Peter Jonas

Peter Jonas
Institute of Science and Technology Austria (ISTA) | IST

About

162
Publications
22,937
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
16,046
Citations
Citations since 2017
39 Research Items
6023 Citations
201720182019202020212022202302004006008001,000
201720182019202020212022202302004006008001,000
201720182019202020212022202302004006008001,000
201720182019202020212022202302004006008001,000

Publications

Publications (162)
Preprint
Full-text available
GABAB receptor (GBR) activation inhibits neurotransmitter release in axon terminals in the brain, except in medial habenula (MHb) terminals, which show robust potentiation. However, mechanisms underlying this enigmatic potentiation remain elusive. Here, we report that GBR activation induces a transition from tonic to phasic release accompanied by a...
Preprint
Full-text available
A bstract Stereological methods for estimating the 3D particle size and density from 2D projections are essential to many research fields. These methods are, however, prone to errors arising from undetected particle profiles due to sectioning and limited resolution, known as ‘lost caps’. A potential solution by Keiding et al. (1972) accounts for lo...
Article
Full-text available
To understand the function of neuronal circuits it is crucial to disentangle the connectivity patterns within the network. However, most tools currently used to explore connectivity have low throughput, low selectivity, or limited accessibility. Here, we report the development of an improved packaging system for the production of the highly neurotr...
Preprint
Full-text available
Mapping the complex and dense arrangement of cells and their connectivity in brain tissue demands nanoscale spatial resolution imaging. Super-resolution optical microscopy excels at visualizing specific molecules and individual cells but fails to provide tissue context. Here we developed Comprehensive Analysis of Tissues across Scales (CATS), a tec...
Article
Full-text available
The mammalian hippocampal formation (HF) plays a key role in several higher brain functions, such as spatial coding, learning and memory. Its simple circuit architecture is often viewed as a trisynaptic loop, processing input originating from the superficial layers of the entorhinal cortex (EC) and sending it back to its deeper layers. Here, we sho...
Preprint
Full-text available
Complex wiring between neurons underlies the information-processing network enabling all brain functions, including cognition and memory. For understanding how the network is structured, processes information, and changes over time, comprehensive visualization of the architecture of living brain tissue with its cellular and molecular components wou...
Preprint
Full-text available
The mammalian hippocampal formation (HF) plays a key role in several higher brain functions, such as spatial coding, learning and memory. Its simple circuit architecture is often viewed as a trisynaptic loop, processing input originating from the superficial layers of the entorhinal cortex (EC) in a linear fashion, and sending it back to its deeper...
Preprint
Full-text available
From the large collection of molecular tools used to investigate neuronal connectivity, envA-pseudotyped rabies viral vectors (RVdGenvA) uniquely enable cell-type specific, trans-synaptic retrograde labeling. However, widespread use of the powerful and flexible method is to date hindered by low-yield and cumbersome production pipelines. Here, we re...
Article
Full-text available
Pattern separation is a fundamental brain computation that converts small differences in input patterns into large differences in output patterns. Several synaptic mechanisms of pattern separation have been proposed, including code expansion, inhibition and plasticity; however, which of these mechanisms play a role in the entorhinal cortex (EC)–den...
Article
Full-text available
The hippocampal mossy fiber synapse is a key synapse of the trisynaptic circuit. Post-tetanic potentiation (PTP) is the most powerful form of plasticity at this synaptic connection. It is widely believed that mossy fiber PTP is an entirely presynaptic phenomenon, implying that PTP induction is input-specific, and requires neither activity of multip...
Article
Full-text available
Rigorous investigation of synaptic transmission requires analysis of unitary synaptic events by simultaneous recording from presynaptic terminals and postsynaptic target neurons. However, this has been achieved at only a limited number of model synapses, including the squid giant synapse and the mammalian calyx of Held. Cortical presynaptic termina...
Article
Full-text available
The synaptic connection from medial habenula (MHb) to interpeduncular nucleus (IPN) is critical for emotion-related behaviors, and uniquely expresses R-type Ca ²⁺ channels (Cav2.3) and auxiliary GABA B receptor (GBR) subunits, the K ⁺ -channel tetramerization domain-containing proteins (KCTDs). Activation of GBRs facilitates or inhibits transmitter...
Article
Full-text available
Background To understand information coding in single neurons, it is necessary to analyze subthreshold synaptic events, action potentials (APs), and their interrelation in different behavioral states. However, detecting excitatory postsynaptic potentials (EPSPs) or currents (EPSCs) in behaving animals remains challenging, because of unfavorable sig...
Article
Full-text available
The hippocampus is the key site for learning and memory and for processing of spatial information in the brain. It is divided into three main subregions: the dentate gyrus (DG), the CA3 area, and the CA1 region, which are linearly interconnected to form a so-called trisynaptic circuit. Thus, the DG sits in a strategic position to gate the flow of i...
Preprint
The hippocampal mossy fiber synapse is a key synapse of the trisynaptic circuit of the hippocampus. Post-tetanic potentiation (PTP) is the most powerful form of plasticity at this synaptic connection. It is widely believed that mossy fiber PTP is an entirely presynaptic phenomenon, implying that PTP induction is input-specific, and requires neither...
Article
Full-text available
Graphical Abstract Highlights d >50% of hippocampal GCs are active, but activity level varies over a wide range. 5% of GCs are place cells, but 50% receive spatially tuned synaptic input d Mixed input of GCs constrains models of grid-place code conversion d GC firing is controlled by intrinsic excitability In Brief Zhang et al. simultaneously measu...
Preprint
Full-text available
To understand the mechanisms of information coding in single neurons, it is necessary to analyze subthreshold synaptic events, action potentials (APs), and the interrelation between these two forms of activity in different behavioral states. However, detecting excitatory postsynaptic potentials (EPSPs) or currents (EPSCs) in awake, behaving animals...
Article
Full-text available
Post-tetanic potentiation (PTP) is an attractive candidate mechanism for hippocampus-dependent short-term memory. Although PTP has a uniquely large magnitude at hippocampal mossy fiber-CA3 pyramidal neuron synapses, it is unclear whether it can be induced by natural activity and whether its lifetime is sufficient to support short-term memory. We co...
Preprint
Full-text available
The connection from medial habenula (MHb) to interpeduncular nucleus is critical for aversion- and addiction-related behaviors. This pathway is unique in selective expression of R-type voltage-gated Ca ²⁺ channels (Cav2.3) in its terminals, and robust potentiation of release via presynaptic GABA B receptors (GBRs). To understand the mechanism under...
Article
Full-text available
How structural and functional properties of synapses relate to each other is a fundamental question in neuroscience. Electrophysiology has elucidated mechanisms of synaptic transmission, and electron microscopy (EM) has provided insight into morphological properties of synapses. Here we describe an enhanced method for functional EM ("flash and free...
Preprint
Full-text available
Pattern separation is a fundamental brain computation that converts small differences in synaptic input patterns into large differences in action potential (AP) output patterns. Pattern separation plays a key role in the dentate gyrus, enabling the efficient storage and recall of memories in downstream hippocampal CA3 networks. Several mechanisms f...
Article
Full-text available
Parvalbumin-positive (PV⁺) GABAergic interneurons in hippocampal microcircuits are thought to play a key role in several higher network functions, such as feedforward and feedback inhibition, network oscillations, and pattern separation. Fast lateral inhibition mediated by GABAergic interneurons may implement a winner-takes-all mechanism in the hip...
Article
Full-text available
Summary Fast-spiking, parvalbumin-expressing GABAergic interneurons (PV+-BCs) express a complex machinery of rapid signaling mechanisms, including specialized voltage-gated ion channels to generate brief action potentials (APs). However, short APs are associated with overlapping Na+ and K+ fluxes and are therefore energetically expensive. How the p...
Article
Full-text available
Synaptotagmin 7 (Syt7) is thought to be a Ca2+ sensor that mediates asynchronous transmitter release and facilitation at synapses. However, Syt7 is strongly expressed in fast-spiking, parvalbumin-expressing GABAergic interneurons, and the output synapses of these neurons produce only minimal asynchronous release and show depression rather than faci...
Article
Full-text available
Gamma oscillations (30–150 Hz) in neuronal networks are associated with the processing and recall of information. We measured local field potentials in the dentate gyrus of freely moving mice and found that gamma activity occurs in bursts, which are highly heterogeneous in their spatial extensions, ranging from focal to global coherent events. Syna...
Article
Synaptotagmin 7 (Syt7) was originally identified as a slow Ca²⁺ sensor for lysosome fusion, but its function at fast synapses is controversial. The paper by Luo and Südhof (2017) in this issue of Neuron shows that at the calyx of Held in the auditory brainstem Syt7 triggers asynchronous release during stimulus trains, resulting in reliable and temp...
Article
Full-text available
Graphical Abstract Highlights d Syt2 is the Ca 2+ sensor of fast transmitter release at a cerebellar GABAergic synapse d Syt2 triggers transmitter release with faster time course than Syt1 d Syt2 ensures faster replenishment of the readily releasable pool than Syt1 d Syt2 is essential for fast feedforward inhibition in cerebellar microcircuits In B...
Article
Full-text available
Sharp wave-ripple (SWR) oscillations play a key role in memory consolidation during non-rapid eye movement sleep, immobility, and consummatory behavior. However, whether temporally modulated synaptic excitation or inhibition underlies the ripples is controversial. To address this question, we performed simultaneous recordings of excitatory and inhi...
Article
Full-text available
Mossy fiber synapses on CA3 pyramidal cells are 'conditional detonators' that reliably discharge postsynaptic targets. The 'conditional' nature implies that burst activity in dentate gyrus granule cells is required for detonation. Whether single unitary excitatory postsynaptic potentials (EPSPs) trigger spikes in CA3 neurons remains unknown. Mossy...
Article
Full-text available
The hippocampal CA3 region plays a key role in learning and memory. Recurrent CA3-CA3 synapses are thought to be the subcellular substrate of pattern completion. However, the synaptic mechanisms of this network computation remain enigmatic. To investigate these mechanisms, we combined functional connectivity analysis with network modeling. Simultan...
Article
Full-text available
CA3-CA3 recurrent excitatory synapses are thought to play a key role in memory storage and pattern completion. Whether the plasticity properties of these synapses are consistent with their proposed network functions remains unclear. Here, we examine the properties of spike timing-dependent plasticity (STDP) at CA3-CA3 synapses. Low-frequency pairin...
Data
Supplementary Figures 1-5, Supplementary Table 1 and Supplementary References.
Article
Full-text available
The hippocampus plays a key role in learning and memory. Previous studies suggested that the main types of principal neurons, dentate gyrus granule cells (GCs), CA3 pyramidal neurons, and CA1 pyramidal neurons, differ in their activity pattern, with sparse firing in GCs and more frequent firing in CA3 and CA1 pyramidal neurons. It has been assumed...
Article
Full-text available
Loss-of-function mutations in the synaptic adhesion protein Neuroligin-4 are among the most common genetic abnormalities associated with autism spectrum disorders, but little is known about the function of Neuroligin-4 and the consequences of its loss. We assessed synaptic and network characteristics in Neuroligin-4 knockout mice, focusing on the h...
Article
Based on extrapolation from excitatory synapses, it is often assumed that depletion of the releasable pool of synaptic vesicles is the main factor underlying depression at inhibitory synapses. In this issue of Neuron, using subcellular patch-clamp recording from inhibitory presynaptic terminals, Kawaguchi and Sakaba (2015) show that at Purkinje cel...
Article
Full-text available
Significance The activity dynamics of cortical circuits are directly determined by the composing cells and their connections. Inhibitory interneurons are important regulators of neuronal network function. However, how the functional properties of their output synapses relate to the spatial dimension of the network is unknown. Here, we show that per...
Article
The success story of fast-spiking, parvalbumin-positive (PV+) GABAergic interneurons (GABA, γ-aminobutyric acid) in the mammalian central nervous system is noteworthy. In 1995, the properties of these interneurons were completely unknown. Twenty years later, thanks to the massive use of subcellular patch-clamp techniques, simultaneous multiple-cell...
Article
Full-text available
Electron microscopy (EM) allows for the simultaneous visualization of all tissue components at high resolution. However, the extent to which conventional aldehyde fixation and ethanol dehydration of the tissue alter the fine structure of cells and organelles, thereby preventing detection of subtle structural changes induced by an experiment, has re...
Article
Fast-spiking, parvalbumin-expressing GABAergic interneurons, a large proportion of which are basket cells (BCs), have a key role in feedforward and feedback inhibition, gamma oscillations and complex information processing. For these functions, fast propagation of action potentials (APs) from the soma to the presynaptic terminals is important. Howe...
Article
Full-text available
From Channel to Sensor The coupling between voltage-activated calcium channels and calcium sensors of exocytosis on synaptic vesicles is a key factor that determines the timing and efficiency of transmitter release. It is still largely unclear how tight this coupling is at mature synapses in the central nervous system. Vyleta and Jonas (p. 665 ) fo...
Article
Full-text available
GABAergic inhibitory interneurons control fundamental aspects of neuronal network function. Their functional roles are assumed to be defined by the identity of their input synapses, the architecture of their dendritic tree, the passive and active membrane properties and finally the nature of their postsynaptic targets. Indeed, interneurons display...
Article
Theta-gamma network oscillations are thought to represent key reference signals for information processing in neuronal ensembles, but the underlying synaptic mechanisms remain unclear. To address this question, we performed whole-cell (WC) patch-clamp recordings from mature hippocampal granule cells (GCs) in vivo in the dentate gyrus of anesthetize...
Data
Supporting Information Figure 8. Axonal Sholl distribution differs among classes. (A) Schematic illustration of the Sholl analysis. Concentric rings were centered at the centroid of the soma with a stepwise increasing radius of 100 μm. (B). Cumulative distribution of axonal length of each interneuron M class defined as the percentage of the total a...
Data
Supporting Information Figure 1. Morphological properties of identified GAD67-eGFP cells are not uniformly distributed. The distribution of dendritic and axonal properties was tested by using maximum likelihood analysis (MLA; see Materials and Methods). Each of the 31 variables was fit with one and the sum of two or more Gaussian functions (Mathema...
Data
Supporting Information Figure 5. Total molecular layer (TML)-like cells (class 3) contributed to classes M3 and P3 (blue code in Fig. 2A,4A,6B). (A,B) Two representative Neurolucida reconstructions of class 3 cells are shown. Note, the axonal arborization distributed throughout the molecular layer (ml). Soma and dendrites are shown in black and the...
Data
Supporting Information Figure 7. Hilar perforant path-associated (HIPP)-like cells (class 4) fall in classes M4, P1 and P3 (purple code in Fig. 2A,4A,6B) with axon predominantly located in the outer two thirds of the molecular layer. (A) Two reconstructions of HIPP-like cells are shown. Note, soma, dendrites are located at the gcl-hilus border and...
Data
Supporting Information Figure 9. Micrographs of representative class 1 - 5 cells. Micrographs of DAB-labeled interneurons are shown for class 1 - 5. Arrows point to axonal projections. Dotted lines represent borders between the hilus and the granule cell layer (gcl), between the gcl and the molecular layer (ml) and in case of the class 4 cell, the...
Data
Supporting Information Figure 2. Electrophysiological properties of identified GAD67-eGFP cells are not uniformly distributed. The distribution of passive and active membrane properties was tested by using MLA (see Materials and Methods). Each of the electrophysiological variables was fit with one and the sum of two and three Gaussian functions (gr...