Use Of Brain Imaging Research Articles

Attention and awareness in stage magic: turning tricks into research

Just as vision scientists study visual art and illusions to elucidate the workings of the visual system, so too can cognitive scientists study cognitive illusions to elucidate the underpinnings of cognition. Magic shows are a manifestation of accomplished magic performers' deep intuition for and understanding of human attention and awareness. By studying magicians and their techniques, neuroscientists can learn powerful methods to manipulate attention and awareness in the laboratory. Such methods could be exploited to directly study the behavioural and neural basis of consciousness itself, for instance through the use of brain imaging and other neural recording techniques.

Brain abnormalities in antisocial individuals: implications for the law

With the increasing popularity in the use of brain imaging on antisocial individuals, an increasing number of brain imaging studies have revealed structural and functional impairments in antisocial, psychopathic, and violent individuals. This review summarizes key findings from brain imaging studies on antisocial/aggressive behavior. Key regions commonly found to be impaired in antisocial populations include the prefrontal cortex (particularly orbitofrontal and dorsolateral prefrontal cortex), superior temporal gyrus, amygdala-hippocampal complex, and anterior cingulate cortex. Key functions of these regions are reviewed to provide a better understanding on how deficits in these regions may predispose to antisocial behavior. Objections to the use of imaging findings in a legal context are outlined, and alternative perspectives raised. It is argued that brain dysfunction is a risk factor for antisocial behavior and that it is likely that imaging will play an increasing (albeit limited) role in legal decision-making.

Monitoring the neonatal brain: A survey of current practice among Australian and New Zealand neonatologists

There is considerable variation in the use of brain imaging and electrophysiological monitoring of encephalopathic term infants. The aims of this study were (i) to document the current practice among Australian and New Zealand neonatologists; and (ii) to identify the factors that influence local practice. A postal questionnaire was sent to all 152 neonatologists in Australia and New Zealand. A hypothetical scenario of an encephalopathic term infant was presented and clinicians were asked a series of questions relating to their use of magnetic resonance imaging (MRI), computed tomography, ultrasound, electroencephalography and amplitude integrated electroencephalography. There was a 62% response rate. Twenty-two per cent of respondents would not routinely perform an MRI brain scan in the given scenario. Limited availability, expense, logistics of transport and a lack of confidence in the ability of MRI to provide additional clinical information appear to be the main factors affecting practice. When a scan is performed, the majority of respondents (72%) perform the scan on day 5 or later. Twenty-three per cent of respondents experience significant delays when they request an MRI scan. Regarding electrophysiological monitoring, amplitude integrated electroencephalography would be used by 62% of respondents in the given scenario. This study demonstrates that MRI is now widely used by neonatologists in Australia and New Zealand. However, local resource limitations and a lack of confidence in the utility of MRI continue to limit its use.

Imaging visceral pain

The application of functional imaging to study visceral sensation has generated considerable interest regarding insight into the function of the brain-gut axis. Brain activation in normal control subjects during visceral sensation includes the perigenual cingulate cortex, which is involved in affective processing and has direct connections to autonomic centers. In contrast, somatic pain rarely activates the perigenual cingulate. This difference in brain activation is highly interpretable because visceral stimuli are experienced as more unpleasant than somatic stimuli. Clinical studies are suggestive of functional changes that may be a consequence or cause of conditions such as irritable bowel syndrome, but the findings are not consistent and are not as obviously interpretable as the differences observed when contrasting visceral and somatic stimulation. Although this is partly because brain imaging is still a relatively new technique, it also reflects weaknesses inherent to the understanding of chronic visceral pain as a biopsychosocial phenomenon. The biopsychosocial concept is very broad and rarely provides for precise predictions or mechanisms that can be directly tested using brain imaging. Future use of brain imaging to examine chronic visceral pain and other pain disorders will be more likely to succeed by describing clear theoretical and clinical endpoints.

Law, responsibility, and the brain.

In perhaps the first attempt to link the brain to mental illness, Hippocrates elegantly wrote that it is the brain that makes us mad or delirious. Epitomizing one of the fundamental assumptions of contemporary neuroscience, Hippocrates’ words resonate far beyond the classic philosophical puzzle of mind and body and posit that our behavior, no matter how monstrous, lies at the mercy of our brain’s integrity. While clinicopathological observations have long pointed to several putative neurobiological systems as important in antisocial and violent criminal behavior, recent advances in brain-imaging have the potential to provide unparalleled insight. Consequently, brain-imaging studies have reinvigorated the neurophilosophical and legal debate of whether we are free agents in control of our own actions or mere prisoners of a biologically determined brain. In this chapter, we review studies pointing to brain dysfunction in criminally violent individuals and address a range of philosophical and practical issues concerning the use of brainimaging in court. We finally lay out several guidelines for its use in the legal system.

Brain imaging in psychiatry – a study of 435 psychiatric in‐patients at a university clinic

The use of brain imaging in psychiatry still lacks clear guidelines. We investigated the referral practice, outcome and predictive factors of neuroimaging in a Swiss psychiatric university clinic. Medical files were reviewed retrospectively for 435 consecutively hospitalized patients who were subjected to neuroimaging. The association between the sociodemographic and clinical characteristics and the scan results was analyzed using bivariate and multivariate analyses. Of overall examinations, 69.4% were normal, 16.3% equivocal and 14.3% abnormal; 2.9% of scans ordered for screening only showed pathology. Neurologic signs and advanced age of patients predicted abnormal scan findings, whereas other variables such as EEG results showed no significant association. Our results support the need for clear indications for using brain imaging in psychiatric in-patients. Focal neurologic signs and advanced patient age seems to predict abnormal scan results. However, these criteria are not sufficiently sensitive to predict significant scan findings in all patients.

Identification of a suitable current waveform for acute stroke imaging

MFEIT (multi-frequency electrical impedance tomography) has the potential to provide a portable non-invasive neuroimaging method ideal for use in acute stroke. Skin perception has not previously occurred in MFEIT with injected frequencies above 2 kHz, but use in brain imaging requires applied current below 100 Hz, which could stimulate cutaneous nerve endings. The purpose of this work was to find the most suitable current pattern that could be employed in MFEIT measurements in the adult head with the UCLH Mk2.5 system, which applies currents from 20 Hz–1.6 MHz. Single frequency current waveforms of 0.28 mA peak-to-peak at 20 Hz–80 Hz were applied to the forearms of three volunteers; although the skin was abraded, none of these were perceived, which agrees with similar studies in the literature. When a full frequency pattern at 20 Hz–1.6 MHz was applied to the forearm or head in four healthy subjects, with the same current amplitude of 0.28 mA for each component, an unpleasant tingling sensation was perceived, due to summation of the applied currents. The sensation was reduced or abolished by attenuation or removal of frequencies below 100 Hz; the optimal compromise was a pattern with absence of 40 Hz, and with 80 and 20 Hz respectively reduced to 75% and 50%.

What is the best imaging strategy for acute stroke?

Objectives: The cost-effectiveness of computed tomographic (CT) scanning after acute stroke was investigated to assess the contribution of brain imaging to the diagnosis and management of stroke and to estimate the costs, benefits, and risks of different imaging strategies to provide data to inform national and local policy on the use of brain imaging in stroke.

Imaging of neurocysticercosis

Cysticercosis is a disease transmitted by the ingestion of the eggs of the worm Taenia solium. It is the most common parasitic disease in humans and its incidence is not increased in patients with AIDS. 1 In addition, cysticercosis is rapidly becoming the most important cause of acquired epilepsy throughout the world. Although in the past, cysticercosis occurred mostly in third-world countries, its distribution is now worldwide, reflecting changes in immigration. The most important aspects in the management of patients with cysticercosis are the availability of CT and MRI for its diagnosis and follow-up, the availability of serodiagnostic assays that help to confirm the diagnosis, and introduction of specific antiparasitic agents. 2 The enthusiastic use of brain imaging and serologic studies have lead to a dramatic increase in the estimated numbers of affected individuals.

93 Children with Headaches: Clinical Predictors of Significant Neurologic Problems

To determine clinical predictors contributing to the diagnosis of children with a neurologic catastrophe who present with headache. A 10-year retrospective case-control study of all children, aged 4–18, with no known neurologic disorder, diagnosed with a neurologic catastrophe (brain tumour, cerebral haemorrhage, pseudotumor cerebri, cerebro-vascular malformation, brain abscess and acute hydrocephalus) who presented to our centre with a chief complaint of headache. The characteristics of the identified cases and there clinical manifestations were compared with matched controls complaining of headaches found to have a normal brain imaging. A logistic regression included all the variables found to have a significant association in a univariate analysis (Mann-Whitney U and Chi-square tests). Thirty cases (4 patients with astrocytomas, 6 pseudotumors cere-bri, 2 glioblastomas, 9 cerebral haemorrhage, 2 ependymomas, 3 medulloblas-tomas, 2 brain abscesses, 1 pineal dysgerminoma, 1 choroid plexus carcinoma, 1 optic glioma) and 30 controls were identified and compared. The majority of children suffering from a neurologic catastrophe had an abnormal neurological exam (p<0.0001), had no family history of migraine (p<0.006), presented vomiting (p<0.008) and had the headache for a shorter duration 5 weeks ±90 (SD) neurologic catastrophe VS 71 weeks ±108 (SD) other headache; p<0.001). On history, not having a family history of migraine resulted in an odds ratio of 12 (p<0.05) and having a history of vomiting resulted in an odds ratio of 17.5 (p<0.05). Having an abnormal neurological exam was associated with an odds ratio of 278 (p<0.05). We consider that our clinical predictors could help in guiding the appropriate use of brain imaging when they will be tested in a prospective study.

Occupational exposure to organic solvents and long-term nervous system damage detectable by brain imaging, neurophysiology or histopathology

The purpose of the present review is to assess the evidence published in scientific literature that industrial organic solvents as a generic group have the ability to induce long-term nervous system damage in workers that can be detected by techniques other than neuropsychological testing. The main body of evidence considered in this review was 40 studies involving the use of brain imaging, neurophysiological testing, gross autopsy or histopathology in groups of workers with long-term solvent exposure. Case reports involving both solvent abuse and occupational exposure, and experimental animal data have also been reviewed as supporting data. A number of the studies in groups of workers provide evidence of the presence of marginal atrophic abnormalities in the brain or deficits in nerve conduction velocity in solvent-exposed workers. However, there are limitations in the design of many of these studies, the strength of association between exposure and effect is not consistently strong, no dose–response relationship can be detected, the reported changes lack specificity and there is no coherence between the human and experimental animal data. Overall, it is not possible to draw reliable conclusions with respect to the presence or absence of nervous system damage related to the common properties of organic solvents.

Functional brain imaging applications to differential diagnosis in the dementias.

The diagnosis of dementia rests on an improved knowledge and a better detection of early impairments, to which functional imaging can certainly contribute. Progress has been observed at different levels. First, the understanding of different dementias has benefited from explorations of the neural substrate of dementia symptoms and from research into new markers. Second, diverse variables (clinical, anatomical, biochemical) have been related to impaired cerebral activity in Alzheimer's disease and other dementias, and progress in image analysis and in multimodal data acquisition has allowed a better understanding of the significance of brain activity disturbances. Third, functional imaging has been applied in well-designed clinical studies, and has provided important arguments for the diagnosis of characteristic clinical syndromes in the dementias. The functioning of neural networks responsible for clinical symptoms in dementia remains an important research topic for functional imaging. The development of new tracers and new techniques for image processing should also improve the usefulness of brain imaging as a diagnostic tool.

Wernicke-Korsakoff syndrome and the use of brain imaging.

The proportion of patients with Korsakoff psychosis (KP) who have a history of Wernicke's encephalopathy is smaller in recent studies compared to previous studies. Neuropsychological tests, magnetic resonance imaging (MRI), and single photon emission computed tomography were conducted in eight patients with KP, only four of whom had had a documented Wernicke episode. All subjects showed amnesia without intellectual deterioration. MRI abnormalities were seen in each group to the same extent (atrophy of mammillary bodies, to a less extent thalamus and some generalized gyral atrophy). No MRI measure differentiated the groups. Cerebral blood flow showed reduction of flow to the anterior temporal regions bilaterally, extending to the parietal lobes, to the same degree in each group. Despite the small number of patients examined, the study supports the belief that patients with an insidious onset of KP have the same pathology as those with classical Wernicke-Korsakoff syndrome. This raises the question of whether episodes of alcohol withdrawal without adequate thiamine protection result in occasionally subclinical Wernicke's events, followed by a subsequently diagnosable KP.

Update on Diagnostic Methods, Natural History and Outcome Variables in Alzheimer’s Disease

The diagnosis of Alzheimer’s disease (AD) currently relies on history obtained from family or friends and on mental status assessment matched to National Institute of Neurological and Communicative Disorders and Stroke criteria. Progression over time may or may not be typical, suggesting alternate diagnoses such as Lewy body or frontotemporal dementias. Apolipoprotein E genotype does not appear to be useful as a diagnostic marker. The usefulness of brain imaging in AD must be reexamined. Critical events in the natural history of AD, such as institutionalization and loss of ability for self-care, could be used as end points. Loss of ability for instrumental tasks, such as driving, traveling alone, or managing finances, would be preferable for early-stage stabilization studies. Different symptomatic domains of AD (mood, cognition, functional autonomy, behavior, motoricity) can be quantified using specific outcome measures. Although cognitive loss has been considered a core symptom of AD from a regulatory perspective, loss of functional autonomy and behavioral disinhibition are considered more important by clinicians and families. Recently, the availability of new scales has led to an interest in all of these domains. Results from symptomatic drug studies suggest a differential effect of cholinesterase inhibitors on cognition versus muscarinic agonists on functional autonomy and behavior. Hence there is a need to measure these domains separately and, eventually, to attempt combination therapy. Quality of life is a difficult but important dimension of AD therapeutic research, and it requires further methodological research.

History of brain imaging in psychiatry.

This is a brief history of the use of brain imaging in neuropsychology and psychiatry. There are two main parts. The first concerns brain imaging using regional cerebral blood flow (rCBF) measurements with xenon clearance. The 2-dimensional rCBF techniques have been used since 1961. The second concerns application of PET techniques starting in the early 80s. Brain imaging has yielded new information on consciousness, cortical localization, language, emotions and will. In psychiatry, brain imaging has revealed regional cerebral abnormalities in schizophrenia, affective disorders, DAMP, as well as following alcohol intake.

Functional brain imaging and hearing

Functional brain imaging techniques such as PET, SPECT, and functional MRI have frequently been applied to the study of speech, language, and cognition, but have seldom been used in investigations of hearing. Even the limited research that combines functional brain imaging and acoustic stimuli has often been concerned with processes other than audition, such as attention. This paper provides brief descriptions of these currently available functional brain imaging procedures and gives examples of what may be learned about hearing from their applications. Possible reasons for the limited use of functional brain imaging in studying hearing are explored because attention to these issues may enhance interest in the use of brain imaging for investigating the neurophysiology of hearing. Several potential research questions that apply functional brain imaging while measuring psychoacoustic performance are considered briefly and strategies for increasing brain imaging research on psychoacoustic topics are discussed.

Physiological uniqueness:A new perspective on the learning disabled/gifted child

Previous studies have established that the LD/G population has educational needs that cross over between gifted education and special education. This study reinforces those findings and furthers understanding of the physiological basis of the LD/G condition through the use of brain imaging and vision testing for hyperacuity and contrast sensitivity. Results from these latter techniques suggest that the interaction of high ability and learning disability results in brain and vision patterns unique to the LD/G group.

Use of brain imaging in animals as a component of drug discovery

Use of brain imaging in animals as a component of drug discovery

Radioiodinated I -substituted-4-phenylpiperazines as potential brain imaging agents

A series of four 125I-labeled 1-substituted-4-phenylpiperazines were prepared and evaluated in rats as potential brain imaging agents. The compounds were labeled using [125I]iodide/chloramine-T or iodine monochloride and isolated in 48–60% radiochemical yields. The tissue distribution studies indicated that a butyrophenone derivative demonstrated the best overall brain-imaging properties. Compared with the compounds having other 1-substituents this agent had a more prolonged retention of activity in the brain and higher brain-to-blood ratios over the 4-h period studied. The in vivo behavior of this agent is comparable to that of radioiodinated N-isopropyl-p-iodoamphetamine, and, because it can be labeled directly via electrophilic methods, it has substantial potential for use in brain imaging with single photon emission computed tomography.