Early Adversity Affects Cerebellar Structure and Function-A Systematic Review of Human and Animal Studies.

Recent research has highlighted cerebellar involvement in cognition and several psychiatric conditions such as mood and anxiety disorders and schizophrenia. Attention-deficit/hyperactivity disorder and autism spectrum disorder have been linked to reduced cerebellar volume as well. Cerebellar alterations are frequently present after early adversity in humans and animals, but a systematic integration of results is lacking.

Alignment of behaviour and tDCS stimulation site induces maximum response: evidence from online tDCS and ERP.

tDCS modulates the activity of the neuronal networks to induce the desired behavioural changes. Two factors determine its effectiveness- (1) whether the network being stimulated is relevant to the task, and (2) if there is a scope for improvement in behavioral performance. To explore this, both dorsal (sub-lexical) and ventral (lexical) reading networks were stimulated (20 min, 2 mA) in 25 healthy young volunteers.

Baseline functional connectivity predicts who will benefit from neuromodulation: evidence from primary progressive aphasia.

Background: Identifying the characteristics of individuals who demonstrate response to an intervention allows us to predict who is most likely to benefit from certain interventions. Prediction is challenging in rare and heterogeneous diseases, such as primary progressive aphasia (PPA), that have varying clinical manifestations. We aimed to determine the characteristics of those who will benefit most from transcranial direct current stimulation (tDCS) of the left inferior frontal gyrus (IFG) using a novel heterogeneity and group identification analysis.

Disrupted executive cerebro-cerebellar functional connectivity in alcohol use disorder.

Background: Alcohol use disorder (AUD) affects 283 million people worldwide and its prevalence is increasing. Despite the role of the cerebellum in executive control and its sensitivity to alcohol, few studies have assessed its involvement in AUD-relevant functional networks. The goal of this study is to compare resting-state functional connectivity (FC) patterns in abstinent adults with a history of AUD and controls (CTL).

The role of the cerebellum in internet gaming disorder-A systematic review.

Recent studies increasingly highlight involvement of the cerebellum in drug craving and addiction. However, its exact role, that is, whether the cerebellum is a critical component of a brain network underlying addictive behaviour, or whether it rather is a facilitator or mediator, is still unclear. Findings concerning the newly recognized internet gaming disorder (IGD) suggest that changes in cerebellar connectivity and functioning are associated with behavioural/non-substance addiction.

Specificity in Generalization Effects of Transcranial Direct Current Stimulation Over the Left Inferior Frontal Gyrus in Primary Progressive Aphasia.

Objectives: Generalization (or near-transfer) effects of an intervention to tasks not explicitly trained are the most desirable intervention outcomes. However, they are rarely reported and even more rarely explained. One hypothesis for generalization effects is that the tasks improved share the same brain function/computation with the intervention task.

Sex differences in effects of tDCS and language treatments on brain functional connectivity in primary progressive aphasia.

Primary Progressive Aphasia (PPA) is a neurodegenerative disorder primarily affecting language functions. Neuromodulatory techniques (e.g.

Variation of cerebrospinal fluid in specific regions regulates focality in transcranial direct current stimulation.

Background: Conventionally, transcranial direct current stimulation (tDCS) aims to focalize the current reaching the target region-of-interest (ROI). The focality can be quantified by the dose-target-determination-index (DTDI). Despite having a uniform tDCS setup, some individuals receive focal stimulation (high DTDI) while others show reduced focality ("non-focal").

Cerebellar Transcranial Magnetic Stimulation (TMS) Impairs Visual Working Memory.

An increasing body of evidence points to the involvement of the cerebellum in cognition. Specifically, previous studies have shown that the superior and inferior portions of the cerebellum are involved in different verbal working memory (WM) mechanisms as part of two separate cerebro-cerebellar loops for articulatory rehearsal and phonological storage mechanisms. In comparison, our understanding of the involvement of the cerebellum in visual WM remains limited.

Neural Correlates of Letter and Semantic Fluency in Primary Progressive Aphasia.

Verbal fluency (VF) is an informative cognitive task. Lesion and functional imaging studies implicate distinct cerebral areas that support letter versus semantic fluency and the understanding of neural and cognitive mechanisms underlying task performance. Most lesion studies include chronic stroke patients.

Sex difference in tDCS current mediated by changes in cortical anatomy: A study across young, middle and older adults.

Introduction: The observed variability in the effects of transcranial direct current stimulation (tDCS) is influenced by the amount of current reaching the targeted region-of-interest (ROI). Age and sex might affect current density at target ROI due to their impact on cortical anatomy. The present tDCS simulation study investigates the effects of cortical anatomical parameters (volumes, dimension, and torque) on simulated tDCS current density in healthy young, middle-aged, and older males and females.

Focality-Oriented Selection of Current Dose for Transcranial Direct Current Stimulation.

In transcranial direct current stimulation (tDCS), the injected current becomes distributed across the brain areas. The objective is to stimulate the target region of interest (ROI) while minimizing the current in non-target ROIs (the 'focality' of tDCS). For this purpose, determining the appropriate current dose for an individual is difficult.

Cerebro-Cerebellar Response to Sequence Violation in a Cognitive Task: an fMRI Study.

The phonological loop is part of Baddeley's verbal working memory (VWM) model that stores phonological information and refreshes its contents through an articulatory process. Many studies have reported the cerebellum's involvement during VWM tasks. In the motor literature, the cerebellum is thought to support smooth and rapid movement sequences through internal models that simulate the action of motor commands, then use the error signals generating from the discrepancy between the predicted and actual sensory consequences to adjust the motor system.

Sensory acquisition functions of the cerebellum in verbal working memory.

Several fMRI studies have shown that the superior cerebellum exhibits load-dependent activations during encoding of letters in a Sternberg verbal working memory (VWM) task. It has been hypothesized that the cerebellum regulates the acquisition of sensory data across all modalities, and thus, that VWM load activations may reflect high- vs low-load differences in sensory acquisition demands. Therefore, increased difficulty in sensory data acquisition should elicit greater activation in the cerebellum.

Cerebellar neuromodulation improves naming in post-stroke aphasia.

Transcranial direct current stimulation has been shown to increase the efficiency of language therapy in chronic aphasia; however, to date, an optimal stimulation site has not been identified. We investigated whether neuromodulation of the right cerebellum can improve naming skills in chronic aphasia. Using a randomized, double-blind, sham-controlled, within-subject crossover study design, participants received anodal cerebellar stimulation ( = 12) or cathodal cerebellar stimulation ( = 12) + computerized aphasia therapy then sham + computerized aphasia therapy, or the opposite order.

Reading proficiency influences the effects of transcranial direct current stimulation: Evidence from selective modulation of dorsal and ventral pathways of reading in bilinguals.

Introduction: tDCS can modulate reading which is processed by lexical (ventral) and sub-lexical (dorsal) pathways. Previous research indicates that pathway recruitment in bilinguals depends on a script's orthographic depth and a reader's proficiency with it. The effect of tDCS on each reading pathway has not been investigated in bilinguals.

i-SATA: A MATLAB based toolbox to estimate current density generated by transcranial direct current stimulation in an individual brain.

Objective: Transcranial Direct Current Stimulation (tDCS) is a technique where a weak current is passed through the electrodes placed on the scalp. The distribution of the electric current induced in the brain due to tDCS is provided by simulation toolbox like Realistic volumetric Approach based Simulator for Transcranial electric stimulation (ROAST). However, the procedure to estimate the total current density induced at the target and the intermediary region of the cortex is complex.

Changes in Hemodynamic Response Function Resulting From Chronic Alcohol Consumption.

Background: Functional MRI (fMRI) task-related analyses rely on an estimate of the brain's hemodynamic response function (HRF) to model the brain's response to events. Although changes in the HRF have been found after acute alcohol administration, the effects of heavy chronic alcohol consumption on the HRF have not been explored, and the potential benefits or pitfalls of estimating each individual's HRF on fMRI analyses of chronic alcohol use disorder (AUD) are not known.

Methods: Participants with AUD and controls (CTL) received structural, functional, and vascular scans.

Contingency awareness, aging, and the parietal lobe.

Contingency awareness is thought to rely on an intact medial temporal lobe and also appears to be a function of age, as older subjects tend to be less aware. The current investigation used functional magnetic resonance imaging, transcranial direct current stimulation, and eyeblink classical conditioning to study brain processes related to contingency awareness as a function of age. Older adults were significantly less aware of the relationship between the tone-airpuff pairings than younger adults.

Neural Substrates Underlying Eyeblink Classical Conditioning in Adults With Alcohol Use Disorders.

Background: Excessive alcohol consumption produces changes in the brain that often lead to cognitive impairments. One fundamental form of learning, eyeblink classical conditioning (EBC), has been widely used to study the neurobiology of learning and memory. Participants with alcohol use disorders (AUD) have consistently shown a behavioral deficit in EBC.

Simulation Analyses of tDCS Montages for the Investigation of Dorsal and Ventral Pathways.

Modulating higher cognitive functions like reading with transcranial direct current stimulation (tDCS) can be challenging as reading involves regions in the dorsal and ventral cortical areas that lie in close proximity. If the two pathways are stimulated simultaneously, the function of dorsal pathway (predominantly used for graphophonological conversion) might interfere with the function of the ventral pathway (used for semantics), and vice-versa. To achieve functional specificity in tDCS for investigating the two pathways of reading, it is important to stimulate each pathway per session such that the spread of current across the cortical areas due to the two montages has minimal overlap.

"The effect of tDCS on functional connectivity in primary progressive aphasia" NeuroImage: Clinical, volume 19 (2018), pages 703-715.

Transcranial direct current stimulation (tDCS) is an innovative technique recently shown to improve language outcomes even in neurodegenerative conditions such as primary progressive aphasia (PPA), but the underlying brain mechanisms are not known. The present study tested whether the additional language gains with repetitive tDCS (over sham) in PPA are caused by changes in functional connectivity between the stimulated area (the left inferior frontal gyrus (IFG)) and the rest of the language network. We scanned 24 PPA participants (11 female) before and after language intervention (written naming/spelling) with a resting-state fMRI sequence and compared changes before and after three weeks of tDCS or sham coupled with language therapy.

Disruption of Cerebellar Prediction in Verbal Working Memory.

Mounting evidence suggests that the right cerebellum contributes to verbal working memory, but the functional role of this contribution remains unclear. In an established theory of motor control, the cerebellum is thought to predict sensory consequences of movements through an internal "forward model." Here, we hypothesize a similar predictive process can generalize to cerebellar non-motor function, and that the right cerebellum plays a predictive role that is beneficial for rapidly engaging the phonological loop in verbal working memory.

The Role of Language Severity and Education in Explaining Performance on Object and Action Naming in Primary Progressive Aphasia.

Despite the common assumption that atrophy in a certain brain area would compromise the function that it subserves, this is not always the case, especially in complex clinical syndromes such as primary progressive aphasia (PPA). Clinical and demographic information may contribute to PPA phenotypes and explain the manifested impairments better than atrophy. In the present study, we asked how much variance of the object and action naming impairments observed in PPA may be attributed to atrophy in the language network alone vs.

Cerebellar contributions to sequence prediction in verbal working memory.

Verbal working memory is one of the most studied non-motor functions with robust cerebellar involvement. While the superior cerebellum (lobule VI) has been associated with articulatory control, the inferior cerebellum (lobule VIIIa) has been linked to phonological storage. The present study was aimed to elucidate the differential roles of these regions by investigating whether the cerebellum might contribute to verbal working memory via predictions based on sequence learning/detection.