The association between the disruption of motor imagery and the number of depressive episodes of major depression

The lateralized effects of Parkinson's Disease on motor imagery: Evidence from mental chronometry

Alterations to the content of action representations may contribute to the movement challenges that characterize Parkinson's Disease (PD). One way to investigate action representations is through motor imagery. As PD motor symptoms typically have a unilateral onset, disease-related deficits related to action representations may follow a similarly lateralized pattern. The present study examined if temporal accuracy of motor imagery in individuals with PD differed according to the side of the body involved in the task. Thirty-eight participants with PD completed a mental chronometry task using their more affected and less affected side. Participants had significantly shorter mental versus physical movement times for the more affected. Higher imagery vividness in the kinaesthetic domain predicted shorter mental versus physical movement times for the more affected side, as did lower imagery vividness in the visual domain and poorer cognitive function. These results indicate that people with PD imagine movements differently when the target actions their more affected versus less affected side. It is additionally possible that side-specific deficits in the accurate processing of kinaesthetic information lead to an increased reliance on visual processes and cognitive resources to successfully execute motor imagery involving the more affected side.

A network model of depressive and anxiety symptoms: a statistical evaluation

BACKGROUND

Although network analysis studies of psychiatric syndromes have increased in recent years, most have emphasized centrality symptoms and robust edges. Broadening the focus to include bridge symptoms within a systematic review could help to elucidate symptoms having the strongest links in network models of psychiatric syndromes. We conducted this systematic review and statistical evaluation of network analyses on depressive and anxiety symptoms to identify the most central symptoms and bridge symptoms, as well as the most robust edge indices of networks.

METHODS

A systematic literature search was performed in PubMed, PsycINFO, Web of Science, and EMBASE databases from their inception to May 25, 2022. To determine the most influential symptoms and connections, we analyzed centrality and bridge centrality rankings and aggregated the most robust symptom connections into a summary network. After determining the most central symptoms and bridge symptoms across network models, heterogeneity across studies was examined using linear logistic regression.

RESULTS

Thirty-three studies with 78,721 participants were included in this systematic review. Seventeen studies with 23 cross-sectional networks based on the Patient Health Questionnaire (PHQ) and Generalized Anxiety Disorder (GAD-7) assessments of clinical and community samples were examined using centrality scores. Twelve cross-sectional networks based on the PHQ and GAD-7 assessments were examined using bridge centrality scores. We found substantial variability between study samples and network features. 'Sad mood', 'Uncontrollable worry', and 'Worrying too much' were the most central symptoms, while 'Sad mood', 'Restlessness', and 'Motor disturbance' were the most frequent bridge centrality symptoms. In addition, the connection between 'Sleep' and 'Fatigue' was the most frequent edge for the depressive and anxiety symptoms network model.

CONCLUSION

Central symptoms, bridge symptoms and robust edges identified in this systematic review can be viewed as potential intervention targets. We also identified gaps in the literature and future directions for network analysis of comorbid depression and anxiety.

T-RAC: Study protocol of a randomised clinical trial for assessing the acceptability and preliminary efficacy of adding an exergame-augmented dynamic imagery intervention to the behavioural activation treatment of depression

BACKGROUND

Improving the existent effective treatments of depression is a promising way to optimise the effects of psychological treatments. Here we examine the effects of adding a rehabilitation type of imagery based on exergames and dynamic simulations to a short behavioural activation treatment of depression. We investigate the acceptability and the efficacy of an exergame-augmented dynamic imagery intervention added to behavioural activation treatment and associated mechanisms of change.

METHODS AND ANALYSES

In a two-arm pilot randomised controlled trial, the acceptability and preliminary efficacy of an exergame-augmented dynamic imagery intervention added to behavioural activation treatment for depressed individuals will be assessed. Participants (age 18-65) meeting criteria for depression are recruited by media and local announcements. 110 participants will be randomly allocated to behavioural activation plus imagery group or to standard behavioural activation group. The primary outcome is depressive symptom severity (Beck Depression Inventory II) and secondary outcomes are anhedonia, apathy and behavioural activation and avoidance. The outcomes are assessed at baseline, mid treatment, posttreatment and 3-month follow-up. Moderation and mediation analyses will be explored. An intention-to-treat approach with additional per-protocol analysis will be used for data analysis.

The Effects of Self-Perceived Parenting Attitudes on Visuo-Spatial Attention and Mental Rotation Abilities among Adolescents

Highlights

Abstract

The present study aimed to investigate the effect of adolescents’ perceived negative evaluation of parenting on their visuo-spatial attention and mental rotation abilities. The useful field of view (UFOV) and mental rotation tasks were used to measure visuo-spatial attention and mental rotation abilities among adolescents. The experimental groups were divided into the negatively evaluating group (M_Age = 18.44, SD = 0.87, 20.7% girls) and positively evaluating group (M_Age = 18.40, SD = 0.81, 23.3% girls) based on their scores on the self-perceived parenting attitude scales. The UFOV task showed lesser accuracy of the negatively evaluating group when compared to the positively evaluating one in target perception presented in 20° visual angle, indicating a deteriorated visuo-spatial attention ability in the negatively evaluating group. In the mental rotation task, the negatively evaluating group exhibited a small trade-off effect between response times and rotation angles, which implied an impatient strategy was employed to perform the task, whereas such a trade-off was not observed in the positively evaluating group. Thus, both experimental groups differed in terms of their visual attention and mental spatial abilities. This study suggests that the reduced visuo-spatial attention and mental rotation abilities may act as precursors for serious psychological symptoms caused by the negative self-evaluation of their parents’ parenting attitudes.

Embodiment-related risk factors for Posttraumatic Stress, Anxiety and Depression in female victims of intimate partner violence

A central notion in the field of embodiment is that body sensorimotor processes and body mental representations influence emotion, cognition and behavior. By affecting the body, intimate partner violence (IPV) can leave victims with a fragile self, and significant physical and mental health problems. In this study, we aim to examine embodiment-related variables and mental health of female victims of IPV, as well as the impact of embodiment on mental health. A total of 38 female victims of IPV (mean age 40.3 ± 10.9 years) were recruited from shelters and the community. The study assessed the levels of Posttraumatic Stress Disorder (PTSD), Anxiety and Depression, and abilities of Movement Imagery, Interoceptive Accuracy, Interoceptive Sensibility, Body Ownership and Bodily Dissociation. Univariate, bivariate and binary regression analysis were used. PTSD, Anxiety and Depression were highly prevalent among our sample, alongside with altered values of body ownership and interoception. All three mental health disorders were significantly correlated with interoceptive self-regulation, interoceptive trusting, and bodily dissociation. For this group of women, each unit rise in the bodily dissociation scale increased two and six times the risk for developing Depression and Anxiety, respectively. The embodiment of female victims of IPV is altered, and higher bodily dissociation can be a risk factor for the development of mental health problems. Restoration of embodiment-related functions could be important for the victims to overcome the negative effects of violent relationships.

" A Motor Imagery Training for Improving Action Cognition Results in the Reduction of Residual Symptoms after Major Depressive Disorder: A Single-Case Study"

The high rate of recurrence and residual symptoms of depression continuously motivate the search for new treatments addressing this challenging condition. In this single-case study, we reported the application of a cognitive rehabilitation skills training based on remote kinematics as a treatment for residual depression by targeting deficits of mental simulations of action. We found that the administration of Kinect-based rehabilitation training resulted in important improvements showed by significant mean baseline reductions (MBLR) of difficulty in imagining positive actions (MBLR= 54 %), negative emotions (MBLR = 36.3 %), cognitive flexibility (MBLR= 69.7 %), depressive symptoms (MBLR= 80%), and physical retardation (MBLR= 50 %). Similarly, improvements in positive affect (MBLR = 107 %) and vividness of motor imagery for positive actions were registered (MBLR= 100 %). We also found unique effects of our intervention such as reports of involuntary action simulations to distant stimuli or extended affordances. The training was well-accepted and the patient considered it was an entertaining way to do physical exercises and to get in physical and mental shape. We concluded that further scientific research of remote Kinematic interventions in depression may be warranted.

Heterogeneous alterations in thalamic subfields in major depression disorder

BACKGROUND

It is well known that the thalamus is not a unitary and homogeneous entity but a complex and highly connected archeocortical structure. Although many neuroimaging studies have reported alterations in the thalamus in major depressive disorder (MDD), the structural alterations in thalamic subfields remain unclear. This study aimed to investigate changes in gray matter volume (GMV) in thalamic subfields in MDD patients.

METHODS

The present study included structural images of 848 MDD patients and 794 age-matched normal controls (NC) from 17 study sites of the REST-meta-MDD consortium. We performed voxel-based morphometric analyses to calculate the GMV in the entire thalamus and its subfields using three different automated anatomical labeling atlases and subsequently compared the differences between first-episode drug-naïve major depressive disorder (FEDN), recurrent major depressive disorder (RMDD), and NC groups. We also evaluated the relationships between thalamic GMV and clinical symptoms in MDD patients.

RESULTS

Compared to NC, the FEDN patients showed increased GMV in thalamic subfields but not in the entire thalamus, while RMDD patients showed no significant alterations in GMV in the entire thalamus and its subfields. Moreover, the mean GMV in the right anterior thalamus and left anteroventral thalamus in RMDD patients were mildly positively correlated with the Hamilton Anxiety Rating Scale scores.

LIMITATIONS

The main limitations are a single-modal analysis based on T1-weighted MR images and a cross-sectional design.

CONCLUSIONS

Our findings suggest that FEDN and RMDD patients show heterogeneous alterations across thalamic subfields, which may help us understand the pathophysiological mechanisms of MDD.

Electrophysiological Processes on Motor Imagery Mediate the Association Between Increased Gray Matter Volume and Cognition in Amnestic Mild Cognitive Impairment

Motor imagery is considered as an ideal window to observe neural processes of action representations. Behavioral evidence has indicated an alteration of motor imagery in amnestic mild cognitive impairment (aMCI). However, it still remains unclear on the altered neurophysiological processing mechanism of motor imagery and whether this mechanism links the abnormal biological basis of motor imagery with impaired cognition in aMCI. This study was to investigate the altered neurophysiological processing mechanism of motor imagery and to examine the relationships between this knowledge and the altered structural basis of motor imagery with impaired cognition in aMCI. A hand mental rotation paradigm was used to manipulate the processing of motor imagery while event-related brain potentials (ERPs) were recorded and gray matter (GM) voxel-based morphometry was performed in 20 aMCI and 29 healthy controls. Compared with controls, aMCI exhibited lower ERP amplitudes in parietal cortex and higher ERP amplitudes in frontal cortex during motor imagery. In addition, aMCI showed reduced GM volumes in cerebellum posterior lobe, insula and hippocampus/parahippocampal gyrus, and increased GM volumes in middle cingulate gyrus and superior frontal gyrus. Most importantly, increased ERP amplitude significantly mediated the association between increased GM and cognition. This study provided a novel evidence for the relationships between the electrophysiological processing mechanism and structural basis of motor imagery with impaired cognition in aMCI. It suggests that improving neural activity by stimulating the frontal lobe can potentially contribute to acquire motor imagery skills for neurological rehabilitation in aMCI subjects.

Give me a kiss! An integrative rehabilitative training program with motor imagery and mirror therapy for recovery of facial palsy

BACKGROUND

Peripheral facial nerve palsy (FNP) can have various causes, such as Bell's palsy or after surgery for acoustic neuroma. Rehabilitation is often required but there is no evidence that any rehabilitation approach is more efficacious than another.

AIM

The purpose of this research was to determine the effects of neurocognitive-rehabilitative approach through mirror-therapy (MT) and motor-imagery (MI), integrated into the traditional rehabilitation with mime-therapy and myofascial-approach.

DESIGN

This study was designed as a double-blind, randomized, controlled trial.

SETTING

This study took place from January 2016 to June 2018 at the Unit of Physical Medicine and Rehabilitation of Umberto I Polyclinic Hospital, Rome, Italy.

POPULATION

Twenty-two patients were randomized into two groups: the mirror therapy group (N.=11, MT and MI) and the traditional rehabilitation group (N.=11, mime-therapy and a myofascial-approach).

METHODS

Outcome assessments were performed before treatment (T0), after one month (T1=10 session, twice/week), after the second and third months (T2=10 twice/week + 5 of MT+MI one/week and T3=10 twice/week + 5 of MT+MI 1/week), and at the 4-week follow-up (T4=2 months follow-up).

RESULTS

The analysis of the functional evaluations show that both groups experienced progressive improvement T0 to T3, with stabilization of the results at the follow-up. There was a significant difference in House-Brackmann-Scale scores between T0 and follow-up in favor of the experimental group. In terms of quality of life (FaCE scale), total scores and social function items improved in both groups from T0 to T3. The experimental group obtained better results with regard to quality of life and emotional depression.

CONCLUSIONS

The integrated use of MT and MI is efficacious in the rehabilitation of FNP, improving facial physical function. Further studies are needed to determine the predictive factors of the recovery of facial mimic.

CLINICAL REHABILITATION IMPACT

The ability of patients with unilateral facial paralysis to recognize and appropriately judge facial expressions and perceive the judgments of others remains underexplored. The likelihood of recovering near-normal facial-function after grade VI facial paralysis is low. Procedures, such as the immediate repair of the facial nerve with an interposed donor graft, might improve facial function in patients with partially injured facial nerves.

Gender-specific associations of depression and anxiety symptoms with mental rotation

BACKGROUND

Men score higher on mental rotation tasks compared to women and suffer from depression and anxiety at half the rate of women. The objective of this study was to confirm the gender-specific effects of depression and anxiety on mental rotation performance.

METHODS

We collected data in non-experimental conditions from 325 university students at three universities. Participants completed rating scales of depressive and anxiety symptoms, and then simultaneously performed a mental rotation task using tablet devices.

RESULTS

We observed no significant difference between men and women in the depressive and anxiety symptoms and task response time. Men had a significantly higher correct answer rate compared with women. The scores of depression and anxiety of all participants were positively correlated. Task response time correlated positively with intensity of depressive symptoms and anxiety in women, but not in men. Women with high depressive symptoms had significantly longer response times than did women with low depressive symptoms, while men had no differences due to depressive symptoms.

LIMITATIONS

We did not directly examine brain functions; therefore, the underlying neurobiological results are only based on previous knowledge and action data.

CONCLUSIONS

The pathology of depression and anxiety was reflected in the correct answer rate and response time in relation to the gender difference of brain function used in mental rotation.

The Effect of Apolipoprotein E ε4 (APOE ε4) on Visuospatial Working Memory in Healthy Elderly and Amnestic Mild Cognitive Impairment Patients: An Event-Related Potentials Study

Background: Apolipoprotein E (APOE) ε4 is the only established risk gene for late-onset, sporadic Alzheimer’s disease (AD). Previous studies have provided inconsistent evidence for the effect of APOE ε4 status on the visuospatial working memory (VSWM).

Objective: The aim was to investigate the effect of APOE ε4 on VSWM with an event-related potential (ERP) study in healthy controls (HC) and amnestic mild cognitive impairment (aMCI) patients.

Methods: The study recorded 39 aMCI patients (27 APOE ε4 non-carriers and 12 APOE ε4 carriers) and their 43 matched controls (25 APOE ε4 non-carriers and 18 APOE ε4 carriers) with an 64-channel electroencephalogram. Participants performed an N-back task, a VSWM paradigm that manipulated the number of items to be stored in memory.

Results: The present study detected reduced accuracy and delayed mean correct response time (RT) in aMCI patients compared to HC. P300, a positive component that peaks between 300 and 500 ms, was elicited by the VSWM task. In addition, aMCI patients showed decreased P300 amplitude at the central–parietal (CP1, CPz, and CP2) and parietal (P1, Pz, and P2) electrodes in 0- and 1-back task compared to HC. In both HC and aMCI patients, APOE ε4 carriers showed reduced P300 amplitude with respect to non-carriers, whereas no significant differences in accuracy or RT were detected between APOE ε4 carriers and non-carriers. Additionally, standardized low-resolution brain electromagnetic tomography analysis (s-LORETA) showed enhanced brain activation in the right parahippocampal gyrus (PHG) during P300 time range in APOE ε4 carriers with respect to non-carriers in aMCI patients.

Conclusion: It demonstrated that P300 amplitude could predict VSWM deficits in aMCI patients and contribute to early detection of VSWM deficits in APOE ε4 carriers.

Brain responses to sound intensity changes dissociate depressed participants and healthy controls

Depression is associated with bias in emotional information processing, but less is known about the processing of neutral sensory stimuli. Of particular interest is processing of sound intensity which is suggested to indicate central serotonergic function. We tested weather event-related brain potentials (ERPs) to occasional changes in sound intensity can dissociate first-episode depressed, recurrent depressed and healthy control participants. The first-episode depressed showed larger N1 amplitude to deviant sounds compared to recurrent depression group and control participants. In addition, both depression groups, but not the control group, showed larger N1 amplitude to deviant than standard sounds. Whether these manifestations of sensory over-excitability in depression are directly related to the serotonergic neurotransmission requires further research. The method based on ERPs to sound intensity change is fast and low-cost way to objectively measure brain activation and holds promise as a future diagnostic tool.

Predictors of neurocognitive impairment at 2years after a first-episode major depressive disorder

BACKGROUND

Neurocognitive impairment is a contributor to major depressive disorder (MDD). However, MDD patients show great variability in the level and course of deficits. The present longitudinal study was to identify predictors of neurocognitive impairment in first-episode MDD patients.

METHODS

Neurocognitive performance was analyzed in a cohort of 100 patients at 2years after a first-episode MDD. Subgroups, deficit type vs. non-deficit type, were compared on baseline clinical, neuropsychological, premorbid and sociodemographic characteristics. The analysis was performed using the multivariate logistic regression to obtain a model for neurocognitive impairment determination. The predicted probabilities of multivariate logistic regression were analyzed using receiver operating characteristic (ROC) curve.

RESULTS

Fifty-two percent of MDD participants presented general neurocognitive impairment. The regression analyses demonstrated that clinical and sociodemographic characteristics were not predictive variables. A model composed of processing speed, executive function, and attention, dexterity correctly classified 85.8% of the MDD patients with deficit type. ROC curve indicated that the changes of these three cognitions could identify MDD with deficit type from MDD with non-deficit type. In addition, ROC curve also indicated that processing speed and executive function could identify MDD from CN subjects. Finally, processing speed performance was negatively correlated with Hamilton Depression Scale scores in both MDD with deficit and non-deficit type.

CONCLUSION

The present study provides novel insights on frequency and neurocognitive profile of subtypes of patients showing impairment. Our results suggest that processing speed impairment is a trait dimension of the disorder related to specific cognitive dysfunctions and the severity of depression.

Mental Imagery in Depression: Phenomenology, Potential Mechanisms, and Treatment Implications

Mental imagery is an experience like perception in the absence of a percept. It is a ubiquitous feature of human cognition, yet it has been relatively neglected in the etiology, maintenance, and treatment of depression. Imagery abnormalities in depression include an excess of intrusive negative mental imagery; impoverished positive imagery; bias for observer perspective imagery; and overgeneral memory, in which specific imagery is lacking. We consider the contribution of imagery dysfunctions to depressive psychopathology and implications for cognitive behavioral interventions. Treatment advances capitalizing on the representational format of imagery (as opposed to its content) are reviewed, including imagery rescripting, positive imagery generation, and memory specificity training. Consideration of mental imagery can contribute to clinical assessment and imagery-focused psychological therapeutic techniques and promote investigation of underlying mechanisms for treatment innovation. Research into mental imagery in depression is at an early stage. Work that bridges clinical psychology and neuroscience in the investigation of imagery-related mechanisms is recommended.

Neurocognitive impairment on motor imagery associated with positive symptoms in patients with first-episode schizophrenia: evidence from event-related brain potentials

Motor imagery provides direct insight into an anatomically interconnected system involved in the integration of sensory information with motor actions, a process that is associated with positive symptoms in schizophrenia (SCZ). However, very little is known about the electrophysiological processing of motor imagery in first episode SCZ. In the current study, we used a visual hand mental rotation (MR) paradigm to manipulate the processing of motor imagery while event-related brain potentials (ERPs) were recorded in 42 SCZ participants and 40 healthy controls (HC). The 400-600 ms window was measured and analyzed for peak latencies and amplitudes. Participants with SCZ had slower reaction time (RT) and made more errors than did HC participants. Moreover, SCZ participants had lower amplitudes in the 400-600 ms window and the typical MR function for amplitudes of MR was lacking. Interestingly, the scalp activity maps for MR in SCZ exhibited an absence of activation in the left parietal site as shown in HC. Furthermore, deficits of amplitude for MR were positively correlated with positive symptom scores in SCZ. These results provide novel evidence for relationships between the electrophysiological processing of motor imagery and positive symptoms in SCZ. They further suggest that the impaired information processing of motor imagery indexed by amplitudes and specific topographic characteristics of the EEG during MR tasks may be a potentially useful and early defining biomarker for SCZ.

Neurophysiological handover from MMN to P3a in first-episode and recurrent major depression

BACKGROUND

Mismatch negativity (MMN) and P3a components are sequential and co-occur. MMN represents the pre-attentive index of deviance detection and P3a represents the attention orienting response. Major depressive disorder (MDD) is characterized by impaired pre-attentive information processing. To assess whether impaired pre-attentive information processing can lead to an impairment of subsequent orienting process as the neurophysiological transmission spreads from MMN to P3a in MDD.

METHODS

MMN/P3a was obtained during a two-tone auditory paradigm with 8% duration deviants in 45 first-episode major depression subjects (F-MD), 40 recurrent major depression subjects (R-MD), and 46 healthy controls (HC).

RESULTS

Compared with HC, F-MD and R-MD had lower MMN amplitudes and no differences were found between F-MD and R-MD. Notably, R-MD had lower P3a amplitudes and longer P3a latencies compared to HC, while F-MD had no differences. Interestingly, no correlations were found between the severity of depression and the deficits of MMN amplitude. The deficits of P3a amplitude, however, were negatively correlated with the severity of depression in F-MD and R-MD. Furthermore, the P3a amplitude deficits were positively correlated with the number of episodes in R-MD.

LIMITATIONS

Patients were on antidepressant medication.

CONCLUSIONS

The recurrence of depressive episodes can lead to impaired pre-attentive information processing, causing an impairment of subsequent orienting process as the neurophysiological transmission from MMN to P3a. It further suggests that the impaired processing indexed by MMN amplitude may be a stable trait biomarker for the appearance of depression, while P3a amplitude can be used a potential biomarker for recurrence.

Distinct facial processing related negative cognitive bias in first-episode and recurrent major depression: evidence from the N170 ERP component

BACKGROUND

States of depression are associated with increased sensitivity to negative events. For this novel study, we have assessed the relationship between the number of depressive episodes and the dysfunctional processing of emotional facial expressions.

METHODOLOGY/PRINCIPAL FINDINGS

We used a visual emotional oddball paradigm to manipulate the processing of emotional information while event-related brain potentials were recorded in 45 patients with first episode major depression (F-MD), 40 patients with recurrent major depression (R-MD), and 46 healthy controls (HC). Compared with the HC group, F-MD patients had lower N170 amplitudes when identifying happy, neutral, and sad faces; R-MD patients had lower N170 amplitudes when identifying happy and neutral faces, but higher N170 amplitudes when identifying sad faces. F-MD patients had longer N170 latencies when identifying happy, neutral, and sad faces relative to the HC group, and R-MD patients had longer N170 latencies when identifying happy and neutral faces, but shorter N170 latencies when identifying sad faces compared with F-MD patients. Interestingly, a negative relationship was observed between N170 amplitude and the depressive severity score for identification of happy faces in R-MD patients while N170 amplitude was positively correlated with the depressive severity score for identification of sad faces in F-MD and R-MD patients. Additionally, the deficits of N170 amplitude for sad faces positively correlated with the number of depressive episodes in R-MD patients.

CONCLUSION/SIGNIFICANCE

These results provide new evidence that having more recurrent depressive episodes and serious depressive states are likely to aggravate the already abnormal processing of emotional facial expressions in patients with depression. Moreover, it further suggests that the impaired processing as indexed by N170 amplitude for positive face identification may be a potentially useful biomarker for predicting propagation of depression while N170 amplitude for negative face identification could be a potential biomarker for depression recurrence.

Neurocognitive impairment of mental rotation in major depressive disorder: evidence from event-related brain potentials

Mental rotation performance may be used as an index of mental slowing or bradyphrenia and may reflect speed of motor preparation. Previous studies suggest that major depressive disorder (MDD) presents correlates of impaired behavioral performance for mental rotation and psychomotor disturbance. Very little is known about the electrophysiological mechanism underlying this deficit. The present study was the first to investigate the event-related brain potential (ERP) correlates of mental rotation and their mental slowing or bradyphrenia in MDD. ERPs were recorded while we tested 25 MDD patients and 26 healthy controls by evaluating the performance of MDD patients on hand and letter rotation tasks at different orientations, and their 400-to-600-msec time window was measured and analyzed for latencies and peak amplitudes over the electrodes. First, individuals with MDD were slower and made more errors in mentally rotating hands and letters than healthy controls did, and individuals with MDD exhibited a greater difference in response times and errors than controls did between hands and letters. Second, the mean peak amplitude was significantly lower and the mean latency was significantly longer in the 400-to-600-msec time window at the parietal site in the hand tasks in MDD patients than in controls, but this was not seen in the letter task, with only lower mean peak amplitude. MDD patients present the absence of a typical mental rotation function for the amplitude of the rotation-related negativity in the hand and letter tasks. Third, the scalp activity maps in MDD patients exhibited the absence of activation in the left parietal site for the mental rotation of hands, as shown in healthy participants. In contrast, their brain activation for the letter task was similar to those of healthy participants. These data suggest that mental imagery of hands and letters relies on different cognitive and neural mechanisms and indicate that the left posterior parietal lobe is a necessary structure for mental transformations of human hands. Importantly, MDD deficits were more seriously present specific to the hands than the letters. Such impairment may also be an important and possibly defining marker of MDD in particular.