23 research outputs found
Phonological contrasts are maintained despite neutralization: an intracranial EEG study
The existence of language-specific abstract sound-structure units (such as the phoneme) is largely uncontroversial in phonology. However, whether the brain performs abstractions comparable to those assumed in phonology has been difficult to ascertain. Using intracranial electroencephalography (EEG) recorded during a passive listening task, this study investigates the representation of phonological units in the brain and the relationship between those units, auditory sensory input, and higher levels of language organization, namely morphology. Leveraging the phonological neutralization of coronal stops to tap in English, this study provides evidence of a dissociation between acoustic similarity and phonemic identity in the neural response to speech. Moreover, leveraging morphophonological alternations of the regular plural and past tense, this study further demonstrates early (<500ms) evidence of dissociation between phonological form and morphological exponence. Together these results highlight the central nature of language-specific knowledge in sublexical language processing and improve our understanding of the ways language-specific knowledge structures and organizes speech perception in the brain
Initial clinical experience with frameless optically guided stereotactic radiosurgery/radiotherapy in pediatric patients
The objective of this study is to report our initial experience treating pediatric patients with central nervous system tumors using a frameless, optically guided linear accelerator.
Pediatric patients were selected for treatment after evaluation by a multidisciplinary neuro-oncology team including neurosurgery, neurology, pathology, oncology, and radiation oncology. Prior to treatment, all patients underwent treatment planning using magnetic resonance imaging (MRI) and treatment simulation on a standard computed tomography scanner (CT). For CT simulation, patients were fitted with a customized plastic face mask with a bite block attached to an optical array with four reflective markers. After ensuring adequate reproducibility, these markers were tracked during treatment by an infra-red camera. All treatments were delivered on a Varian Trilogy linear accelerator. The follow-up period ranges from 1–18 months, with a median follow-up of 6 months.
Nine patients, ages ranging from 12 to 19 years old (median age 15 years old), with a variety of tumors have been treated. Patients were treated for juvenile pilocytic astrocytoma (JPA; n = 2), pontine low-grade astrocytoma (n = 1), pituitary adenoma (n = 3), metastatic medulloblastoma (n = 1), acoustic neuroma (n = 1), and pineocytoma (n = 1). We followed patients for a median of 12 months (range 3–18 months) with no in-field failures and were able to obtain encouraging toxicity profiles.
Frameless stereotactic optically guided radiosurgery and radiotherapy provides a feasible and accurate tool to treat a number of benign and malignant tumors in children with minimal treatment-related morbidity
Neurosurgical Treatments for Cancer Pain
Cancer-related pain is a uniquely challenging entity for treating practitioners for a variety of reasons, including its often severe and medically refractory nature, the emotional and social circumstances surrounding the disease process, and the frequently associated limited life expectancy
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Acoustic and language-specific sources for phonemic abstraction from speech.
Spoken language comprehension requires abstraction of linguistic information from speech, but the interaction between auditory and linguistic processing of speech remains poorly understood. Here, we investigate the nature of this abstraction using neural responses recorded intracranially while participants listened to conversational English speech. Capitalizing on multiple, language-specific patterns where phonological and acoustic information diverge, we demonstrate the causal efficacy of the phoneme as a unit of analysis and dissociate the unique contributions of phonemic and spectrographic information to neural responses. Quantitive higher-order response models also reveal that unique contributions of phonological information are carried in the covariance structure of the stimulus-response relationship. This suggests that linguistic abstraction is shaped by neurobiological mechanisms that involve integration across multiple spectro-temporal features and prior phonological information. These results link speech acoustics to phonology and morphosyntax, substantiating predictions about abstractness in linguistic theory and providing evidence for the acoustic features that support that abstraction
Neurosurgical Management of Cancer Facial Pain
Facial pain occurs in approximately 80% of patients with head and neck cancers. Pain in these settings may result directly from the tumor, or indirectly as a side effect of oncological treatment of the tumor. Optimizing treatment for cancer pain of the face, therefore, involves a variety of diagnostic and treatment considerations, with the development of a successful treatment algorithm dependent on accurate diagnosis of the anatomical location of the pain, its relationship to the facial pain pathway, the type of pain being treated and, finally, patient\u27s prognosis and preference for treatment modality. Beyond direct treatments to reduce tumor burden, a wide variety of neuro-ablative and neuro-augmentative approaches are available that may be tailored to a patient\u27s specific pain syndrome and individual clinical context, taking into account the patient\u27s treatment goals, life expectancy, other cancer-related medical problems, and end-of-life issues
Acoustic and language-specific sources for phonemic abstraction from speech
Abstract Spoken language comprehension requires abstraction of linguistic information from speech, but the interaction between auditory and linguistic processing of speech remains poorly understood. Here, we investigate the nature of this abstraction using neural responses recorded intracranially while participants listened to conversational English speech. Capitalizing on multiple, language-specific patterns where phonological and acoustic information diverge, we demonstrate the causal efficacy of the phoneme as a unit of analysis and dissociate the unique contributions of phonemic and spectrographic information to neural responses. Quantitive higher-order response models also reveal that unique contributions of phonological information are carried in the covariance structure of the stimulus-response relationship. This suggests that linguistic abstraction is shaped by neurobiological mechanisms that involve integration across multiple spectro-temporal features and prior phonological information. These results link speech acoustics to phonology and morphosyntax, substantiating predictions about abstractness in linguistic theory and providing evidence for the acoustic features that support that abstraction
Gender Equality in Neurosurgery and Strategic Goals Toward a More Balanced Workforce
The Women in Neurosurgery (WINS) and the American Association of Neurological Surgeons published a white paper in 2008 setting an ambitious goal for women to comprise 20% of neurosurgery residents by 2012 and 20% of practicing neurosurgeons by 2020. Although there has been steady progress, we have fallen short of these benchmarks. We take this opportunity to look back at the accomplishments made over the past decade and provide an update on our present status. We evaluate current barriers toward progress and propose new goals, highlighting the systemic changes necessary to accomplish them. We propose the following updated recommendations to recruit and retain diverse talent into the neurosurgical workforce. (1) Neurosurgical departments and societies should provide diverse, early formal mentorship opportunities for medical students, residents, and junior faculty members. (2) Parental leave policies must be delineated, promoted, and enforced for all neurosurgeons, with greater awareness of internal discrimination and normalization of the discussion surrounding this topic. (3) We need to strive for compensation equity, with transparency in compensation mechanisms and regular assessment of compensation metrics. (4) Departments and institutions must have a zero-tolerance policy for sexual harassment and discrimination and establish a safe reporting structure. Finally, we propose attainable benchmarks toward achieving gender balance in the neurosurgical workforce, with a goal for women to comprise 30% of the entering residency class by 2030 and to comprise 30% of practicing neurosurgeons by 2038. We hope that this will guide further progress toward our future of building a balanced workforce
The importance of basal-temporal white matter to pre- and post-surgical naming ability in temporal lobe epilepsy
ObjectiveEmerging research highlights the importance of basal-temporal cortex, centered on the fusiform gyrus, to both pre-surgical naming ability and post-surgical naming outcomes in temporal lobe epilepsy (TLE). In this study, we investigate whether integrity of the white matter network that interconnects this basal region to the distributed language network affects naming ability and risk for post-surgical naming decline.MethodsPatients with drug-resistant TLE were recruited from two epilepsy centers in a prospective longitudinal study. The pre-surgical dataset included 50 healthy controls, 47 left TLE (L-TLE), and 41 right TLE (R-TLE) patients. All participants completed pre-surgical T1- and diffusion-weighted MRI (dMRI), as well as neuropsychological tests of auditory and visual naming. Nineteen L-TLE and 18 R-TLE patients underwent anterior temporal lobectomy (ATL) and also completed post-surgical neuropsychological testing. Pre-surgical fractional anisotropy (FA) of the white matter directly beneath the fusiform neocortex (i.e., superficial white matter; SWM) and of deep white matter tracts with connections to the basal-temporal cortex [inferior longitudinal fasciculus (ILF) and inferior frontal occipital fasciculus (IFOF)] was calculated. Clinical variables, hippocampal volume, and FA of each white matter tract or region were examined in linear regressions with naming scores, or change in naming scores, as the primary outcomes.ResultsPre-surgically, higher FA in the bilateral ILF, bilateral IFOF, and left fusiform SWM was associated with better visual and auditory naming scores (all ps < 0.05 with FDR correction). In L-TLE, higher pre-surgical FA was also associated with less naming decline post-surgically, but results varied across tracts. When including only patients with typical language dominance, only integrity of the right fusiform SWM was associated with less visual naming decline (p = .0018).DiscussionAlthough a broad network of white matter network matter may contribute to naming ability pre-surgically, the reserve capacity of the contralateral (right) fusiform SWM may be important for mitigating visual naming decline following ATL in L-TLE. This shows that the study of the structural network interconnecting the basal-temporal region to the wider language network has implications for understanding both pre- and post-surgical naming in TLE