Retrosplenial cortex connectivity in schizophrenia.

In this paper, we build on our previous analysis [Bluhm, R.L., Miller, J.

Alterations in default network connectivity in posttraumatic stress disorder related to early-life trauma.

Background: The "default network" consists of a number of brain regions that exhibit correlated low-frequency activity at rest and that have been suggested to be involved in the processing of self-relevant stimuli. Activity in many of these areas has also been shown to be altered in individuals with posttraumatic stress disorder (PTSD). We hypothesized that the posterior cingulate cortex (PCC)/precuneus, part of the default network, would exhibit altered connectivity at rest with other areas of the default network and regions associated with PTSD.

Default mode network connectivity: effects of age, sex, and analytic approach.

The 'default mode network' is a set of brain regions showing correlated, low-frequency activity during rest. It includes the posterior cingulate/precuneus, medial prefrontal cortex, and bilateral inferior parietal cortex. Earlier studies have characterized this network using either region of interest-based correlation analyses or data-driven techniques; however, there is some disagreement over which method is superior.

Spontaneous low-frequency fluctuations in the BOLD signal in schizophrenic patients: anomalies in the default network.

Spontaneous low-frequency fluctuations in the blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (MRI) signal have been shown to reflect neural synchrony between brain regions. A "default network" of spontaneous low-frequency fluctuations has been described in healthy volunteers during stimulus-independent thought. Negatively correlated with this network are regions activated during attention-demanding tasks.

A 4.0-T fMRI study of brain connectivity during word fluency in first-episode schizophrenia.

Objective: To use functional magnetic resonance imaging (fMRI) to investigate functional connectivity, and hence, underlying neural networks, in never-treated, first-episode patients with schizophrenia using a word fluency paradigm known to activate prefrontal, anterior cingulate, and thalamic regions. Abnormal connectivity between the prefrontal cortex (PFC) and other brain regions has been demonstrated in chronic, medicated patients in previous positron emission tomography (PET) studies, but has not to our knowledge, previously been demonstrated using both first-episode, drug-naïve patients and fMRI technology.

Methods: A 4.

Functional connectivity of dissociative responses in posttraumatic stress disorder: a functional magnetic resonance imaging investigation.

Background: The purpose of this study was to assess interregional brain activity covariations during traumatic script-driven imagery in subjects with posttraumatic stress disorder (PTSD).

Methods: Functional magnetic resonance imaging and functional connectivity analyses were used to assess interregional brain activity covariations during script-driven imagery in PTSD subjects with a dissociative response, PTSD subjects with a flashback response, and healthy control subjects.

Results: Significant between-group differences in functional connectivity were found.

The nature of traumatic memories: a 4-T FMRI functional connectivity analysis.

Objective: This study used functional connectivity analyses to assess interregional brain activity correlations during the recall of traumatic memories in traumatized subjects with and without posttraumatic stress disorder (PTSD).

Method: Both 4-T functional magnetic resonance imaging (fMRI) and functional connectivity analyses were used to assess interregional brain activity correlations during script-driven symptom provocation in traumatized subjects with (N=11) and without (N=13) PTSD. Functional connectivity analyses were carried out by using data for brain regions activated in both the PTSD group and the comparison group.

Recall of emotional states in posttraumatic stress disorder: an fMRI investigation.

Background: The goal of this study was to examine the neuronal circuitry underlying different emotional states (neutral, sad, anxious, and traumatic) in posttraumatic stress disorder (PTSD) in traumatized subjects versus traumatized subjects without PTSD.

Methods: Traumatized subjects with (n = 10) and without (n = 10) PTSD were studied using the script-driven symptom provocation paradigm adapted to functional magnetic resonance imaging (fMRI) at a 4 Tesla field strength.

Results: Compared to the trauma-exposed comparison group, PTSD subjects showed significantly less activation of the thalamus and the anterior cingulate gyrus (area 32) in all three emotional states (sad, anxious, and traumatic).

Application of stochastic modeling to the assessment of group and individual differences in cognitive functioning.

This article begins with a guiding schema of relations among cognitive science, clinical science, and assessment technology. Emphasis is placed on stochastic modeling of cognitive processes. Basic models are adjusted so as to parsimoniously accommodate performance deviations occurring with psychopathology.

Brain activation during script-driven imagery induced dissociative responses in PTSD: a functional magnetic resonance imaging investigation.

Background: The goal of this study was to examine the neuronal circuitry underlying dissociative responses to traumatic script-driven imagery in sexual-abuse-related posttraumatic stress disorder (PTSD). Pilot studies in our laboratory have shown that PTSD patients had very different responses to traumatic script-driven imagery. Approximately 70% of patients relived their traumatic experience and showed an increase in heart rate while recalling the traumatic memory.