scholarly journals Activity based checkpoints ensure circuit stability in the olfactory system

2017 ◽  
Author(s):  
Kiely N James ◽  
Benjamin T Throesch ◽  
Weston Davini ◽  
Kevin T Eade ◽  
Sulagna Ghosh ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Computational Models ◽  
Adult Life ◽  
Adult Brain ◽  
Cortical Circuits ◽  
Mt Neurons ◽  
Perceptual Stability ◽  
The Face ◽  
Sensory Activity ◽  
Activity Dependent

AbstractOlfactory circuits function at birth, yet are continuously remodeled through the integration of adult-born interneurons into the olfactory bulb in a manner that preserves olfactory perceptual stability throughout adult life. The mechanisms that ensure appropriate circuit stability in this dynamic context remain poorly understood. Since interneurons sculpt the excitatory output of mitral and tufted (MT) neurons to the olfactory cortex, we predicted that MT neurons might instruct interneuron wiring in the adult brain. By blocking synaptic transmission from MT neurons we show that MT neuronal activity is critical to maintain olfactory bulb integrity and interneuron survival. Blocking interneuron death uncovered a second activity-dependent checkpoint regulating dendrite branching. In contrast, cortical circuits and MT neurons remain stable in the face of these silent and degenerating olfactory circuits. These studies identify a circuit-specific role for non-sensory activity in regulating integration of neurons into the adult brain, as predicted by previous computational models.

scholarly journals Activity-DependentNPAS4Expression and the Regulation of Gene Programs Underlying Plasticity in the Central Nervous System

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
José Fernando Maya-Vetencourt
Keyword(s):  
Nervous System ◽  
Hot Spot ◽  
Adult Life ◽  
Adult Brain ◽  
Genetic Manipulations ◽  
System A ◽  
Environmental Stimulation ◽  
The Central Nervous System ◽  
Activity Dependent

The capability of the brain to change functionally in response to sensory experience is most active during early stages of development but it decreases later in life when major alterations of neuronal network structures no longer take place in response to experience. This view has been recently challenged by experimental strategies based on the enhancement of environmental stimulation levels, genetic manipulations, and pharmacological treatments, which all have demonstrated that the adult brain retains a degree of plasticity that allows for a rewiring of neuronal circuitries over the entire life course. A hot spot in the field of neuronal plasticity centres on gene programs that underlie plastic phenomena in adulthood. Here, I discuss the role of the recently discovered neuronal-specific and activity-dependent transcription factor NPAS4 as a critical mediator of plasticity in the nervous system. A better understanding of how modifications in the connectivity of neuronal networks occur may shed light on the treatment of pathological conditions such as brain damage or disease in adult life, some of which were once considered untreatable.

scholarly journals γ-Aminobutyric acid-mediated regulation of the activity-dependent olfactory bulb dopaminergic phenotype

2009 ◽  
Vol 87 (10) ◽  
pp. 2211-2221 ◽  
Author(s):  
Yosuke Akiba ◽  
Hayato Sasaki ◽  
Patricio T. Huerta ◽  
Alvaro G. Estevez ◽  
Harriet Baker ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Aminobutyric Acid ◽  
Activity Dependent

Pharmacological Manipulation of Critical Period Plasticity

2018 ◽  
Author(s):  
Ramon Guirado ◽  
Eero Castrén
Keyword(s):  
Critical Period ◽  
Adult Brain ◽  
Brain Disorders ◽  
Critical Periods ◽  
Pharmacological Treatments ◽  
New Paradigm ◽  
Early Postnatal Development ◽  
Pharmacological Manipulation ◽  
Efficient Recovery ◽  
Activity Dependent

Neuronal networks are refined through an activity-dependent competition during critical periods of early postnatal development. Recent studies have shown that critical period plasticity is influenced by a number of environmental factors, including drugs that are widely used for the treatment of brain disorders. These findings suggest a new paradigm, where pharmacological treatments can be used to open critical period–like plasticity in the adult brain. The plastic networks can then be modified through rehabilitation or psychotherapy to rewire those abnormally wired during development. This kind of combination of pharmacotherapy with physical or psychological rehabilitation may open a new opportunity for a more efficient recovery of a number of neurological and neuropsychiatric disorders.

scholarly journals Vigor in the Face of Fluctuating Rates of Reward: An Experimental Examination

2011 ◽  
Vol 23 (12) ◽  
pp. 3933-3938 ◽  
Author(s):  
Marc Guitart-Masip ◽  
Ulrik R. Beierholm ◽  
Raymond Dolan ◽  
Emrah Duzel ◽  
Peter Dayan
Keyword(s):  
Reinforcement Learning ◽  
Computational Models ◽  
Average Rate ◽  
Empirical Studies ◽  
Empirical Work ◽  
Healthy Human ◽  
Average Return ◽  
The Face ◽  
Cost Of Time ◽  
Human Participants

Two fundamental questions underlie the expression of behavior, namely what to do and how vigorously to do it. The former is the topic of an overwhelming wealth of theoretical and empirical work particularly in the fields of reinforcement learning and decision-making, with various forms of affective prediction error playing key roles. Although vigor concerns motivation, and so is the subject of many empirical studies in diverse fields, it has suffered a dearth of computational models. Recently, Niv et al. [Niv, Y., Daw, N. D., Joel, D., & Dayan, P. Tonic dopamine: Opportunity costs and the control of response vigor. Psychopharmacology (Berlin), 191, 507–520, 2007] suggested that vigor should be controlled by the opportunity cost of time, which is itself determined by the average rate of reward. This coupling of reward rate and vigor can be shown to be optimal under the theory of average return reinforcement learning for a particular class of tasks but may also be a more general, perhaps hard-wired, characteristic of the architecture of control. We, therefore, tested the hypothesis that healthy human participants would adjust their RTs on the basis of the average rate of reward. We measured RTs in an odd-ball discrimination task for rewards whose magnitudes varied slowly but systematically. Linear regression on the subjects' individual RTs using the time varying average rate of reward as the regressor of interest, and including nuisance regressors such as the immediate reward in a round and in the preceding round, showed that a significant fraction of the variance in subjects' RTs could indeed be explained by the rate of experienced reward. This validates one of the key proposals associated with the model, illuminating an apparently mandatory form of coupling that may involve tonic levels of dopamine.

scholarly journals Recurrent cortical circuits implement concentration-invariant odor coding

Science ◽  
2018 ◽  
Vol 361 (6407) ◽  
pp. eaat6904 ◽  
Author(s):  
Kevin A. Bolding ◽  
Kevin M. Franks
Keyword(s):  
Olfactory Bulb ◽  
Concentration Dependence ◽  
Neural Circuit ◽  
Feedback Inhibition ◽  
Piriform Cortex ◽  
Cortical Activity ◽  
Cortical Circuits ◽  
Odor Coding ◽  
Recurrent Collateral ◽  
The Impact

Animals rely on olfaction to find food, attract mates, and avoid predators. To support these behaviors, they must be able to identify odors across different odorant concentrations. The neural circuit operations that implement this concentration invariance remain unclear. We found that despite concentration-dependence in the olfactory bulb (OB), representations of odor identity were preserved downstream, in the piriform cortex (PCx). The OB cells responding earliest after inhalation drove robust responses in sparse subsets of PCx neurons. Recurrent collateral connections broadcast their activation across the PCx, recruiting global feedback inhibition that rapidly truncated and suppressed cortical activity for the remainder of the sniff, discounting the impact of slower, concentration-dependent OB inputs. Eliminating recurrent collateral output amplified PCx odor responses rendered the cortex steeply concentration-dependent and abolished concentration-invariant identity decoding.

scholarly journals Localization of phosphotyrosine adaptor protein ShcD/SHC4 in the adult rat central nervous system

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Hannah N. Robeson ◽  
Hayley R. Lau ◽  
Laura A. New ◽  
Jasmin Lalonde ◽  
John N. Armstrong ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Olfactory Bulb ◽  
Adaptor Protein ◽  
Cell Types ◽  
Olfactory Nerve ◽  
Adult Brain ◽  
Specific Cell ◽  
Adult Rat ◽  
Fiber Tracts

Abstract Background Mammalian Shc (Src homology and collagen) proteins comprise a family of four phosphotyrosine adaptor molecules which exhibit varied spatiotemporal expression and signaling functions. ShcD is the most recently discovered homologue and it is highly expressed in the developing central nervous system (CNS) and adult brain. Presently however, its localization within specific cell types of mature neural structures has yet to be characterized. Results In the current study, we examine the expression profile of ShcD in the adult rat CNS using immunohistochemistry, and compare with those of the neuronally enriched ShcB and ShcC proteins. ShcD shows relatively widespread distribution in the adult brain and spinal cord, with prominent levels of staining throughout the olfactory bulb, as well as in sub-structures of the cerebellum and hippocampus, including the subgranular zone. Co-localization studies confirm the expression of ShcD in mature neurons and progenitor cells. ShcD immunoreactivity is primarily localized to axons and somata, consistent with the function of ShcD as a cytoplasmic adaptor. Regional differences in expression are observed among neural Shc proteins, with ShcC predominating in the hippocampus, cerebellum, and some fiber tracts. Interestingly, ShcD is uniquely expressed in the olfactory nerve layer and in glomeruli of the main olfactory bulb. Conclusions Together our findings suggest that ShcD may provide a distinct signaling contribution within the olfactory system, and that overlapping expression of ShcD with other Shc proteins may allow compensatory functions in the brain.

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