cone-beam computed tomography or three-dimensional rotational angiography in our institute, were included. The frequency, type of branch, penetrating point, and termination of intraosseous feeders were retrospectively evaluated. RESULTS: A total of 31 patients with 36 lesions in CSDAVFs and 8 patients with 8 lesions in condylar AVFs underwent angiography. For CSDAVFs, 38 transosseous feeders were detected in 23 out of 31 patients, including 22 in the pharyngeal branch of the ascending pharyngeal artery (APhA), 6 in the hypoglossal branch of the APhA, 6 in the accessory meningeal artery, 3 in the meningohypophyseal trunk (MHT), and 1 in the anterior branch of the middle meningeal artery. For condylar AVFs, 24 transosseous feeders were detected in all 8 patients, including 11 in the pharyngeal branches of the APhA, 7 in the hypoglossal branch of the APhA, 6 in the segmental artery from the vertebral artery, and 2 in the MHT. CONCLUSION: Transosseous feeders of AVFs around the clivus, which are frequently seen in AVFs of this area, mainly arise from ventral clival branches and from pharyngeal branches of the APhA.

Long-term progression-free survival achieved in the skull base metastasis of gastrointestinal stromal tumor with introduction of tyrosine kinase inhibitor: illustrative case.

BACKGROUND: Gastrointestinal stromal tumors (GISTs) are common subepithelial tumors that rarely metastasize to the intracranial space. Because the standard treatment for metastatic intracranial GISTs has not been established, multimodal therapies are needed, especially in the case of skull base metastasis. However, its outcome has not always been favorable. The authors report the longest known surviving case of skull base metastasis of GIST treated with imatinib only. OBSERVATIONS: A 52-year-old male with a history of GIST presented with left facial swelling and numbness. Examinations revealed a 70-mm tumor occupying the left middle cranial fossa and the orbit. The authors performed transnasal endoscopic tumor biopsy for definitive diagnosis and reintroduced imatinib treatment. The tumor significantly decreased in size early after the introduction of imatinib, and symptoms completely disappeared within several weeks. The lesion has remained shrunk radiologically for 63 months, and the patient is continuously being followed up under imatinib treatment. LESSONS: The authors reported a rare case of skull base metastasis of GIST successfully treated solely with systemic therapy with a tyrosine kinase inhibitor, achieving tumor control for over 5 years. This case suggests that tyrosine kinase inhibitors might play a key role in the multidisciplinary treatment for skull base metastases of GIST.

Spatiotemporal target selection for intracranial neural decoding of abstract and concrete semantics.

Decoding the inner representation of a word meaning from human cortical activity is a substantial challenge in the development of speech brain-machine interfaces (BMIs). The semantic aspect of speech is a novel target of speech decoding that may enable versatile communication platforms for individuals with impaired speech ability; however, there is a paucity of electrocorticography studies in this field. We decoded the semantic representation of a word from single-trial cortical activity during an imageability-based property identification task that required participants to discriminate between the abstract and concrete words. Using high gamma activity in the language-dominant hemisphere, a support vector machine classifier could discriminate the 2-word categories with significantly high accuracy (73.1 ± 7.5%). Activities in specific time components from two brain regions were identified as significant predictors of abstract and concrete dichotomy. Classification using these feature components revealed that comparable prediction accuracy could be obtained based on a spatiotemporally targeted decoding approach. Our study demonstrated that mental representations of abstract and concrete word processing could be decoded from cortical high gamma activities, and the coverage of implanted electrodes and time window of analysis could be successfully minimized. Our findings lay the foundation for the future development of semantic-based speech BMIs.

Impact of Coronavirus Disease 2019 on Time Delay and Functional Outcome of Mechanical Thrombectomy in Tokyo, Japan.

OBJECTIVES: An association has been reported between delays in the onset-to-door (O2D) time for mechanical thrombectomy (MT) and outbreaks of coronavirus disease 2019 (COVID-19). However, the association between other MT time courses or functional outcomes and COVID-19 outbreaks remains unclear. We compared the time courses of stroke pathways or functional outcomes in 2020 (the COVID-19 era) with those in 2019 (the pre-COVID-19 era) in Tokyo, Japan. MATERIALS AND METHODS: This retrospective observational study used data from the Tokyo-tama-REgistry of Acute endovascular Thrombectomy (TREAT), a multicenter registry of MT for acute large vessel occlusion in the Tokyo Metropolitan Area. Patients who had undergone acute MT from January 2019 to December 2020 were included. Patients were classified by the year they had undergone MT (2019 or 2020). RESULTS: In total, 477 patients were analyzed. O2D time was significantly longer in 2020 (146.0 min) than in 2019 (105.0 min; p = 0.034). No significant difference in door-to-puncture time (D2P) time or modified Rankin Scale (mRS) score 0-2 at 90 days was seen between 2019 and 2020. In the subgroup analysis, O2D time was significantly longer in the first half of 2020 compared with 2019. Multivariable logistic regression analysis revealed that the year 2020 was a independent predictor of longer O2D time, but not for mRS score 0-2 at 90 days. CONCLUSIONS: Although O2D time was significantly longer in the COVID-19 compared with the pre-COVID-19 era, D2P may not be significantly delayed and functional outcomes may not be different, despite the COVID-19 pandemic.

A Rare Anomalous Origin of the Right Vertebral Artery from the Internal Carotid Artery with an Aberrant Right Subclavian Artery.

BACKGROUND: An anomalous origin of the right vertebral artery (VA) from the right internal carotid artery (ICA) occurs only rarely. CASE DESCRIPTION: A 70-year-old man underwent carotid artery stenting for right internal carotid artery stenosis. In this patient, the right VA arose from the right ICA associated with an aberrant right subclavian artery. CONCLUSION: Embryologically, failure of involution of 1 of the first 6 intersegmental arteries causes various abnormal origins of the VA. The embryonic development of this anomaly is also reviewed.

Two cases of symptomatic common carotid artery occlusion treated by carotid endarterectomy with L-shaped ministernotomy.

BACKGROUND: Common carotid artery occlusion (CCAO) is rare. Symptomatic lesions are resistant to medical treatment and revascularization are often required, but there is no consensus on the treatment of CCAO. In this paper, two cases of symptomatic CCAO treated by carotid endarterectomy (CEA) with L-shaped ministernotomy, in which the lesions extended to the beginning part of the CCA, are reported. CASE DESCRIPTION: Case 1 involved a 74-year-old man who presented with transient left limb numbness and an abnormal right visual field. Cerebrovascular angiography showed that the right CCA was occluded immediately after its origin and blood was supplied from the posterior circulation. CEA was performed with an L-shaped ministernotomy that allowed exposure of the CCA origin with minimal invasion. There were no complications associated with the sternal incision and he was discharged with a modified Rankin Scale (mRS) score of 0. Case 2 involved a 70-year-old man who presented with left half-blindness. Magnetic resonance imaging showed infarction in the right posterior cerebral artery region and neck echo showed CCA pseudo occlusion just before the carotid bulb. A new infarction in the right middle cerebral artery region developed during hospitalization. CEA with partial sternotomy was performed. The patient was rehabilitated with no deterioration of neurological findings and transferred with an mRS score of 3. CONCLUSION: There were no complications resulting from partial sternotomy in the two cases presented. CEA with partial sternotomy could be an effective treatment option for CCAO in which the internal carotid artery is patent and thrombus extends to the proximal CCA.

Factors predicting contralateral hematoma growth after unilateral drainage of bilateral chronic subdural hematoma.

OBJECTIVE Chronic subdural hematoma (CSDH) is a common form of intracranial hemorrhage with a recurrence rate of 9.2%-26.5% after bur hole surgery. Occasionally patients with bilateral CSDH undergo unilateral surgery because the contralateral hematoma is deemed to be asymptomatic, and in some of these patients the contralateral hematoma may subsequently enlarge, requiring additional surgery. The authors investigated the factors related to the growth of these hematomas. METHODS Ninety-three patients with bilateral CSDH who underwent unilateral bur hole surgery at Aizu Chuo Hospital were included in a retrospective analysis. Findings on preoperative MRI, preoperative thickness of the drained hematoma, and the influence of antiplatelet or anticoagulant drugs were considered and evaluated in univariate and multivariate analyses. RESULTS The overall growth rate was 19% (18 of 93 hematomas), and a significantly greater percentage of the hematomas that were iso- or hypointense on preoperative T1-weighted imaging showed growth compared with other hematomas (35.4% vs 2.3%, p < 0.001). Multivariate logistic regression analysis showed that findings on preoperative T1-weighted MRI were the sole significant predictor of hematoma growth, and other factors such as antiplatelet or anticoagulant drug use, patient age, patient sex, thickness of the treated hematoma, and T2-weighted MRI findings were not significantly related to hematoma growth. The adjusted odds ratio for hematoma growth in the T1 isointense/hypointense group relative to the T1 hyperintense group was 25.12 (95% CI 3.89-51.58, p < 0.01). CONCLUSIONS The findings of preoperative MRI, namely T1-weighted sequences, may be useful in predicting the growth of hematomas that did not undergo bur hole surgery in patients with bilateral CSDH.