Positron Emission Tomography of Auditory Sensation in Deaf Patients and Patients with Cochlear Implants

1993 ◽  
Vol 102 (10) ◽  
pp. 797-801 ◽  
Author(s):  
Juichi Ito ◽  
Yasushi Iwasaki ◽  
Junji Sakakibara ◽  
Yoshiharu Yonekura
Keyword(s):  
Auditory Cortex ◽  
Brain Activity ◽  
Emission Computed Tomography ◽  
Speech Comprehension ◽  
Metabolic Rates ◽  
Quantitative Measurements ◽  
Positron Emission ◽  
Before And After ◽  
Auditory Cortices ◽  
The Brain

The present study investigated the function of the auditory cortices in severely hearing-impaired or deaf patients and cochlear implant patients before and after auditory stimulation. Positron emission computed tomography (PET), which can detect brain activity by providing quantitative measurements of the metabolic rates of oxygen and glucose, was used. In patients with residual hearing, the activity of the auditory cortex measured by PET was almost normal. Among the totally deaf patients, the longer the duration of deafness, the lower the brain activity in the auditory cortex measured by PET. Patients who had been deaf for a long period showed remarkably reduced metabolic rates in the auditory cortices. However, following implantation of the cochlear device, the metabolic activity returned to nearnormal levels. These findings suggest that activation of the speech comprehension mechanism of the higher brain system can be initiated by sound signals from the implant devices.

Neuroreceptor Imaging of Stress and Mood Disorders

CNS Spectrums ◽  
2004 ◽  
Vol 9 (4) ◽  
pp. 292-301 ◽  
Author(s):  
Susan E. Kennedy ◽  
Jon-Kar Zubieta
Keyword(s):  
Mood Disorders ◽  
Single Photon ◽  
Imaging Techniques ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Positron Emission ◽  
Before And After ◽  
Neuroreceptor Imaging ◽  
The Brain ◽  
Photon Emission Computed Tomography

ABSTRACTTechniques such as positron emission tomography and single photon emission computed tomography allow for the imaging of neurotransmitter receptors and transporters in the brain. These tools have been used to investigate serotonergic, dopaminergic, and opioidergic function in healthy subjects as well as in patients with major depressive disorder, bipolar disorder, and other mood disorders. Pharmacologic challenges, such as amphetamine challenge, and physiologic stressors, such as pain challenge, have been used to further examine the function of these neurotransmitter systems. Neuroimaging of patient populations before and after medication treatment may be useful to understand changes in neurotransmission that accompany disease remission. As new radiotracers with higher selectivity for the various receptors and transporters are developed, imaging techniques may provide new insights into the pathophysiolagy of mood disorders, leading to improved diagnosis and treatment.

Neuroimaging in dementia and depression

2000 ◽  
Vol 6 (2) ◽  
pp. 109-119 ◽  
Author(s):  
John O'Brien ◽  
Bob Barber
Keyword(s):  
Computed Tomography ◽  
Brain Mapping ◽  
Single Photon ◽  
Photon Emission ◽  
Emission Computed Tomography ◽  
Positron Emission ◽  
Magnetic Resonance Imaging Mri ◽  
Near Future ◽  
The Brain ◽  
Photon Emission Computed Tomography

Neuroimaging is traditionally divided into structural and functional imaging. Structural imaging looks at brain structure or anatomy and includes computed tomography (CT) and magnetic resonance imaging (MRI). Functional techniques seek to examine the physiological functioning of the brain, either at rest or during activation, and include single photon emission computed tomography (SPECT), positron emission tomography (PET), MRI spectroscopy, functional MRI (fMRI) and encephalographic brain mapping. Although fMRI, MRI spectroscopy and brain mapping are likely to have clinical applications in the near future, the main imaging modalities of current clinical relevance to psychiatrists are CT, MRI and SPECT, which will be the focus of this article.

The Use of Positron Emission Computed Tomography and Computed Tomography in the Treatment of Gynecological Malignant Tumor

2020 ◽  
Vol 10 (9) ◽  
pp. 2062-2066
Author(s):  
Lang Yang ◽  
Xiaoxia Hu.
Keyword(s):  
Computed Tomography ◽  
Comprehensive Treatment ◽  
Emission Computed Tomography ◽  
Conventional Imaging ◽  
Ct Diagnosis ◽  
Positron Emission ◽  
Pet Ct ◽  
Before And After ◽  
Predictive Rate ◽  
Fdg Pet Ct

Objective: Investigating the value of 18Fluorine-Fluorodesoxyglucose (18F-FDG) positron emission computed tomography/computed tomography (PET/CT) before and after the comprehensive treatment of gynecological malignant tumors is the study purpose. Method: In this study, the patients with gynecological malignant tumor who are examined by 18F-FDG PET/CT test are taken as the study objects, supplemented by image fusion algorithm to achieve the best fusion effect. At the same time, routine imaging examination is performed and confirmed by histopathology. Before and after comprehensive treatment, in terms of PET/CT, its predictive rate of positive as well as negative, sensitivity, specificity as well as accuracy are compared with conventional imaging. Results: Before comprehensive treatment, the positive predictive rate of PET/CT diagnosis is 100%, the sensitivity is 95.00%, and the accuracy is 95.00%. The positive predictive rate of conventional imaging diagnosis is 100%, the sensitivity is 73.75%, and the accuracy is 73.75%. In terms of the PET/CT sensitivity as well as accuracy, conventional imaging is lower than that of it. After comprehensive treatment, the positive predictive rate of PET/CT diagnosis is 96.30%, the negative predictive rate is 100.00%, the sensitivity is 100.00%, the specificity is 92.86%, and the accuracy is 95.50%. The positive predictive rate of conventional imaging diagnosis is 94.87%, the negative predictive rate is 68.29%, the sensitivity is 74.00%, the specificity is 93.33%, and the accuracy is 81.25%. In terms of the above indexes, conventional imaging is lower than PET/CT diagnosis. Conclusion: When it is compared with conventional imaging, 18F-FDG PET/CT has higher accuracy. Besides, it is more comprehensive when diagnosing gynecological cancer before and after comprehensive treatment, which is worthy of clinical promotion.

scholarly journals Brain oscillator(s) underlying rhythmic cerebral and buccal motor output in the mollusc, Pleurobranchaea californica

1984 ◽  
Vol 110 (1) ◽  
pp. 1-15
Author(s):  
W. J. Davis ◽  
M. P. Kovac ◽  
R. P. Croll ◽  
E. M. Matera
Keyword(s):  
Neural Control ◽  
Brain Activity ◽  
Neural Oscillator ◽  
Neural Oscillation ◽  
Buccal Ganglion ◽  
Pleurobranchaea Californica ◽  
Long Latency ◽  
Before And After ◽  
The Central Nervous System ◽  
The Brain

Tonic (d.c.) intracellular depolarization of the previously identified phasic paracerebral feeding command interneurones (PCps) in the brain of the carnivorous gastropod Pleurobranchaea causes oscillatory neural activity in the brain, both before and after transecting the cerebrobuccal connectives. Therefore, cycle-by-cycle ascending input from the buccal ganglion is not essential to cyclic brain activity. Instead the brain contains an independent neural oscillator(s), in addition to the oscillator(s) demonstrated previously in the buccal ganglion (Davis et al. 1973). Transection of the cerebrobuccal connectives immediately reduces the previously demonstrated (Kovac, Davis, Matera & Croll, 1983) long-latency polysynaptic excitation of the PCps by the polysynaptic excitors (PSEs) of the PCps. Therefore polysynaptic excitation of the PCps by the PSEs is mediated by an ascending neurone(s) from the buccal ganglion. The capacity of feeding command interneurones to induce neural oscillation in the isolated brain declines to near zero within 1 h after transection of the cerebrobuccal connectives, suggesting that this capacity is normally maintained by ascending information from the buccal ganglion. The results show that this motor system conforms to a widely applicable general model of the neural control of rhythmic behaviour, by which independent neural oscillators distributed widely in the central nervous system are coupled together to produce coordinated movement.

scholarly journals Neurophysiological network dynamics of pitch change detection

2020 ◽  
Author(s):  
Soheila Samiee ◽  
Dominique Vuvan ◽  
Esther Florin ◽  
Philippe Albouy ◽  
Isabelle Peretz ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Auditory Cortex ◽  
Change Detection ◽  
Brain Activity ◽  
Inferior Frontal Gyrus ◽  
Brain Network ◽  
Slow Phase ◽  
Speech Comprehension ◽  
Pitch Change ◽  
Phase Amplitude

AbstractThe detection of pitch changes is crucial to sound localization, music appreciation and speech comprehension, yet the brain network oscillatory dynamics involved remain unclear. We used time-resolved cortical imaging in a pitch change detection task. Tone sequences were presented to both typical listeners and participants affected with congenital amusia, as a model of altered pitch change perception.Our data show that tone sequences entrained slow (2-4 Hz) oscillations in the auditory cortex and inferior frontal gyrus, at the pace of tone presentations. Inter-regional signaling at this slow pace was directed from auditory cortex towards the inferior frontal gyrus and motor cortex. Bursts of faster (15-35Hz) oscillations were also generated in these regions, with directed influence from the motor cortex. These faster components occurred precisely at the expected latencies of each tone in a sequence, yielding a form of local phase-amplitude coupling with slower concurrent activity. The intensity of this coupling peaked dynamically at the moment of anticipated pitch changes.We clarify the mechanistic relevance of these observations in relation to behavior as, by task design, typical listeners outperformed amusic participants. Compared to typical listeners, inter-regional slow signaling toward motor and inferior frontal cortices was depressed in amusia. Also, the auditory cortex of amusic participants over-expressed tonic, fast-slow phase-amplitude coupling, pointing at a possible misalignment between stimulus encoding and internal predictive signaling. Our study provides novel insight into the functional architecture of polyrhythmic brain activity in auditory perception and emphasizes active, network processes involving the motor system in sensory integration.

Neuroimaging technologies

2020 ◽  
pp. 101-112
Author(s):  
Mark Woolrich ◽  
Mark Jenkinson ◽  
Clare Mackay
Keyword(s):  
Brain Imaging ◽  
Single Photon ◽  
Photon Emission ◽  
Experimental Medicine ◽  
Emission Computed Tomography ◽  
Positron Emission ◽  
Brain Structure And Function ◽  
Magnetic Resonance Imaging Mri ◽  
And Function ◽  
The Brain

The brain is a highly complex system that is inaccessible to biopsy, which puts human brain imaging at the heart of our attempts to understand psychiatric disorders. Imaging has the potential to uncover the pathophysiology, provide biomarkers for use in the development and monitoring of treatments, and stratify patients for studies and trials. This chapter introduces the three main brain imaging technologies that are used to assay brain structure and function: magnetic resonance imaging (MRI), molecular imaging positron emission tomography (PET), and single-photon emission computed tomography (SPECT); electrophysiology [electroencephoaography (EEG)]; and magnetoencephalograpy (MEG). The chapter outlines the principles behind their use and the nature of the information that can be extracted. Together, these brain imaging methods can provide complementary windows into the living brain as an increasingly essential suite of tools for experimental medicine in psychiatry.

scholarly journals Imaging robust microglial activation after lipopolysaccharide administration in humans with PET

2015 ◽  
Vol 112 (40) ◽  
pp. 12468-12473 ◽  
Author(s):  
Christine M. Sandiego ◽  
Jean-Dominique Gallezot ◽  
Brian Pittman ◽  
Nabeel Nabulsi ◽  
Keunpoong Lim ◽  
...  
Keyword(s):  
Inflammatory Cytokines ◽  
Microglial Activation ◽  
Protein A ◽  
Sickness Behavior ◽  
Translocator Protein ◽  
Blood Levels ◽  
Lps Challenge ◽  
Positron Emission ◽  
Before And After ◽  
The Brain

Neuroinflammation is associated with a broad spectrum of neurodegenerative and psychiatric diseases. The core process in neuroinflammation is activation of microglia, the innate immune cells of the brain. We measured the neuroinflammatory response produced by a systemic administration of the Escherichia coli lipopolysaccharide (LPS; also called endotoxin) in humans with the positron emission tomography (PET) radiotracer [11C]PBR28, which binds to translocator protein, a molecular marker that is up-regulated by microglial activation. In addition, inflammatory cytokines in serum and sickness behavior profiles were measured before and after LPS administration to relate brain microglial activation with systemic inflammation and behavior. Eight healthy male subjects each had two 120-min [11C]PBR28 PET scans in 1 d, before and after an LPS challenge. LPS (1.0 ng/kg, i.v.) was administered 180 min before the second [11C]PBR28 scan. LPS administration significantly increased [11C]PBR28 binding 30–60%, demonstrating microglial activation throughout the brain. This increase was accompanied by an increase in blood levels of inflammatory cytokines, vital sign changes, and sickness symptoms, well-established consequences of LPS administration. To our knowledge, this is the first demonstration in humans that a systemic LPS challenge induces robust increases in microglial activation in the brain. This imaging paradigm to measure brain microglial activation with [11C]PBR28 PET provides an approach to test new medications in humans for their putative antiinflammatory effects.

The Similarity of Brain Activity Associated with True and False Recognition Memory Depends On Test Format

1997 ◽  
Vol 8 (3) ◽  
pp. 250-257 ◽  
Author(s):  
Marcia K. Johnson ◽  
Scott F. Nolde ◽  
Mara Mather ◽  
John Kounios ◽  
Daniel L. Schacter ◽  
...  
Keyword(s):  
Source Monitoring ◽  
Brain Activity ◽  
Event Related Potentials ◽  
Emission Tomography ◽  
Test Format ◽  
Test Items ◽  
Positron Emission ◽  
Related Potentials ◽  
False Recognitions ◽  
The Brain

Event-related potentials (ERPs) were compared for correct recognitions of previously presented words and false recognitions of associatively related, nonpresented words (lures) When the test items were presented blocked by test type (old, new, lure), waveforms for old and lure items were different, especially at frontal and left parietal electrode sites, consistent with previous positron emission tomography (PET) data (Schacter, Reiman, et al, 1996) When the test format randomly intermixed the types of items, waveforms for old and lure items were more similar We suggest that test format affects the type of processing subjects engage in, consistent with expectations from the source-monitoring framework (Johnson, Hashtroudi, & Lindsay, 1993) These results also indicate that brain activity as assessed by neuroimaging designs requiring blocked presentation of trials (e.g., PET) do not necessarily reflect the brain activity that occurs in cognitive-behavioral paradigms, in which types of test trials are typically intermixed

scholarly journals The Brain at High Altitude: Hypometabolism as a Defense against Chronic Hypoxia?

1994 ◽  
Vol 14 (4) ◽  
pp. 671-679 ◽  
Author(s):  
P. W. Hochachka ◽  
C. M. Clark ◽  
W. D. Brown ◽  
C. Stanley ◽  
C. K. Stone ◽  
...  
Keyword(s):  
High Altitude ◽  
Chronic Hypoxia ◽  
Large Fraction ◽  
Brain Regions ◽  
Proton Nuclear Magnetic Resonance ◽  
Resonance Spectroscopy ◽  
Metabolic Rates ◽  
Positron Emission Tomographic ◽  
Positron Emission ◽  
The Brain

The brain of hypoxia-tolerant vertebrates is known to survive extreme limitations of oxygen in part because of very low rates of energy production and utilization. To assess if similar adaptations may be involved in humans during hypoxia adaptation over generational time, volunteer Quechua natives, indigenous to the high Andes between about 3,700 and 4,900 m altitude, served as subjects in positron emission tomographic measurements of brain regional glucose metabolic rates. Two metabolic states were analyzed: (a) the presumed normal (high altitude-adapted) state monitored as soon as possible after leaving the Andes and (b) the deacclimated state monitored after 3 weeks at low altitudes. Proton nuclear magnetic resonance spectroscopy studies of the Quechua brain found normal spectra, with no indication of any unusual lactate accumulation; in contrast, in hypoxia-tolerant species, a relatively large fraction of the glucose taken up by the brain is released as lactate. Positron emission tomographic measurements of [18F]2-deoxy-2-fluoro-d-glucose (FDG) uptake rates, quantified in 26 regions of the brain, indicated systematically lower region-by-region glucose metabolic rates in Quechuas than in lowlanders. The metabolic reductions were least pronounced in primitive brain structures (e.g., cerebellum) and most pronounced in regions classically associated with higher cortical functions (e.g., frontal cortex). These differences between Quechuas with lifetime exposure to hypobaric hypoxia and lowlanders, which seem to be expressed to some degree in most brain regions examined, may be the result of a defense adaptation against chronic hypoxia.

scholarly journals Initial Cerebral HM-PAO Distribution Compared to LCBF: Use of a Model Which Considers Cerebral HM-PAO Trapping Kinetics

1988 ◽  
Vol 8 (1_suppl) ◽  
pp. S31-S37 ◽  
Author(s):  
James L. Lear
Keyword(s):  
Arterial Input Function ◽  
Input Function ◽  
Brain Regions ◽  
Male Rats ◽  
Type Model ◽  
Emission Computed Tomography ◽  
Intravenous Injections ◽  
Positron Emission ◽  
Uptake Pattern ◽  
The Brain

The cerebral uptake of [99mTc]– d,l-hexamethylpropyleneamine oxime complex (HM-PAO) was compared to LCBF determined simultaneously with [14C]iodoantipyrine (IAP) using double radionuclide quantitative digital autoradiography. Awake male rats were given intravenous injections of a mixture of 50 μCi IAP and 15 mCi of HM-PAO and killed 20 s after tracer activity had first reached the brain. Two separate autoradiograms were produced from each 20 μm brain section. The autoradiograms were digitized, corrected for cross-contamination, and then converted into images of individual tracer concentration. The diffusible tracer model was used to convert the IAP concentration images into LCBF images. Regional HM-PAO concentration was found not to be linearly related to LCBF as determined with the IAP, and therefore a simple microsphere type model was inadequate in relating HM-PAO uptake to LCBF. A better HM-PAO uptake–LCBF correlation was obtained when the HM-PAO arterial input function was corrected for very rapidly produced, non-cerebrally extracted, metabolites and a kinetic model was used that considered the rate of intracerebral metabolism of HM-PAO to a retained metabolite. Even using this model, however, some differences between HM-PAO uptake and LCBF occurred in certain brain regions. Because these differences were small and the HM-PAO uptake pattern has been shown to be constant for many minutes, HM-PAO can probably be used to estimate LCBF in patients with single positron emission computed tomography (SPECT) imaging.

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