Understanding how neurones communicate with each other requires a detailed knowledge not only of the anatomical arrangement of the neuronal networks but knowledge of the events at the points of contact (synaptic transmission) and how this can be modulated by prior or concurrent activity.
Our group is working at the level of single neuronal cells in acute slices of rodent brain tissue. We are set-up to visualise and record from living cells within a slice of tissue. We can also inject biochemical markers to help identify the cells for subsequent morphological analysis. In our experiments, we can determine the strength of connections (synapses) between cells as well as the cellular properties of the receiving cell which determine the processing of afferent information.
We work in three different areas, each addressing a particular cellular property of transmission between cells. We record from cell pairs in various layers of cerebral cortex and investigate the characteristics of communication between cells. The goal is to determine the efficacy of the contacts between the cells, the mechanisms underlying its modulation, as well as the efficiency of information transfer between cells.
The efficacy of intercellular communication can change over time, i.e. the synapses are plastic. This is an important feature allowing the brain to adjust efficiently to changes in the environment. It is the basis of learning and memory. We are investigating aspects of both short- and long-term plasticity in the cortex. We are also interested in how different neuronal networks show specific forms of plasticity.
Using Two-Photon Laser Scanning Microscopy (TPLSM) we can image changes in calcium concentration within nerve terminals. Our aim is to investigate the sources of calcium that contribute to spontaneous and evoked synaptic transmission as well as calcium dynamics during short-term plasticity.
The electrical activity of presynaptic neurones is communicated via a chemical signal at the synapse to the postsynaptic cells where it is again converted to an electrical response. The postsynaptic specialisation of the synapse distant from the cell body on long processes (dendrites). This allows interaction between numerous cells (because of the large surface area for contacts) but has the disadvantage that much of the current initiated at the synapse is lost over the surface area of the cell. In most instances, only the current arriving at the cell body contributes to the discharge of the cell. We can build synthetic synapses on the living dendrite, inject a known current at this location, and quantify the amount of current that arrives at the cell body. Using this technique we can measure the interaction between specific synaptic sites and the cell body.
Our investigations will lead to a detailed and quantitative understanding of how neuronal microcircuits are built in our brain.
If you are interested in doing a PhD or Honours project in our laboratory, we are interested in talking with you.
Research support officer
Agahari FA & Stricker C (2021). Serotonergic modulation of spontaneous and evoked transmitter release in layer II pyramidal cells of rat somatosensory cortex. Cereb Cortex 31, 1182–1200.
Choy JMC, Agahari FA, Li L & Stricker C (2018). Noradrenaline increases mEPSC frequency in pyramidal cells in layer II of rat barrel cortex via calcium release from presynaptic stores. Front Cell Neurosci 12, 213(16)
Tran V & Stricker C (2018). Diffusion of Ca2+ from small boutons en passant into the axon shapes ap-evoked Ca2+ transients. Biophys J 115, 1344–1356.
Tran V, Park MCH & Stricker C (2018). An improved measurement of the Ca2+-binding affinity of fluorescent Ca2+ indicators. Cell Calcium 71, 86–94.
Choy JMC, Sané SS, Lee WM, Stricker C, Bachor H-A & Daria VR (2017). Improving focal photostimulation of cortical neurons with pre-derived wavefront correction. Front Cell Neurosci 11, 105.
Go MA, Choy JMC, Colibaba AS, Redman SJ, Bachor H-A, Stricker C & Daria VR (2016). Targeted pruning of a neuron’s dendritic tree via femtosecond laser dendrotomy. Sci Rep 6, 19078.
Zhang T, Go MA, Stricker C, Daria VR & Tricoli A (2015). Low-cost photo-responsive nanocarriers by one-step functionalization of flame-made titania agglomerates with L-lysine. J Mater Chem B 3, 1677–1687.
Gautam V, Drury J, Choy JMC, Stricker C, Bachor H-A & Daria VR (2015). Improved two-photon imaging of living neurons in brain tissue through temporal gating. Biomed Opt Express 6, 4027–4036.
McDonnell MD, Mohan A & Stricker C (2013). Mathematical analysis and algorithms for efficiently and accurately implementing stochastic simulations of short-term synaptic depression and facilitation. Front Comput Neurosci 7, 58.
Mohan A, McDonnell MD & Stricker C (2013). Interaction of short-term depression and firing dynamics in shaping single neuron encoding. Front Comput Neurosci 7, 41.
Go MA, To M-S, Stricker C, Redman SJ, Bachor H-A, Stuart GJ & Daria VR (2013). Four-dimensional multi-site photolysis of caged neurotransmitters. Front Cell Neurosci 7, 231.
Go MA, Stricker C, Redman SJ, Bachor H-A & Daria VR (2012). Simultaneous multi-site two-photon photostimulation in three dimensions. J Biophotonics 5, 745–753.
Scott PC, Cowan AI & Stricker C (2012). Quantifying impacts of short-term plasticity on neuronal information transfer. Physical Reviews E 85, 041921.
McDonnell MD, Mohan A, Stricker C & Ward LM (2012). Input-rate modulation of gamma oscillations is sensitive to network topology, delays and short-term plasticity. Brain Res 1434, 162–177.
Wölfle SE, Navarro-Gonzalez MF, Grayson TH, Stricker C & Hill CE (2010). Involvement of nonselective cation channels in the depolarisation initiating vasomotion. Clin Exp Pharmacol Physiol 37, 536–543.
Daria VR, Stricker C, Bowman R, Redman SJ & Bachor H-A (2009). Arbitrary multisite two-photon excitation in four dimensions. Appl Phys Lett 95, 093701.
Graham BP & Stricker C (2008). Short term plasticity provides temporal filtering at chemical synapses. Lecture Notes in Computer Science 5164, 268–276.
Cheung A, Zhang S, Stricker C & Srinivasan MV (2008). Animal navigation: General properties of directed walks. Biol Cybern 99, 197–217.
Cheung A, Zhang S, Stricker C & Srinivasan MV (2007). Animal navigation: The difficulty of moving in a straight line. Biol Cybern 97, 47–61.
Cowan AI & Stricker C (2004). Functional connectivity in layer IV local circuits of rat somatosensory cortex. J Neurophysiol 92, 2137–2150
Fuhrmann G, Cowan AI, Segev I, Tsodyks MV & Stricker C (2004). Multiple mechanisms govern synaptic dynamics at neocortical synapses. J Physiol 557, 415–438.
Stricker C & Redman SJ (2003). Quantal analysis based on density estimation. J Neurosci Methods 130, 159–171.
Stricker C (2002). Central synaptic integration - linear after all? News in the Physiological Sciences 17, 138–143.
Simkus CRL & Stricker C (2002). The contribution of intracellular calcium stores to mEPSCs recorded in layer II neurons of rat barrel cortex. J Physiol 545, 521–535.
Simkus CRL & Stricker C (2002). Analysis of mEPSCs recorded in layer II neurons of rat barrel cortex. J Physiol 545, 509–520.
Gao B-X, Stricker C & Ziskind-Conhaim L (2001). Transition from GABAergic to glycinergic synaptic transmission in newly formed spinal networks. J Neurophysiol 86, 492–502.
Ulrich D & Stricker C (2000). Dendrosomatic voltage and charge transfer in rat neocortical pyramidal cells in vitro. J Neurophysiol 84, 1445–1452.
Stricker C, Cowan AI, Field AC & Redman SJ (1999). Analysis of NMDA-independent long-term potentiation of EPSCs in rat CA1 neurones in vitro. J Physiol 520, 513–525.
Cowan AI, Stricker C, Reece LJ & Redman SJ (1998). Long-term plasticity at excitatory synapses on aspinous interneurons in area CA1 lacks synaptic specificity. J Neurophysiol 79, 13–20.
Buhl EH, Tamás G, Szilágyi T, Stricker C, Paulsen O & Somogyi P (1997). Effect, number and location of synapses made by single pyramidal cells onto aspiny interneurones of cat visual cortex. J Physiol 500, 689–713.
Stricker C, Field AC & Redman SJ (1996). Statistical analysis of amplitude fluctuations in EPSCs evoked in rat CA1 pyramidal neurones in vitro. J Physiol 490, 419–441.
Stricker C, Field AC & Redman SJ (1996). Changes in quantal parameters of EPSCs in rat CA1 neurones in vitro after the induction of long-term potentiation. J Physiol 490, 443–454.
Stricker C & Redman SJ (1994). Statistical models of synaptic transmission evaluated using the expectation-maximization algorithm. Biophys J 67, 656–670.
Stricker C, Daley D & Redman SJ (1994). Statistical analysis of synaptic transmission: Model discrimination and confidence limits. Biophys J 67, 532–547.
Lüscher H-R, Stricker C, Henneman E & Vardar U (1989). Influences of morphology and topography of motoneurons and muscle spindle afferents on amplitude of single fibre excitatory postsynaptic potentials in the cat. Exp Brain Res 74, 493–500.
Stricker C, Redman SJ, Field AC & Perrett SP (1998). Statistical Analysis of Evoked EPSCs before and after the Induction of LTP and LTD. In Central Synapses: Quantal Mechanisms and Plasticity. eds. Faber DS, Korn H, Redman SJ, Thompson SM & Altman JS pp. 198-207. HFSP, Strasbourg.
Redman, SJ & Stricker, C. (1998). Non-Uniform Release Probabilities, Serial Dependence and Coupling between Adjacent Release Sites in Evoked Transmitter Release. In Central Synapses: Quantal Mechanisms and Plasticity. eds. Faber, D.S. Korn, H. Redman S.J., Thompson, S.M & Altman, J.S. pp. 168-177. HFSP, Strasbourg.
Paulsen O, Buhl EH, Heggelund O, Somogyi P, Stricker C & Tamás G (1998). The Importance of Independent Estiamtes of Quantal Parameters. In Central Synapses: Quantal Mechanisms and Plasticity. eds. Faber, D.S. Korn, H. Redman S.J., Thompson, S.M & Altman, J.S. pp. 47-55. HFSP, Strasbourg.
Stricker C (1997). Slices of Brain Tissue. In Neuroscience Methods: A Guide for Advanced Students. ed. Martin RML. pp. 3-10. Harwood Academic Press, Amsterdam, NL.