- Email: [email protected]
Modification of visual cortex by experience
Int. J. Devl Neuroscience 26 (2008) 827–828
Contents lists available at ScienceDirect
International Journal of Developmental Neuroscience journal homepage: www.elsevier.com/locate/ijdevneu
Plenary Lecture Abstracts [PL01]
a broad impact, ranging from novel insights into the pathophysiology of developmental disorders to new strategies to enhance perceptual learning and recovery from environmental deprivation.
Spike timing-dependent plasticity: Hebb’s postulate revisited Mu-Ming Poo University of California, Berkeley, USA Sixty years ago Donald Hebb postulated that perceptual memory of sensory experience may be stored in the neural circuit by strengthening the synapses among a specific group of cells (‘‘cell assembly’’), through the action of reverberatory activities created by sensory experience within the cell assembly. In this lecture, I will summarize our work over the past 10 years in addressing the validity of the Hebb’s postulate. First, I will describe our discovery of spike timing-dependent plasticity (STDP) in the developing Xenopus retinotectal system, indicating that the timing of pre- and postsynaptic activities plays an important role in the synaptic modification by correlated activities. I will then address the idea of synapsespecificity associated with activity-induced LTP and LTD. I will show that LTP/LTD may undergo extensive spread both in vitro and in vivo from the site of induction to other unstimulated synaptic sites within the neural circuit, in a manner that suggests specific longrange cytoplasmic signaling. Finally, I will present our recent studies of neuronal ensemble activities in the visual system. We found that following the termination of repetitive conditioning visual stimuli, specific cell assembly in the zebrafish optic tectum undergoes regular reverberatory activities at the conditioned time interval (in the absence of sensory stimuli), suggesting circuit reverberatory activities may serve as a mechanism for short-term memory of the time interval of the visual stimuli. Inspired initially by Hebb’s postulate, these studies have revealed rather complex rules of activity-dependent synaptic and circuit modifications, the implications of which for perception and memory remain to be elucidated. doi: 10.1016/j.ijdevneu.2008.09.008 [PL02] Modification of visual cortex by experience Mark Bear Massachusetts Institute of Technology, USA Proper brain function requires the sculpting of connections between neurons during postnatal life. Synapses are formed and strengthened, weakened and lost, under the influence of sensory experience. Over four decades of research on visual cortex have culminated in a deep understanding of the mechanisms for this synaptic plasticity. The knowledge gained by these studies has had 0736-5748/$34.00 ß 2008 Published by Elsevier Ltd on behalf of ISDN. doi:10.1016/j.ijdevneu.2008.09.007
doi: 10.1016/j.ijdevneu.2008.09.009 [PL03] Control of dendritic morphogenesis Yuh-Nung Jan University of California, San Francisco, USA Keywords: Dendritic morphogenesis; Drosophila; Maintenance; Remodeling
The nervous system is composed of a vast number of neurons with strikingly different dendritic morphology. We have been using the dendritic arborization (da) neurons of the Drosophila peripheral nervous system as a model system to study the problems of dendrite development. I will describe some recent progress that begins to answer the questions including: (1) How do different types of neuron acquire their distinctive dendritic morphology? (2) How are the dendritic arbors of different types of neuron organized in the nervous system? (3) What are the mechanisms that control the maintenance and remodeling of dendritic fields? doi: 10.1016/j.ijdevneu.2008.09.010 [PL04] Neural stem cells: From development to repair Freda Miller Hospital for Sick Children, University of Toronto, Canada Keywords: Stem cells; Development; Cortex; Neural crest
This lecture will focus upon the field of mammalian neural stem cells and precursors from two perspectives. The first part of the lecture will focus on our work examining how the environment regulates the behavior of embryonic neural precursors, and how this is perturbed in genetic syndromes that cause cognitive dysfunction. The second part of the lecture will focus upon our work characterizing neural crest-like adult precursor cells from skin (skin-derived precursors or SKPs) both with regard to their basic biology and their potential therapeutic use for treatment of the damaged or degenerating nervous system. doi: 10.1016/j.ijdevneu.2008.09.011
Contents lists available at ScienceDirect
International Journal of Developmental Neuroscience journal homepage: www.elsevier.com/locate/ijdevneu
Plenary Lecture Abstracts [PL01]
a broad impact, ranging from novel insights into the pathophysiology of developmental disorders to new strategies to enhance perceptual learning and recovery from environmental deprivation.
Spike timing-dependent plasticity: Hebb’s postulate revisited Mu-Ming Poo University of California, Berkeley, USA Sixty years ago Donald Hebb postulated that perceptual memory of sensory experience may be stored in the neural circuit by strengthening the synapses among a specific group of cells (‘‘cell assembly’’), through the action of reverberatory activities created by sensory experience within the cell assembly. In this lecture, I will summarize our work over the past 10 years in addressing the validity of the Hebb’s postulate. First, I will describe our discovery of spike timing-dependent plasticity (STDP) in the developing Xenopus retinotectal system, indicating that the timing of pre- and postsynaptic activities plays an important role in the synaptic modification by correlated activities. I will then address the idea of synapsespecificity associated with activity-induced LTP and LTD. I will show that LTP/LTD may undergo extensive spread both in vitro and in vivo from the site of induction to other unstimulated synaptic sites within the neural circuit, in a manner that suggests specific longrange cytoplasmic signaling. Finally, I will present our recent studies of neuronal ensemble activities in the visual system. We found that following the termination of repetitive conditioning visual stimuli, specific cell assembly in the zebrafish optic tectum undergoes regular reverberatory activities at the conditioned time interval (in the absence of sensory stimuli), suggesting circuit reverberatory activities may serve as a mechanism for short-term memory of the time interval of the visual stimuli. Inspired initially by Hebb’s postulate, these studies have revealed rather complex rules of activity-dependent synaptic and circuit modifications, the implications of which for perception and memory remain to be elucidated. doi: 10.1016/j.ijdevneu.2008.09.008 [PL02] Modification of visual cortex by experience Mark Bear Massachusetts Institute of Technology, USA Proper brain function requires the sculpting of connections between neurons during postnatal life. Synapses are formed and strengthened, weakened and lost, under the influence of sensory experience. Over four decades of research on visual cortex have culminated in a deep understanding of the mechanisms for this synaptic plasticity. The knowledge gained by these studies has had 0736-5748/$34.00 ß 2008 Published by Elsevier Ltd on behalf of ISDN. doi:10.1016/j.ijdevneu.2008.09.007
doi: 10.1016/j.ijdevneu.2008.09.009 [PL03] Control of dendritic morphogenesis Yuh-Nung Jan University of California, San Francisco, USA Keywords: Dendritic morphogenesis; Drosophila; Maintenance; Remodeling
The nervous system is composed of a vast number of neurons with strikingly different dendritic morphology. We have been using the dendritic arborization (da) neurons of the Drosophila peripheral nervous system as a model system to study the problems of dendrite development. I will describe some recent progress that begins to answer the questions including: (1) How do different types of neuron acquire their distinctive dendritic morphology? (2) How are the dendritic arbors of different types of neuron organized in the nervous system? (3) What are the mechanisms that control the maintenance and remodeling of dendritic fields? doi: 10.1016/j.ijdevneu.2008.09.010 [PL04] Neural stem cells: From development to repair Freda Miller Hospital for Sick Children, University of Toronto, Canada Keywords: Stem cells; Development; Cortex; Neural crest
This lecture will focus upon the field of mammalian neural stem cells and precursors from two perspectives. The first part of the lecture will focus on our work examining how the environment regulates the behavior of embryonic neural precursors, and how this is perturbed in genetic syndromes that cause cognitive dysfunction. The second part of the lecture will focus upon our work characterizing neural crest-like adult precursor cells from skin (skin-derived precursors or SKPs) both with regard to their basic biology and their potential therapeutic use for treatment of the damaged or degenerating nervous system. doi: 10.1016/j.ijdevneu.2008.09.011