Synaptic integration in neural networks

About

Our aim is to understand how information is processed and computed by neuronal circuits, and relate this to the control of behaviour. We primarily study neuronal circuit operations in the neocortex and retina using state of the art multi-site electrophysiological and optical recording techniques. We have discovered that active dendritic integration in the output neurons of the retina and neocortex underlies behaviourally engaged circuit-level computations. Our ongoing work at the single cell level determines how regenerative activity is generated in and spreads throughout the complex dendritic tree of neurons to control action potential output and, at the network level, the neuromodulatory control of neuronal circuit operations.

We use advanced electrophysiological and optical techniques to mechanistically dissect physiologically engaged computations in the retinal and neocortical micro-circuitry. Pioneering work has revealed that neuronal circuit computations occur in the fine tree-like dendritic arbours of central neurons, a finding that demonstrates that the fine-scale interplay between network connectivity and sub-cellular information processing lies at the heart of brain computations.

Ongoing work in the laboratory is aimed at discovering the circuit elements that drive and control physiologically engaged dendritic information processing. For example, the group’s recent work has demonstrated that active dendritic integration in the output neurons of the neocortex is strongly modulated by the cholinergic system, providing a plausible candidate mechanism for attentional processing. Furthermore, in the retina they are dissecting the functional impact of the co-release of neurotransmitters from interneurons on the control of network computations, in order to better understand visual processing.

Contact

  +61 7 334 66352

  srw@uq.edu.au


Group Publications

Research Areas

  • Neuronal circuits
  • Control of behaviour
  • Dendritic information processing
  • Neurotransmitters in the retina
  • Visual processing 

Group Leader


Research Members


Students


Integrating neuroscience and learning: now’s the time

Sah, Pankaj, Fanselow, Michael, Hattie, John, Magsamen, Susan, Mattingley, Jason, Quirk, Gregory and Williams, Stephen (2016) Integrating neuroscience and learning: now’s the time. n p j Science of Learning1 . doi:10.1038/npjscilearn.2016.7

Distribution and function of HCN channels in the apical dendritic tuft of neocortical pyramidal neurons

Harnett, Mark T, Magee, Jeffrey C and Williams, Stephen R (2015) Distribution and function of HCN channels in the apical dendritic tuft of neocortical pyramidal neurons. Journal of Neuroscience35 3: 1024-1037. doi:10.1523/JNEUROSCI.2813-14.2015

Activity-dependent modulation of layer 1 inhibitory neocortical circuits by acetylcholine

Brombas, Arne, Fletcher, Lee N. and Williams, Stephen R. (2014) Activity-dependent modulation of layer 1 inhibitory neocortical circuits by acetylcholine. Journal of Neuroscience34 5: 1932-1941. doi:10.1523/JNEUROSCI.4470-13.2014

Sensory-evoked synaptic integration in cerebellar and cerebral cortical neurons

Chadderton, Paul, Schaefer, Andreas T., Williams, Stephen R.  and Margrie, Troy W.  (2014) Sensory-evoked synaptic integration in cerebellar and cerebral cortical neurons. Nature Reviews Neuroscience15 2: 71-83. doi:10.1038/nrn3648

Synchrony and the single neuron

Williams, Stephen R. (2013) Synchrony and the single neuron. Nature Neuroscience16 12: 1714-1715. doi:10.1038/nn.3586

Potassium channels control the interaction between active dendritic integration compartments in layer 5 cortical pyramidal neurons

Harnett, Mark T., Xu, Ning-Long, Magee, Jeffrey C. and Williams, Stephen R. (2013) Potassium channels control the interaction between active dendritic integration compartments in layer 5 cortical pyramidal neurons. Neuron79 3: 516-529. doi:10.1016/j.neuron.2013.06.005

Nonlinear dendritic integration of sensory and motor input during an active sensing task

Xu, Ning-long, Harnett, Mark T., Williams, Stephen R., Huber, Daniel, O'Connor, Daniel H., Svoboda, Karel and Magee, Jeffrey C. (2012) Nonlinear dendritic integration of sensory and motor input during an active sensing task.Nature492 7428: 247-251. doi:10.1038/nature11601

Postnatal development of intrinsic and synaptic properties transforms signaling in the layer 5 excitatory neural network of the visual cortex

Etherington, Sarah J. and Williams, Stephen R. (2011) Postnatal development of intrinsic and synaptic properties transforms signaling in the layer 5 excitatory neural network of the visual cortex. Journal of Neuroscience31 26: 9526-9537. doi:10.1523/JNEUROSCI.0458-11.2011

Cyclic AMP signaling controls action potential firing rate and molecular circadian pacemaking in the suprachiasmatic nucleus

Atkinson, Susan E., Maywood, Elizabeth S., Chesham, Johanna E., Wozny, Christian, Colwell, Christopher S., Hastings, Michael H. and Williams, Stephen R. (2011) Cyclic AMP signaling controls action potential firing rate and molecular circadian pacemaking in the suprachiasmatic nucleus. Journal of Biological Rhythms26 3: 210-220. doi:10.1177/0748730411402810

Errors in the measurement of voltage-activated ion channels in cell-attached patch-clamp recordings

Williams, Stephen R. and Wozny, Christian (2011) Errors in the measurement of voltage-activated ion channels in cell-attached patch-clamp recordings. Nature Communications2 242: 242-1-242-9. doi:10.1038/ncomms1225

Specificity of synaptic connectivity between layer 1 inhibitory interneurons and layer 2/3 pyramidal neurons in the rat neocortex

Wozny, Christian and Williams, Stephen R. (2011) Specificity of synaptic connectivity between layer 1 inhibitory interneurons and layer 2/3 pyramidal neurons in the rat neocortex. Cerebral Cortex21 8: 1818-1826. doi:10.1093/cercor/bhq257

Neuroscience: The chain reaction of dendritic integration

Williams, Stephen R. and Wozny, Christian (2009) Neuroscience: The chain reaction of dendritic integration. Current Biology19 20: R956-R957. doi:10.1016/j.cub.2009.08.031

Postnatal development of dendritic synaptic integration in rat neocortical pyramidal neurons

Atkinson, Susan E. and Williams, Stephen R. (2009) Postnatal development of dendritic synaptic integration in rat neocortical pyramidal neurons. Journal of Neurophysiology102 2: 735-751. doi:10.1152/jn.00083.2009

Dendritic synaptic integration in central neurons

Williams, Stephen R. and Atkinson, Susan E. (2008) Dendritic synaptic integration in central neurons. Current Biology18 22: R1045-R1047. doi:10.1016/j.cub.2008.08.060

Gating motions underlie AMPA receptor secretion from the endoplasmic reticulum

Penn, Andrew C., Williams, Stephen R . and Greger, Ingo H. (2008) Gating motions underlie AMPA receptor secretion from the endoplasmic reticulum. EMBO Journal27 22: 3056-3068. doi:10.1038/emboj.2008.222

Direct measurement of somatic voltage clamp errors in central neurons

Williams, Stephen R. and Mitchell, Simon J. (2008) Direct measurement of somatic voltage clamp errors in central neurons. Nature Neuroscience11 7: 790-798. doi:10.1038/nn.2137

Action potential generation requires a high sodium channel density in the axon initial segment

Kole, Maarten H. P ., Ilschner, Susanne U., Kampa, Bjorn M., Williams, Stephen R., Ruben, Peter C. and Stuart, Greg J. (2008) Action potential generation requires a high sodium channel density in the axon initial segment. Nature Neuroscience11 2: 178-186. doi:10.1038/nn2040

The back and forth of dendritic plasticity

Williams, Stephen R., Wozny, Christian and Mitchell, Simon J. (2007) The back and forth of dendritic plasticity.Neuron56 6: 947-953. doi:10.1016/j.neuron.2007.12.004

Pathway-specific use-dependent dynamics of excitatory synaptic transmission in rat intracortical circuits

Williams, Stephen R. and Atkinson, Susan E. (2007) Pathway-specific use-dependent dynamics of excitatory synaptic transmission in rat intracortical circuits. The Journal of Physiology585 3: 759-777. doi:10.1113/jphysiol.2007.138453

Dopamine gates action potential backpropagation in midbrain dopaminergic neurons

Gentet, Luc J. and Williams, Stephen R. (2007) Dopamine gates action potential backpropagation in midbrain dopaminergic neurons. Journal of Neuroscience27 8: 1892-1901. doi:10.1523/JNEUROSCI.5234-06.2007

Encoding and decoding of dendritic excitation during active states in pyramidal neurons

Williams, Stephen R. (2005) Encoding and decoding of dendritic excitation during active states in pyramidal neurons.Journal of Neuroscience25 25: 5894-5902. doi:10.1523/JNEUROSCI.0502-05.2005

Spatial compartmentalization and functional impact of conductance in pyramidal neurons

Williams, Stephen R. (2004) Spatial compartmentalization and functional impact of conductance in pyramidal neurons. Nature Neuroscience7 9: 961-967. doi:10.1038/nn1305

Dependence of EPSP efficacy on synapse location in neocortical pyramidal neurons

Williams, Stephen R. and Stuart, Greg J. (2002) Dependence of EPSP efficacy on synapse location in neocortical pyramidal neurons. Science295 5561: 1907-1910. doi:10.1126/science.1067903