How to automatically detect intracranial aneurysms from Three-Dimension Time of Flight Magnetic Resonance Angiography images is a typical 3D image classification problem. Currently, the commonly used method is the Maximum Intensity Projection- based way. It transfers 3D classification into 2D case by projecting the 3D patch into 2D planes along different directions on the basis of voxel’s intensity. After then, the 2D Convolutional Neural Network is established to do classification. It has been shown that the MIP-based method can reduce (...) the demands for the samples and increase the computation efficiency. Meanwhile, the accuracy is comparable with that of 3D image classification. Inspired by the strategy of MIP, we want to further reduce the demands for samples and accelerate the training by transferring the 2D image classification into 1D case, i.e., we want to generate the 1D vectors from the MIP images and then establish a 1D CNN to do intracranial aneurysm detection and classification for 3D TOF MRA image. Specifically, our method first extracts a series of patches as the Region of Interests along the blood vessels from the original 3D TOF MRA 3D image. The corresponding MIP images of each ROI will be obtained through maximum intensity projecting. Then, we generate a series of 1D vectors by accumulating each MIP image along different directions. Meanwhile, a 1D CNN is established to detect aneurysms, in which, the input is the obtained 1D vectors and the output is the binary classification result denoting whether there are intracranial aneurysms in the considered patch. Generally, compared with 2D- and 3D-CNN, the 1D CNN-based way greatly accelerates the training and shows stronger robustness in the case of fewer samples. The efficiency of the proposed method outperforms the 2D CNN about 10 times in CPU training. Yet, their accuracies are close. (shrink)

High-resolution neuroimaging modalities are used often in studies involving healthy volunteers. Subsequently, a significant increase in the incidental discovery of asymptomatic intracranial abnormalities raised the important ethical issues of when follow-up and treatment may be necessary. We examined the literature to establish a practical set of criteria for approaching incidental findings. Our objective is to develop an algorithm for when follow-up may be important and to provide recommendations that would increase the likelihood of follow-up. A systematic literature search was (...) performed using the PubMed and MEDLINE databases to identify articles describing brain tumors and intracranial aneurysms. The treatment algorithm we present suggests that incidental intracranial masses suspicious for glioma should be biopsied or resected, while other masses are to be followed with serial imaging based on the expected growth pattern. Lack of follow-up can result in adverse outcomes that can be mitigated by using technology to facilitate communication and improve follow-up care. The importance of training physicians to be good communicators is also stressed. New technology including automated telephone systems, texting and email will improve access to patients and hopefully encourage compliance and follow-up. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:To Be or Not to Be:Waiving Informed Consent in Emergency ResearchCharles R. McCarthy (bio)The requirements for prior, legally authorized informed consent constitute a necessary condition for recruiting subjects into biomedical or behavioral research. However, informed consent requirements pose a serious problem for most research conducted in emergency care settings. For this reason, the Food and Drug Administration's (FDA) regulations governing investigational devices and the Department of Health and Human (...) Services' (HHS) regulations for the protection of human subjects allow narrow exceptions to the general requirements of informed consent. In a joint effort to clarify the applicability of the current FDA regulations and to better understand the intent of the HHS regulations as they apply to emergency research, the FDA and the National Institutes of Health (NIH) cosponsored a public forum on the ethical conduct of emergency research in January 1995.Although the forum was not designed as a consensus conference and participants vigorously disagreed on some of the details, a broad consensus emerged on several major points: (1) both HHS and FDA regulations should, in the immediate future, be interpreted to allow for randomized clinical trials in emergency situations so long as the subjects are carefully protected; and (2) consideration should be given to producing new, closely harmonized regulations from both agencies that will provide greater clarity concerning what kinds of emergency research may be allowed without obtaining prior informed consent.The FDA-NIH forum in January was occasioned primarily by controversy about the hypothermia research protocol described below, but it is obvious that many other kinds of emergency research also await the outcome of deliberations concerning waiver of informed consent in emergency situations. These include research into the care and treatment of: occlusive stroke; subarachnoid hemorrhage due to intracranial aneurysm; metabolic coma; status epilepticus; cardiac arrest; myocardial infarction; cardiac arrhythmia; hemorrhagic shock; pulmonary embolism; acute asthmatic attack; and poisoning. All of these conditions [End Page 155] are encountered in emergency settings where obtaining informed consent from the patient-subjects to participate in research is seldom possible, and obtaining consent from legally authorized representatives of the subjects is either not feasible, or, if obtained, is of doubtful validity.The Hypothermia Research Case and HHS RegulationsA $7.2 million grant for research on the use of hypothermia in the treatment of severe head trauma, the largest award ever made to the University of Texas Health Sciences Center at Houston, is in danger of expiring before the study is completed. The protocol, which involves the use of cooling blankets to induce hypothermia in patients suffering from severe head injuries, is designed to test the hypothesis that: "Early lowering of the body temperature of patients suffering from severe head trauma to approximately 91 degrees Fahrenheit will slow patients' metabolism and will/will not, as a consequence, reduce the rates of both morbidity and mortality in these patients." The protocol was approved by seven Institutional Review Boards (IRBs), each of which waived the requirement to obtain informed consent from research subjects in accordance with Sec. 46. 116(d) of the HHS Regulations for the Protection of Human Subjects.1However, NIH's Office for Protection from Research Risks (OPRR), which is responsible for assuring compliance with the HHS regulations, has taken a controversial regulatory position by requiring informed consent from a legally authorized representative of each subject to be entered in the hypothermia trial. Because the obtaining of surrogate consent has proved to be very difficult, OPRR's position has slowed the research to a point where it may have to be terminated.At issue in the controversy is a fundamental question of ethics and public policy. Is it ever permissible to involve incompetent subjects in research without either their consent, or the consent of their legally authorized representatives? Pertinent HHS regulations for the protection of human subjects seem to answer the question affirmatively by allowing local IRBs to waive some or all of the elements of informed consent under carefully limited circumstances (45 CFR 46 116(d)). Nevertheless, OPRR has signalled the research community that use of the informed consent waiver provision for the Houston hypothermia study is not permitted under the regulations. OPRR judged that the risks... (shrink)

In lieu of an abstract, here is a brief excerpt of the content:The Intersection of Medicine and ReligionJohn C. DormoisThe practice of medicine offers a host of rewards to the practitioner. Besides the obvious intellectual satisfaction of solving a difficult diagnostic problem or the ability to make a comfortable living, I have found the greatest personal sense of moral gratification when helping [End Page 196] families negotiate the most challenging event in life: making decisions at end of life. Whether the (...) condition was a ruptured intracranial aneurysm with brain death or a patient with far advanced cancer struggling with the choice between experimental chemotherapy or choosing comfort therapy at home surrounded by family for the remaining days of life, the moral courage required to provide the best guidance was considerable. In my early years of practice I didn’t call my actions in these situations “courageous” nor were there moral “guidelines” providing a blueprint. I knew I responded with empathy and compassion and that this ability had a lot to do with being raised in a religious or spiritual home. At the same time, I suspected that some of the lack of empathy and compassion I witnessed in some of my colleagues was related to the very training programs of physicians. This essay traces the origin of my moral and ethical concerns about medical education and my intention to reinvigorate the spiritual or existential voice in medicine.An early life experience had a great deal to do with shaping my moral development. At age seven my family traveled through the West Indies. My father’s amateur radio hobby meant that at every stop we would be greeted by one of his radio contacts. One stop in particular was life changing.Port au Prince, Haiti was an unknown place to this seven year–old, but to say it was a culture shock to a boy from Kansas would be an understatement of epic proportions. It was during this visit that I experienced true poverty in its most blatant form. In downtown Port au Prince I saw limbless beggars and the deformed from polio and malnutrition. But it was the sight of the garbage dump near the center of town that changed my world forever. There, among piles of detritus, I saw children and families making their home in the dump. They had hollowed out a sort of cavern in the piles of trash that served as a place of refuge from both the rain and the sun.This experience in many ways has served as a framework and background for my life. Although seen through the eyes of a seven year–old, the picture can only be adequately understood within the context of being raised by religiously faithful parents, parents free of hypocrisy whose lives personified the best in Christian virtues and practices. These early experiences planted the seeds that would only fully blossom some 60 years later.Medical school was a demanding but exhilarating experience. Each day was a day of discovery … anatomy, physiology, pathology … all subjects opening up a whole new world to explore. Internal medicine suited me best since it was the specialty that most closely integrated all the basic sciences necessary to arrive at a diagnosis. I loved the elegance of endocrinology in particular where a given hormone mediator could cause widely different effects if present in excess or completely absent. But I was in the end drawn to cardiology since it combined complex physiology with my avocation, the love of running.There was, however, a disturbing aspect of medicine education that I observed affecting many of my classmates. Although I can vividly recall the enthusiasm that all of us shared as we donned our white coats for the first time and envisioned a future of caring for our patients, things gradually and insidiously changed over the next four years. The altruism and empathy that was so evident in the early years gradually lessened as graduation approached. I could not help being struck by this change and wondered at the time why that should happen. I had no insight then that what I had observed was a well recognized consequence of the medical school experience. I’m sure that the passage from professional training to practice in... (shrink)

Power density spectra and phase synchrony measurements were taken from intracranial electrode grids implanted in epileptic subjects. Comparisons were made between data from the waking state and from the period of unconsciousness immediately following a generalised tonic–clonic seizure. Power spectra in the waking state resembled coloured noise. Power spectra in the unconscious state resembled coloured noise from 1 to about 5 Hz, but at higher frequencies changed in two out of three subjects to resemble white noise. This boosted unconscious (...) gamma power to a higher level than conscious gamma power. For both gamma and beta passbands, synchrony measurements showed more widespread phase synchrony in the unconscious than the conscious state. We conclude that neither gamma activity per se nor phase synchrony per se are neural correlates of consciousness. (shrink)

Advances in intracranial electroencephalography and neurophysiology have enabled the study of previously inaccessible brain regions with high fidelity temporal and spatial resolution. Studies of iEEG have revealed a rich neural code subserving healthy brain function and which fails in disease states. Machine learning, a form of artificial intelligence, is a modern tool that may be able to better decode complex neural signals and enhance interpretation of these data. To date, a number of publications have applied ML to iEEG, but (...) clinician awareness of these techniques and their relevance to neurosurgery, has been limited. The present work presents a review of existing applications of ML techniques in iEEG data, discusses the relative merits and limitations of the various approaches, and examines potential avenues for clinical translation in neurosurgery. One-hundred-seven articles examining artificial intelligence applications to iEEG were identified from 3 databases. Clinical applications of ML from these articles were categorized into 4 domains: i) seizure analysis, ii) motor tasks, iii) cognitive assessment, and iv) sleep staging. The review revealed that supervised algorithms were most commonly used across studies and often leveraged publicly available timeseries datasets. We conclude with recommendations for future work and potential clinical applications. (shrink)

Déjà vu and involuntary autobiographical memories (IAM) can be induced by intracranial electric brain stimulation in epileptic patients, sometimes in the same individual. We suggest that there may be different types of IAM which should be taken into account and provide several ideas to test the hypothesis of a continuity between IAM and déjà vu phenomena.

Motivated by exploitation concerns, we argue for the importance of participant engagement in basic human intracranial electrophysiology research. This research takes advantage of unique neurosurgical opportunities to better understand complex systems of the human brain, but it also exposes participants to additional risks without immediate therapeutic intent. We argue that understanding participant values and incorporating their perspectives into the research process may help determine whether and to what extent research practices and the resulting distributions of risks and benefits constitute (...) exploitation and contribute to building a brain research paradigm that is genuinely responsive to participant values. More broadly, we highlight the importance of paying attention to participant interests in non-therapeutic brain research. (shrink)

A central debate in philosophy and neuroscience pertains to whether PFC activity plays an essential role in the neural basis of consciousness. Neuroimaging and electrophysiology studies have revealed that the contents of conscious perceptual experience can be successfully decoded from PFC activity, but these findings might be confounded by post- perceptual cognitive processes, such as thinking, reasoning, and decision-making, that are not necessary for con- sciousness. To clarify the involvement of the PFC in consciousness, we present a synthesis of research (...) that has used intracranial electrical stimulation (iES) for the causal modulation of neural activity in the human PFC. This research provides compelling evidence that iES of only certain prefrontal regions (i.e., orbitofrontal cortex and anterior cingu- late cortex) reliably perturbs conscious experience. Conversely, stimulation of anterolateral prefrontal sites, often con- sidered crucial in higher-order and global workspace theories of consciousness, seldom elicits any reportable alterations in consciousness. Furthermore, the wide variety of iES-elicited effects in the PFC (e.g., emotions, thoughts, and olfactory and visual hallucinations) exhibits no clear relation to the immediate environment. Therefore, there is no evidence for the kinds of alterations in ongoing perceptual experience that would be predicted by higher-order or global workspace theories. Nevertheless, effects in the orbitofrontal and anterior cingulate cortices suggest a specific role for these PFC subregions in supporting emotional aspects of conscious experience. Overall, this evidence presents a challenge for higher-order and global workspace theories, which commonly point to the PFC as the basis for con- scious perception based on correlative and possibly confounded information. (shrink)

Rationale: High-frequency oscillations in intracranial EEG are used to delineate the epileptogenic zone during presurgical diagnostic assessment in patients with epilepsy. HFOs are historically divided into ripples, fast ripples, and their co-occurrence. In a previous study, we had validated the rate of FRandRs during deep sleep to predict seizure outcome. Here, we ask whether epileptic FRandRs might be confounded by physiological FRandRs that are unrelated to epilepsy.Methods: We recorded iEEG in the medial temporal lobe MTL in 17 patients while (...) they performed cognitive tasks. The three cognitive tasks addressed verbal working memory, visual working memory, and emotional processing. In our previous studies, these tasks activated the MTL. We re-analyzed the data of these studies with the automated detector that focuses on the co-occurrence of ripples and FRs.Results: For each task, we identified those channels in which the HFO rate was modulated during the task condition compared to the control condition. However, the number of these channels did not exceed the chance level. Interestingly, even during wakefulness, the HFO rate was higher for channels within the seizure onset zone than for channels outside the SOZ.Conclusion: Our prospective definition of an epileptic HFO, the FRandR, is not confounded by physiological HFOs that might be elicited by our cognitive tasks. This is reassuring for the clinical use of FRandR as a biomarker of the EZ. (shrink)

The idea that it is acceptable to ‘nudge’ people to opt for the ‘healthy choice’ is gaining currency in health care policy circles. This article investigates whether researchers evaluating Abdominal Aortic Aneurysm Screening Programmes (AAASP) attempt to influence decision makers in ways that are similar to popular ‘nudging’ techniques. Comparing two papers on the health economics of AAASP both published in the BMJ within the last 3 years, it is shown that the values chosen for the health economics modelling (...) are not representative of the literature and consistently favour the conclusions of the articles. It is argued (1) that this and other features of these articles may be justified within a Libertarian Paternalist framework as ‘nudging’ like ways of influencing decision makers, but also (2) that these ways of influencing decision makers raise significant ethical issues in the context of democratic decision making. (shrink)

Leveraging firsthand experience, BRAIN-funded investigators conducting intracranial human neuroscience research propose two fundamental ethical commitments: (1) maintaining the integrity of clinical care and (2) ensuring voluntariness. Principles, practices, and uncertainties related to these commitments are offered for future investigation.

Contingent transcranialists claim that the physical mechanisms of mind are not exclusively intracranial and that genuine cognitive systems can extend into cognizers' physical and socio-cultural environments. They further claim that extended cognitive systems must include the deep functional integration of external environmental resources with internal neural resources. They have found it difficult, however, to explicate the precise nature of such deep functional integration and provide compelling examples of it. Contingent intracranialists deny that extracranial resources can be components of genuine (...) extended cognitive systems. They claim that transcranialists fallaciously conflate coupling with constitution and construe cognition as extending always from brains into world rather than world into brains. By using insights from recent research in developmental psychology and by explicating the nature of one form that deep functional integration can take, I argue that (i) transcranialists do not fallaciously conflate coupling wth constitution, and (ii) human emotional ontogenesis is a world-to-brain transcranial achievement. Jennifer Greenwood is a PhD Candidate in Philosophy at the School of History, Philosophy, Religion, and Classics, University of Queensland. (shrink)

A comparative method of studying the biological bases of personality compares human trait dimensions with likely animal models in terms of genetic determination and common biological correlates. The approach is applied to the trait of sensation seeking, which is defined on the human level by a questionnaire, reports of experience, and observations of behavior, and on the animal level by general activity, behavior in novel situations, and certain types of naturalistic behavior in animal colonies. Moderately high genetic determination has been (...) found for human sensation seeking, and marked strain differences in rodents have been found in open-field behavior that may be related to basic differences in brain neurochemistry. Agonistic and sociable behaviors in both animals and humans and the trait measure of sensation seeking in humans have been related to certain common biological correlates such as gonadal hormones, monoamine oxidase (MAO), and augmenting of the cortical evoked potential.The monoamine systems in the rodent brain are involved in general activity, exploratory behavior, emotionality, socialization, dominance, sexual and consummately behaviors, and intracranial self-stimulation. Preliminary studies have related norepinephrine and enzymes involved in its production and degradation to human sensation seeking. A model is suggested that relates mood, behavioral activity, sociability, and clinical states to activity of the central catecholamine neurotransmitters and to neuroregulators and other transmitters that act in opposite ways on behavior or stabilize activity in the arousal systems. Stimulation and behavioral activity act on the catecholamine systems in a brain–behavior feedback loop. At optimal levels of catecholamine systems activity (CSA) mood is positive and activity and sociability are adaptive. At very low or very high levels of CSA mood is dysphoric, activity is restricted or stereotyped, and the organism is unsocial or aggressively antisocial. Novelty, in the absence of threat, may be rewarding through activation of noradrenergic neurons. (shrink)

During the past decade, the so-called “hypothesis of cognitive extension,” according to which the material vehicles of some cognitive processes are spatially distributed over the brain and the extracranial parts of the body and the world, has received lots of attention, both favourable and unfavourable. The debate has largely focussed on three related issues: (1) the role of parity considerations, (2) the role of functionalism, and (3) the importance of a mark of the cognitive. This paper critically assesses these issues (...) and their interconnections. Section 1 provides a brief introduction. Section 2 argues that some of the most prominent objections against the appeal to parity considerations fail. Section 3 shows that such considerations are nevertheless unsuitable as an argument for cognitive extension. First, the actual argumentative burden is carried by an underlying commitment to functionalism, not by the parity considerations themselves. Second, in the absence of an independently motivated mark of the cognitive, the argument based on parity considerations does not get off the ground, but given such a mark, it is superfluous. Section 4 argues that a similar dilemma arises for the attempt to defend cognitive extension by a general appeal to functionalism. Unless it can be independently settled what it is for a process to be cognitive, functionalism itself will be undermined by the possibility of cognitive extension. Like parity considerations, functionalism is thus either unable to support cognitive extension or superfluous. Hence, nothing short of the specification of an appropriate mark of the cognitive that can be fulfilled not only by intracranial but also by extended processes will do as an argument for cognitive extension. (shrink)