
Giorgi BatsikadzeUniversity Hospital Essen | UK Essen · Clinic for Neurology
Giorgi Batsikadze
PhD
About
56
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Introduction
Additional affiliations
April 2016 - present
April 2014 - March 2016
March 2010 - March 2014
Publications
Publications (56)
Fear is a vital defense mechanism to potential threats, which is influenced by the cerebellum. While the cerebellum’s role in acquiring fear responses is well understood, limited knowledge exists about its involvement in fear extinction. In this study, we investigated the effects of cerebellar theta band transcranial alternating current stimulation...
Functional cortical circuits for central executive functions have been shown to emerge by theta (~6 Hz) phase-coupling of distant cortical areas. It has been repeatedly shown that frontoparietal theta coupling at ~0° relative phase is associated with recognition, encoding, short-term retention, and planning; however, a causal link has not been demo...
Key points
Application of 2 mA cathodal transcranial direct current stimulation for 20 min results in cortical excitability enhancement instead of inhibition.
Longer or more intensive stimulation does not necessarily increase its efficacy.
Short intracortical inhibition and facilitation are shifted towards excitability enhancement after both 2 mA a...
Background:
Cerebellar transcranial direct current stimulation (ctDCS) is increasingly used to modulate cerebellar excitability and plasticity in healthy subjects and various patient populations. ctDCS parameters are poorly standardized, and its physiology remains little understood. Our aim was to compare the physiological effects of three differe...
Inhibition of the amygdala slows down acquisition of conditioned eyeblink responses (CRs). Based on the two-stage or two-factor theory of aversive conditioning, amygdala-dependent conditioned fear is a necessary prerequisite to acquire eyeblink CRs but is no longer needed after eyeblink CRs are attained. According to the sensory gating hypothesis o...
Very preterm infants are at higher risk of long‐term neurodevelopmental and psychiatric impairments, including anxiety. Prematurity is also linked to altered programming of the hypothalamus–pituitary–adrenal (HPA) axis, associated with stress‐related diseases. The cortisol awakening response (CAR), marked by a rapid cortisol increase after waking,...
The key elements for fear extinction learning are unexpected omissions of expected aversive events, which are considered to be rewarding. Given its reception of reward information, we tested the hypothesis that the cerebellum contributes to reward prediction error processing driving extinction learning via its connections with the ventral tegmental...
The key elements for fear extinction learning are unexpected omissions of expected aversive events, which are considered to be rewarding. Given its reception of reward information, we tested the hypothesis that the cerebellum contributes to reward prediction error processing driving extinction learning via its connections with the ventral tegmental...
Fear extinction is a major component of exposure therapy for anxiety disorders. There is initial evidence that the cerebellum contributes to fear extinction learning, i.e., the ability to learn that certain stimuli are no longer associated with an aversive outcome. So far, however, knowledge of the cerebellum's role in extinction is scarce. In the...
Fear extinction is the foundation of exposure therapy for anxiety and phobias. However, the stability of extinction memory diminishes over time, coinciding with fear recovery. To augment long-term extinction retention, the temporal distribution of extinction learning sessions is critical. This study investigated the effects of massed and spaced tra...
The key elements for fear extinction learning are unexpected omissions of expected aversive events, which are considered to be rewarding. Given its reception of reward information, we tested the hypothesis that the cerebellum contributes to reward prediction error processing driving extinction learning via its connections with the ventral tegmental...
Transcranial direct current stimulation (tDCS) has been studied extensively for its potential to enhance human cognitive functions in healthy individuals and to treat cognitive impairment in various clinical populations. However, little is known about how tDCS modulates the neural networks supporting cognition and the complex interplay with mediati...
Functional brain imaging studies in humans suggest involvement of the cerebellum in fear conditioning but do not allow conclusions about the functional significance. The main aim of the present study was to examine whether patients with cerebellar degeneration show impaired fear conditioning and whether this is accompanied by alterations in cerebel...
Very preterm birth is associated with an increased risk for anxiety disorders. Abnormal brain development may result in disordered fear learning processes, which may be exacerbated by environmental risk factors and persist in adulthood. We tested the hypotheses that very preterm-born young adults displayed higher levels of fear conditioning, less d...
The degenerative ataxias comprise a heterogeneous group of inherited and acquired disorders that are characterized by a progressive cerebellar syndrome, frequently in combination with one or more extracerebellar signs. Specific disease-modifying interventions are currently not available for many of these rare conditions, which underscores the neces...
Very preterm birth is associated with an increased risk for anxiety disorders. Abnormal brain development may result in disordered fear learning processes, which may be exacerbated by environmental risk factors and persist in adulthood. We tested the hypotheses that very preterm-born young adults displayed higher levels of fear conditioning, less d...
Background
A brief bedside test has recently been introduced by Hoche et al. (Brain, 2018) to screen for the Cerebellar Cognitive Affective Syndrome (CCAS) in patients with cerebellar disease.
Objective
This multicenter study tested the ability of the CCAS-Scale to diagnose CCAS in individual patients with common forms of hereditary ataxia.
Metho...
The cerebellum is involved in the acquisition and consolidation of learned fear responses. Knowledge about its contribution to extinction learning, however, is sparse. Extinction processes likely involve erasure of memories, but there is ample evidence that at least part of the original memory remains. We asked the question whether memory persists...
Dopamine is crucial for neuroplasticity, which is considered to be the neurophysiological foundation of learning and memory. The specific effect of dopamine on plasticity such as long-term potentiation (LTP) and long-term depression (LTD) is determined by receptor subtype specificity, concentration level, and the kind of plasticity induction techni...
Cerebellar transcranial direct current stimulation (tDCS) has been reported to enhance the acquisition of conditioned eyeblink responses (CR), a form of associative motor learning. The aim of the present study was to determine possible long-term effects of cerebellar tDCS on the acquisition and extinction of CRs. Delay eyeblink conditioning was per...
Background
Cerebellar transcranial direct current stimulation (tDCS) is widely considered as a promising non-invasive tool to foster motor performance and learning in health and disease. The results of previous studies, however, are inconsistent. Our group failed to provide evidence for an effect of cerebellar tDCS on learning of a complex whole bo...
Transcranial direct current stimulation (tDCS) induces polarity‐ and dose‐dependent neuroplastic aftereffects on cortical excitability and cortical activity, as demonstrated by transcranial magnetic stimulation (TMS) and functional imaging (fMRI) studies. However, lacking systematic comparative studies between stimulation‐induced changes in cortica...
An extended neural network is known to underlie extinction learning. As yet, comparatively little is known about the possible contribution of the cerebellum and the dorsolateral prefrontal cortex (dlPFC). In the present study, transcranial direct current stimulation (tDCS) was used to provide further evidence that the dlPFC and the cerebellum are i...
Key point:
Nicotine modulates cognition and memory function by targeting the nicotinic acetylcholine receptor and releasing different transmitter systems postsynaptically. With both nicotine-generated mechanisms, calcium influx and calcium permeability can be regulated, which is a key requirement for the induction of long-term potentiation, the ph...
Background
Recently, transcranial direct current stimulation (tDCS) became a popular method to non-invasively modulate cerebellar excitability and help us broaden our understanding of cerebellar functions and introduce new therapeutic applications. Despite its popularity, its parameters, such as current polarity, stimulation intensity and electrode...
Nicotine modulates neuroplasticity and improves cognitive functions in animals and humans. In the brain of smoking individuals, calcium-dependent plasticity induced by non-invasive brain stimulation methods such as transcranial direct current stimulation (tDCS) and paired associative stimulation (PAS) is impaired by nicotine withdrawal, but partial...
The posterior parietal cortex (P3) is part of the cortical network involved in motor learning and is structurally and functionally connected withM1.We aimed to explore plastic and functional alterations of parieto-motor connectivity by transcranial direct current stimulation (tDCS). In the first experiment, 15 subjects received anodal, cathodal and...
Nicotine modulates cognition and neuroplasticity in smokers and non-smokers. A possible mechanism for its effect on learning and memory performance is its impact on long-term potentiation (LTP) and long-term depression (LTD). As neuroplasticity is closely connected to learning processes, we aimed to explore the effect of nicotine in healthy, young...
Background:
Noradrenaline is a major neuromodulator in the central nervous system, and it is involved in the pathophysiology of diverse neuropsychiatric diseases. Previous transcranial magnetic stimulation (TMS) studies suggested that acute application of selective noradrenaline reuptake inhibitors (NRI) enhances cortical excitability in the human...
There is good evidence that the human cerebellum is involved in the acquisition and timing of classically conditioned eyeblink responses (CRs). Animal studies suggest that the cerebellum is also important in CR extinction and savings. Cerebellar transcranial direct current stimulation (tDCS) was reported to modulate CR acquisition and timing in a p...
Key points:
Chronic administration of the selective noradrenaline reuptake inhibitor (NRI) reboxetine (RBX) increased and prolonged the long-term potentiation-like plasticity induced by anodal transcranial direct current stimulation (tDCS) for over 24 h. Chronic administration of RBX converted cathodal tDCS-induced long-term depression-like plasti...
Key points:
Applications of transcranial direct current stimulation to modulate human neuroplasticity have increased in research and clinical settings. However, the need for longer-lasting effects, combined with marked inter-individual variability, necessitates a deeper understanding of the relationship between stimulation parameters and physiolog...
Transcranial direct current stimulation (tDCS) of the cerebellum is of increasing interest as a non-invasive technique to modulate motor performance and learning in health and disease. Previous studies have shown that cerebellar tDCS facilitates reach adaptation and associative motor learning in healthy subjects. In the present study it was tested...
Legend explaining parameters in submitted data spreadsheets (Platform Angle-Data Spreadsheet, Balance Time-Data Spreadsheet) and Equivalence Test.
(DOCX)
Platform Angle-Data Spreadsheet.
(XLS)
Balance Time-Data Spreadsheet.
(XLS)
Informed Consent of Individuum shown in Fig 1.
(PDF)
Serotonin affects memory formation via modulating long-term potentiation (LTP) and depression (LTD). Accordingly, acute selective serotonin reuptake inhibitor (SSRI) administration enhanced LTP-like plasticity induced by transcranial direct current stimulation (tDCS) in humans. However, it usually takes some time for SSRI to reduce clinical symptom...
The impact of nicotine (NIC) on plasticity is thought to be primarily determined via calcium channel properties of nicotinic receptor subtypes, and glutamatergic plasticity is likewise calcium-dependent. Therefore glutamatergic plasticity is likely modulated by the impact of nicotinic receptor-dependent neuronal calcium influx. We tested this hypot...
Background:
Although neuronavigation is increasingly used for optimizing coil positioning, the inter-session reliability of hotspot location remains unsatisfactory, probably due to the variability of motor evoked potentials (MEPs) and residual investigator bias.
Purpose:
To increase the reliability and accuracy of hotspot location we introduce a...
Serotonin affects memory formation via modulating long-term potentiation (LTP) and depression (LTD). Accordingly, acute selective serotonin reuptake inhibitor (SSRI) administration enhanced LTP-like plasticity induced by transcranial direct current stimulation (tDCS) in humans. However, it usually takes some time for SSRI to reduce clinical symptom...
Nicotine has been shown to affect cortical excitability measured using transcranial magnetic stimulation in smoking and non-smoking subjects in different ways. In tobacco-deprived smokers, administration of nicotine restores compromised cortical facilitation while in non-smokers, it enhances cortical inhibition. As cortical excitability and activit...
The posterior parietal cortex is part of the cortical network involved in motor learning and is structurally and functionally connected with the primary motor cortex (M1). Neuroplastic alterations of neuronal connectivity might be an important basis for learning processes. These have however not been explored for parieto-motor connections in humans...
Nicotine alters cognitive functions in animals and humans most likely by modification of brain plasticity. In the human brain, it alters plasticity induced by transcranial direct current stimulation (tDCS) and paired associative stimulation (PAS), probably by interference with calcium-dependent modulation of the glutamatergic system. We aimed to te...
Min-Fang Kuo and Michael A. Nitsche contributed equally to this study. Nicotine alters cognitive functions in animals and humans most likely by modification of brain plasticity. In the human brain, it alters plasticity induced by transcranial direct current stimulation (tDCS) and paired associative stimulation (PAS), probably by interference with c...
Serotonin modulates diverse brain functions. Beyond its clinical antidepressant effects, it improves motor performance, learning and memory formation. These effects might at least be partially caused by the impact of serotonin on neuroplasticity, which is thought to be an important foundation of the respective functions. In principal accordance, se...
Transcranial direct current stimulation (tDCS) at an intensity of 1 mA has been shown to be effective in increasing (in case of anodal tDCS) or decreasing (in case of cathodal tDCS) motor cortex excitability. In clinical pilot studies, stronger stimulation intensities are used frequently, but their effect on cortical excitability has not been explo...