Functional Imaging Research Papers - Academia.edu (original) (raw)

Functional imaging in humans and anatomical data in monkeys have implicated the insula as a multimodal sensory integrative brain region. The topography of insular connections is organized by its cytoarchitectonic regions. Previous... more

Functional imaging in humans and anatomical data in monkeys have implicated the insula as a multimodal sensory integrative brain region. The topography of insular connections is organized by its cytoarchitectonic regions. Previous attempts to measure the insula have utilized either indirect or automated methods. This study was designed to develop a reliable method for obtaining volumetric magnetic resonance imaging (MRI) measurements of the human insular cortex, and to validate that method by examining the anatomy of insular cortex in adults with Williams syndrome (WS) and healthy age-matched controls. Statistical reliability was obtained among three raters for this method, supporting its reproducibility not only across raters, but within different software packages. The procedure described here utilizes native-space morphometry as well as a method for dividing the insula into connectivity-based sub-regions estimated from cytoarchitectonics. Reliability was calculated in both ANALYZE (n=3) and BrainImageJava (N=10) where brain scans were measured once in each hemisphere by each rater. This highly reliable method revealed total, anterior, and posterior insular volume reduction bilaterally (all p’s < .002) in WS, after accounting for reduced total brain volumes in these participants. Although speculative, the reduced insular volumes in WS may represent a neural risk for the development of hyperaffiliative social behavior with increased specific phobias, and implicate the insula as a critical limbic integrative region. Native-space quantification of the insula may be valuable in the study of neurodevelopmental or neuropsychiatric disorders related to anxiety and social behavior.

The superior capability of cognitive experts largely depends on quick automatic processes. To reveal their neural bases, we used functional magnetic resonance imaging to study brain activity of professional and amateur players in a board... more

The superior capability of cognitive experts largely depends on quick automatic processes. To reveal their neural bases, we used functional magnetic resonance imaging to study brain activity of professional and amateur players in a board game named shogi. We found two activations specific to professionals: one in the precuneus of the parietal lobe during perception of board patterns, and the other in the caudate nucleus of the basal ganglia during quick generation of the best next move. Activities at these two sites covaried in relevant tasks. These results suggest that the precuneus-caudate circuit implements the automatic, yet complicated, processes of board-pattern perception and next-move generation in board game experts.

Background Real world cardiology is faced with a low diagnostic yield of coronary angiography (CXA) in patients presenting with ACC/AHA class II CXA indication. Our aim was to analyze the clinical implication of a Cardiac MR (CMR)... more

Background Real world cardiology is faced with a low diagnostic yield of coronary angiography (CXA) in patients presenting with ACC/AHA class II CXA indication. Our aim was to analyze the clinical implication of a Cardiac MR (CMR) protocol including adenosine stress perfusion in this patient population. We examined whether CMR could enhance appropriate CXA indication and thus reduce the rate of pure diagnostic CXA. In addition, we compared the relative impact of CMR exam components (perfusion, function and viability assessment) in achieving this target. Methods 176 patients were referred for CXA with class II indication. 171 underwent complete additional CMR exam in a 1.5-T whole body CMR-scanner for myocardial function, ischemia and viability prior to CXA. The routine protocol for assessment of CAD consisted of functional imaging (long and short axes), adenosine stress- and rest-perfusion in short axis orientation and “late enhancement” imaging in long and short axes. Images were analyzed by two independent and blinded investigators. Interobserver differences were resolved by a third reader. Results There was a high association between CMR results and subsequent invasive findings (chi square for CMR perfusion deficit and stenosis >70% in CXA: 113.7, p70%. Four (2.3%) patients had false negative CMR findings. In 58 patients (33.9%) no relevant coronary artery stenosis could be observed, correctly predicted by CMR in 48 cases; in 10 (5.8%) patients CMR provided false positive results. Sensitivity of CMR to detect relevant CAD (>70% luminal narrowing) was 0.96, specificity 0.83, positive predictive value 0.92 and negative predictive value 0.92. Of the CMR components, perfusion deficit was the strongest independent predictor (odds ratio 132.3, p Conclusion In a great number of patients being referred to cath lab with ACC/AHA class II indication for CXA, CMR provides a high accuracy for decision making regarding appropriateness of the invasive exam. CMR prior to CXA could substantially reduce pure diagnostic coronary angiographies in patients with intermediate probability for CAD, in our patient-cohort from approximately 34% to 6%. Further studies are warranted to identify rare false negative CMR results.

Summary: Rasmussen encephalitis is a chronic, progres- sive inflammation of the brain of unknown origin. Early diagnosis and treatment with immunoactive agents and/or hemispherectomy are sought to prevent the progressive cognitive decline... more

Summary: Rasmussen encephalitis is a chronic, progres- sive inflammation of the brain of unknown origin. Early diagnosis and treatment with immunoactive agents and/or hemispherectomy are sought to prevent the progressive cognitive decline that accompanies this disease. Combined anatomic and functional neuroimaging may serve to focus the diagnostic workup and to hasten brain biopsy for de- finitive diagnosis. Two biopsy proved

We review behavioral- and neuroeconomic research that identifies temporal discounting as an important component in the development and maintenance of drug addiction. First we review behavioral economic research that explains and documents... more

We review behavioral- and neuroeconomic research that identifies temporal discounting as an important component in the development and maintenance of drug addiction. First we review behavioral economic research that explains and documents the contribution of temporal discounting to addiction. This is followed with recent insights from neuroeconomics that may provide an explanation of why drug dependent individuals discount the future. Specifically, neuroeconomics has identified two competing neural systems that are related to temporal discounting using brain-imaging techniques that examine the relative activation of different brain regions for temporal discounting. According to the competing neural systems account, choices for delayed outcomes are related to the prefrontal cortex (i.e., the “executive system”) and choices for immediate outcomes are related to the limbic brain regions (i.e., the “impulsive system”). Temporal discounting provides a useful framework for future imaging research, and suggests a novel approach to designing effective drug dependence prevention and treatment programs.

As individuals who abuse methamphetamine (MA) often exhibit socially maladaptive behaviors such as violence and aggression, it is possible that they respond abnormally to social cues. To investigate this issue, we exposed 12 MA-dependent... more

As individuals who abuse methamphetamine (MA) often exhibit socially maladaptive behaviors such as violence and aggression, it is possible that they respond abnormally to social cues. To investigate this issue, we exposed 12 MA-dependent participants (abstinent 5-16 days) and 12 healthy comparison participants to fearful and angry faces while they performed an affect matching task during functional magnetic resonance imaging (fMRI). Although the groups did not differ in task performance, the healthy participants showed more task-related activity than the MA-dependent participants in a set of cortical regions consisting of the ventrolateral prefrontal cortex (VLPFC), temporoparietal junction (TPJ), anterior and posterior temporal cortex, and fusiform gyrus in the right hemisphere, and the cuneus in the left hemisphere. In contrast, the MA-dependent participants showed more task-related activity than the healthy participants in the dorsal anterior cingulate cortex (dACC). As expected, the task elicited activation of the amygdala in both groups; however, contrary to expectation, we found no difference between groups in this activation. Dorsal ACC hyperactivity, along with high self-ratings of hostility and interpersonal sensitivity in the MA-dependent group, suggest a hyper-sensitivity to socially threatening cues in the MA-dependent participants, while lower VLPFC activation could point to a deficit in integrating socio-emotional information and/or regulating this limbic hyperactivity. Additional activation differences in neural circuitry related to social cognition (TPJ, anterior, and posterior temporal cortex) suggest further socio-emotional deficits. Together, the results point to cortical abnormalities that could underlie the socially inappropriate behaviors often shown by individuals who abuse MA.

Dissociations in the recognition of specific classes of words have been documented in brain-injured populations. These include deficits in the recognition and production of morphologically complex words as well as impairments specific to... more

Dissociations in the recognition of specific classes of words have been documented in brain-injured populations. These include deficits in the recognition and production of morphologically complex words as well as impairments specific to particular syntactic classes such as verbs. However, functional imaging evidence for distinctions among the neural systems underlying these dissociations has been inconclusive. We explored the neural systems involved in processing different word classes in a functional Magnetic Resonance Imaging study, contrasting four groups of words co-varying morphological complexity (simple, monomorphemic words vs complex derived or inflected words) and syntactic class (verbs vs nouns/adjectives). Subtraction of word from letter string processing showed activation in left frontal and temporal lobe regions consistent with prior studies of visual word processing. No differences were observed for morphologically complex and simple words, despite adequate power to detect stimulus specific effects. A region of posterior left middle temporal gyrus showed significantly increased activation for verbs. Post hoc analyses showed that this elevated activation could also be related to semantic properties of the stimulus items (verbs have stronger action associations than nouns, and action association is correlated with activation). Results suggest that semantic as well as syntactic factors should be considered when assessing the neural systems involved in single word comprehension.

Although religious belief is often claimed to help with physical ailments including pain, it is unclear what psychological and neural mechanisms underlie the influence of religious belief on pain. By analogy to other top-down processes of... more

Although religious belief is often claimed to help with physical ailments including pain, it is unclear what psychological and neural mechanisms underlie the influence of religious belief on pain. By analogy to other top-down processes of pain modulation we hypothesized that religious belief helps believers reinterpret the emotional significance of pain, leading to emotional detachment from it. Recent findings on emotion regulation support a role for the right ventrolateral prefrontal cortex (VLPFC), a region also important for driving top-down pain inhibitory circuits. Using functional magnetic resonance imaging in practicing Catholics and avowed atheists and agnostics during painful stimulation, here we show the existence of a context-dependent form of analgesia that was triggered by the presentation of an image with a religious content but not by the presentation of a non-religious image. As confirmed by behavioral data, contemplation of the religious image enabled the religious ...

Functional imaging techniques in nuclear medicine provide crucial diagnostic information in a variety of clinical settings that are encountered regularly in orthopaedic practice. It is important that the orthopaedic surgeon is aware of... more

Functional imaging techniques in nuclear medicine provide crucial diagnostic information in a variety of clinical settings that are encountered regularly in orthopaedic practice. It is important that the orthopaedic surgeon is aware of the modalities on offer and appreciates the relative strengths and limitations of these techniques. This article will describe the physical principles underlying nuclear medicine imaging with single-photon

Vivid visual images can be voluntarily generated in our minds in the absence of simultaneous visual input. While trying to count the number of flowers in Van Gogh's Sunflowers, understanding a description or recalling a path, subjects... more

Vivid visual images can be voluntarily generated in our minds in the absence of simultaneous visual input. While trying to count the number of flowers in Van Gogh's Sunflowers, understanding a description or recalling a path, subjects report forming an image in their "mind's eye". Whether this process is accomplished by the same neuronal mechanisms as visual perception has long been a matter of debate. Evidence from functional imaging, psychophysics, neurological studies and monkey electrophysiology suggests a common process, yet there are patients with deficits in one but not the other. Here we directly investigated the neuronal substrates of visual recall by recording from single neurons in the human medial temporal lobe while the subjects were asked to imagine previously viewed images. We found single neurons in the hippocampus, amygdala, entorhinal cortex and parahippocampal gyrus that selectively altered their firing rates depending on the stimulus the subject...

Perspective-taking is a stepping stone to human empathy. When empathizing with another individual, one can imagine how the other perceives the situation and feels as a result. To what extent does imagining the other differs from imagining... more

Perspective-taking is a stepping stone to human empathy. When empathizing with another individual, one can imagine how the other perceives the situation and feels as a result. To what extent does imagining the other differs from imagining oneself in similar painful situations? In this functional magnetic resonance imaging experiment, participants were shown pictures of people with their hands or feet in painful or non-painful situations and instructed to imagine and rate the level of pain perceived from different perspectives. ...

Functional imaging has become a primary tool in the study of human psychology, but is not without its detractors. Although cognitive neuroscientists have made great strides in understanding the neural instantiation of countless cognitive... more

Functional imaging has become a primary tool in the study of human psychology, but is not without its detractors. Although cognitive neuroscientists have made great strides in understanding the neural instantiation of countless cognitive processes, commentators have sometimes argued that functional imaging provides little or no utility for psychologists. And indeed, myriad studies over the last quarter century have employed the technique of brain mapping—identifying the neural correlates of various psychological phenomena—in ways that bear minimally on psychological theory. How can brain mapping be made more relevant to behavioral scientists broadly? Here, we describe three trends that increase precisely this relevance: (i) the use of neuroimaging data to adjudicate between competing psychological theories through forward inference (ii) isolating neural markers of information processing steps to better understand complex tasks and psychological phenomena through probabilistic reverse inference, and (iii) using brain activity to predict subsequent behavior. Critically, these new approaches build on the extensive tradition of brain mapping, suggesting that efforts in this area—although not initially maximally relevant to psychology—can indeed be used in ways that constrain and advance psychological theory.