Movement, mood and cognition: Preliminary insights into the therapeutic effects of electroconvulsive therapy for depression through a resting-state connectivity analysis.

BACKGROUND: Electroconvulsive therapy (ECT) is a highly effective treatment for depression but how it achieves its clinical effects remains unclear. METHODS: We set out to study the brain's response to ECT from a large-scale brain-network perspective. Using a voxelwise analysis, we looked at resting-state functional connectivity before and after a course of ECT at the whole-brain and the between- and within-network levels in 17 patients with a depressive episode. Using a group-independent component analysis approach, we focused on four networks known to be affected in depression: the salience network (SN), the default mode network (DMN), the cognitive executive network (CEN), and a subcortical network (SCN). Our clinical measures included mood, cognition, and psychomotor symptoms. RESULTS: We found ECT to have increased the connectivity of the left CEN with the left angular gyrus and left middle frontal gyrus as well as its within-network connectivity. Both the right CEN and the SCN showed increased connectivity with the precuneus and the anterior DMN with the left amygdala. Finally, improvement of psychomotor retardation was positively correlated with an increase of within-posterior DMN connectivity. LIMITATIONS: The limitations of our study include its small sample size and the lack of a control dataset to confirm our findings. CONCLUSION: Our voxelwise data demonstrate that ECT induces a significant increase of connectivity across the whole brain and at the within-network level. Furthermore, we provide the first evidence on the association between an increase of within-posterior DMN connectivity and an improvement of psychomotor retardation, a core symptom of depression.

Toward Targeted ECT: The Interdependence of Predictors of Treatment Response in Depression Further Explained.

OBJECTIVE: Several clinical variables assumed to be predictive of electroconvulsive therapy (ECT) outcome in major depressive disorder show substantial interrelations. The current study tries to disentangle this interdependence to distill the most important predictors of treatment success to help improve patient-treatment matching. METHODS: We constructed a conceptual framework of interdependence capturing age, episode duration, and treatment resistance, all variables associated with ECT outcome, and the clinical symptoms of what we coin core depression, ie, depression with psychomotor agitation, retardation, psychotic features, or a combination of the three. The model was validated in a sample of 73 patients with a major depressive episode according to DSM-5 treated twice weekly with ECT (August 2015-January 2018) using path analyses, with the size and direction of all direct and indirect paths being estimated using structural equation modeling. Reduction in Montgomery-Asberg Depression Rating Scale (MADRS) scores during treatment was the ECT outcome measure. RESULTS: The baseline presence of psychomotor agitation, retardation, and/or psychotic symptoms strongly correlated with beneficial ECT outcome (z = 0.84 [SE = 0.17]; P < .001), and the association between age and the effect of ECT appears to be mediated by their presence (z = 0.53 [SE = 0.18]; P = .004). There was no direct correlation between age and ECT response (P = .479), but there was for episode duration and ECT outcome (z = -0.38 [SE = 0.08]; P < .001). CONCLUSIONS: ECT is a very effective treatment option for severe depressive disorder, especially for patients suffering from severe depression characterized by the presence of psychomotor agitation, psychomotor retardation, psychotic symptoms, or a combination of these 3 features, with the chance of a beneficial outcome being reduced in patients with a longer episode duration. Age may heretofore have been given too much weight in ECT decision making. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02562846.

Task switching in autism: An EEG study on intentions and actions.

One of the main symptoms of Autism Spectrum Conditions (ASC) is experiencing cognitive inflexibility when adjustments of behaviour are required. While this so-called behavioural rigidity is broadly recognised in ASC, finding evidence for the underlying neurocognitive mechanisms remains challenging. In this electroencephalographic (EEG) study, participants with ASC and matched controls were instructed to choose between two cognitive tasks in each trial, and to respond to the subsequently presented target stimulus according to their task choice. While doing so, we tracked the frontally distributed contingent negative variation (CNV) during the task preparation interval as a measure of intentional control, and the posteriorly measured P3 during the task execution interval to monitor the translation of intentions into actions. The results support the notion of intentional control difficulties in ASC, where the CNV was attenuated in the ASC group compared to the control group. Furthermore, the CNV was differentiated between the tasks and transition types in the control group only, suggesting that the ASC group was less fine-tuning the required amount of intentional control to contextual circumstances. In contrast, the P3 showed no significant differences between the groups. Together, these findings highlight the importance of intentional control mechanisms as a crucial future route for a better understanding of cognitive flexibility and behavioural rigidity in ASC.

Task intentions and their implementation into actions: cognitive control from adolescence to middle adulthood.

Cognitive control processes involved in human multitasking arise, mature, and decline across age. This study investigated how age modulates cognitive control at two different levels: the level of task intentions and the level of the implementation of intentions into the corresponding actions. We were particularly interested in specifying maturation of voluntary task choice (intentions) and task-switching execution (their implementations) between adolescence and middle adulthood. Seventy-four participants were assigned to one of the four age groups (adolescents, 12-17 years; emerging adults, 18-22 years; young adults, 23-27 years; middle-aged adults, 28-56 years). Participants chose between two simple cognitive tasks at the beginning of each trial before pressing a spacebar to indicate that the task choice was made. Next, a stimulus was presented in one of the three adjacent boxes, with participants identifying either the location or the shape of the stimulus, depending on their task choice. This voluntary task-switching paradigm allowed us to investigate the intentional component (task choice) separately from its implementation (task execution). Although all participants showed a tendency to repeat tasks more often than switching between them, this repetition bias was significantly stronger in adolescents than in any adult group. Furthermore, participants generally responded slower after task switches than after task repetitions. This switch cost was similar across tasks in the two younger groups but larger for the shape than the location task in the two older groups. Together, our results demonstrate that both task intentions and their implementation into actions differ across age in quite specific ways.

Understanding Behavioural Rigidity in Autism Spectrum Conditions: The Role of Intentional Control.

Although behavioural rigidity belongs to the core symptoms of autism spectrum conditions, little is known about its underlying cognitive mechanisms. The current study investigated the role of intentional control mechanisms in behavioural rigidity in autism. Autistic individuals and their matched controls were instructed to repeatedly choose between two simple cognitive tasks and to respond accordingly to the subsequently presented stimulus. Results showed that autistic participants chose to repeat tasks more often than their controls and when choosing to switch, they demonstrated larger performance costs. These findings illustrate that when required to make their own choices, autistic people demonstrate rigidity at different performance levels, suggesting that intentional control mechanisms might be important for a better understanding of behavioural rigidity in autism.

Reduced accuracy and sensitivity in the perception of emotional facial expressions in individuals with high autism spectrum traits.

Autism spectrum disorder (ASD) is among other things characterized by specific impairments in emotion processing. It is not clear, however, to what extent the typical decline in affective functioning is related to the specific autistic traits. We employed The Autism Spectrum-Quotient (AQ) to quantify autistic traits in a group of 500 healthy individuals and investigate whether we could detect similar difficulties in the perception of emotional expressions in a broader autistic phenotype. The group with high AQ score was less accurate and needed higher emotional content to recognize emotions of anger, disgust, and sadness. Our findings demonstrate a selective impairment in identification of emotional facial expressions in healthy individuals that is primarily related to the extent of autistic traits.

Cognitive control of intentions for voluntary actions in individuals with a high level of autistic traits.

Impairments in cognitive control generating deviant adaptive cognition have been proposed to account for the strong preference for repetitive behavior in autism. We examined if this preference reflects intentional deficits rather than problems in task execution in the broader autism phenotype using the Autism-Spectrum Quotient (AQ). Participants chose between two tasks differing in their relative strength by indicating first their voluntary task choice and then responding to the subsequently presented stimulus. We observed a stronger repetition bias for the harder task in high AQ participants, with no other differences between the two groups. These findings indicate that the interference between competing tasks significantly contributes to repetitive behavior in autism by modulating the formation of task intentions when choosing tasks voluntarily.

Perceptual wholes can reduce the conscious accessibility of their parts.

Humans can rapidly extract object and category information from an image despite surprising limitations in detecting changes to the individual parts of that image. In this article we provide evidence that the construction of a perceptual whole, or Gestalt, reduces awareness of changes to the parts of this object. This result suggests that the rapid extraction of a perceptual Gestalt, and the inaccessibility of the parts that make up that Gestalt, may in fact reflect two sides of the same coin whereby human vision provides only the most useful level of abstraction to conscious awareness.

Integrating biological motion: the role of grouping in the perception of point-light actions.

The human visual system is highly sensitive to biological motion and manages to organize even a highly reduced point-light stimulus into a vivid percept of human action. The current study investigated to what extent the origin of this saliency of point-light displays is related to its intrinsic Gestalt qualities. In particular, we studied whether biological motion perception is facilitated when the elements can be grouped according to good continuation and similarity as Gestalt principles of perceptual organization. We found that both grouping principles enhanced biological motion perception but their effects differed when stimuli were inverted. These results provide evidence that Gestalt principles of good continuity and similarity also apply to more complex and dynamic meaningful stimuli.

Reduced recognition of fear and sadness in post-traumatic stress disorder.

Post-traumatic stress disorder (PTSD) is associated with impairments in emotional experience and expression. The current study examined the recognition of emotional facial expressions in PTSD patients and matched healthy controls, both in terms of accuracy and sensitivity. The task involved short video clips of a neutral face changing (morphing) into one of the six basic emotions (happiness, anger, fear, surprise, disgust and sadness). Clips differed in length, with short clips terminating at 20% of maximum emotional intensity, and the longest ones ending with a full-blown expression. We observed a specific impairment in the PTSD group for recognizing the emotions fear and sadness. This result was observed via a reduced accuracy and a decreased sensitivity for these emotions. We discuss the observed altered affective processing and its possible clinical implications.

Localization of the plane of regard in space.

When we fixate an object in space, the rotation centers of the eyes, together with the object, define a plane of regard. People perceive the elevation of objects relative to this plane accurately, irrespective of eye or head orientation (Poljac et al. (2004) Vision Res, in press). Yet, to create a correct representation of objects in space, the orientation of the plane of regard in space is required. Subjects pointed along an eccentric vertical line on a touch screen to the location where their plane of regard intersected the touch screen positioned on their right. The distance of the vertical line to the subject's eyes varied from 10 to 40 cm. Subjects were sitting upright and fixating one of the nine randomly presented directions ranging from 20 degrees left and down to 20 degrees right and up relative to their straight ahead. The eccentricity of fixations relative to the pointing location varied by up to 40 degrees . Subjects underestimated the elevation of their plane of regard (on average by 3.69 cm, SD=1.44 cm), regardless of the fixation direction or pointing distance. However, when the targets were shown on a display mounted in a table, to provide support of the subject's hand throughout the trial, subjects pointed accurately (average error 0.3 cm, SD=0.8 cm). In addition, head tilt 20 degrees to the left or right did not cause any change in accuracy. The bias observed in the first task could be caused by maintained tonus in arm muscles when the arm is raised, that might interfere with the transformation from visual to motor signals needed to perform the pointing movement. We conclude that the plane of regard is correctly localized in space. This may be a good starting point for representing objects in head-centric coordinates.

Representation of heading direction in far and near head space.

Manipulation of objects around the head requires an accurate and stable internal representation of their locations in space, also during movements such as that of the eye or head. For far space, the representation of visual stimuli for goal-directed arm movements relies on retinal updating, if eye movements are involved. Recent neurophysiological studies led us to infer that a transformation of visual space from retinocentric to a head-centric representation may be involved for visual objects in close proximity to the head. The first aim of this study was to investigate if there is indeed such a representation for remembered visual targets of goal-directed arm movements. Participants had to point toward an initially foveated central target after an intervening saccade. Participants made errors that reflect a bias in the visuomotor transformation that depends on eye displacement rather than any head-centred variable. The second issue addressed was if pointing toward the centre of a wide-field expanding motion pattern involves a retinal updating mechanism or a transformation to a head-centric map and if that process is distance dependent. The same pattern of pointing errors in relation to gaze displacement was found independent of depth. We conclude that for goal-directed arm movements, representation of the remembered visual targets is updated in a retinal frame, a mechanism that is actively used regardless of target distance, stimulus characteristics or the requirements of the task.