1
|
Camon J, Hugues S, Erlandson MA, Robbe D, Lagoun S, Marouane E, Bureau I. The Timing of Sensory-Guided Behavioral Response is Represented in the Mouse Primary Somatosensory Cortex. Cereb Cortex 2019; 29:3034-3047. [PMID: 30060069 DOI: 10.1093/cercor/bhy169] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 06/01/2018] [Accepted: 06/25/2018] [Indexed: 11/13/2022] Open
Abstract
Whisker-guided decision making in mice is thought to critically depend on information processing occurring in the primary somatosensory cortex. However, it is not clear if neuronal activity in this "early" sensory region contains information about the timing and speed of motor response. To address this question we designed a new task in which freely moving mice learned to associate a whisker stimulus to reward delivery. The task was tailored in such a way that a wide range of delays between whisker stimulation and reward collection were observed due to differences of motivation and perception. After training, mice were anesthetized and neuronal responses evoked by stimulating trained and untrained whiskers were recorded across several cortical columns of barrel cortex. We found a strong correlation between the delay of the mouse behavioral response and the timing of multiunit activity evoked by the trained whisker, outside its principal cortical column, in layers 4 and 5A but not in layer 2/3. Circuit mapping ex vivo revealed this effect was associated with a weakening of layer 4 to layer 2/3 projection. We conclude that the processes controlling the propagation of key sensory inputs to naive cortical columns and the timing of sensory-guided action are linked.
Collapse
Affiliation(s)
- Jérémy Camon
- INMED, INSERM U1249, Université Aix-Marseille, Marseille, France
| | - Sandrine Hugues
- INMED, INSERM U1249, Université Aix-Marseille, Marseille, France
| | | | - David Robbe
- INMED, INSERM U1249, Université Aix-Marseille, Marseille, France
| | - Sabria Lagoun
- INMED, INSERM U1249, Université Aix-Marseille, Marseille, France
| | - Emna Marouane
- INMED, INSERM U1249, Université Aix-Marseille, Marseille, France
| | - Ingrid Bureau
- INMED, INSERM U1249, Université Aix-Marseille, Marseille, France
| |
Collapse
|
2
|
Kole K, Scheenen W, Tiesinga P, Celikel T. Cellular diversity of the somatosensory cortical map plasticity. Neurosci Biobehav Rev 2017; 84:100-115. [PMID: 29183683 DOI: 10.1016/j.neubiorev.2017.11.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 11/21/2017] [Accepted: 11/21/2017] [Indexed: 01/23/2023]
Abstract
Sensory maps are representations of the sensory epithelia in the brain. Despite the intuitive explanatory power behind sensory maps as being neuronal precursors to sensory perception, and sensory cortical plasticity as a neural correlate of perceptual learning, molecular mechanisms that regulate map plasticity are not well understood. Here we perform a meta-analysis of transcriptional and translational changes during altered whisker use to nominate the major molecular correlates of experience-dependent map plasticity in the barrel cortex. We argue that brain plasticity is a systems level response, involving all cell classes, from neuron and glia to non-neuronal cells including endothelia. Using molecular pathway analysis, we further propose a gene regulatory network that could couple activity dependent changes in neurons to adaptive changes in neurovasculature, and finally we show that transcriptional regulations observed in major brain disorders target genes that are modulated by altered sensory experience. Thus, understanding the molecular mechanisms of experience-dependent plasticity of sensory maps might help to unravel the cellular events that shape brain plasticity in health and disease.
Collapse
Affiliation(s)
- Koen Kole
- Department of Neurophysiology, Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Nijmegen, The Netherlands; Department of Neuroinformatics, Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Nijmegen, The Netherlands.
| | - Wim Scheenen
- Department of Neurophysiology, Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Paul Tiesinga
- Department of Neuroinformatics, Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Tansu Celikel
- Department of Neurophysiology, Donders Institute for Brain, Cognition, and Behaviour, Radboud University, Nijmegen, The Netherlands
| |
Collapse
|
3
|
Zhao X, Huang L, Guo R, Liu Y, Zhao S, Guan S, Ge R, Cui S, Wang S, Wang JH. Coordinated Plasticity among Glutamatergic and GABAergic Neurons and Synapses in the Barrel Cortex Is Correlated to Learning Efficiency. Front Cell Neurosci 2017; 11:221. [PMID: 28798668 PMCID: PMC5526921 DOI: 10.3389/fncel.2017.00221] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 07/12/2017] [Indexed: 01/29/2023] Open
Abstract
Functional plasticity at cortical synapses and neurons is presumably associated with learning and memory. Additionally, coordinated refinement between glutamatergic and GABAergic neurons occurs in associative memory. If these assumptions are present, neuronal plasticity strength and learning efficiency should be correlated. We have examined whether neuronal plasticity strength and learning efficiency are quantitatively correlated in a mouse model of associative learning. Paired whisker and odor stimulations in mice induce odorant-induced whisker motions. The fully establishment of this associative memory appears fast and slow, which are termed as high learning efficiency and low learning efficiency, respectively. In the study of cellular mechanisms underlying this differential learning efficiency, we have compared the strength of neuronal plasticity in the barrel cortices that store associative signals from the mice with high vs. low learning efficiencies. Our results indicate that the levels of learning efficiency are linearly correlated with the upregulated strengths of excitatory synaptic transmission on glutamatergic neurons and their excitability, as well as the downregulated strengths of GABAergic neurons' excitability, their excitatory synaptic inputs and inhibitory synaptic outputs in layers II~III of barrel cortices. The correlations between learning efficiency in associative memory formation and coordinated plasticity at cortical glutamatergic and GABAergic neurons support the notion that the plasticity of associative memory cells is a basis for memory strength.
Collapse
Affiliation(s)
- Xin Zhao
- Department of Pathophysiology, Bengbu Medical CollegeBengbu, China
| | - Li Huang
- Department of Pathophysiology, Bengbu Medical CollegeBengbu, China
| | - Rui Guo
- Department of Pathophysiology, Bengbu Medical CollegeBengbu, China
| | - Yulong Liu
- Department of Pathophysiology, Bengbu Medical CollegeBengbu, China
| | - Shidi Zhao
- Department of Pathophysiology, Bengbu Medical CollegeBengbu, China
| | - Sudong Guan
- Department of Pathophysiology, Bengbu Medical CollegeBengbu, China
| | - Rongjing Ge
- Department of Pathophysiology, Bengbu Medical CollegeBengbu, China
| | - Shan Cui
- Laboratory of Brain and Cognitive Science, Institute of Biophysics and University of Chinese Academy of SciencesBeijing, China.,University of Chinese Academy of SciencesBeijing, China
| | - Shirlene Wang
- Department of Psychiatry and Behavioral Sciences, Northwestern University, Feinberg School of MedicineChicago, IL, United States
| | - Jin-Hui Wang
- Department of Pathophysiology, Bengbu Medical CollegeBengbu, China.,Laboratory of Brain and Cognitive Science, Institute of Biophysics and University of Chinese Academy of SciencesBeijing, China.,University of Chinese Academy of SciencesBeijing, China.,School of Pharmacy, Qingdao UniversityQingdao, China
| |
Collapse
|
4
|
Guo R, Ge R, Zhao S, Liu Y, Zhao X, Huang L, Guan S, Lu W, Cui S, Wang S, Wang JH. Associative Memory Extinction Is Accompanied by Decayed Plasticity at Motor Cortical Neurons and Persistent Plasticity at Sensory Cortical Neurons. Front Cell Neurosci 2017; 11:168. [PMID: 28659764 PMCID: PMC5469894 DOI: 10.3389/fncel.2017.00168] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 05/31/2017] [Indexed: 01/04/2023] Open
Abstract
Associative memory is essential for cognition, in which associative memory cells and their plasticity presumably play important roles. The mechanism underlying associative memory extinction vs. maintenance remains unclear, which we have studied in a mouse model of cross-modal associative learning. Paired whisker and olfaction stimulations lead to a full establishment of odorant-induced whisker motion in training day 10, which almost disappears if paired stimulations are not given in a week, and then recovers after paired stimulation for an additional day. In mice that show associative memory, extinction and recovery, we have analyzed the dynamical plasticity of glutamatergic neurons in layers II–III of the barrel cortex and layers IV–V of the motor cortex. Compared with control mice, the rate of evoked spikes as well as the amplitude and frequency of excitatory postsynaptic currents increase, whereas the amplitude and frequency of inhibitory postsynaptic currents (IPSC) decrease at training day 10 in associative memory mice. Without paired training for a week, these plastic changes are persistent in the barrel cortex and decayed in the motor cortex. If paired training is given for an additional day to revoke associative memory, neuronal plasticity recovers in the motor cortex. Our study indicates persistent neuronal plasticity in the barrel cortex for cross-modal memory maintenance as well as the dynamical change of neuronal plasticity in the motor cortex for memory retrieval and extinction. In other words, the sensory cortices are essential for long-term memory while the behavior-related cortices with the inability of memory retrieval are correlated to memory extinction.
Collapse
Affiliation(s)
- Rui Guo
- Department of Pathophysiology, Bengbu Medical CollegeAnhui, China
| | - Rongjing Ge
- Department of Pathophysiology, Bengbu Medical CollegeAnhui, China
| | - Shidi Zhao
- Department of Pathophysiology, Bengbu Medical CollegeAnhui, China
| | - Yulong Liu
- Department of Pathophysiology, Bengbu Medical CollegeAnhui, China
| | - Xin Zhao
- Department of Pathophysiology, Bengbu Medical CollegeAnhui, China
| | - Li Huang
- Department of Pathophysiology, Bengbu Medical CollegeAnhui, China
| | - Sodong Guan
- Department of Pathophysiology, Bengbu Medical CollegeAnhui, China
| | - Wei Lu
- School of Pharmacy, Qingdao UniversityQingdao, China
| | - Shan Cui
- Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of SciencesBeijing, China
| | - Shirlene Wang
- Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern UniversityChicago, IL, United States
| | - Jin-Hui Wang
- Department of Pathophysiology, Bengbu Medical CollegeAnhui, China.,School of Pharmacy, Qingdao UniversityQingdao, China.,Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of SciencesBeijing, China.,Department of Biology, University of Chinese Academy of SciencesBeijing, China
| |
Collapse
|
5
|
Coordinated Plasticity between Barrel Cortical Glutamatergic and GABAergic Neurons during Associative Memory. Neural Plast 2016; 2016:5648390. [PMID: 28070425 PMCID: PMC5192352 DOI: 10.1155/2016/5648390] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 10/16/2016] [Accepted: 11/09/2016] [Indexed: 12/22/2022] Open
Abstract
Neural plasticity is associated with memory formation. The coordinated refinement and interaction between cortical glutamatergic and GABAergic neurons remain elusive in associative memory, which we examine in a mouse model of associative learning. In the mice that show odorant-induced whisker motion after pairing whisker and odor stimulations, the barrel cortical glutamatergic and GABAergic neurons are recruited to encode the newly learnt odor signal alongside the innate whisker signal. These glutamatergic neurons are functionally upregulated, and GABAergic neurons are refined in a homeostatic manner. The mutual innervations between these glutamatergic and GABAergic neurons are upregulated. The analyses by high throughput sequencing show that certain microRNAs related to regulating synapses and neurons are involved in this cross-modal reflex. Thus, the coactivation of the sensory cortices through epigenetic processes recruits their glutamatergic and GABAergic neurons to be the associative memory cells as well as drive their coordinated refinements toward the optimal state for the storage of the associated signals.
Collapse
|
6
|
Lebida K, Mozrzymas JW. Spike Timing-Dependent Plasticity in the Mouse Barrel Cortex Is Strongly Modulated by Sensory Learning and Depends on Activity of Matrix Metalloproteinase 9. Mol Neurobiol 2016; 54:6723-6736. [PMID: 27744572 PMCID: PMC5622912 DOI: 10.1007/s12035-016-0174-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 09/28/2016] [Indexed: 12/14/2022]
Abstract
Experience and learning in adult primary somatosensory cortex are known to affect neuronal circuits by modifying both excitatory and inhibitory transmission. Synaptic plasticity phenomena provide a key substrate for cognitive processes, but precise description of the cellular and molecular correlates of learning is hampered by multiplicity of these mechanisms in various projections and in different types of neurons. Herein, we investigated the impact of associative learning on neuronal plasticity in distinct types of postsynaptic neurons by checking the impact of classical conditioning (pairing whisker stroking with tail shock) on the spike timing-dependent plasticity (t-LTP and t-LTD) in the layer IV to II/III vertical pathway of the mouse barrel cortex. Learning in this paradigm practically prevented t-LTP measured in pyramidal neurons but had no effect on t-LTD. Since classical conditioning is known to affect inhibition in the barrel cortex, we examined its effect on tonic GABAergic currents and found a strong downregulation of these currents in the layer II/III interneurons but not in pyramidal cells. Matrix metalloproteinases emerged as crucial players in synaptic plasticity and learning. We report that the blockade of MMP-9 (but not MMP-3) abolished t-LTP having no effect on t-LTD. Moreover, associative learning resulted in an upregulation of gelatinolytic activity within the "trained" barrel. We conclude that LTP induced by spike timing-dependent plasticity (STDP) paradigm is strongly correlated with associative learning and critically depends on the activity of MMP-9.
Collapse
Affiliation(s)
- Katarzyna Lebida
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University, Chalubinskiego 3a, 50-368, Wroclaw, Poland.
| | - Jerzy W Mozrzymas
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University, Chalubinskiego 3a, 50-368, Wroclaw, Poland.,Department of Animal Molecular Physiology, Institute of Experimental Biology, Wroclaw University, Wroclaw, Poland
| |
Collapse
|
7
|
Wang D, Zhao J, Gao Z, Chen N, Wen B, Lu W, Lei Z, Chen C, Liu Y, Feng J, Wang JH. Neurons in the barrel cortex turn into processing whisker and odor signals: a cellular mechanism for the storage and retrieval of associative signals. Front Cell Neurosci 2015; 9:320. [PMID: 26347609 PMCID: PMC4543922 DOI: 10.3389/fncel.2015.00320] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 08/03/2015] [Indexed: 12/28/2022] Open
Abstract
Associative learning and memory are essential to logical thinking and cognition. How the neurons are recruited as associative memory cells to encode multiple input signals for their associated storage and distinguishable retrieval remains unclear. We studied this issue in the barrel cortex by in vivo two-photon calcium imaging, electrophysiology, and neural tracing in our mouse model that the simultaneous whisker and olfaction stimulations led to odorant-induced whisker motion. After this cross-modal reflex arose, the barrel and piriform cortices connected. More than 40% of barrel cortical neurons became to encode odor signal alongside whisker signal. Some of these neurons expressed distinct activity patterns in response to acquired odor signal and innate whisker signal, and others encoded similar pattern in response to these signals. In the meantime, certain barrel cortical astrocytes encoded odorant and whisker signals. After associative learning, the neurons and astrocytes in the sensory cortices are able to store the newly learnt signal (cross-modal memory) besides the innate signal (native-modal memory). Such associative memory cells distinguish the differences of these signals by programming different codes and signify the historical associations of these signals by similar codes in information retrievals.
Collapse
Affiliation(s)
- Dangui Wang
- State Key Lab of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences Beijing, China
| | - Jun Zhao
- State Key Lab of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences Beijing, China ; Department of Biology, University of Chinese Academy of Sciences Beijing, China
| | - Zilong Gao
- State Key Lab of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences Beijing, China ; Department of Biology, University of Chinese Academy of Sciences Beijing, China
| | - Na Chen
- State Key Lab of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences Beijing, China
| | - Bo Wen
- State Key Lab of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences Beijing, China
| | - Wei Lu
- Department of Pharmacology and Collaborative Innovation, Center for Neurodegenerative Disorders in Shandong, Qingdao University, Medical College Dengzhou, China
| | - Zhuofan Lei
- Department of Pharmacology and Collaborative Innovation, Center for Neurodegenerative Disorders in Shandong, Qingdao University, Medical College Dengzhou, China
| | - Changfeng Chen
- Department of Physiology, Bengbu Medical College Bengbu, China
| | - Yahui Liu
- Department of Physiology, Bengbu Medical College Bengbu, China
| | - Jing Feng
- State Key Lab of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences Beijing, China
| | - Jin-Hui Wang
- State Key Lab of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences Beijing, China ; Department of Biology, University of Chinese Academy of Sciences Beijing, China ; Department of Physiology, Bengbu Medical College Bengbu, China
| |
Collapse
|
8
|
Erlandson MA, Manzoni OJ, Bureau I. The Functional Organization of Neocortical Networks Investigated in Slices with Local Field Recordings and Laser Scanning Photostimulation. PLoS One 2015; 10:e0132008. [PMID: 26134668 PMCID: PMC4489676 DOI: 10.1371/journal.pone.0132008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 06/09/2015] [Indexed: 02/07/2023] Open
Abstract
The organization of cortical networks can be investigated functionally in brain slices. Laser scanning photostimulation (LSPS) with glutamate-uncaging allows for a rapid survey of all connections impinging on single cells recorded in patch-clamp. We sought to develop a variant of the method that would allow for a more exhaustive mapping of neuronal networks at every experiment. We found that the extracellular field recordings could be used to detect synaptic responses evoked by LSPS. One to two electrodes were placed in all six cortical layers of barrel cortex successively and maps were computed from the size of synaptic negative local field potentials. The field maps displayed a laminar organization similar to the one observed in maps computed from excitatory postsynaptic currents recorded in patch-clamp mode. Thus, LSPS combined with field recording is an interesting alternative to obtain for every animal tested a comprehensive map of the excitatory intracortical network.
Collapse
Affiliation(s)
- Melissa A. Erlandson
- U901 INMED, INSERM, Marseille, France
- UMRS 901, Aix-Marseille University, Marseille, France
| | - Olivier J. Manzoni
- U901 INMED, INSERM, Marseille, France
- UMRS 901, Aix-Marseille University, Marseille, France
| | - Ingrid Bureau
- U901 INMED, INSERM, Marseille, France
- UMRS 901, Aix-Marseille University, Marseille, France
- * E-mail:
| |
Collapse
|
9
|
Levita L, Howsley P, Jordan J, Johnston P. Potentiation of the early visual response to learned danger signals in adults and adolescents. Soc Cogn Affect Neurosci 2014; 10:269-77. [PMID: 24652856 DOI: 10.1093/scan/nsu048] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The reinforcing effects of aversive outcomes on avoidance behaviour are well established. However, their influence on perceptual processes is less well explored, especially during the transition from adolescence to adulthood. Using electroencephalography, we examined whether learning to actively or passively avoid harm can modulate early visual responses in adolescents and adults. The task included two avoidance conditions, active and passive, where two different warning stimuli predicted the imminent, but avoidable, presentation of an aversive tone. To avoid the aversive outcome, participants had to learn to emit an action (active avoidance) for one of the warning stimuli and omit an action for the other (passive avoidance). Both adults and adolescents performed the task with a high degree of accuracy. For both adolescents and adults, increased N170 event-related potential amplitudes were found for both the active and the passive warning stimuli compared with control conditions. Moreover, the potentiation of the N170 to the warning stimuli was stable and long lasting. Developmental differences were also observed; adolescents showed greater potentiation of the N170 component to danger signals. These findings demonstrate, for the first time, that learned danger signals in an instrumental avoidance task can influence early visual sensory processes in both adults and adolescents.
Collapse
Affiliation(s)
- Liat Levita
- Department of Psychology, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK and Department of Psychology, The University of York, York YO10 5DD, UK
| | - Philippa Howsley
- Department of Psychology, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK and Department of Psychology, The University of York, York YO10 5DD, UK
| | - Jeff Jordan
- Department of Psychology, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK and Department of Psychology, The University of York, York YO10 5DD, UK
| | - Pat Johnston
- Department of Psychology, The University of Sheffield, Western Bank, Sheffield S10 2TN, UK and Department of Psychology, The University of York, York YO10 5DD, UK
| |
Collapse
|
10
|
Abraham NM, Vincis R, Lagier S, Rodriguez I, Carleton A. Long term functional plasticity of sensory inputs mediated by olfactory learning. eLife 2014; 3:e02109. [PMID: 24642413 PMCID: PMC3953949 DOI: 10.7554/elife.02109] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Sensory inputs are remarkably organized along all sensory pathways. While sensory representations are known to undergo plasticity at the higher levels of sensory pathways following peripheral lesions or sensory experience, less is known about the functional plasticity of peripheral inputs induced by learning. We addressed this question in the adult mouse olfactory system by combining odor discrimination studies with functional imaging of sensory input activity in awake mice. Here we show that associative learning, but not passive odor exposure, potentiates the strength of sensory inputs up to several weeks after the end of training. We conclude that experience-dependent plasticity can occur in the periphery of adult mouse olfactory system, which should improve odor detection and contribute towards accurate and fast odor discriminations. DOI:http://dx.doi.org/10.7554/eLife.02109.001 The mammalian brain is not static, but instead retains a significant degree of plasticity throughout an animal’s life. It is this plasticity that enables adults to learn new things, adjust to new environments and, to some degree, regain functions they have lost as a result of brain damage. However, information about the environment must first be detected and encoded by the senses. Odors, for example, activate specific receptors in the nose, and these in turn project to structures called glomeruli in a region of the brain known as the olfactory bulb. Each odor activates a unique combination of glomeruli, and the information contained within this ‘odor fingerprint’ is relayed via olfactory bulb neurons to the olfactory cortex. Now, Abraham et al. have revealed that the earliest stages of odor processing also show plasticity in adult animals. Two groups of mice were exposed to the same two odors: however, the first group was trained to discriminate between the odors to obtain a reward, whereas the second group was passively exposed to them. When both groups of mice were subsequently re-exposed to the odors, the trained group activated more glomeruli, more strongly, than a control group that had never encountered the odors before. By contrast, the responses of mice in the passively exposed group did not differ from those of a control group. Given that the response of glomeruli correlates with the ability of mice to discriminate between odors, these results suggest that trained animals would now be able to discriminate between the odors more easily than other mice. In other words, sensory plasticity ensures that stimuli that have been associatively learned with or without reward will be easier to detect should they be encountered again in the future. DOI:http://dx.doi.org/10.7554/eLife.02109.002
Collapse
Affiliation(s)
- Nixon M Abraham
- Department of Basic Neurosciences, School of Medicine, University of Geneva, Geneva, Switzerland
| | | | | | | | | |
Collapse
|
11
|
Margolis DJ, Lütcke H, Helmchen F. Microcircuit dynamics of map plasticity in barrel cortex. Curr Opin Neurobiol 2013; 24:76-81. [PMID: 24492082 DOI: 10.1016/j.conb.2013.08.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 08/26/2013] [Accepted: 08/27/2013] [Indexed: 10/26/2022]
Abstract
Functional reorganization of the whisker map in rodent barrel cortex has long served as a model for cortical plasticity following changes in sensory experience. Given the heterogeneity of neuronal response properties in neocortex, it has remained unclear how individual neurons in the cortical microcircuit are affected. Novel in vivo imaging and electrophysiology methods allow longitudinal recording of the same neurons' functional properties and therefore have the critical ability to resolve the direction and dynamics of change as plasticity progresses. Tracking sensory responsiveness before and after whisker trimming has uncovered diverse effects in individual neurons, suggesting that longitudinal recording will be essential for elucidating plasticity mechanisms within cortical microcircuits.
Collapse
Affiliation(s)
- David J Margolis
- Brain Research Institute, University of Zurich, Zurich, Switzerland; Department of Cell Biology and Neuroscience, Rutgers University, New Brunswick, NJ, USA.
| | - Henry Lütcke
- Brain Research Institute, University of Zurich, Zurich, Switzerland
| | - Fritjof Helmchen
- Brain Research Institute, University of Zurich, Zurich, Switzerland
| |
Collapse
|
12
|
A role for silent synapses in the development of the pathway from layer 2/3 to 5 pyramidal cells in the neocortex. J Neurosci 2012; 32:13085-99. [PMID: 22993426 DOI: 10.1523/jneurosci.1262-12.2012] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The integration of neurons within the developing cerebral cortex is a prolonged process dependent on a combination of molecular and physiological cues. To examine the latter we used laser scanning photostimulation (LSPS) of caged glutamate in conjunction with whole-cell patch-clamp electrophysiology to probe the integration of pyramidal cells in the sensorimotor regions of the mouse neocortex. In the days immediately after postnatal day 5 (P5) the origin of the LSPS-evoked AMPA receptor (AMPAR)-mediated synaptic inputs were diffuse and poorly defined with considerable variability between cells. Over the subsequent week this coalesced and shifted, primarily influenced by an increased contribution from layers 2/3 cells, which became a prominent motif of the afferent input onto layer 5 pyramidal cells regardless of cortical region. To further investigate this particular emergent translaminar connection, we alternated our mapping protocol between two holding potentials (-70 and +40 mV) allowing us to detect exclusively NMDA receptor (NMDAR)-mediated inputs. This revealed distal MK-801-sensitive synaptic inputs that predict the formation of the mature, canonical layer 2/3 to 5 pathway. However, these were a transient feature and had been almost entirely converted to AMPAR synapses at a later age (P16). To examine the role of activity in the recruitment of early NMDAR synapses, we evoked brief periods (20 min) of rhythmic bursting. Short intense periods of activity could cause a prolonged augmentation of the total input onto pyramidal cells up until P12; a time point when the canonical circuit has been instated and synaptic integration shifts to a more consolidatory phase.
Collapse
|
13
|
Gambino F, Holtmaat A. Spike-timing-dependent potentiation of sensory surround in the somatosensory cortex is facilitated by deprivation-mediated disinhibition. Neuron 2012; 75:490-502. [PMID: 22884332 DOI: 10.1016/j.neuron.2012.05.020] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/15/2012] [Indexed: 10/28/2022]
Abstract
Functional maps in the cerebral cortex reorganize in response to changes in experience, but the synaptic underpinnings remain uncertain. Here, we demonstrate that layer (L) 2/3 pyramidal cell synapses in mouse barrel cortex can be potentiated upon pairing of whisker-evoked postsynaptic potentials (PSPs) with action potentials (APs). This spike-timing-dependent long-term potentiation (STD-LTP) was only effective for PSPs evoked by deflections of a whisker in the neuron's receptive field center, and not its surround. Trimming of all except two whiskers rapidly opened the possibility to drive STD-LTP by the spared surround whisker. This facilitated STD-LTP was associated with a strong decrease in the surrounding whisker-evoked inhibitory conductance and partially occluded picrotoxin-mediated LTP facilitation. Taken together, our data demonstrate that sensory deprivation-mediated disinhibition facilitates STD-LTP from the sensory surround, which may promote correlation- and experience-dependent expansion of receptive fields.
Collapse
Affiliation(s)
- Frédéric Gambino
- Department of Basic Neurosciences, Faculty of Medicine, University of Geneva, CMU, 1 rue Michel Servet, 1211 Geneva, Switzerland.
| | | |
Collapse
|
14
|
Gdalyahu A, Tring E, Polack PO, Gruver R, Golshani P, Fanselow MS, Silva AJ, Trachtenberg JT. Associative fear learning enhances sparse network coding in primary sensory cortex. Neuron 2012; 75:121-32. [PMID: 22794266 DOI: 10.1016/j.neuron.2012.04.035] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/20/2012] [Indexed: 11/26/2022]
Abstract
Several models of associative learning predict that stimulus processing changes during association formation. How associative learning reconfigures neural circuits in primary sensory cortex to "learn" associative attributes of a stimulus remains unknown. Using 2-photon in vivo calcium imaging to measure responses of networks of neurons in primary somatosensory cortex, we discovered that associative fear learning, in which whisker stimulation is paired with foot shock, enhances sparse population coding and robustness of the conditional stimulus, yet decreases total network activity. Fewer cortical neurons responded to stimulation of the trained whisker than in controls, yet their response strength was enhanced. These responses were not observed in mice exposed to a nonassociative learning procedure. Our results define how the cortical representation of a sensory stimulus is shaped by associative fear learning. These changes are proposed to enhance efficient sensory processing after associative learning.
Collapse
Affiliation(s)
- Amos Gdalyahu
- Department of Neurobiology, University of California Los Angeles, Los Angeles, CA 90095, USA.
| | | | | | | | | | | | | | | |
Collapse
|