Gürsel Caliskan

Gürsel Caliskan
Otto-von-Guericke-Universität Magdeburg | OvGU · Institute of Biology (IBIO)

PhD

About

48
Publications
9,199
Reads
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533
Citations
Introduction
My current research focuses on identification of physiological and pathological alterations in the hippocampal activity patterns and their relation to modulation of hippocampal engrams in animal models of neuropsychiatric and neurodegenerative disorders. I am also interested in the impact of environmental factors and their interactions with the immune system in mediation of affective behaviour.
Additional affiliations
January 2020 - May 2021
Otto-von-Guericke-Universität Magdeburg
Position
  • Principal Investigator
August 2014 - December 2019
Otto-von-Guericke-Universität Magdeburg
Position
  • PostDoc Position
February 2011 - April 2011
Otto-von-Guericke-Universität Magdeburg
Position
  • Researcher
Description
  • Long-lasting increase in plasma corticosterone associated with changes in anxiety behaviour and hippocampal gamma oscillations following fear memory reconsolidation

Publications

Publications (48)
Article
Full-text available
Parvalbumin-positive (PV) basket cells provide perisomatic inhibition in the cortex and hippocampus and control generation of memory-related network activity patterns, such as sharp wave ripples (SPW-R). Deterioration of this class of fast-spiking interneurons has been observed in neuropsychiatric disorders and evidence from animal models suggests...
Article
Full-text available
Cholinergic neuromodulation in the hippocampus controls the salience of background context memory acquired in the presence of elemental stimuli predicting an aversive reinforcement. With pharmacogenetic inhibition we here demonstrate that hilar perforant path-associated (HIPP) cells of the dentate gyrus mediate the devaluation of background context...
Preprint
Full-text available
Fragile X syndrome (FXS) is the most common inherited form of intellectual disability arising from the loss of fragile X mental retardation protein (FMRP), a protein that plays a central role in neuronal function and plasticity. FXS patients show sensory hypersensitivity, hyperarousal and hippocampus-dependent learning deficits that can be recapitu...
Article
Antibiotics are widely applied for the treatment of bacterial infections, but their long-term use may lead to gut flora dysbiosis and detrimental effects on brain physiology, behavior as well as cognitive performance. Still, a striking lack of knowledge exists concerning electrophysiological correlates of antibiotic-induced changes in gut microbiot...
Article
Remembering the location of food is essential for survival. Rodents and humans employ mainly hippocampus-dependent spatial strategies, but when being stressed they shift to striatum-mediated stimulus-based strategies. To investigate underlying brain circuits, we tested mice with a heightened stress susceptibility due to a lack of the GABA-synthetiz...
Preprint
Remembering the location of food is essential for survival. Rodents and humans employ mainly hippocampus-dependent spatial strategies, but when being stressed they shift to striatum-mediated stimulus-based strategies. To investigate underlying brain circuits, we tested mice with a heightened stress susceptibility due to a lack of the GABA-synthetiz...
Preprint
Full-text available
Generalization is a critical feature of aversive memories and significantly contributes to post-traumatic stress disorder (PTSD) pathogenesis. While fear memories over time tend to generalize across differences in the contextual background and even to novel contextual settings, this effect can be counteracted by exposure to controlled reminder sess...
Poster
Lower graphs: Long-term potentiation (LTP) induction in young animals is achieved regardless of changes in NPYergic neurotransmission with 4xTBS, marked by * p<0.05 (paired t-test; one-tailed). Besides the graphs: Example traces from 30 of Input-Output curve. Example traces are plotted in grey after TBS and in blue/red before. Young and aged mice d...
Article
Full-text available
Objective: Memory impairment is common in patients with temporal lobe epilepsy and seriously affects life quality. Chronic stress is a recognized cofactor in epilepsy and can also impair memory function. Furthermore, increased cortisol levels have been reported in epilepsy patients. Animal models have suggested that aggravating effects of stress o...
Preprint
Full-text available
Antibiotics are widely applied for the treatment of bacterial infections, but their long-term use may lead to gut flora dysbiosis and detrimental effects on brain physiology, behavior as well as cognitive performance. Still, a striking lack of knowledge exists concerning electrophysiological correlates of antibiotic-induced changes in gut microbiot...
Article
Full-text available
A presynaptic active zone organizer protein Bassoon orchestrates numerous important functions at the presynaptic active zone. We previously showed that the absence of Bassoon exclusively in forebrain glutamatergic presynapses (BsnEmx1cKO) in mice leads to developmental disturbances in dentate gyrus (DG) affecting synaptic excitability, morphology,...
Article
Full-text available
Duplications and deletions of short chromosomal fragments are increasingly recognized as the cause for rare neurodevelopmental conditions and disorders. The NDR2 gene encodes a protein kinase important for neuronal development and is part of a microduplication region on chromosome 12 that is associated with intellectual disabilities, autism and epi...
Article
Full-text available
Adverse experiences during childhood are among the most prominent risk factors for developing mood and anxiety disorders later in life. Early-life stress interventions have been established as suitable models to study the neurobiological basis of childhood adversity in rodents. Different models such as maternal separation, impaired maternal care an...
Poster
Full-text available
These authors contributed equally to this work ‡ These authors share senior authorship Anxiety and inclusion load in the BLA is already evident but amenable to rescue Inducible P90CGG mouse model Scheme of the transgene activation by the Tet-On system P90CGG mouse model & induction schedule DOX induction timelines showing the DOX ON and OFF (wash-o...
Poster
Full-text available
Introduction: Phytoestrogens are non-steroidal estrogen analogues and are found primarily in soy products. They have received increasing attention as dietary supplements for estrogen deficiency and as modulators of endogenous estrogen functions, including cognition and emotion. In addition to modifying the levels of circulating sex hormones, phytoe...
Poster
Full-text available
Impact of sex hormones and gender on memory formation, plasticity and excitability has been extensively studied. Apart from its direct effects on neuronal functions and plasticity, the sex hormone estrogen interacts with other neuromodulatory systems and alter the use of cognitive resources via regulation of circuit plasticity and excitability. One...
Article
A traumatic childhood is among the most important risk factors for developing stress-related psychopathologies such as posttraumatic stress disorder or depression later in life. However, despite the proven role of astrocytes in regulating transmitter release and synaptic plasticity, the contribution of astrocytic transmitter metabolism to such stre...
Article
Full-text available
The hippocampus plays a central role as a hub for episodic memory and as an integrator of multimodal sensory information in time and space. Thereby, it critically determines contextual setting and specificity of episodic memories. It is also a key site for the control of innate anxiety states and involved in psychiatric diseases with heightened anx...
Article
Full-text available
Bassoon is a large scaffolding protein of the presynaptic active zone involved in the development of presynaptic terminals and in the regulation of neurotransmitter release at both excitatory and inhibitory brain synapses. Mice with constitutive ablation of the Bassoon (Bsn) gene display impaired presynaptic function, show sensory deficits and deve...
Article
Behavioural metaplasticity is evident in experience-dependent changes of network activity patterns in neuronal circuits that connect the hippocampus, amygdala and medial prefrontal cortex. These limbic regions are key structures of a brain-wide neural network that translates emotionally salient events into persistent and vivid memories. Communicati...
Article
ALBRECHT, A., MÜLLER, I., ARDI, Z., ÇALIŞKAN, G., GRUBER, D., IVENS, S., SEGAL, M., BEHR, J., HEINEMANN, U., STORK, O., and RICHTER-LEVIN, G. Neurobiological consequences of juvenile stress: a GABAergic perspective on risk and resilience. NEUROSCI BIOBEHAV REV XXX-XXX, 2016. − Childhood adversity is among the most potent risk factors for developing...
Article
Objective: The need for alternative pharmacologic strategies in treatment of epilepsies is pressing for about 30% of patients with epilepsy who do not experience satisfactory seizure control with present treatments. In temporal lobe epilepsy (TLE) even up to 80% of patients are pharmacoresistant, and surgical resection of the ictogenic tissue is o...
Article
Childhood trauma is a well-described risk factor for the development of stress-related psychopathology such as posttraumatic stress disorder or depression later in life. Childhood adversity can be modeled in rodents by juvenile stress (JS) protocols, resulting in impaired coping with stressful challenges in adulthood. In the current study, we inves...
Article
Aversive experiences in early life are thought to dispose to psychopathologies such as mood or anxiety disorders. In a two-hit stress model, we assessed the effects of juvenile and/or adult stress on the 5-HT-mediated modulation of synaptic inhibition of ventral dentate gyrus granule cells. Combined but not single stress exposure led to a significa...
Article
Full-text available
The CA3 associative network plays a critical role in the generation of network activity patterns related to emotional state and fear memory. We investigated long-term changes in the corticosterone (CORT)-sensitive function of this network following fear conditioning and fear memory reactivation. In acute slice preparations from mice trained in eith...
Article
Full-text available
The CA3 associative network plays a critical role in the generation of network activity patterns related to emotional state and fear memory. We investigated long-term changes in the corticosterone-sensitive function of this network following fear conditioning and fear memory reactivation. In acute slice preparations from mice trained in either cond...
Article
Stressful experiences do not only cause peripheral changes in stress hormone levels, but also affect central structures such as the hippocampus, implicated in spatial orientation, stress evaluation, and learning and memory. It has been suggested that formation of memory traces is dependent on hippocampal gamma oscillations observed during alert beh...
Article
The GABA synthetic enzyme glutamic acid decarboxylase (GAD)65 is critically involved in the activity-dependent regulation of GABAergic inhibition in the central nervous system. It is also required for the maturation of the GABAergic system during adolescence, a phase that is critical for the development of several neuropsychiatric diseases. Mice be...
Article
Full-text available
The mechanisms that regulate the strength of synaptic transmission and intrinsic neuronal excitability are well characterized; however, the mechanisms that promote disease-causing neural network dysfunction are poorly defined. We generated mice with targeted neuron type-specific expression of a gain-of-function variant of the neurotransmitter recep...
Article
Full-text available
Fearful associations can be replaced by neutral associations through repetitive exposure of an individual to the fearful situation without the aversive component. Recently, Peña and his colleagues demonstrated that pairing activation of noradrenergic (NA) pathways through vagus nerve stimulation (VNS) with extinction learning accelerates consolidat...
Article
Agents such as sertindole and astemizole affect heart action by inducing long-QT syndrome, suggesting that apart from their neuronal actions through histamine receptors, 5-HT2 serotonin receptors and D2 dopamine receptors they also affect ether-a-go-go channels and particularly ether-a-go-go-related (ERG) potassium (K(+) ) channels, comprising the...
Article
Full-text available
Pathological fear and anxiety can be studied, in rodents, with fear conditioning and exposure to reminder cues. These paradigms are thought to critically involve the ventral hippocampus, which also serves as key site of glucocorticoid action in the brain. Here, we demonstrate a long-lasting reduction of kainate-induced gamma oscillations in slice p...
Article
We investigated the interaction between ambient histamine and acetylcholine by studying γ oscillations in rat hippocampus, induced by bath application of acetylcholine (10 µM combined with 2 µM physostigmine). The power of γ was significantly increased by the H1 antagonist, fexofenadine, and H2 receptor agonist, dimaprit, and reduced by the H2 rece...
Article
Full-text available
Sharp wave-ripple complexes (SPW-Rs) in the intact rodent hippocampus are characterized by slow field potential transients superimposed by close to 200-Hz ripple oscillations. Similar events have been recorded in hippocampal slices where SPW-Rs occur spontaneously or can be induced by repeated application of high-frequency stimulation, a standard p...

Questions

Questions (2)
Question
I am having difficulties having LTP in the dorsal DG medial perforant path. I know that it is quite hard to get LTP without blocking the GABAergic transmission.
Here are the conditions I used:
I check if there is pair pulse depression at 50ms interval before I continue with the recordings. Once I am sure I am recording from MPP pathway, I measure IO and PP (10-1000 ms). I arrange my test stimulus 30-40 % of the max amplitude. As the next step I perfuse the slices with GABA-A blocker (picrotoxin or bicuculline) for the whole LTP experiment to record pure excitatory transmission. After 20 min of stable baseline I tried the following LTP induction protocols:
HFS (100 Hz, 1s) 4 times, 60 s interval ( also some varieties of it, like increasing each stimulation duration from 100 microsecond to 200 microseconds or changing the number and interval between the trains)
Theta burst stimulation: Ten stimulus trains (200 ms interval) each containing 5 stimuli (200 Hz) and I repeat it 3 times with 20 s interval.
None of the protocols work. I use tungsten bipolar electrodes (1 megaohm, 75 micrometer distance, Science products)
I am trying this protocol with normal black6 mice before I start with the real experiments. But, the time is running..
I am quite frustrated right now. Does anybody have a good trick or sth that might help?
cheers, Gürsel
Question
I do not want to use a tissue chopper. Foe ventral portion horizontal slices work pretty good. Does anyone have any tricks like cutting coronal slices and changing the angle of the platform?

Projects

Projects (3)
Project
Here, we aim to identify electrophysiological biomarkers for pathological fear and anxiety through investigation of hippocampal network oscillations and its interactions with other limbic oscillations using variety of behavioural tests and rodent models of impaired fear extinction and exessive anxiety.