جستجوی مقالات مرتبط با کلیدواژه "functional mri" در نشریات گروه "پزشکی"

Non-specific chronic low back pain (CLBP) is a common painful condition and is responsible for different physical disorders. Despite alternative therapies, patients still suffer from persistent pain. Repetitive transcranial magnetic stimulation (rTMS) has provided much evidence of pain reduction, but results have not been examined deeply in CLBP symptoms.

The analgesic effect of rTMS in non-specific CLBP patients was evaluated by the amplitude of low-frequency fluctuation (ALFF) analysis in resting-state fMRI.

In this experimental study, fifteen non-specific CLBP participants (46.87±10.89 years) received 20 Hz rTMS over the motor cortex. The pain intensity and brain functional scan were obtained during pre and post-stimulation for all participants. The ALFF maps of the brain in two scan sessions were identified and the percentage of pain reduction (PPR%) was determined using paired t-test. Also, correlation analysis was used to find a relationship between ALFFs and pain intensity.

Pain intensity was significantly reduced after induced-rTMS in non-specific CLBP (36.22%±13.28, P<0.05). Positive correlation was found between ALFF in the insula (INS) and pain intensity (rpre-rTMS=0.59, rpost-rTMS=0.58) while ALFF in medial prefrontal cortex (mPFC) and pain intensity had negatively correlated (rpre-rTMS=-0.54, rpost-rTMS=-0.56) (P<0.05). ALFF increased in mPFC while INS, thalamus (THA), and supplementary motor area (SMA) showed decremental ALFF followed by rTMS. 

This study demonstrated that ALFF in INS, THA, mPFC, and SMA is associated with CLBP symptoms and analgesic effects of rTMS. ALFF potentially seems to be a proper objective neuroimaging parameter to link spontaneous brain activity with pain intensity in non-specific CLBP patients.

This study aimed to assess the effect of controlled mouth breathing during the resting state using functional magnetic resonance imaging (fMRI).

Eleven subjects participated in this experiment in which the controlled “Nose” and “Mouth” breathings of 6 s respiratory cycle were performed with a visual cue at 3T MRI. Voxel-wise seed-to-voxel maps and whole-brain region of interest (ROI)-to-ROI connectome maps were analyzed in both “Nose>Mouth” and “Mouth>Nose” contrasts.

As a result, there were more connection pairs in the “Mouth” breathing condition, i.e., 14 seeds and 14 connecting pairs in the “Mouth>Nose” contrast, compared to 7 seeds and 4 connecting pairs in the “Nose>Mouth” contrast (false discovery rate [FDR] of P<0.05).

The present study demonstrated that mouth breathing with controlled respiratory cycles could significantly induce alterations in functional connectivity in the resting-state network, suggesting that it can differently affect resting brain function; in particular, the brain can hardly rest during mouth breathing, as opposed to conventional nasal breathing.

Cognitive control of brain regions can be determined by the tasks involving the cognitive control such as the color word Stroop task. Stroop task define the reduction in function in incongruent condition, which requires more attention and control of competitive responses.

The purpose of this study was to evaluate the activity of brain using the Modified Conflict Stroop Task in Military Personnel.

In this applied experimental study, to specify the activity of different regions of brain in response to conflict Persian color-word Stroop task, 20 healthy persons participated in this study. To evaluate selective attention, the traditional color-word Stroop Task Model was modified, and the Stroop test was designed in high- and low-threat zones. We used functional magnetic resonance imaging (fMRI) to evaluate the brain activation during the Stroop task performance. The color-word Stroop task consists of incongruent, congruent, and neutral conditions, and the subjects were requested to carefully choose the correct answer.

The mean response time was longer in incongruent condition (867.6±193.5ms) compared to congruent and neutral conditions. Analysis of neuroimaging data revealed that the brain conflict-related regions are activated by the Stroop interference. In incongruent trial, the superior frontal gyrus (SFG) and inferior frontal gyrus (IFG) showed the most active and stronger BOLD responses. In congruent trials, the activation in the brain was less and had difference compared with incongruent trials.

Our result offers that the frontal cortex and the anterior cingulate cortex are sensitive to different trials of Persian Stroop task. Using modified Stroop task, we determined the brain responses to the selective attention test.