Decreased functional connectivity between the amygdala and the left ventral prefrontal cortex in treatment-naive patients with major depressive disorder: a resting-state functional magnetic resonance imaging study

BACKGROUND

Convergent studies provide support for abnormalities in the structure and functioning of the prefrontal cortex (PFC) and the amygdala, the key components of the neural system that subserves emotional processing in major depressive disorder (MDD). We used resting-state functional magnetic resonance imaging (fMRI) to examine potential amygdala-PFC functional connectivity abnormalities in treatment-naive subjects with MDD.

METHODS

Resting-state fMRI data were acquired from 28 individuals with MDD and 30 healthy control (HC) subjects. Amygdala-PFC functional connectivity was compared between the MDD and HC groups.

RESULTS

Decreased functional connectivity to the left ventral PFC (VPFC) from the left and right amygdala was observed in the MDD group, compared with the HC group (p < 0.05, corrected).

CONCLUSIONS

The treatment-naive subjects with MDD showed decreased functional connectivity from the amygdala to the VPFC, especially to the left VPFC. This suggests that these connections may play an important role in the neuropathophysiology of MDD at its onset.

Abnormal prefrontal activity subserving attentional control of emotion in remitted depressed patients during a working memory task with emotional distracters

BACKGROUND

Patients with major depressive disorder (MDD) show deficits in processing of facial emotions that persist beyond recovery and cessation of treatment. Abnormalities in neural areas supporting attentional control and emotion processing in remitted depressed (rMDD) patients suggests that there may be enduring, trait-like abnormalities in key neural circuits at the interface of cognition and emotion, but this issue has not been studied systematically.

METHOD

Nineteen euthymic, medication-free rMDD patients (mean age 33.6 years; mean duration of illness 34 months) and 20 age- and gender-matched healthy controls (HC; mean age 35.8 years) performed the Emotional Face N-Back (EFNBACK) task, a working memory task with emotional distracter stimuli. We used blood oxygen level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to measure neural activity in the dorsolateral (DLPFC) and ventrolateral prefrontal cortex (VLPFC), orbitofrontal cortex (OFC), ventral striatum and amygdala, using a region of interest (ROI) approach in SPM2.

RESULTS

rMDD patients exhibited significantly greater activity relative to HC in the left DLPFC [Brodmann area (BA) 9/46] in response to negative emotional distracters during high working memory load. By contrast, rMDD patients exhibited significantly lower activity in the right DLPFC and left VLPFC compared to HC in response to positive emotional distracters during high working memory load. These effects occurred during accurate task performance.

CONCLUSIONS

Remitted depressed patients may continue to exhibit attentional biases toward negative emotional information, reflected by greater recruitment of prefrontal regions implicated in attentional control in the context of negative emotional information.

Improving the Reliability of Shape Comparison by Perturbation

Shape comparison is a key scenario in morphometric study, where registration is often involved and found to be unreliable: different registrations can lead to different shape differences. This paper proposes a generic scheme applicable to most registration methods, to reduce this unreliability. It perturbs the registration processes by feeding them with resampled shape groups, and then aggregates the results to yield the final result. This scheme can be simplified for pair-wise registration methods to reduce the computation. Experiments are conducted on both synthetic and biomedical shapes using different registration methods, which demonstrate its effectiveness.

Increased anterior cingulate and caudate activity in bipolar mania

BACKGROUND

Executive control of cognition, emotion, and behavior are disrupted in the manic state of bipolar disorder. Whereas frontal systems are implicated in such dysfunction, the localization of functional brain abnormalities in the manic state is not well understood.

METHODS

We utilized a high-sensitivity H(2)(15)0 positron emission tomography technique to investigate regions of increased brain activity in mania, compared to euthymia, in bipolar disorder.

RESULTS

The principal findings were manic state-related increased activity in left dorsal anterior cingulate, and left head of caudate.

CONCLUSIONS

The findings suggest that the manic state of bipolar disorder may be associated with heightened activity in a frontal cortical-subcortical neural system that includes the anterior cingulate and caudate.

Rostral and orbital prefrontal cortex dysfunction in the manic state of bipolar disorder

OBJECTIVE

This study investigated prefrontal cortex function in the manic state of bipolar disorder.

METHOD

High-sensitivity [15O]H2O positron emission tomography and a word generation activation paradigm were used to study regional cerebral blood flow in five manic and six euthymic individuals with bipolar disorder and in five healthy individuals.

RESULTS

Decreased right rostral and orbital prefrontal cortex activation during word generation and decreased orbitofrontal activity during rest were associated with mania.

CONCLUSIONS

The data support the presence of rostral and orbital prefrontal dysfunction in primary mania. These findings, when seen in the context of the human brain lesion and the behavioral neuroanatomic literatures, may help to explain some of the neurobehavioral abnormalities characteristic of the manic state.

Psychiatric complications in a patient with complex partial seizures

This case highlights the complexities of evaluating and treating psychiatric symptoms that are concurrent with a seizure disorder. Interictal and postictal psychoses, affective disorders, personality changes, and cognitive deficits are common problems that require modified psychiatric treatments.