Biomedical subjects

Jadwiga Rogowska

Publications and source records attributed to Jadwiga Rogowska.

12 recordsLinked to original sources

PubMed2006

Recognition of happy facial affect in panic disorder: an fMRI study.

BACKGROUND: This study investigated activation of the anterior cingulate cortex (ACC) and amygdala during the presentation of happy facial affect images in patients with panic disorder (PD) as measured by blood oxygen level dependent (BOLD) functional magnetic resonance imaging (fMRI). METHODS: Eight patients with PD and eight sex-matched controls were recruited for the study. Scanning was performed on a general electric (GE) Signa 1.5T scanner retrofitted with a whole body echo planar coil. Using a quadrature head coil, echo planar images and high-resolution MR images were acquired. RESULTS: After covarying for age, examination of group differences revealed greater ACC activation bilaterally in patients with PD compared to controls in response to happy faces. However, there were no differences in amygdala activation between the groups. These findings contrasted with regional brain activation in response to neutral faces where there were was also greater bilateral ACC activation in the PD group, but only 44 ACC voxels showed significant increases as opposed to 509 voxels for the happy condition. There were no between group differences in activation in the amygdala. CONCLUSION: This is the first fMRI study to our knowledge that demonstrates ACC abnormalities in response to happy facial affect recognition in PD.

Adult↗

PubMed2006

fMRI of fearful facial affect recognition in panic disorder: the cingulate gyrus-amygdala connection.

BACKGROUND: This study investigated cingulate cortex (CC) and amygdala response to fearful facial affect recognition in patients with panic disorder (PD) as measured by BOLD fMRI during the presentation of static facial images. METHODS: Eight patients with PD and eight controls were studied. Scanning was performed on a GE Signa 1.5-T scanner. Echo planar and high-resolution MR images were acquired. RESULTS: Controls produced greater CC activation compared to patients with PD in response to fearful faces. Furthermore, patients with PD produced less amygdala activation than controls in response to fearful faces. During the neutral face condition, overall activation for the CC was significantly greater in PD patients although anterior cingulate cortex (ACC) activation was not as markedly different between both groups. There were no between group differences in amygdala activation on exposure to the neutral face. Only left CC activation was significantly correlated negatively with HAM-A in PD patients in the fearful facial affect condition. LIMITATIONS: Although comparable to similar studies, the sample size is small enough to warrant further investigation. Also, the effects of medication need to be considered when interpreting these results. CONCLUSIONS: Patients with PD activate the ACC and amygdala significantly less than controls when asked to identify fearful facial affect during fMRI. The higher the anxiety, the lower the left CC activation. Thus, chronic hyperarousal in PD may diminish attentional resources and emotional response reflected in reduced ACC and amygdala activation. Even if these are medication effects, the differences from controls are clinically relevant.

Adult↗

PubMed2006

Involvement of matrix metalloproteinase in neuroblast cell migration from the subventricular zone after stroke.

After brain injury, neuroblast cells from the subventricular zone (SVZ) expand and migrate toward damaged tissue. The mechanisms that mediate these neurogenic and migratory responses remain to be fully dissected. Here, we show that bromodeoxyuridine-labeled and doublecortin-positive cells from the SVZ colocalize with the extracellular protease matrix metalloproteinase-9 (MMP-9) during the 2 week recovery period after transient focal cerebral ischemia in mice. Treatment with the broad spectrum MMP inhibitor GM6001 significantly decreases the migration of doublecortin-positive cells that extend from the SVZ into the striatum. These data suggest that MMPs are involved in endogenous mechanisms of neurogenic migration as the brain seeks to heal itself after injury.

Animals↗

PubMed2005

Structural group classification technique based on regional fMRI BOLD responses.

This paper presents a new multigroup classification method based on subtle differences in regional brain activity during the completion of a functional magnetic resonance imaging (fMRI) challenge paradigm. Classification is performed based on features derived from BOLD time intensity curves in selected regions of interest (ROI). For each ROI, a mean time intensity curve [called mean regional response (MRR)] is calculated from realigned and normalized datasets. The overall subject performance is characterized with a vector of features obtained using nonlinear modeling of all subject's MRRs with a mixture of time shifted Gaussian functions. The classification is performed in the reduced-dimension optimal discrimination space, obtained through canonical transformations of original feature space. In order to demonstrate feasibility of the proposed method, classification of three groups of subjects is presented. The three groups are defined as heavy marijuana smokers after 24 hours of abstinence, heavy marijuana smokers after 28 days of abstinence, and healthy nonusing controls. The proposed method can be useful as an analytic tool for the discrimination of different groups of subjects based on temporal features of functional magnetic resonance imaging activation.

Adult↗

PubMed2004

Neurophysiology of motor function following cannabis discontinuation in chronic cannabis smokers: an fMRI study.

The objective of this study was to identify the differences in cerebral activation between chronic cannabis smokers and controls in response to finger sequencing. We hypothesized that attentional areas related to motor function as well as primary and supplementary motor cortices would show diminished activation in chronic cannabis smokers. Nine cannabis smokers and 16 controls were included in these analyses. Scanning was performed on a GE 1.5T scanner. Echo planar images and high-resolution MR images were acquired. The challenge paradigm included left and right finger sequencing. Group differences in cerebral activation were examined for Brodmann areas (BA) 4, 6, 24, and 32 using ROI analyses in SPM. Cannabis users, tested within 4-36 h of discontinuation, exhibited significantly less activation than controls in BA 24 and 32 bilaterally during right- and left-sided sequencing and for BA 6 in all tasks except for left-sided sequencing in the left hemisphere. There were no statistically significant differences for BA 4. None of these regional activations correlated with urinary cannabis concentration and verbal IQ for smokers. These results suggest that recently abstinent chronic cannabis smokers produce reduced activation in motor cortical areas in response to finger sequencing compared to controls.

Adult↗

PubMed2004

Decreased activation of the anterior cingulate in bipolar patients: an fMRI study.

BACKGROUND: Previous neuroimaging investigations of patients with bipolar disorder have reported abnormalities of the frontal subcortical network. The role of the anterior cingulate cortex (ACC) and the dorsolateral prefrontal cortex (DLPFC) in bipolar disorder are not clear, although both regions have been shown to be components of a neural network which plays a critical role in the completion of tasks requiring self-monitoring and inhibition, functions often noted to be altered in bipolar patients. fMRI studies have helped clarify the role of specific subdivisions of the ACC and the DLPFC during the performance of cognitive challenges, including the Stroop color word test. To date, studies that have examined ACC function in bipolar patients have not differentiated subregions within this area, nor have they examined changes in these subregions in relation with DLPFC activation. METHODS: To help clarify the specific roles of these regions in bipolar patients, we examined stable patients and control subjects during performance of the Stroop test using BOLD fMRI techniques. We hypothesized that bipolar patients would demonstrate reduced activation of two subdivisions of the ACC (AAA and VOA), as well as altered activation of the DLPFC, during the interference condition. RESULTS: Results indicate that relative to controls, bipolar patients demonstrated significantly reduced signal intensity within the right AAA subdivision (p=0.011), which accompanied an increase in the DLPFC (p=0.049) during the task. LIMITATIONS: The study sample was somewhat small (11 patients, 10 controls) which limits the generalizability of the study findings, however, the patient sample consisted of well-diagnosed, stable, chronic individuals with bipolar disorder and the sample size provided enough power to detect between-group differences. CONCLUSIONS: These findings suggest differential processing strategies of bipolar patients and support the theory of altered frontal systems in these patients during the performance of cognitive tasks.

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PubMed2004

Spatial working memory in heavy cannabis users: a functional magnetic resonance imaging study.

RATIONALE: Many neuropsychological studies have documented deficits in working memory among recent heavy cannabis users. However, little is known about the effects of cannabis on brain activity. OBJECTIVE: We assessed brain function among recent heavy cannabis users while they performed a working memory task. METHODS: Functional magnetic resonance imaging was used to examine brain activity in 12 long-term heavy cannabis users, 6-36 h after last use, and in 10 control subjects while they performed a spatial working memory task. Regional brain activation was analyzed and compared using statistical parametric mapping techniques. RESULTS: Compared with controls, cannabis users exhibited increased activation of brain regions typically used for spatial working memory tasks (such as prefrontal cortex and anterior cingulate). Users also recruited additional regions not typically used for spatial working memory (such as regions in the basal ganglia). These findings remained essentially unchanged when re-analyzed using subjects' ages as a covariate. Brain activation showed little or no significant correlation with subjects' years of education, verbal IQ, lifetime episodes of cannabis use, or urinary cannabinoid levels at the time of scanning. CONCLUSIONS: Recent cannabis users displayed greater and more widespread brain activation than normal subjects when attempting to perform a spatial working memory task. This observation suggests that recent cannabis users may experience subtle neurophysiological deficits, and that they compensate for these deficits by "working harder"-calling upon additional brain regions to meet the demands of the task.

Adult↗

PubMed2004

Functional magnetic resonance imaging in schizophrenia: cortical response to motor stimulation.

Previous functional magnetic resonance imaging (fMRI) studies suggest that motor system abnormalities are present in schizophrenia. However, these studies have often produced conflicting or ambiguous findings. The purpose of this study was to ascertain whether activation differences could be identified in stable schizophrenic patients on the basis of BOLD measures in two motor regions, the primary motor cortex, Brodmann area 4 (BA4) and the premotor and supplementary motor area, Brodmann area 6 (BA6). Twenty-one schizophrenic patients and 21 healthy control subjects were studied with BOLD fMRI methods during a sequential finger tapping task. Statistical parametric maps were generated for each subject, and anatomic regions were automatically defined using an anatomic atlas. Compared with controls, the schizophrenic patients showed a significant reduction in contralateral activation for both BA4 and BA6 (P<0.001), and in ipsilateral activation in BA4 (P=0.007) and BA6 (P=0.002). In healthy controls, the coactivation in the ipsilateral cortex is reduced in comparison with the contralateral cortex for right and left handed tasks. In BA4, this reduction is significant for right (P=0.007) and left (P=0.003) finger tapping. Similar results were obtained for BA6. Further analyses are necessary to evaluate the activation in other motor system regions.

Adult↗

PubMed2003

Cortical and limbic activation during viewing of high- versus low-calorie foods.

Despite the high prevalence of obesity, eating disorders, and weight-related health problems in modernized cultures, the neural systems regulating human feeding remain poorly understood. Therefore, we applied functional magnetic resonance imaging (fMRI) to study the cerebral responses of 13 healthy normal-weight adult women as they viewed color photographs of food. The motivational salience of the stimuli was manipulated by presenting images from three categories: high-calorie foods, low-calorie foods, and nonedible dining-related utensils. Both food categories were associated with bilateral activation of the amygdala and ventromedial prefrontal cortex. High-calorie foods yielded significant activation within the medial and dorsolateral prefrontal cortex, thalamus, hypothalamus, corpus callosum, and cerebellum. Low-calorie foods yielded smaller regions of focal activation within medial orbitofrontal cortex; primary gustatory/somatosensory cortex; and superior, middle, and medial temporal regions. Findings suggest that the amygdala may be responsive to a general category of biologically relevant stimuli such as food, whereas separate ventromedial prefrontal systems may be activated depending on the perceived reward value or motivational salience of food stimuli.

Adult↗

PubMed2003

Cartilage thickness measurements from optical coherence tomography.

We describe a new semiautomatic image processing method for detecting the cartilage boundaries in optical coherence tomography (OCT). In particular, we focus on rabbit cartilage since this is an important animal model for testing both chondroprotective agents and cartilage repair techniques. The novel boundary-detection system presented here consists of (1) an adaptive filtering technique for image enhancement and speckle reduction, (2) edge detection, and (3) edge linking by graph searching. The procedure requires several steps and can be automated. The quantitative measurements of cartilage thickness on OCT images correlated well with measurements from histology.

Algorithms↗

PubMed2002

Image processing techniques for noise removal, enhancement and segmentation of cartilage OCT images.

Osteoarthritis, whose hallmark is the progressive loss of joint cartilage, is a major cause of morbidity worldwide. Recently, optical coherence tomography (OCT) has demonstrated considerable promise for the assessment of articular cartilage. Among the most important parameters to be assessed is cartilage width. However, detection of the bone cartilage interface is critical for the assessment of cartilage width. At present, the quantitative evaluations of cartilage thickness are being done using manual tracing of cartilage-bone borders. Since data is being obtained near video rate with OCT, automated identification of the bone-cartilage interface is critical. In order to automate the process of boundary detection on OCT images, there is a need for developing new image processing techniques. In this paper we describe the image processing techniques for speckle removal, image enhancement and segmentation of cartilage OCT images. In particular, this paper focuses on rabbit cartilage since this is an important animal model for testing both chondroprotective agents and cartilage repair techniques. In this study, a variety of techniques were examined. Ultimately, by combining an adaptive filtering technique with edge detection (vertical gradient, Sobel edge detection), cartilage edges can be detected. The procedure requires several steps and can be automated. Once the cartilage edges are outlined, the cartilage thickness can be measured.

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PubMed2002

Stroop performance in normal control subjects: an fMRI study.

In an attempt to clarify regional signal intensity changes, which may accompany the performance of the Stroop Color-Word task, healthy subjects were imaged using the fMRI BOLD technique while performing a modified version of the task. Both the AAA and VOA subdivisions of the anterior cingulate cortex were significantly activated during the interference condition; however, only the signal intensity change within the VOA correlated with task performance. Additionally, signal intensity change was significantly increased in the VOA subdivision of the cingulate cortex when controlling for signal intensity change present during the performance of a color naming task. This study extends previous findings by demonstrating that in healthy adults, a subdivision of the cingulate cortex is specifically associated with the cognitive demands present in the interference condition.

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