***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Temporolimbic circuits play a crucial role in the regulation of human emotion . A highly sensitive single-shot multiecho functional magnetic resonance imaging ( fMRI ) technique with gradient compensation of local magnetic field inhomogeneities and real-time data analysis were used to measure increases in amygdala activation during single 60-s trials of self-induced sadness . Six healthy male and female subjects performed a vali date d mood induction paradigm with r and omized presentation of sad or neutral faces in 10 trials per scan . Subjects reported the intensity of experienced sadness after each trial . Immediate feedback of amygdala activation was given to the subjects during the ongoing scan to reinforce mood induction . Correspondence between increased intensity of predominantly left sided amygdala activation and self-rating of sadness was found in 78 % of 120 sad trials , in contrast to only 14 % of neutral trials . Amygdala activation was reproducible during repeated scanning sessions and displayed the strongest correlation with self-rating among all regions . These results suggest that amygdala activation may be closely associated with self-induced sadness . This novel real-time fMRI technology is applicable to a wide range of neuroscience studies , particularly those of the limbic system , and to neuropsychiatric conditions , such as depression , in which pathology of the amygdala has been implicated The impact of voxel geometry on the blood oxygenation level-dependent ( BOLD ) signal detectability in the presence of field inhomogeneity is assessed and a quantitative approach to selecting appropriate voxel geometry is developed in this report . Application of the developed technique to BOLD sensitivity improvement of the human amygdala is presented . Field inhomogeneity was measured experimentally at 1.5 T and 3 T and the dominant susceptibility field gradient in the human amygdala was observed approximately along the superior-inferior direction . Based on the field mapping studies , an optimal selection for the slice orientation would be an oblique pseudo-coronal plane with its frequency-encoding direction parallel to the field gradient measured from each subject . Experimentally this was confirmed by comparing the normalized st and ard deviation of time-series echo-planar imaging signals acquired with different slice orientations , in the absence of a functional stimulus . A further confirmation with a carefully design ed functional magnetic resonance imaging study is needed . Although the BOLD sensitivity may generally be improved by a voxel size commensurable with the activation volume , our quantitative analysis shows that the optimal voxel size also depends on the susceptibility field gradient and is usually smaller than the activation volume . The predicted phenomenon is confirmed with a hybrid simulation , in which the functional activation was mathematically added to the experimentally acquired rest-period echo-planar imaging data The amygdala is known to play an important role in conscious and unconscious processing of emotional and highly arousing stimuli . Neuroanatomical evidence suggests that the amygdala participates in the control of autonomic responses , such as skin conductance responses ( SCRs ) , elicited by emotionally salient stimuli , but little is known regarding its functional role in such control . We investigated this issue by showing emotional visual stimuli of varying arousal to patients with left ( n = 12 ) , right ( n = 8) , and bilateral ( n = 3 ) amygdala damage and compared their results with those from 38 normal controls .  Stimuli were presented both subliminally ( using backward masking ) and supraliminally under lateralized presentation to one visual hemifield . We collected SCRs as a physiological index of emotional responses . Subjects subsequently rated each stimulus on valence and arousal under free viewing conditions . There were two key findings : ( 1 ) impaired overall SCR after right amygdala damage ; and ( 2 ) impaired correlation of SCR with the rated arousal of the stimuli after left amygdala damage . The second finding was strengthened further by finding a positive correlation between the evoked SCR magnitude and postsurgery amygdala volume , indicating impaired autonomic responses with larger tissue damage . Bilateral amygdala damage result ed in severe impairments on both of the above measures . Our results provide support for the hypothesis that the left and right amygdalae subserve different functions in emotion processing : the left may decode the arousal signaled by the specific stimulus , whereas the right may provide a global level of autonomic activation triggered automatically by any arousing stimulus We compared the sensitivity of st and ard single-shot 2D echo planar imaging ( EPI ) to three advanced EPI sequences , i.e. , 2D multi-echo EPI , 3D high resolution EPI and 3D dual-echo fast EPI in fixed effect and r and om effects group level fMRI analyses at 3 T. The study focused on how well the variance reduction in fixed effect analyses achieved by advanced EPI sequences translates into increased sensitivity in the r and om effects group level analysis . The sensitivity was estimated in a functional MRI experiment of an emotional learning and a reward based learning tasks in a group of 24 volunteers . Each experiment was acquired with the four different sequences . The task-related response amplitude , contrast level and respective t-value were proxies for the functional sensitivity across the brain . All three advanced EPI methods increased the sensitivity in the fixed effects analyses , but st and ard single-shot 2D EPI provided a comparable performance in r and om effects group analysis when whole brain coverage and moderate resolution are required . In this experiment inter-subject variability determined the sensitivity of the r and om effects analysis for most brain regions , making the impact of EPI pulse sequence improvements less relevant or even negligible for r and om effects analyses . An exception concerns the optimization of EPI reducing susceptibility-related signal loss that translates into an enhanced sensitivity e.g. in the orbitofrontal cortex for multi-echo EPI . Thus , future optimization strategies may best aim at reducing inter-subject variability for higher sensitivity in st and ard fMRI group studies at moderate spatial resolution OBJECTIVE Patients with depression show blunted amygdala hemodynamic activity to positive stimuli , including autobiographical memories . The authors examined the therapeutic efficacy of real-time functional MRI neurofeedback ( rtfMRI-nf ) training aim ed at increasing the amygdala 's hemodynamic response to positive memories in patients with depression . METHOD In a double-blind , placebo-controlled , r and omized clinical trial , unmedicated adults with depression ( N=36 ) were r and omly assigned to receive two sessions of rtfMRI-nf either from the amygdala ( N=19 ) or from a parietal control region not involved in emotional processing ( N=17 ) . Clinical scores and autobiographical memory performance were assessed at baseline and 1 week after the final rtfMRI-nf session . The primary outcome measure was change in score on the Montgomery-Åsberg Depression Rating Scale ( MADRS ) , and the main analytic approach consisted of a linear mixed-model analysis . RESULTS In participants in the experimental group , the hemodynamic response in the amygdala increased relative to their own baseline and to the control group . Twelve participants in the amygdala rtfMRI-nf group , compared with only two in the control group , had a > 50 % decrease in MADRS score . Six participants in the experimental group , compared with one in the control group , met conventional criteria for remission at study end , result ing in a number needed to treat of 4 . In participants receiving amygdala rtfMRI-nf , the percent of positive specific memories recalled increased relative to baseline and to the control group . CONCLUSIONS rtfMRI-nf training to increase the amygdala hemodynamic response to positive memories significantly decreased depressive symptoms and increased the percent of specific memories recalled on an autobiographical memory test . These data support a role of the amygdala in recovery from depression The optimum parameters for single-shot gradient-recalled ( GR ) EPI-based fMRI studies of the limbic region are systematic ally established at 3 T via their ability to mitigate intravoxel dephasing-measured via SNR and T2 * in the amygdalae- and their implication s for temporal resolution ( or brain coverage ) . Conventional imaging parameters ( 64 x 64 matrix size and 4 - 6 mm thick slices ) are confirmed to be inadequate for functional studies at 3 T. Measurements of main magnetic field variations across the amygdalae suggest that such variations are equal in the craniocaudal and anterior-posterior directions , and slightly lower in the mediolateral direction , with this and other considerations leading us to conclude an oblique axial orientation to be most suitable . In-plane resolution of approximately 1.7 mm was sufficient to recover signal in the area of the amygdalae . SNR was found to peak at a slice thickness of between 2.0 and 2.5 mm , dependent on the subject . T2 * time in the amygdalae was measured with a st and ard EPI protocol to be 22 + /- 3 ms . Using the optimized ( high resolution ) EPI protocol proposed here , the measured T2 * time increased to 48 + /- 2 ms ( compared with 43 + /- 3 ms for a reference FLASH scan ) , only slightly lower than the cortex ( 49 + /- 2 ms measured with optimized EPI and 52 + /- 2 ms with FLASH ) . The FLASH measurement of 43 ms is taken to be a suitable effective echo time ( TE(eff ) ) to achieve maximum BOLD sensitivity in the amygdalae . Time series data acquired with these parameters showed a 60 % increase in SNR in the amygdala over that obtained with a st and ard low-resolution protocol and suggest sufficient SNR and BOLD sensitivity to make functional studies feasible . Arteries , but no substantial draining veins , were found in high-resolution BOLD venograms of the region . Our results indicate that EPI protocol s need to be carefully optimized for structures of interest if reliable results from single subjects are to be established in this brain region Self-regulation of brain activity in humans based on real-time feedback of functional magnetic resonance imaging ( fMRI ) signal is emerging as a potentially powerful , new technique . Here , we assessed whether patients with Parkinson 's disease ( PD ) are able to alter local brain activity to improve motor function .  Five patients learned to increase activity in the supplementary motor complex over two fMRI sessions using motor imagery . They attained as much activation in this target brain region as during a localizer procedure with overt movements . Concomitantly , they showed an improvement in motor speed ( finger tapping ) and clinical ratings of motor symptoms ( 37 % improvement of the motor scale of the Unified Parkinson 's Disease Rating Scale ) . Activation during neurofeedback was also observed in other cortical motor areas and the basal ganglia , including the subthalamic nucleus and globus pallidus , which are connected to the supplementary motor area ( SMA ) and crucial nodes in the pathophysiology of PD . A PD control group of five patients , matched for clinical severity and medication , underwent the same procedure but did not receive feedback about their SMA activity . This group attained no control of SMA activation and showed no motor improvement . These findings demonstrate that self-modulation of cortico-subcortical motor circuits can be achieved by PD patients through neurofeedback and may result in clinical benefits that are not attainable by motor imagery alone 
    Output:
    
We identified critical features influencing inference on the quality of the intervention as : the inclusion of a Practice Run , a Transfer Run and a Control Group in the protocol , and to choose adequate Emotion Regulation strategies-in particular , the effective recall of autobiographic memories .
Surprisingly , the Regulated vs. Control Condition was lacking in most of the studies , precluding valid inference of amygdala neuromodulation within Session .
The best controlled studies nevertheless showed positive effects .
The type of stimulus/interface did not seem critical for amygdala modulation .
We also identified potential effects of lateralization of amygdala responses following Up- or Down-Regulation , and the impact of fMRI parameters for data acquisition and analysis .