Transcranial direct current stimulation over the right parietal cortex improves the depressive disorder: A preliminary study.

OBJECTIVE: The right posterior parietal cortex is the core brain region of emotional processing and executive control network in the human brain, and the function of the right posterior parietal cortex is decreased in patients with major depressive disorder. This study aims to preliminarily investigate whether the excitation of the right posterior parietal cortex by transcranial direct current stimulation (tDCS) could improve their clinical symptoms. METHODS: In this study, 12 patients with major depressive disorder were given tDCS treatment at Xuanwu Hospital of Capital Medical University and the First Hospital of Hebei Medical University. The stimulating electrode (anode) was placed on the patients' right parietal cortex, whereas the reference electrode (cathode) was placed on the patients' left mastoid. The stimulation intensity was set as 2.0 mA. The patients with depressive disorder were treated for 20 min at a time twice a day for 14 consecutive days. The severity of the clinical symptoms was evaluated using the Hamilton Depression Rating Scale-17 (HDRS-17) and the Hamilton Anxiety Rating Scale (HARS) at before and right after treatment. RESULTS: The HDRS-17 scores of patients with depressive disorder decreased significantly following the tDCS treatment compared with those before treatment (p < .001). Further analysis revealed that the patients' anxiety/somatization, cognitive deficit, retardation, and sleep disorder scores all decreased significantly after the tDCS treatment (p < .05), although there was no significant change in their weight. Moreover, the patients' HARS scores decreased significantly after the tDCS treatment when compared with those before treatment (p < .01). CONCLUSION: The right parietal cortex may be another key stimulation targets to improving the efficacy of tDCS treatment to the patients with major depressive disorder.

Repeated exposure to multiple concurrent stressors alters visual processing in the adult posterior parietal cortex.

Chronic stress is well known to erode cognitive functions. Yet, our understanding of how repeated stress exposure impacts one of the fundamental bases of cognition: sensory processing, remains limited. The posterior parietal cortex (PPC) is a high order visual region, known for its role in visually guided decision making, multimodal integration, attention, and working memory. Here, we used functional measures to determine how repeated exposure to multiple concurrent stressors (RMS) affects sensory processing in the PPC in adult male mice. A longitudinal experimental design, repeatedly surveying the same population of neurons using in vivo two-photon imaging, revealed that RMS disrupts the balanced turnover of visually responsive cells in layer 2/3 of the PPC. Across the population, RMS-induced changes in visual responsiveness followed a bimodal distribution suggesting idiosyncratic stress effects. In cells that maintained their responsiveness across recording sessions, we found that stress reduced visual response magnitudes and feature selectivity. While we did not observe stress-induced elimination of excitatory synapses, noise correlation statistics indicated that RMS altered visual input to the neuronal population. The impact of RMS was restricted to visually evoked responses and was not evident in neuronal activity associated with locomotion onset. Together, our results indicate that despite no apparent synaptic reorganization, stress exposure in adulthood can disrupt sensory processing in the PPC, with the effects showing remarkable individual variation.

Repeated spaced cortical paired associative stimulation promotes additive plasticity in the human parietal-motor circuit.

OBJECTIVE: Repeated spaced sessions of repetitive transcranial magnetic stimulation (TMS) to the human primary motor cortex can lead to dose-dependent increases in motor cortical excitability. However, this has yet to be demonstrated in a defined cortical circuit. We aimed to examine the effects of repeated spaced cortical paired associative stimulation (cPAS) on excitability in the motor cortex. METHODS: cPAS was delivered to the primary motor cortex (M1) and posterior parietal cortex (PPC) with two coils. In the multi-dose condition, three sessions of cPAS were delivered 50-min apart. The single-dose condition had one session of cPAS, followed by two sessions of a control cPAS protocol. Motor-evoked potentials were evaluated before and up to 40 min after each cPAS session as a measure of cortical excitability. RESULTS: Compared to a single dose of cPAS, motor cortical excitability significantly increased after multi-dose cPAS. Increasing the number of cPAS sessions resulted in a cumulative, dose-dependent effect on excitability in the motor cortex, with each successive cPAS session leading to notable increases in potentiation. CONCLUSION: Repeated spaced cPAS sessions summate to increase motor cortical excitability induced by single cPAS. SIGNIFICANCE: Repeated spaced cPAS could potentially restore abilities lost due to disorders like stroke.

Erratum: Neuromodulatory effects of high-definition theta transcranial alternating current stimulation on the parietal cortex: a pilot study of healthy males.

[This corrects the article DOI: 10.3389/fnins.2023.1255124.].

Symptomatology after damage to the angular gyrus through the lenses of modern lesion-symptom mapping.

Brain-behavior relationships are complex. For instance, one might know a brain region's function(s) but still be unable to accurately predict deficit type or severity after damage to that region. Here, I discuss the case of damage to the angular gyrus (AG) that can cause left-right confusion, finger agnosia, attention deficit, and lexical agraphia, as well as impairment in sentence processing, episodic memory, number processing, and gesture imitation. Some of these symptoms are grouped under AG syndrome or Gerstmann's syndrome, though its exact underlying neuronal systems remain elusive. This review applies recent frameworks of brain-behavior modes and principles from modern lesion-symptom mapping to explain symptomatology after AG damage. It highlights four major issues for future studies: (1) functionally heterogeneous symptoms after AG damage need to be considered in terms of the degree of damage to (i) different subdivisions of the AG, (ii) different AG connectivity profiles that disconnect AG from distant regions, and (iii) lesion extent into neighboring regions damaged by the same infarct. (2) To explain why similar symptoms can also be observed after damage to other regions, AG damage needs to be studied in terms of the networks of regions that AG functions with, and other independent networks that might subsume the same functions. (3) To explain inter-patient variability on AG symptomatology, the degree of recovery-related brain reorganisation needs to account for time post-stroke, demographics, therapy input, and pre-stroke differences in functional anatomy. (4) A better integration of the results from lesion and functional neuroimaging investigations of AG function is required, with only the latter so far considering AG function in terms of a hub within the default mode network. Overall, this review discusses why it is so difficult to fully characterize the AG syndrome from lesion data, and how this might be addressed with modern lesion-symptom mapping.

The self-in-the-world map emerged in the primate brain as a basis for Homo sapiens abilities.

The brain in the genus Homo expanded rapidly during evolution, accelerated by a reciprocated interaction between neural, cognitive, and ecological niches (triadic niche construction, or TNC). This biologically costly expansion incubated latent cognitive capabilities that, with a quick and inexpensive rewiring of brain areas in a second phase of TNC, provided the basis for Homo sapiens specific abilities. The neural demands for perception of the human body in interaction with tools and the environment required highly integrated sensorimotor domains, inducing the parietal lobe expansion seen in humans. These newly expanded brain areas allowed connecting the sensations felt in the body to the actions in the world through the cognitive function of "projection". In this opinion article, we suggest that as a relationship of equivalence between body parts, tools and their external effects was established, mental mechanisms of self-objectification might have emerged as described previously, grounding notions of spatial organization, idealized objects, and their transformations, as well as socio-emotional states in the sensing agent through a self-in-the-world map. Therefore, human intelligence and its features such as symbolic thought, language, mentalizing, and complex technical and social behaviors could have stemmed from the explicit awareness of the causal relationship between the self and intentional modifications to the environment.

Characteristics of Visual Cognition in Patients with Anoxic Encephalopathy: An Eye-tracking Study.

Objectives: : Despite the frequent occurrence of visual cognitive impairment after anoxic encephalopathy, only a few studies have analyzed gaze movements following encephalopathy. This study determined the visual cognitive characteristics of patients with anoxic encephalopathy using an eye-tracking system. Methods: : This study included ten patients with anoxic encephalopathy and ten age/sex-matched controls. Factors for anoxic encephalopathy onset and brain imaging findings were extracted from medical records. An eye-tracking system was used to track eye movements during three visual search tasks (pop-out, serial search, and saliency) in patient and healthy control groups. The average target search time, number of saccades, and number of fixations to salient stimuli were compared. Results: : Stagnant blood flow, observed in six of ten patients, was the most common cause of disease onset, four of whom exhibited hypoperfusion in bilateral occipital or parietal lobes on single-photon emission computed tomography. The patient group required longer search times during all visual search tasks and a higher number of saccades during pop-out and serial search tasks. However, no significant difference was observed between the two groups for the number of fixations to salient stimuli during the saliency task. Conclusions: : Following anoxic encephalopathy, bottom-up (pop-out task) and top-down (serial search task) gaze control were considered impaired because of extensive parieto-occipital lobe damage after blood flow stagnation. Patients exhibited reduced top-down function for finding targets (serial search task) but relatively retain inhibitory function for salient stimuli (saliency task). Gaze analysis can be used to reveal the clinical characteristics of anoxic encephalopathy.

Frequency-specific directed connectivity between the hippocampus and parietal cortex during verbal and spatial episodic memory: an intracranial EEG replication.

Hippocampus-parietal cortex circuits are thought to play a crucial role in memory and attention, but their neural basis remains poorly understood. We employed intracranial intracranial electroencephalography (iEEG) to investigate the neurophysiological underpinning of these circuits across three memory tasks spanning verbal and spatial domains. We uncovered a consistent pattern of higher causal directed connectivity from the hippocampus to both lateral parietal cortex (supramarginal and angular gyrus) and medial parietal cortex (posterior cingulate cortex) in the delta-theta band during memory encoding and recall. This connectivity was independent of activation or suppression states in the hippocampus or parietal cortex. Crucially, directed connectivity from the supramarginal gyrus to the hippocampus was enhanced in participants with higher memory recall, highlighting its behavioral significance. Our findings align with the attention-to-memory model, which posits that attention directs cognitive resources toward pertinent information during memory formation. The robustness of these results was demonstrated through Bayesian replication analysis of the memory encoding and recall periods across the three tasks. Our study sheds light on the neural basis of casual signaling within hippocampus-parietal circuits, broadening our understanding of their critical roles in human cognition.

Cerebellum and social abilities: A structural and functional connectivity study in a transdiagnostic sample.

The cerebellum has been involved in social abilities and autism. Given that the cerebellum is connected to the cortex via the cerebello-thalamo-cortical loop, the connectivity between the cerebellum and cortical regions involved in social interactions, that is, the right temporo-parietal junction (rTPJ) has been studied in individuals with autism, who suffer from prototypical deficits in social abilities. However, existing studies with small samples of categorical, case-control comparisons have yielded inconsistent results due to the inherent heterogeneity of autism, suggesting that investigating how clinical dimensions are related to cerebellar-rTPJ functional connectivity might be more relevant. Therefore, our objective was to study the functional connectivity between the cerebellum and rTPJ, focusing on its association with social abilities from a dimensional perspective in a transdiagnostic sample. We analyzed structural magnetic resonance imaging (MRI) and functional MRI (fMRI) scans obtained during naturalistic films watching from a large transdiagnostic dataset, the Healthy Brain Network (HBN), and examined the association between cerebellum-rTPJ functional connectivity and social abilities measured with the social responsiveness scale (SRS). We conducted univariate seed-to-voxel analysis, multivariate canonical correlation analysis (CCA), and predictive support vector regression (SVR). We included 1404 subjects in the structural analysis (age: 10.516 ± 3.034, range: 5.822-21.820, 506 females) and 414 subjects in the functional analysis (age: 11.260 ± 3.318 years, range: 6.020-21.820, 161 females). Our CCA model revealed a significant association between cerebellum-rTPJ functional connectivity, full-scale IQ (FSIQ) and SRS scores. However, this effect was primarily driven by FSIQ as suggested by SVR and univariate seed-to-voxel analysis. We also demonstrated the specificity of the rTPJ and the influence of structural anatomy in this association. Our results suggest that there is a complex relationship between cerebellum-rTPJ connectivity, social performance and IQ. This relationship is specific to the cerebellum-rTPJ connectivity, and is largely related to structural anatomy in these two regions. PRACTITIONER POINTS: We analyzed cerebellum-right temporoparietal junction (rTPJ) connectivity in a pediatric transdiagnostic sample. We found a complex relationship between cerebellum and rTPJ connectivity, social performance and IQ. Cerebellum and rTPJ functional connectivity is related to structural anatomy in these two regions.

Similar neural states, but dissimilar decoding patterns for motor control in parietal cortex.

Discrete neural states are associated with reaching movements across the fronto-parietal network. Here, the Hidden Markov Model (HMM) applied to spiking activity of the somato-motor parietal area PE revealed a sequence of states similar to those of the contiguous visuomotor areas PEc and V6A. Using a coupled clustering and decoding approach, we proved that these neural states carried spatiotemporal information regarding behaviour in all three posterior parietal areas. However, comparing decoding accuracy, PE was less informative than V6A and PEc. In addition, V6A outperformed PEc in target inference, indicating functional differences among the parietal areas. To check the consistency of these differences, we used both a supervised and an unsupervised variant of the HMM, and compared its performance with two more common classifiers, Support Vector Machine and Long-Short Term Memory. The differences in decoding between areas were invariant to the algorithm used, still showing the dissimilarities found with HMM, thus indicating that these dissimilarities are intrinsic in the information encoded by parietal neurons. These results highlight that, when decoding from the parietal cortex, for example, in brain machine interface implementations, attention should be paid in selecting the most suitable source of neural signals, given the great heterogeneity of this cortical sector.

Applying HMMs to spiking activity recorded from the somato-motor parietal area PE revealed discrete neural states related to reaching movements. These states were extremely similar to those present in the neighbouring visuomotor areas PEc and V6A. Our decoding approach showed that these states conveyed spatiotemporal behaviour information across all three posterior parietal areas. However, decoding accuracy was lower in PE compared to V6A and PEc, with V6A excelling in target inference. These differences held true even when changing the decoding algorithm, indicating intrinsic dissimilarities in information encoding by parietal different areas. These findings highlight the importance of selecting the appropriate neural signal sources in applications such as brain machine interfaces and pave the way for further investigation of the nontrivial diversity within the parietal cortex.

The engagement of temporal attention in left spatial neglect.

Previous literature showed how left spatial neglect arises from an asymmetrical distribution of spatial attention. However, it was also suggested that left spatial neglect might be partially caused or at least worsened by non-spatial attention disorders of the right-lateralized stimulus-driven attentional fronto-parietal network. Here, we psychophysically tested the efficiency of temporal attentional engagement of foveal perception through meta-contrast (Experiment 1) and "attentional" masking (Experiment 2) tasks in patients with right-hemisphere stroke with left neglect (N+), without left neglect (N-) and matched healthy controls (C). In both experiments, N+ patients showed higher thresholds, not only than Cs, but also than N- patients. Temporal engagement was clinically impaired in all N+ patients and highly correlated with their typical inability to direct spatial attention towards stimuli on the left side. Our findings suggest that a temporal impairment of attentional engagement is a relevant deficit of left spatial neglect.

On the role of prefrontal and parietal cortices in mind wandering and dynamic thought.

Mind wandering is a common phenomenon in our daily lives and can have both an adaptive and detrimental impact. Recently, a dynamic framework has been proposed to characterise the heterogeneity of internal thoughts, suggesting there are three distinct thought types which can change over time - freely moving, deliberately constrained, and automatically constrained (thoughts). There is currently very little evidence on how different types of dynamic thought are represented in the brain. Previous research has applied non-invasive transcranial direct current stimulation (tDCS) to causally implicate the prefrontal cortex and inferior parietal lobule in mind wandering. However, a more recently developed and nuanced technique, high-definition tDCS (HD-tDCS), delivers more focal stimulation able to target specific brain regions. Therefore, the current study investigated the effect of anodal HD-tDCS applied to the left prefrontal and right inferior parietal cortices (with the occipital cortex included as an active control) on mind wandering, and specifically, the causal neural substrates of the three internal dynamic thought types. This was a single session study using a novel task which allows investigation into how dynamic thoughts are associated with behavioural variability and the recruitment of executive control operations across the three brain regions. There was no evidence to support our hypothesised effect of stimulation reducing task unrelated thought. Furthermore, the hypothesis driven analyses found no evidence of stimulation affecting the dynamic thought types, nor any evidence for our hypothesised effects of stimulation reducing behavioural variability and increasing randomness. There was only evidence for a relationship between these two measures of performance when participants thoughts were freely moving. However, there was evidence from our exploratory analyses that anodal stimulation to the prefrontal cortex decreased freely moving thought and anodal stimulation to the parietal lobule decreased deliberately constrained thought, relative to the sham conditions. The exploratory analyses also suggested stimulation may increase freely moving thought in the occipital cortex. Overall, these findings suggest stimulation does not affect the dynamic thought types, however there is preliminary evidence to support the heterogenous nature of mind wandering, whereby different brain regions may be causally implicated in distinct dynamic thought types.

The disengagement deficit after right-hemisphere damage: Distinct roles of lateral frontal and parietal damage.

An influential model of spatial attention postulates three main attention-orienting mechanisms: disengagement, shifting, and engagement. Early research linked disengagement deficits with superior parietal damage, regardless of hemisphere or presence of spatial neglect. Subsequent studies supported the involvement of more ventral parietal regions, especially in the right hemisphere, and linked spatial neglect to deficient disengagement from ipsilateral cues. However, previous lesion studies faced serious limitations, such as small sample sizes and the lack of brain-injured controls without neglect. Additionally, some studies employed symbolic cues or used long cue-target intervals, which may fail to reveal impaired disengagement. We here used a machine-learning approach to conduct lesion-symptom mapping (LSM) on 89 patients with focal cerebral lesions to the left (LH) or right (RH) cerebral hemisphere. A group of 54 healthy participants served as controls. The paradigm used to uncover disengagement deficits employed non-predictive cues presented in the visual periphery and at short cue-target intervals, targeting exogenous attention. The main factors of interest were group (healthy participants, LH, RH), target position (left, right hemifield) and cue validity (valid, invalid). LSM-analyses were performed on two indices: the validity effect, computed as the absolute difference between reaction times (RTs) following invalid compared to valid cues, and the disengagement deficit, determined by the difference between contralesional and ipsilesional validity effects. While LH patients showed general slowing of RTs to contralesional targets, only RH patients exhibited a disengagement deficit from ipsilesional cues. LSM associated the validity effect with a right lateral frontal cluster, which additionally affected subcortical white matter of the right arcuate fasciculus, the corticothalamic pathway, and the superior longitudinal fasciculus. In contrast, the disengagement deficit was related to damage involving the right temporoparietal junction. Thus, our results support the crucial role of right inferior parietal and posterior temporal regions for attentional disengagement, but also emphasize the importance of lateral frontal regions, for the reorienting of attention.

Region-specific Effects of Transcranial Direct Current Stimulation Over Posterior Parietal Cortex and Cerebellum on Standing Postural Displacement After Prism Adaptation.

Prism adaptation (PA) induces the after-effects of adapted tasks and transfers after-effects of non-adapted tasks, in which PA with pointing movements transfers to postural displacement during eyes-closed standing. However, the neural mechanisms underlying the transfer of PA after-effects on standing postural displacement remain unclear. The present study investigated the region-specific effects of transcranial direct current stimulation (tDCS) over the posterior parietal cortex (PPC) and cerebellum during prism exposure (PE) on standing postural displacement in healthy adults. Forty-two healthy young adults were grouped into pointing during PE with cathodal tDCS over the right PPC, anodal tDCS over the right cerebellum, and sham tDCS groups. They received 20 min of tDCS, during which they pointed to the visual targets while wearing prism lenses with a leftward visual shift (30 diopters) for 15 min. During the early PE, the pointing errors in the cerebellum group were significantly displaced more accurately toward the targets than those in the PPC group. However, after leftward PE, all groups had similar rightward displacements of the straight-ahead pointing with eyes closed. The PPC group only exhibited significant rightward center-of-pressure displacement during eyes-closed standing with feet-closed after leftward PE. The perception of longitudinal body axis rotation, as an indicator of the subjective body vertical axis, did not differ significantly between the pre- and post-evaluations in all groups. These results show that the PPC during PE could make an important neural contribution to inducing transfer of PA after-effect on standing postural displacement.

The thalamic reticular nucleus orchestrates social memory.

Social memory has been developed in humans and other animals to recognize familiar conspecifics and is essential for their survival and reproduction. Here, we demonstrated that parvalbumin-positive neurons in the sensory thalamic reticular nucleus (sTRNPvalb) are necessary and sufficient for mice to memorize conspecifics. sTRNPvalb neurons receiving glutamatergic projections from the posterior parietal cortex (PPC) transmit individual information by inhibiting the parafascicular thalamic nucleus (PF). Mice in which the PPCCaMKII→sTRNPvalb→PF circuit was inhibited exhibited a disrupted ability to discriminate familiar conspecifics from novel ones. More strikingly, a subset of sTRNPvalb neurons with high electrophysiological excitability and complex dendritic arborizations is involved in the above corticothalamic pathway and stores social memory. Single-cell RNA sequencing revealed the biochemical basis of these subset cells as a robust activation of protein synthesis. These findings elucidate that sTRNPvalb neurons modulate social memory by coordinating a hitherto unknown corticothalamic circuit and inhibitory memory engram.

Parietal-Frontal Pathway Controls Relapse of Fear Memory in a Novel Context.

Background: Fear responses significantly affect daily life and shape our approach to uncertainty. However, the potential resurgence of fear in unfamiliar situations poses a significant challenge to exposure-based therapies for maladaptive fear responses. Nonetheless, how novel contextual stimuli are associated with the relapse of extinguished fear remains unknown. Methods: Using a context-dependent fear renewal model, the functional circuits and underlying mechanisms of the posterior parietal cortex (PPC) and anterior cingulate cortex (ACC) were investigated using optogenetic, histological, in vivo, and ex vivo electrophysiological and pharmacological techniques. Results: We demonstrated that the PPC-to-ACC pathway governs fear relapse in a novel context. We observed enhanced populational calcium activity in the ACC neurons that received projections from the PPC and increased synaptic activity in the basolateral amygdala-projecting PPC-to-ACC neurons upon renewal in a novel context, where excitatory postsynaptic currents amplitudes increased but inhibitory postsynaptic current amplitudes decreased. In addition, we found that parvalbumin-expressing interneurons controlled novel context-dependent fear renewal, which was blocked by the chronic administration of fluoxetine. Conclusions: Our findings highlight the PPC-to-ACC pathway in mediating the relapse of extinguished fear in novel contexts, thereby contributing significant insights into the intricate neural mechanisms that govern fear renewal.

To improve outcomes for exposure-based therapy, it is vital to understand the renewal of fear after extinction in new environments. Using optogenetics and other techniques, Joo et al. found that a brain circuit connecting the posterior parietal cortex (PPC) to the anterior cingulate cortex (ACC) is crucial for the return of fear memories in mice exposed to a novel context. Certain PPC→ACC neuron types and their connections to the amygdala became more active during fear renewal in a novel context, and inhibiting parvalbumin-expressing interneurons reduced this fear response. This study provides insights into the brain mechanisms underlying the reappearance of fear in unfamiliar situations.

Attention facilitates initiation of perceptual decision making: a combined psychophysical and electroencephalography study.

Humans can selectively process information and make decisions by directing their attention to desired locations in their daily lives. Numerous studies have shown that attention increases the rate of correct responses and shortens reaction time, and it has been hypothesized that this phenomenon is caused by an increase in sensitivity of the sensory signals to which attention is directed. The present study employed psychophysical methods and electroencephalography (EEG) to test the hypothesis that attention accelerates the onset of information accumulation. Participants were asked to discriminate the motion direction of one of two random dot kinematograms presented on the left and right sides of the visual field, one of which was cued by an arrow in 80% of the trials. The drift-diffusion model was applied to the percentage of correct responses and reaction times in the attended and unattended fields of view. Attention primarily increased sensory sensitivity and shortened the time unrelated to decision making. Next, we measured centroparietal positivity (CPP), an EEG measure associated with decision making, and found that CPP latency was shorter in attended trials than in unattended trials. These results suggest that attention not only increases sensory sensitivity but also accelerates the initiation of decision making.

Updating the sulcal landscape of the human lateral parieto-occipital junction provides anatomical, functional, and cognitive insights.

Recent work has uncovered relationships between evolutionarily new small and shallow cerebral indentations, or sulci, and human behavior. Yet, this relationship remains unexplored in the lateral parietal cortex (LPC) and the lateral parieto-occipital junction (LPOJ). After defining thousands of sulci in a young adult cohort, we revised the previous LPC/LPOJ sulcal landscape to include four previously overlooked, small, shallow, and variable sulci. One of these sulci (ventral supralateral occipital sulcus, slocs-v) is present in nearly every hemisphere and is morphologically, architecturally, and functionally dissociable from neighboring sulci. A data-driven, model-based approach, relating sulcal depth to behavior further revealed that the morphology of only a subset of LPC/LPOJ sulci, including the slocs-v, is related to performance on a spatial orientation task. Our findings build on classic neuroanatomical theories and identify new neuroanatomical targets for future "precision imaging" studies exploring the relationship among brain structure, brain function, and cognitive abilities in individual participants.

Developmental refinements to neural attentional state during semantic memory retrieval through adolescence.

Despite the fact that attention undergoes protracted development, little is known about how it may support memory refinements in childhood and adolescence. Here, we asked whether people differentially focus their attention on semantic or perceptual information over development during memory retrieval. First, we trained a multivoxel classifier to characterize whole-brain neural patterns reflecting semantic versus perceptual attention in a cued attention task. We then used this classifier to quantify how attention varied in a separate dataset in which children, adolescents, and adults retrieved autobiographical, semantic, and episodic memories. All age groups demonstrated a semantic attentional bias during memory retrieval, with significant age differences in this bias during the semantic task. Trials began with a preparatory picture cue followed by a retrieval question, which allowed us to ask whether attentional biases varied by trial period. Adults showed a semantic bias earlier during the picture cues, whereas adolescents showed this bias during the question. Adults and adolescents also engaged different brain regions-superior parietal cortex and ventral visual regions, respectively-during preparatory picture cues. Our results demonstrate that retrieval-related attention undergoes refinement beyond childhood. These findings suggest that alongside expanding semantic knowledge, attention-related changes may support the maturation of factual knowledge retrieval.

Effects of parietal repetitive transcranial magnetic stimulation in prolonged disorders of consciousness: A pilot study.

Objective: Although the parietal cortex is related to consciousness, the dorsolateral prefrontal and primary motor cortices are the usual targets for repetitive transcranial magnetic stimulation (rTMS) for prolonged disorders of consciousness (pDoC). Herein, we applied parietal rTMS to patients with pDoC, to verify its neurobehavioral effects and explore a new potential rTMS target. Materials and methods: Twenty-six patients with pDoC were assigned to a rTMS or sham group. The rTMS group received 10 sessions of parietal rTMS; the sham group received 10 sessions of sham stimulation. The Coma Recovery Scale-Revised (CRS-R) and event-related potential (ERP) were collected before and after the 10 sessions or sham sessions. Results: After the 10 sessions, the rTMS group showed: a significant CRS-R score increase; ERP appearance of a P300 waveform and significantly increased Fz amplitudes; increased potentials on topographic mapping, especially in the left prefrontal cortex; and an increase in delta and theta band powers at Fz, Cz, and Pz. The sham group did not show such changes in CRS-R score or ERP results statistically. Conclusion: Parietal rTMS shows promise as a novel intervention in the recovery of consciousness in pDoC. It showed neurobehavioral enhancement of residual brain function and may promote frontal activity by enhancing frontal-parietal connections. The parietal cortex may thus be an alternative for rTMS therapy protocols.