1
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Respiratory influence on brain dynamics: the preponderant role of the nasal pathway and deep slow regime. Pflugers Arch 2023; 475:23-35. [PMID: 35768698 DOI: 10.1007/s00424-022-02722-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 06/17/2022] [Accepted: 06/21/2022] [Indexed: 01/31/2023]
Abstract
As a possible body signal influencing brain dynamics, respiration is fundamental for perception, cognition, and emotion. The olfactory system has recently acquired its credentials by proving to be crucial in the transmission of respiratory influence on the brain via the sensitivity to nasal airflow of its receptor cells. Here, we present recent findings evidencing respiration-related activities in the brain. Then, we review the data explaining the fact that breathing is (i) nasal and (ii) being slow and deep is crucial in its ability to stimulate the olfactory system and consequently influence the brain. In conclusion, we propose a possible scenario explaining how this optimal respiratory regime can promote changes in brain dynamics of an olfacto-limbic-respiratory circuit, providing a possibility to induce calm and relaxation by coordinating breathing regime and brain state.
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2
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LaValley D. Equivocating on unconsciousness. THEORY & PSYCHOLOGY 2022. [DOI: 10.1177/09593543221092708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In the language used by those who take an empirical approach to the study of consciousness, the subliminal–supraliminal binary and the unconscious–conscious process binary are treated as one and the same, despite the unconscious–conscious process distinction having a historical association to a different meaning. The historical meaning of the unconscious–conscious process distinction may then become implicitly associated with the interpretations of related studies, resulting in a misinterpretation of evidence. This is to say, where the ability to differentially respond to subliminal and supraliminal stimuli may be indicative of a variety of “unconscious” and “conscious” processes, as these terms relate to a qualitative conception of consciousness, subliminal threshold testing does not tell us anything about consciousness and the associated binary of “unconscious” and “conscious” processes as these terms relate to their historical, metacognitive conceptions.
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3
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Smell-induced gamma oscillations in human olfactory cortex are required for accurate perception of odor identity. PLoS Biol 2022; 20:e3001509. [PMID: 34986157 PMCID: PMC8765613 DOI: 10.1371/journal.pbio.3001509] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 01/18/2022] [Accepted: 12/08/2021] [Indexed: 11/24/2022] Open
Abstract
Studies of neuronal oscillations have contributed substantial insight into the mechanisms of visual, auditory, and somatosensory perception. However, progress in such research in the human olfactory system has lagged behind. As a result, the electrophysiological properties of the human olfactory system are poorly understood, and, in particular, whether stimulus-driven high-frequency oscillations play a role in odor processing is unknown. Here, we used direct intracranial recordings from human piriform cortex during an odor identification task to show that 3 key oscillatory rhythms are an integral part of the human olfactory cortical response to smell: Odor induces theta, beta, and gamma rhythms in human piriform cortex. We further show that these rhythms have distinct relationships with perceptual behavior. Odor-elicited gamma oscillations occur only during trials in which the odor is accurately perceived, and features of gamma oscillations predict odor identification accuracy, suggesting that they are critical for odor identity perception in humans. We also found that the amplitude of high-frequency oscillations is organized by the phase of low-frequency signals shortly following sniff onset, only when odor is present. Our findings reinforce previous work on theta oscillations, suggest that gamma oscillations in human piriform cortex are important for perception of odor identity, and constitute a robust identification of the characteristic electrophysiological response to smell in the human brain. Future work will determine whether the distinct oscillations we identified reflect distinct perceptual features of odor stimuli. Intracranial recordings from human olfactory cortex reveal a characteristic spectrotemporal response to odors, including theta, beta and gamma oscillations, and show that high-frequency responses are critical for accurate perception of odors.
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4
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Kesserwani H. The Clinical, Philosophical, Evolutionary and Mathematical Machinery of Consciousness: An Analytic Dissection of the Field Theories and a Consilience of Ideas. Cureus 2020; 12:e12139. [PMID: 33489551 PMCID: PMC7813534 DOI: 10.7759/cureus.12139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2020] [Indexed: 11/05/2022] Open
Abstract
The Cartesian model of mind-body dualism concurs with religious traditions. However, science has supplanted this idea with an energy-matter theory of consciousness, where matter is equivalent to the body and energy replaces the mind or soul. This equivalency is analogous to the concept of the interchange of mass and energy as expressed by Einstein's famous equation [Formula: see text]. Immanuel Kant, in his Critique of Pure Reason, provided the intellectual and theoretical framework for a theory of mind or consciousness. Any theory of consciousness must include the fact that a conscious entity, as far as is known, is a wet biological medium (the brain), of stupendously high entropy. This organ or entity generates a field that must account for the "binding problem", which we will define. This proposed field, the conscious electro-magnetic information (CEMI) field, also has physical properties, which we will outline. We will also demonstrate the seamless transition of the Kantian philosophy of the a priori conception of space and time, the organs of perception and conception, into the CEMI field of consciousness. We will explore the concept of the CEMI field and its neurophysiological correlates, and in particular, synchronous and coherent gamma oscillations of various neuronal ensembles, as in William J Freeman's experiments in the early 1970s with olfactory perception in rabbits. The expansion of the temporo-parietal-occipital (TPO) cortex in hominid evolution epitomizes metaphorical and abstract thinking. This area of the cortex, with synchronous thalamo-cortical oscillations has the best fit for a minimal neural correlate of consciousness. Our field theory shifts consciousness from an abstract idea to a tangible energy with defined properties and a mathematical framework. Even further, it is not a coincidence that the cerebral cortex is very thin with respect to the diameter of the brain. This is in keeping with its fantastically high entropy, as we see in the event horizon of a black hole and the conformal field theory/anti-de Sitter (CFT/ADS) holographic model of the universe. We adumbrate the uniqueness of consciousness of an advanced biological system such as the human brain and draw insight from Avicenna's gendanken, floating man thought experiment. The multi-system high volume afferentation of a biological wet system honed after millions of years of evolution, its high entropy, and the CEMI field variation inducing currents in motor output pathways are proposed to spark the seeds of consciousness. We will also review Karl Friston's free energy principle, the concept of belief-update in a Bayesian inference framework, the minimization of the divergence of prior and posterior probability distributions, and the entropy of the brain. We will streamline these highly technical papers, which view consciousness as a minimization principle akin to Hilbert's action in deriving Einstein's field equation or Feynman's sum of histories in quantum mechanics. Consciousness here is interpreted as flow of probability densities on a Riemmanian manifold, where the gradient of ascent on this manifold across contour lines determines the magnitude of perception or the degree of update of the belief-system in a Bayesian inference model. Finally, the science of consciousness has transcended metaphysics and its study is now rooted in the latest advances of neurophysiology, neuro-radiology under the aegis of mathematics.
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5
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Kontaris I, East BS, Wilson DA. Behavioral and Neurobiological Convergence of Odor, Mood and Emotion: A Review. Front Behav Neurosci 2020; 14:35. [PMID: 32210776 PMCID: PMC7076187 DOI: 10.3389/fnbeh.2020.00035] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 02/19/2020] [Indexed: 12/18/2022] Open
Abstract
The affective state is the combination of emotion and mood, with mood reflecting a running average of sequential emotional events together with an underlying internal affective state. There is now extensive evidence that odors can overtly or subliminally modulate mood and emotion. Relying primarily on neurobiological literature, here we review what is known about how odors can affect emotions/moods and how emotions/moods may affect odor perception. We take the approach that form can provide insight into function by reviewing major brain regions and neural circuits underlying emotion and mood, and then reviewing the olfactory pathway in the context of that emotion/mood network. We highlight the extensive neuroanatomical opportunities for odor-emotion/mood convergence, as well as functional data demonstrating reciprocal interactions between these processes. Finally, we explore how the odor- emotion/mood interplay is, or could be, used in medical and/or commercial applications.
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Affiliation(s)
- Ioannis Kontaris
- Givaudan UK Limited, Health and Well-being Centre of Excellence, Ashford, United Kingdom
| | - Brett S East
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NC, United States.,Child and Adolescent Psychiatry, NYU School of Medicine, New York University, New York, NY, United States
| | - Donald A Wilson
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NC, United States.,Child and Adolescent Psychiatry, NYU School of Medicine, New York University, New York, NY, United States
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6
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Losacco J, Ramirez-Gordillo D, Gilmer J, Restrepo D. Learning improves decoding of odor identity with phase-referenced oscillations in the olfactory bulb. eLife 2020; 9:e52583. [PMID: 31990271 PMCID: PMC6986879 DOI: 10.7554/elife.52583] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/30/2019] [Indexed: 01/04/2023] Open
Abstract
Local field potential oscillations reflect temporally coordinated neuronal ensembles-coupling distant brain regions, gating processing windows, and providing a reference for spike timing-based codes. In phase amplitude coupling (PAC), the amplitude of the envelope of a faster oscillation is larger within a phase window of a slower carrier wave. Here, we characterized PAC, and the related theta phase-referenced high gamma and beta power (PRP), in the olfactory bulb of mice learning to discriminate odorants. PAC changes throughout learning, and odorant-elicited changes in PRP increase for rewarded and decrease for unrewarded odorants. Contextual odorant identity (is the odorant rewarded?) can be decoded from peak PRP in animals proficient in odorant discrimination, but not in naïve mice. As the animal learns to discriminate the odorants the dimensionality of PRP decreases. Therefore, modulation of phase-referenced chunking of information in the course of learning plays a role in early sensory processing in olfaction.
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Affiliation(s)
- Justin Losacco
- Neuroscience Graduate ProgramUniversity of Colorado Anschutz Medical CampusAuroraUnited States
- Department of Cell and Developmental BiologyUniversity of Colorado Anschutz Medical CampusAuroraUnited States
| | - Daniel Ramirez-Gordillo
- Department of Cell and Developmental BiologyUniversity of Colorado Anschutz Medical CampusAuroraUnited States
| | - Jesse Gilmer
- Neuroscience Graduate ProgramUniversity of Colorado Anschutz Medical CampusAuroraUnited States
- Department of Physiology and BiophysicsUniversity of Colorado Anschutz Medical CampusAuroraUnited States
| | - Diego Restrepo
- Neuroscience Graduate ProgramUniversity of Colorado Anschutz Medical CampusAuroraUnited States
- Department of Cell and Developmental BiologyUniversity of Colorado Anschutz Medical CampusAuroraUnited States
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7
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Heck DH, Kozma R, Kay LM. The rhythm of memory: how breathing shapes memory function. J Neurophysiol 2019; 122:563-571. [PMID: 31215344 DOI: 10.1152/jn.00200.2019] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The mammalian olfactory bulb displays a prominent respiratory rhythm, which is linked to the sniff cycle and is driven by sensory input from olfactory receptors in the nasal sensory epithelium. In rats and mice, respiratory frequencies occupy the same band as the hippocampal θ-rhythm, which has been shown to be a key player in memory processes. Hippocampal and olfactory bulb rhythms were previously found to be uncorrelated except in specific odor-contingency learning circumstances. However, many recent electrophysiological studies in both rodents and humans reveal a surprising cycle-by-cycle influence of nasal respiration on neuronal activity throughout much of the cerebral cortex beyond the olfactory system, including the prefrontal cortex, hippocampus, and subcortical structures. In addition, respiratory phase has been shown to influence higher-frequency oscillations associated with cognitive functions, including attention and memory, such as the power of γ-rhythms and the timing of hippocampal sharp wave ripples. These new findings support respiration's role in cognitive function, which is supported by studies in human subjects, in which nasal respiration has been linked to memory processes. Here, we review recent reports from human and rodent experiments that link respiration to the modulation of memory function and the neurophysiological processes involved in memory in rodents and humans. We argue that respiratory influence on the neuronal activity of two key memory structures, the hippocampus and prefrontal cortex, provides a potential neuronal mechanism behind respiratory modulation of memory.
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Affiliation(s)
- Detlef H Heck
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center
| | - Robert Kozma
- Department of Mathematical Sciences, University of Memphis, Memphis, Tennessee.,Department of Computer Sciences, University of Massachusetts Amherst, Massachusetts
| | - Leslie M Kay
- Department of Psychology and Institute for Mind and Biology, The University of Chicago, Chicago, Illinois
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8
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Harnessing olfactory bulb oscillations to perform fully brain-based sleep-scoring and real-time monitoring of anaesthesia depth. PLoS Biol 2018; 16:e2005458. [PMID: 30408025 PMCID: PMC6224033 DOI: 10.1371/journal.pbio.2005458] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 10/04/2018] [Indexed: 12/11/2022] Open
Abstract
Real-time tracking of vigilance states related to both sleep or anaesthesia has been a goal for over a century. However, sleep scoring cannot currently be performed with brain signals alone, despite the deep neuromodulatory transformations that accompany sleep state changes. Therefore, at heart, the operational distinction between sleep and wake is that of immobility and movement, despite numerous situations in which this one-to-one mapping fails. Here we demonstrate, using local field potential (LFP) recordings in freely moving mice, that gamma (50–70 Hz) power in the olfactory bulb (OB) allows for clear classification of sleep and wake, thus providing a brain-based criterion to distinguish these two vigilance states without relying on motor activity. Coupled with hippocampal theta activity, it allows the elaboration of a sleep scoring algorithm that relies on brain activity alone. This method reaches over 90% homology with classical methods based on muscular activity (electromyography [EMG]) and video tracking. Moreover, contrary to EMG, OB gamma power allows correct discrimination between sleep and immobility in ambiguous situations such as fear-related freezing. We use the instantaneous power of hippocampal theta oscillation and OB gamma oscillation to construct a 2D phase space that is highly robust throughout time, across individual mice and mouse strains, and under classical drug treatment. Dynamic analysis of trajectories within this space yields a novel characterisation of sleep/wake transitions: whereas waking up is a fast and direct transition that can be modelled by a ballistic trajectory, falling asleep is best described as a stochastic and gradual state change. Finally, we demonstrate that OB oscillations also allow us to track other vigilance states. Non-REM (NREM) and rapid eye movement (REM) sleep can be distinguished with high accuracy based on beta (10–15 Hz) power. More importantly, we show that depth of anaesthesia can be tracked in real time using OB gamma power. Indeed, the gamma power predicts and anticipates the motor response to stimulation both in the steady state under constant anaesthetic and dynamically during the recovery period. Altogether, this methodology opens the avenue for multi-timescale characterisation of brain states and provides an unprecedented window onto levels of vigilance. Real-time tracking of vigilance states related to wake, sleep, and anaesthesia has been a goal for over a century. However identification of wakefulness and different sleep states cannot currently be performed routinely with brain signals and instead relies on motor activity. Here we demonstrate that 50–70 Hz electrical oscillations in the olfactory bulb (OB) of mice are a reliable indicator for global brain states. Recording this activity with an implanted electrode allows for clear classification of sleep and wake, without the need for motor activity monitoring. We construct a fully automatic sleep scoring algorithm that relies on brain activity alone and is robust throughout time, between animals, and after drug administration. Our method also tracks in real time the depth of anaesthesia both in the steady state under constant anaesthetic and dynamically during the recovery period from anaesthesia. Furthermore, this index predicts responsiveness to noxious stimulation under anaesthesia. Altogether, this methodology opens the avenue for characterisation of vigilance states based on OB recordings.
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9
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Aversive learning-induced plasticity throughout the adult mammalian olfactory system: insights across development. J Bioenerg Biomembr 2018; 51:15-27. [PMID: 30171506 DOI: 10.1007/s10863-018-9770-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 08/27/2018] [Indexed: 10/28/2022]
Abstract
Experiences, such as sensory learning, are known to induce plasticity in mammalian sensory systems. In recent years aversive olfactory learning-induced plasticity has been identified at all stages of the adult olfactory pathway; however, the underlying mechanisms have yet to be identified. Much of the work regarding mechanisms of olfactory associative learning comes from neonates, a time point before which the brain or olfactory system is fully developed. In addition, pups and adults often express different behavioral outcomes when subjected to the same olfactory aversive conditioning paradigm, making it difficult to directly attribute pup mechanisms of plasticity to adults. Despite the differences, there is evidence of similarities between pups and adults in terms of learning-induced changes in the olfactory system, suggesting at least some conserved mechanisms. Identifying these conserved mechanisms of plasticity would dramatically increase our understanding of how the brain is able to alter encoding and consolidation of salient olfactory information even at the earliest stages following aversive learning. The focus of this review is to systematically examine literature regarding olfactory associative learning across developmental stages and search for similarities in order to build testable hypotheses that will inform future studies of aversive learning-induced sensory plasticity in adults.
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10
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Theta and Alpha Oscillations Are Traveling Waves in the Human Neocortex. Neuron 2018; 98:1269-1281.e4. [PMID: 29887341 DOI: 10.1016/j.neuron.2018.05.019] [Citation(s) in RCA: 151] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 03/30/2018] [Accepted: 05/11/2018] [Indexed: 12/12/2022]
Abstract
Human cognition requires the coordination of neural activity across widespread brain networks. Here, we describe a new mechanism for large-scale coordination in the human brain: traveling waves of theta and alpha oscillations. Examining direct brain recordings from neurosurgical patients performing a memory task, we found contiguous clusters of cortex in individual patients with oscillations at specific frequencies within 2 to 15 Hz. These oscillatory clusters displayed spatial phase gradients, indicating that they formed traveling waves that propagated at ∼0.25-0.75 m/s. Traveling waves were relevant behaviorally because their propagation correlated with task events and was more consistent when subjects performed the task well. Human traveling theta and alpha waves can be modeled by a network of coupled oscillators because the direction of wave propagation correlated with the spatial orientation of local frequency gradients. Our findings suggest that oscillations support brain connectivity by organizing neural processes across space and time.
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11
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Abstract
Top-down processes conveying contextual information play a major role in shaping odor representations within the olfactory system, yet the underlying mechanisms are poorly understood. The hippocampus (HPC) is a major source of olfactory top-down modulation, providing direct excitatory inputs to the anterior olfactory nucleus (AON). However, HPC-AON projections remain uncharacterized. In an effort to understand how hippocampal inputs are distributed within the AON, we systematically outlined their organization using anterograde and retrograde tracing methods. We found that AON-projecting hippocampal pyramidal neurons are located mostly in the ventral two-thirds of the HPC and are organized topographically such that cells with a ventral to intermediate hippocampal point of origin terminate, respectively, at the medial to lateral AON. Our neuroanatomical findings suggest a potential role for the HPC in the early processing and contextualization of odors which merits further investigation.
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Affiliation(s)
- Afif J Aqrabawi
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Jun Chul Kim
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON, Canada.,Department of Psychology, University of Toronto, Toronto, ON, Canada
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12
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Li G, Cleland TA. A coupled-oscillator model of olfactory bulb gamma oscillations. PLoS Comput Biol 2017; 13:e1005760. [PMID: 29140973 PMCID: PMC5706731 DOI: 10.1371/journal.pcbi.1005760] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 11/29/2017] [Accepted: 09/01/2017] [Indexed: 11/19/2022] Open
Abstract
The olfactory bulb transforms not only the information content of the primary sensory representation, but also its underlying coding metric. High-variance, slow-timescale primary odor representations are transformed by bulbar circuitry into secondary representations based on principal neuron spike patterns that are tightly regulated in time. This emergent fast timescale for signaling is reflected in gamma-band local field potentials, presumably serving to efficiently integrate olfactory sensory information into the temporally regulated information networks of the central nervous system. To understand this transformation and its integration with interareal coordination mechanisms requires that we understand its fundamental dynamical principles. Using a biophysically explicit, multiscale model of olfactory bulb circuitry, we here demonstrate that an inhibition-coupled intrinsic oscillator framework, pyramidal resonance interneuron network gamma (PRING), best captures the diversity of physiological properties exhibited by the olfactory bulb. Most importantly, these properties include global zero-phase synchronization in the gamma band, the phase-restriction of informative spikes in principal neurons with respect to this common clock, and the robustness of this synchronous oscillatory regime to multiple challenging conditions observed in the biological system. These conditions include substantial heterogeneities in afferent activation levels and excitatory synaptic weights, high levels of uncorrelated background activity among principal neurons, and spike frequencies in both principal neurons and interneurons that are irregular in time and much lower than the gamma frequency. This coupled cellular oscillator architecture permits stable and replicable ensemble responses to diverse sensory stimuli under various external conditions as well as to changes in network parameters arising from learning-dependent synaptic plasticity.
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Affiliation(s)
- Guoshi Li
- Dept. Psychology, Cornell University, Ithaca, NY United States of America
| | - Thomas A. Cleland
- Dept. Psychology, Cornell University, Ithaca, NY United States of America
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13
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Cavelli M, Rojas-Líbano D, Schwarzkopf N, Castro-Zaballa S, Gonzalez J, Mondino A, Santana N, Benedetto L, Falconi A, Torterolo P. Power and coherence of cortical high-frequency oscillations during wakefulness and sleep. Eur J Neurosci 2017; 48:2728-2737. [DOI: 10.1111/ejn.13718] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Revised: 09/13/2017] [Accepted: 09/13/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Matías Cavelli
- Laboratorio de Neurobiología del Sueño; Departamento de Fisiología; Facultad de Medicina; Universidad de la República; General Flores 2125 11800 Montevideo Uruguay
| | - Daniel Rojas-Líbano
- Laboratorio de Neurociencia Cognitiva y Social; Facultad de Psicología; Universidad Diego Portales; Santiago Chile
| | - Natalia Schwarzkopf
- Laboratorio de Neurobiología del Sueño; Departamento de Fisiología; Facultad de Medicina; Universidad de la República; General Flores 2125 11800 Montevideo Uruguay
| | - Santiago Castro-Zaballa
- Laboratorio de Neurobiología del Sueño; Departamento de Fisiología; Facultad de Medicina; Universidad de la República; General Flores 2125 11800 Montevideo Uruguay
| | - Joaquín Gonzalez
- Laboratorio de Neurobiología del Sueño; Departamento de Fisiología; Facultad de Medicina; Universidad de la República; General Flores 2125 11800 Montevideo Uruguay
| | - Alejandra Mondino
- Laboratorio de Neurobiología del Sueño; Departamento de Fisiología; Facultad de Medicina; Universidad de la República; General Flores 2125 11800 Montevideo Uruguay
| | - Noelia Santana
- Laboratorio de Neurobiología del Sueño; Departamento de Fisiología; Facultad de Medicina; Universidad de la República; General Flores 2125 11800 Montevideo Uruguay
| | - Luciana Benedetto
- Laboratorio de Neurobiología del Sueño; Departamento de Fisiología; Facultad de Medicina; Universidad de la República; General Flores 2125 11800 Montevideo Uruguay
| | - Atilio Falconi
- Laboratorio de Neurobiología del Sueño; Departamento de Fisiología; Facultad de Medicina; Universidad de la República; General Flores 2125 11800 Montevideo Uruguay
| | - Pablo Torterolo
- Laboratorio de Neurobiología del Sueño; Departamento de Fisiología; Facultad de Medicina; Universidad de la República; General Flores 2125 11800 Montevideo Uruguay
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14
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Gamma and Beta Oscillations Define a Sequence of Neurocognitive Modes Present in Odor Processing. J Neurosci 2017; 36:7750-67. [PMID: 27445151 DOI: 10.1523/jneurosci.0569-16.2016] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 06/06/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Olfactory system beta (15-35 Hz) and gamma (40-110 Hz) oscillations of the local field potential in mammals have both been linked to odor learning and discrimination. Gamma oscillations represent the activity of a local network within the olfactory bulb, and beta oscillations represent engagement of a systemwide network. Here, we test whether beta and gamma oscillations represent different cognitive modes using the different demands of go/no-go and two-alternative choice tasks that previously were suggested to favor beta or gamma oscillations, respectively. We reconcile previous studies and show that both beta and gamma oscillations occur in both tasks, with gamma dominating the early odor sampling period (2-4 sniffs) and beta dominating later. The relative power and coherence of both oscillations depend separately on multiple factors within both tasks without categorical differences across tasks. While the early/gamma-associated period occurs in all trials, rats can perform above chance without the later/beta-associated period. Longer sampling, which includes beta oscillations, is associated with better performance. Gamma followed by beta oscillations therefore represents a sequence of cognitive and neural states during odor discrimination, which can be separately modified depending on the demands of a task and odor discrimination. Additionally, fast (85 Hz) and slow (70 Hz) olfactory bulb gamma oscillation sub-bands have been hypothesized to represent tufted and mitral cell networks, respectively (Manabe and Mori, 2013). We find that fast gamma favors the early and slow gamma the later (beta-dominated) odor-sampling period and that the relative contributions of these oscillations are consistent across tasks. SIGNIFICANCE STATEMENT Olfactory system gamma (40-110 Hz) and beta (15-35 Hz) oscillations of the local field potential indicate different neural firing statistics and functional circuits. We show that gamma and beta oscillations occur in stereotyped sequence during odor sampling in associative tasks, with local gamma dominating the first 250 ms of odor sniffing, followed by systemwide beta as behavioral responses are prepared. Oscillations and coupling strength between brain regions are modulated by task, odor, and learning, showing that task features can dramatically adjust the dynamics of a cortical sensory system, which changes state every ∼250 ms. Understanding cortical circuits, even at the biophysical level, depends on careful use of multiple behavioral contexts and stimuli.
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15
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Yang J, Litscher G, Sun Z, Tang Q, Kishi K, Oda S, Takayanagi M, Sheng Z, Liu Y, Guo W, Zhang T, Wang L, Gaischek I, Litscher D, Lippe IT, Kuroda M. Quantitative analysis of axon collaterals of single pyramidal cells of the anterior piriform cortex of the guinea pig. BMC Neurosci 2017; 18:25. [PMID: 28178946 PMCID: PMC5299671 DOI: 10.1186/s12868-017-0342-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 01/24/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND The role of the piriform cortex (PC) in olfactory information processing remains largely unknown. The anterior part of the piriform cortex (APC) has been the focus of cortical-level studies of olfactory coding, and associative processes have attracted considerable attention as an important part in odor discrimination and olfactory information processing. Associational connections of pyramidal cells in the guinea pig APC were studied by direct visualization of axons stained and quantitatively analyzed by intracellular biocytin injection in vivo. RESULTS The observations illustrated that axon collaterals of the individual cells were widely and spatially distributed within the PC, and sometimes also showed a long associational projection to the olfactory bulb (OB). The data showed that long associational axons were both rostrally and caudally directed throughout the PC, and the intrinsic associational fibers of pyramidal cells in the APC are omnidirectional connections in the PC. Within the PC, associational axons typically followed rather linear trajectories and irregular bouton distributions. Quantitative data of the axon collaterals of two pyramidal cells in the APC showed that the average length of axonal collaterals was 101 mm, out of which 79 mm (78% of total length) were distributed in the PC. The average number of boutons was 8926 and 7101, respectively, with 79% of the total number of boutons being distributed in the PC. The percentage of the total area of the APC and the posterior piriform cortex occupied by the average distribution region of the axon collaterals of two superficial pyramidal (SP) cells was about 18 and 5%, respectively. CONCLUSION Our results demonstrate that omnidirectional connection of pyramidal cells in the APC provides a substrate for recurrent processes. These findings indicate that the axon collaterals of SP cells in the PC could make synaptic contacts with all granule cells in the OB. This study provides the morphological evidence for understanding the mechanisms of information processing and associative memory in the APC.
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Affiliation(s)
- Junli Yang
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China.
- Department of Anatomy, School of Medicine, Toho University, Tokyo, 143-8540, Japan.
| | - Gerhard Litscher
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China.
- Research Unit for Complementary and Integrative Laser Medicine, Research Unit of Biomedical Engineering in Anesthesia and Intensive Care Medicine, and TCM Research Center Graz, Medical University of Graz, 8036, Graz, Austria.
| | - Zhongren Sun
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China.
| | - Qiang Tang
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China
| | - Kiyoshi Kishi
- Department of Anatomy, School of Medicine, Toho University, Tokyo, 143-8540, Japan
| | - Satoko Oda
- Department of Anatomy, School of Medicine, Toho University, Tokyo, 143-8540, Japan
| | - Masaaki Takayanagi
- Department of Anatomy, School of Medicine, Toho University, Tokyo, 143-8540, Japan
| | - Zemin Sheng
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China
- Privatclinic Lassnitzhoehe, 8301, Lassnitzhoehe, Austria
| | - Yang Liu
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China
| | - Wenhai Guo
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China
| | - Ting Zhang
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China
| | - Lu Wang
- Second Affiliated Hospital of Heilongjiang University of Chinese Medicine, Harbin, 150001, China
- Research Unit for Complementary and Integrative Laser Medicine, Research Unit of Biomedical Engineering in Anesthesia and Intensive Care Medicine, and TCM Research Center Graz, Medical University of Graz, 8036, Graz, Austria
| | - Ingrid Gaischek
- Research Unit for Complementary and Integrative Laser Medicine, Research Unit of Biomedical Engineering in Anesthesia and Intensive Care Medicine, and TCM Research Center Graz, Medical University of Graz, 8036, Graz, Austria
| | - Daniela Litscher
- Research Unit for Complementary and Integrative Laser Medicine, Research Unit of Biomedical Engineering in Anesthesia and Intensive Care Medicine, and TCM Research Center Graz, Medical University of Graz, 8036, Graz, Austria
| | - Irmgard Th Lippe
- Institute of Experimental and Clinical Pharmacology, Medical University of Graz, 8036, Graz, Austria
| | - Masaru Kuroda
- Department of Anatomy, School of Medicine, Toho University, Tokyo, 143-8540, Japan
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Courtiol E, Wilson DA. The Olfactory Mosaic: Bringing an Olfactory Network Together for Odor Perception. Perception 2016; 46:320-332. [PMID: 27687814 DOI: 10.1177/0301006616663216] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Olfactory perception and its underlying neural mechanisms are not fixed, but rather vary over time, dependent on various parameters such as state, task, or learning experience. In olfaction, one of the primary sensory areas beyond the olfactory bulb is the piriform cortex. Due to an increasing number of functions attributed to the piriform cortex, it has been argued to be an associative cortex rather than a simple primary sensory cortex. In fact, the piriform cortex plays a key role in creating olfactory percepts, helping to form configural odor objects from the molecular features extracted in the nose. Moreover, its dynamic interactions with other olfactory and nonolfactory areas are also critical in shaping the olfactory percept and resulting behavioral responses. In this brief review, we will describe the key role of the piriform cortex in the larger olfactory perceptual network, some of the many actors of this network, and the importance of the dynamic interactions among the piriform-trans-thalamic and limbic pathways.
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Affiliation(s)
- Emmanuelle Courtiol
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA; Department of Child and Adolescent Psychiatry, New York University Langone Medical Center, New York, NY, USA
| | - Donald A Wilson
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY, USA; Department of Child and Adolescent Psychiatry, New York University Langone Medical Center, New York, NY, USA
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17
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Abstract
This article explores the potential that the natural sciences of complexity may have for offering analogies and insights with regard to communicative processes in a group and the concept of the group matrix. Foulkes's last formulation of the concept of the group matrix is reviewed, before the author draws on the thoughts of G.H. Mead on mind, self and society, and on some analogies from the complexity sciences, to suggest a formulation of the emergence of mind in communicative interaction within a group.
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18
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Pérez de los Cobos Pallarés F, Stanić D, Farmer D, Dutschmann M, Egger V. An arterially perfused nose-olfactory bulb preparation of the rat. J Neurophysiol 2015; 114:2033-42. [PMID: 26108959 DOI: 10.1152/jn.01048.2014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 06/18/2015] [Indexed: 11/22/2022] Open
Abstract
A main feature of the mammalian olfactory bulb network is the presence of various rhythmic activities, in particular, gamma, beta, and theta oscillations, with the latter coupled to the respiratory rhythm. Interactions between those oscillations as well as the spatial distribution of network activation are likely to determine olfactory coding. Here, we describe a novel semi-intact perfused nose-olfactory bulb-brain stem preparation in rats with both a preserved olfactory epithelium and brain stem, which could be particularly suitable for the study of oscillatory activity and spatial odor mapping within the olfactory bulb, in particular, in hitherto inaccessible locations. In the perfused olfactory bulb, we observed robust spontaneous oscillations, mostly in the theta range. Odor application resulted in an increase in oscillatory power in higher frequency ranges, stimulus-locked local field potentials, and excitation or inhibition of individual bulbar neurons, similar to odor responses reported from in vivo recordings. Thus our method constitutes the first viable in situ preparation of a mammalian system that uses airborne odor stimuli and preserves these characteristic features of odor processing. This preparation will allow the use of highly invasive experimental procedures and the application of techniques such as patch-clamp recording, high-resolution imaging, and optogenetics within the entire olfactory bulb.
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Affiliation(s)
- Fernando Pérez de los Cobos Pallarés
- Systems Neurobiology, Department of Biology II, Ludwigs-Maximilians-Universität München, Martinsried, Germany; Neurophysiology, Zoological Institute, Regensburg University, Regensburg, Germany; and
| | - Davor Stanić
- Florey Institute of Neuroscience and Mental Health, University of Melbourne Victoria, Melbourne, Victoria, Australia
| | - David Farmer
- Florey Institute of Neuroscience and Mental Health, University of Melbourne Victoria, Melbourne, Victoria, Australia
| | - Mathias Dutschmann
- Florey Institute of Neuroscience and Mental Health, University of Melbourne Victoria, Melbourne, Victoria, Australia
| | - Veronica Egger
- Systems Neurobiology, Department of Biology II, Ludwigs-Maximilians-Universität München, Martinsried, Germany; Neurophysiology, Zoological Institute, Regensburg University, Regensburg, Germany; and
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19
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Cohen Y, Wilson DA, Barkai E. Differential modifications of synaptic weights during odor rule learning: dynamics of interaction between the piriform cortex with lower and higher brain areas. Cereb Cortex 2015; 25:180-91. [PMID: 23960200 PMCID: PMC4415065 DOI: 10.1093/cercor/bht215] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Learning of a complex olfactory discrimination (OD) task results in acquisition of rule learning after prolonged training. Previously, we demonstrated enhanced synaptic connectivity between the piriform cortex (PC) and its ascending and descending inputs from the olfactory bulb (OB) and orbitofrontal cortex (OFC) following OD rule learning. Here, using recordings of evoked field postsynaptic potentials in behaving animals, we examined the dynamics by which these synaptic pathways are modified during rule acquisition. We show profound differences in synaptic connectivity modulation between the 2 input sources. During rule acquisition, the ascending synaptic connectivity from the OB to the anterior and posterior PC is simultaneously enhanced. Furthermore, post-training stimulation of the OB enhanced learning rate dramatically. In sharp contrast, the synaptic input in the descending pathway from the OFC was significantly reduced until training completion. Once rule learning was established, the strength of synaptic connectivity in the 2 pathways resumed its pretraining values. We suggest that acquisition of olfactory rule learning requires a transient enhancement of ascending inputs to the PC, synchronized with a parallel decrease in the descending inputs. This combined short-lived modulation enables the PC network to reorganize in a manner that enables it to first acquire and then maintain the rule.
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Affiliation(s)
- Yaniv Cohen
- Departments of Biology
- Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa31905, Israel,
- Department of Child and Adolescent Psychiatry, New York University Langone School of Medicine, New York, NY 10016, USA and
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Donald A. Wilson
- Department of Child and Adolescent Psychiatry, New York University Langone School of Medicine, New York, NY 10016, USA and
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, Orangeburg, NY 10962, USA
| | - Edi Barkai
- Departments of Biology
- Department of Neurobiology, Faculty of Natural Sciences, University of Haifa, Haifa31905, Israel,
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20
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Srinivasa N, Cho Y. Unsupervised discrimination of patterns in spiking neural networks with excitatory and inhibitory synaptic plasticity. Front Comput Neurosci 2014; 8:159. [PMID: 25566045 PMCID: PMC4266024 DOI: 10.3389/fncom.2014.00159] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 11/18/2014] [Indexed: 12/02/2022] Open
Abstract
A spiking neural network model is described for learning to discriminate among spatial patterns in an unsupervised manner. The network anatomy consists of source neurons that are activated by external inputs, a reservoir that resembles a generic cortical layer with an excitatory-inhibitory (EI) network and a sink layer of neurons for readout. Synaptic plasticity in the form of STDP is imposed on all the excitatory and inhibitory synapses at all times. While long-term excitatory STDP enables sparse and efficient learning of the salient features in inputs, inhibitory STDP enables this learning to be stable by establishing a balance between excitatory and inhibitory currents at each neuron in the network. The synaptic weights between source and reservoir neurons form a basis set for the input patterns. The neural trajectories generated in the reservoir due to input stimulation and lateral connections between reservoir neurons can be readout by the sink layer neurons. This activity is used for adaptation of synapses between reservoir and sink layer neurons. A new measure called the discriminability index (DI) is introduced to compute if the network can discriminate between old patterns already presented in an initial training session. The DI is also used to compute if the network adapts to new patterns without losing its ability to discriminate among old patterns. The final outcome is that the network is able to correctly discriminate between all patterns—both old and new. This result holds as long as inhibitory synapses employ STDP to continuously enable current balance in the network. The results suggest a possible direction for future investigation into how spiking neural networks could address the stability-plasticity question despite having continuous synaptic plasticity.
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Affiliation(s)
- Narayan Srinivasa
- Center for Neural and Emergent Systems, Information and Systems Sciences Department, HRL Laboratories LLC Malibu, CA, USA
| | - Youngkwan Cho
- Center for Neural and Emergent Systems, Information and Systems Sciences Department, HRL Laboratories LLC Malibu, CA, USA
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21
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Brennan P, Keverne EB. Biological complexity and adaptability of simple mammalian olfactory memory systems. Neurosci Biobehav Rev 2014; 50:29-40. [PMID: 25451762 DOI: 10.1016/j.neubiorev.2014.10.020] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 08/20/2014] [Accepted: 10/22/2014] [Indexed: 12/26/2022]
Abstract
Chemosensory systems play vital roles in the lives of most mammals, including the detection and identification of predators, as well as sex and reproductive status and the identification of individual conspecifics. All of these capabilities require a process of recognition involving a combination of innate (kairomonal/pheromonal) and learned responses. Across very different phylogenies, the mechanisms for pheromonal and odour learning have much in common. They are frequently associated with plasticity of GABA-ergic feedback at the initial level of processing the chemosensory information, which enhances its pattern separation capability. Association of odourant features into an odour object primarily involves anterior piriform cortex for non-social odours. However, the medial amygdala appears to be involved in both the recognition of social odours and their association with chemosensory information sensed by the vomeronasal system. Unusually not only the sensory neurons themselves, but also the GABA-ergic interneurons in the olfactory bulb are continually being replaced, with implications for the induction and maintenance of learned chemosensory responses.
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Affiliation(s)
- P Brennan
- School of Physiology and Pharmacology, University of Bristol, Bristol, UK
| | - E B Keverne
- Sub-Department of Animal Behaviour, University of Cambridge, Cambridge, UK.
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22
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Ohl FW. Role of cortical neurodynamics for understanding the neural basis of motivated behavior - lessons from auditory category learning. Curr Opin Neurobiol 2014; 31:88-94. [PMID: 25241212 DOI: 10.1016/j.conb.2014.08.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 08/26/2014] [Accepted: 08/28/2014] [Indexed: 11/25/2022]
Abstract
Rhythmic activity appears in the auditory cortex in both microscopic and macroscopic observables and is modulated by both bottom-up and top-down processes. How this activity serves both types of processes is largely unknown. Here we review studies that have recently improved our understanding of potential functional roles of large-scale global dynamic activity patterns in auditory cortex. The experimental paradigm of auditory category learning allowed critical testing of the hypothesis that global auditory cortical activity states are associated with endogenous cognitive states mediating the meaning associated with an acoustic stimulus rather than with activity states that merely represent the stimulus for further processing.
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Affiliation(s)
- Frank W Ohl
- Leibniz Institute for Neurobiology, Department of Systems Physiology of Learning, Brenneckestr. 6, D-39118 Magdeburg, Germany.
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23
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Fourcaud-Trocmé N, Courtiol E, Buonviso N. Two distinct olfactory bulb sublaminar networks involved in gamma and beta oscillation generation: a CSD study in the anesthetized rat. Front Neural Circuits 2014; 8:88. [PMID: 25126057 PMCID: PMC4115636 DOI: 10.3389/fncir.2014.00088] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 07/07/2014] [Indexed: 12/18/2022] Open
Abstract
A prominent feature of olfactory bulb (OB) dynamics is the expression of characteristic local field potential (LFP) rhythms, including a slow respiration-related rhythm and two fast alternating oscillatory rhythms, beta (15-30 Hz) and gamma (40-90 Hz). All of these rhythms are implicated in olfactory coding. Fast oscillatory rhythms are known to involve the mitral-granule cell loop. Although the underlying mechanisms of gamma oscillation have been studied, the origin of beta oscillation remains poorly understood. Whether these two different rhythms share the same underlying mechanism is unknown. This study uses a quantitative and detailed current-source density (CSD) analysis combined with multi-unit activity (MUA) recordings to shed light on this question in freely breathing anesthetized rats. In particular, we show that gamma oscillation generation involves mainly the upper half of the external plexiform layer (EPL) and superficial areas of granule cell layer (GRL). In contrast, the generation of beta oscillation involves the lower part of the EPL and deep granule cells. This differential involvement of sublaminar networks is neither dependent on odor quality nor on the precise frequency of the fast oscillation under study. Overall, this study demonstrates a functional sublaminar organization of the rat OB, which is supported by previous anatomical findings.
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Affiliation(s)
- Nicolas Fourcaud-Trocmé
- Team Olfaction from Coding to Memory, Center for Research in Neuroscience of Lyon, CNRS UMR5292 - INSERM U1028 Lyon, France ; Team Olfaction from Coding to Memory, Center for Research in Neuroscience of Lyon, Université Claude Bernard Lyon 1 Lyon, France
| | - Emmanuelle Courtiol
- Team Olfaction from Coding to Memory, Center for Research in Neuroscience of Lyon, CNRS UMR5292 - INSERM U1028 Lyon, France ; Team Olfaction from Coding to Memory, Center for Research in Neuroscience of Lyon, Université Claude Bernard Lyon 1 Lyon, France
| | - Nathalie Buonviso
- Team Olfaction from Coding to Memory, Center for Research in Neuroscience of Lyon, CNRS UMR5292 - INSERM U1028 Lyon, France ; Team Olfaction from Coding to Memory, Center for Research in Neuroscience of Lyon, Université Claude Bernard Lyon 1 Lyon, France
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24
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Martin C, Ravel N. Beta and gamma oscillatory activities associated with olfactory memory tasks: different rhythms for different functional networks? Front Behav Neurosci 2014; 8:218. [PMID: 25002840 PMCID: PMC4066841 DOI: 10.3389/fnbeh.2014.00218] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 05/28/2014] [Indexed: 11/18/2022] Open
Abstract
Olfactory processing in behaving animals, even at early stages, is inextricable from top down influences associated with odor perception. The anatomy of the olfactory network (olfactory bulb, piriform, and entorhinal cortices) and its unique direct access to the limbic system makes it particularly attractive to study how sensory processing could be modulated by learning and memory. Moreover, olfactory structures have been early reported to exhibit oscillatory population activities easy to capture through local field potential recordings. An attractive hypothesis is that neuronal oscillations would serve to “bind” distant structures to reach a unified and coherent perception. In relation to this hypothesis, we will assess the functional relevance of different types of oscillatory activity observed in the olfactory system of behaving animals. This review will focus primarily on two types of oscillatory activities: beta (15–40 Hz) and gamma (60–100 Hz). While gamma oscillations are dominant in the olfactory system in the absence of odorant, both beta and gamma rhythms have been reported to be modulated depending on the nature of the olfactory task. Studies from the authors of the present review and other groups brought evidence for a link between these oscillations and behavioral changes induced by olfactory learning. However, differences in studies led to divergent interpretations concerning the respective role of these oscillations in olfactory processing. Based on a critical reexamination of those data, we propose hypotheses on the functional involvement of beta and gamma oscillations for odor perception and memory.
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Affiliation(s)
- Claire Martin
- Laboratory Imagerie et Modélisation en Neurobiologie et Cancérologie, CNRS UMR 8165, Université Paris Sud, Université Paris Diderot Orsay, France
| | - Nadine Ravel
- Team "Olfaction: Du codage à la mémoire," Centre de Recherche en Neurosciences de Lyon CNRS UMR 5292, INSERM U1028, Université Lyon 1 Lyon, France
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25
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Mandairon N, Kermen F, Charpentier C, Sacquet J, Linster C, Didier A. Context-driven activation of odor representations in the absence of olfactory stimuli in the olfactory bulb and piriform cortex. Front Behav Neurosci 2014; 8:138. [PMID: 24808838 PMCID: PMC4010734 DOI: 10.3389/fnbeh.2014.00138] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/04/2014] [Indexed: 12/26/2022] Open
Abstract
Sensory neural activity is highly context dependent and shaped by experience and expectation. In the olfactory bulb (OB), the first cerebral relay of olfactory processing, responses to odorants are shaped by previous experiences including contextual information thanks to strong feedback connections. In the present experiment, mice were conditioned to associate an odorant with a visual context and were then exposed to the visual context alone. We found that the visual context alone elicited exploration of the odor port similar to that elicited by the stimulus when it was initially presented. In the OB, the visual context alone elicited a neural activation pattern, assessed by mapping the expression of the immediate early gene zif268 (egr-1) that was highly similar to that evoked by the conditioned odorant, but not other odorants. This OB activation was processed by olfactory network as it was transmitted to the piriform cortex. Interestingly, a novel context abolished neural and behavioral responses. In addition, the neural representation in response to the context was dependent on top-down inputs, suggesting that context-dependent representation is initiated in cortex. Modeling of the experimental data suggests that odor representations are stored in cortical networks, reactivated by the context and activate bulbar representations. Activation of the OB and the associated behavioral response in the absence of physical stimulus showed that mice are capable of internal representations of sensory stimuli. The similarity of activation patterns induced by imaged and the corresponding physical stimulus, triggered only by the relevant context provides evidence for an odor-specific internal representation.
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Affiliation(s)
- Nathalie Mandairon
- Centre de Recherche en Neurosciences de Lyon, UMR CNRS 5292 INSERM 1028, Université Lyon1 Lyon, France
| | - Florence Kermen
- Centre de Recherche en Neurosciences de Lyon, UMR CNRS 5292 INSERM 1028, Université Lyon1 Lyon, France
| | - Caroline Charpentier
- Centre de Recherche en Neurosciences de Lyon, UMR CNRS 5292 INSERM 1028, Université Lyon1 Lyon, France
| | - Joelle Sacquet
- Centre de Recherche en Neurosciences de Lyon, UMR CNRS 5292 INSERM 1028, Université Lyon1 Lyon, France
| | - Christiane Linster
- Computational Physiology Lab, Neurobiology and Behavior, Cornell University Ithaca, NY, USA
| | - Anne Didier
- Centre de Recherche en Neurosciences de Lyon, UMR CNRS 5292 INSERM 1028, Université Lyon1 Lyon, France
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26
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Watrous AJ, Ekstrom AD. The spectro-contextual encoding and retrieval theory of episodic memory. Front Hum Neurosci 2014; 8:75. [PMID: 24600373 PMCID: PMC3927099 DOI: 10.3389/fnhum.2014.00075] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 01/29/2014] [Indexed: 11/13/2022] Open
Abstract
The spectral fingerprint hypothesis, which posits that different frequencies of oscillations underlie different cognitive operations, provides one account for how interactions between brain regions support perceptual and attentive processes (Siegel etal., 2012). Here, we explore and extend this idea to the domain of human episodic memory encoding and retrieval. Incorporating findings from the synaptic to cognitive levels of organization, we argue that spectrally precise cross-frequency coupling and phase-synchronization promote the formation of hippocampal-neocortical cell assemblies that form the basis for episodic memory. We suggest that both cell assembly firing patterns as well as the global pattern of brain oscillatory activity within hippocampal-neocortical networks represents the contents of a particular memory. Drawing upon the ideas of context reinstatement and multiple trace theory, we argue that memory retrieval is driven by internal and/or external factors which recreate these frequency-specific oscillatory patterns which occur during episodic encoding. These ideas are synthesized into a novel model of episodic memory (the spectro-contextual encoding and retrieval theory, or "SCERT") that provides several testable predictions for future research.
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Affiliation(s)
- Andrew J Watrous
- Center for Neuroscience, University of California Davis, CA, USA ; University of Bonn, Bonn Germany
| | - Arne D Ekstrom
- Center for Neuroscience, University of California Davis, CA, USA ; Neuroscience Graduate Group, University of California Davis, CA, USA ; Department of Psychology, University of California Davis, CA, USA
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27
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Fletcher ML, Bendahmane M. Visualizing olfactory learning functional imaging of experience-induced olfactory bulb changes. PROGRESS IN BRAIN RESEARCH 2014; 208:89-113. [PMID: 24767480 DOI: 10.1016/b978-0-444-63350-7.00004-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The anatomical organization of sensory neuron input allows odor information to be transformed into odorant-specific spatial maps of mitral/tufted cell glomerular activity. In other sensory systems, neuronal representations of sensory stimuli can be reorganized or enhanced following learning or experience. Similarly, several studies have demonstrated both structural and physiological experience-induced changes throughout the olfactory system. As experience-induced changes within this circuit likely serve as an initial site for odor memory formation, the olfactory bulb is an ideal site for optical imaging studies of olfactory learning, as they allow for the visualization of experience-induced changes in the glomerular circuit following learning and how these changes impact of odor representations with the bulb. Presently, optical imaging techniques have been used to visualize experience-induced changes in glomerular odor representations in a variety of paradigms in short-term habituation, chronic odor exposure, and olfactory associative conditioning.
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Affiliation(s)
- Max L Fletcher
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA.
| | - Mounir Bendahmane
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
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28
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Abstract
Olfactory system neural oscillations as seen in the local field potential have been studied for many decades. Recent research has shown that there is a functional role for the most studied gamma oscillations (40-100Hz in rats and mice, and 20Hz in insects), without which fine odor discrimination is poor. When these oscillations are increased artificially, fine discrimination is increased, and when rats learn difficult and highly overlapping odor discriminations, gamma is increased in power. Because of the depth of study on this oscillation, it is possible to point to specific changes in neural firing patterns as represented by the increase in gamma oscillation amplitude. However, we know far less about the mechanisms governing beta oscillations (15-30Hz in rats and mice), which are best associated with associative learning of responses to odor stimuli. These oscillations engage every part of the olfactory system that has so far been tested, plus the hippocampus, and the beta oscillation frequency band is the one that is most reliably coherent with other regions during odor processing. Respiratory oscillations overlapping with the theta frequency band (2-12Hz) are associated with odor sniffing and normal breathing in rats. They also show coupling in some circumstances between olfactory areas and rare coupling between the hippocampus and olfactory bulb. The latter occur in specific learning conditions in which coherence strength is negatively or positively correlated with performance, depending on the task. There is still much to learn about the role of neural oscillations in learning and memory, but techniques that have been brought to bear on gamma oscillations (current source density, computational modeling, slice physiology, behavioral studies) should deliver much needed knowledge of these events.
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Affiliation(s)
- Leslie M Kay
- Department of Psychology, Institute for Mind and Biology, The University of Chicago, Chicago, IL, USA.
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29
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31
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McCollum J, Larson J, Otto T, Schottler F, Granger R, Lynch G. Short-latency single unit processing in olfactory cortex. J Cogn Neurosci 2013; 3:293-9. [PMID: 23964843 DOI: 10.1162/jocn.1991.3.3.293] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Abstract Single-unit recording of layer II-III cells in olfactory (piriform) cortex was performed on awake, unrestrained rats actively engaged in learning novel odors in an olfactory discrimination task. Five of the 67 cells tested had very brief monophasic action potentials and high spontaneous firing rates (30-80 Hz); it is suggested that these units were interneurons. The remainder of the neurons had broader spikes and did not discharge for prolonged periods. Thirty-nine percent of the broad spike cells responded to at least one and usually more of the odors presented to the rats during either of the first two trials on which that odor was present, but, in most cases, these responses occurred only very infrequently over the course of subsequent trials. Six percent of the broad-spike group, how ever, continued firing robustly to a single odor but not to others. From these results it appears that most cells in piriform cortex do not respond to most odors, i.e., coding is exceedingly sparse. A subgroup of the predominant broad-spike cell type does react to several odors but this response drops out with repeated exposure, perhaps because of training. However, a few members of this class (a small fraction of the total cell population) do go on responding to a particular odor, thus exhibiting a form of odor specificity. The results are discussed with regard to predictions from recently developed models of the olfactory cortex.
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32
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Polyn SM, Sederberg PB. Brain rhythms in mental time travel. Neuroimage 2013; 85 Pt 2:678-84. [PMID: 23850576 DOI: 10.1016/j.neuroimage.2013.06.084] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 06/21/2013] [Accepted: 06/27/2013] [Indexed: 11/26/2022] Open
Abstract
The memory theorist Endel Tulving referred to the ability to search through one's memories, and revisit events and episodes from one's past, as mental time travel. This process involves the reactivation of past mental states reflecting the perceptual and conceptual characteristics of the original experience. Widely distributed neural circuitry is engaged in the service of memory search, and the dynamics of these circuits are reflected in rhythmic oscillatory signals at widespread frequencies, recorded both in the local field around neurons and more globally at the scalp. Retrieved-context theory provides a theoretical bridge between the behavioral phenomena exhibited by participants in memory search tasks, and the neural signals reflecting the dynamics of the underlying circuitry. Computational models based on this theory make broad predictions regarding the representational structure of neural activity recorded during these tasks. In recent work, researchers have used multivariate analytic techniques on topographic patterns of oscillatory neural activity to confirm critical predictions of retrieved-context theory. We review the cognitive theory motivating this recent work, and the analytic techniques being developed to create integrated neural-behavioral models of human memory search.
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Affiliation(s)
- Sean M Polyn
- Department of Psychology, Vanderbilt University, USA.
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van Gerven MAJ, Maris E, Sperling M, Sharan A, Litt B, Anderson C, Baltuch G, Jacobs J. Decoding the memorization of individual stimuli with direct human brain recordings. Neuroimage 2013; 70:223-32. [PMID: 23298746 DOI: 10.1016/j.neuroimage.2012.12.059] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 12/01/2012] [Accepted: 12/22/2012] [Indexed: 11/29/2022] Open
Abstract
Through decades of research, neuroscientists and clinicians have identified an array of brain areas that each activate when a person views a certain category of stimuli. However, we do not have a detailed understanding of how the brain represents individual stimuli within a category. Here we used direct human brain recordings and machine-learning algorithms to characterize the distributed patterns that distinguish specific cognitive states. Epilepsy patients with surgically implanted electrodes performed a working-memory task and we used machine-learning algorithms to predict the identity of each viewed stimulus. We found that the brain's representation of stimulus-specific information is distributed across neural activity at multiple frequencies, electrodes, and timepoints. Stimulus-specific neuronal activity was most prominent in the high-gamma (65-128 Hz) and theta/alpha (4-16 Hz) bands, but the properties of these signals differed significantly between individuals and for novel stimuli compared to common ones. Our findings are helpful for understanding the neural basis of memory and developing brain-computer interfaces by showing that the brain distinguishes specific cognitive states by diverse spatiotemporal patterns of neuronal.
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Affiliation(s)
- Marcel A J van Gerven
- Radboud University Nijmegen, Donders Institute for Brain, Cognition and Behaviour, Nijmegen, The Netherlands.
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Comments on Aur’s “From Neuroelectrodynamics to Thinking Machines”. Cognit Comput 2012. [DOI: 10.1007/s12559-012-9128-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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35
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Brown SR. Emergence in the central nervous system. Cogn Neurodyn 2012; 7:173-95. [PMID: 24427200 DOI: 10.1007/s11571-012-9229-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 10/04/2012] [Accepted: 11/20/2012] [Indexed: 11/30/2022] Open
Abstract
"Emergence" is an idea that has received much attention in consciousness literature, but it is difficult to find characterizations of that concept which are both specific and useful. I will precisely define and characterize a type of epistemic ("weak") emergence and show that it is a property of some neural circuits throughout the CNS, on micro-, meso- and macroscopic levels. I will argue that possession of this property can result in profoundly altered neural dynamics on multiple levels in cortex and other systems. I will first describe emergent neural entities (ENEs) abstractly. I will then show how ENEs function specifically and concretely, and demonstrate some implications of this type of emergence for the CNS.
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Affiliation(s)
- Steven Ravett Brown
- Department of Neuroscience, Mt. Sinai School of Medicine, Icahn Medical Institute, 1425 Madison Ave, Rm 10-70E, New York, NY 10029 USA ; 158 W 23rd St, Fl 3, New York, NY 10011 USA
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36
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Charra R, Datiche F, Gigot V, Schaal B, Coureaud G. Pheromone-induced odor learning modifies Fos expression in the newborn rabbit brain. Behav Brain Res 2012; 237:129-40. [PMID: 23000352 DOI: 10.1016/j.bbr.2012.09.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Revised: 09/08/2012] [Accepted: 09/13/2012] [Indexed: 12/24/2022]
Abstract
Associative learning contributes crucially to adjust the behavior of neonates to the permanently changing environment. In the European rabbit, the mammary pheromone (MP) excreted in milk triggers sucking behavior in newborns, and additionally promotes very rapid learning of initially neutral odor cues. Such stimuli become then as active as the MP itself to elicit the orocephalic motor responses involved in suckling. In this context, the rabbit is an interesting model to address the question of brain circuits early engaged by learning and memory. Here, we evaluated the brain activation (olfactory bulb and central regions) induced in 4-day-old pups by an odorant (ethyl acetoacetate, EAA) after single pairing with the MP and its subsequent acquired ability to elicit sucking-related behavior (conditioned group) or after mere exposure to EAA alone (unconditioned group). The brain-wide mapping of c-Fos expression was used to compare neural activation patterns in both groups. Evidence of high immunostaining to odorant EAA occurred in the mitral+granule cells layer of the main olfactory bulb in pups previously exposed to EAA in association with the MP. These pups also showed higher expression of Fos in the piriform cortex, the hypothalamic lateral preoptic area and the amygdala (cortical and basal nuclei). Thus, MP-induced odor learning induces rapid brain modifications in rabbit neonates. The cerebral framework supporting the acquisition appears however different compared to the circuit involved in the processing of the MP itself.
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Affiliation(s)
- R Charra
- Developmental Ethology and Cognitive Psychology Group and Brain, Sensoriality and Metabolism Group, Centre des Sciences du Goût et de l'Alimentation, UMR 6265 CNRS, 1324 INRA, Université de Bourgogne, Dijon, France
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37
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Devore S, Linster C. Noradrenergic and cholinergic modulation of olfactory bulb sensory processing. Front Behav Neurosci 2012; 6:52. [PMID: 22905025 PMCID: PMC3417301 DOI: 10.3389/fnbeh.2012.00052] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Accepted: 07/25/2012] [Indexed: 01/18/2023] Open
Abstract
Neuromodulation in sensory perception serves important functions such as regulation of signal to noise ratio, attention, and modulation of learning and memory. Neuromodulators in specific sensory areas often have highly similar cellular, but distinct behavioral effects. To address this issue, we here review the function and role of two neuromodulators, acetylcholine (Ach) and noradrenaline (NE) for olfactory sensory processing in the adult main olfactory bulb. We first describe specific bulbar sensory computations, review cellular effects of each modulator and then address their specific roles in bulbar sensory processing. We finally put these data in a behavioral and computational perspective.
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Affiliation(s)
- Sasha Devore
- Computational Physiology Lab, Department of Neurobiology and Behavior, Cornell University Ithaca, NY, USA
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Kavoi BM, Makanya AN, Plendl J, Johanna P, Kiama SG. Morphofunctional adaptations of the olfactory mucosa in postnatally developing rabbits. Anat Rec (Hoboken) 2012; 295:1352-63. [PMID: 22707244 DOI: 10.1002/ar.22520] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 05/29/2012] [Indexed: 11/08/2022]
Abstract
Rabbits are born blind and deaf and receive unusually limited maternal care. Consequently, their suckling young heavily rely on the olfactory cue for nipple attachment. However, the postnatal morphofunctional adaptations of olfactory mucosa (OM) are not fully elucidated. To clarify on the extent and the pattern of refinement of the OM following birth in the rabbit, morphologic and morphometric analysis of the mucosa were done at neonatal (0-1 days), suckling (2 weeks), weanling (4 weeks), and adult (6-8 months) stages of postnatal development. In all the age groups, the basic components of the OM were present. However, proliferative activity of cells of the mucosal epithelium decreased with increasing age as revealed by Ki-67 immunostaining. Diameters of axon bundles, packing densities of olfactory cells, and cilia numbers per olfactory cell knob increased progressively with age being 5.5, 2.1, and 2.6 times, respectively, in the adult as compared with the neonate. Volume fraction values for the bundles increased by 5.3% from birth to suckling age and by 7.4% from weaning to adulthood and the bundle cores were infiltrated with blood capillaries in all ages except in the adult where such vessels were lacking. The pattern of cilia projection from olfactory cell knobs also showed age-related variations, that is, arose as a tuft from the tips of the knobs in neonates and sucklings and in a radial pattern from the knob bases in weanlings and adults. These morphological changes may be attributed to the high olfactory functional demand associated with postnatal development in the rabbit.
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Affiliation(s)
- Boniface M Kavoi
- Department of Veterinary Anatomy & Physiology, University of Nairobi, Nairobi, Kenya.
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Fletcher ML. Olfactory aversive conditioning alters olfactory bulb mitral/tufted cell glomerular odor responses. Front Syst Neurosci 2012; 6:16. [PMID: 22461771 PMCID: PMC3309973 DOI: 10.3389/fnsys.2012.00016] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 03/05/2012] [Indexed: 11/23/2022] Open
Abstract
The anatomical organization of receptor neuron input into the olfactory bulb (OB) allows odor information to be transformed into an odorant-specific spatial map of mitral/tufted (M/T) cell glomerular activity at the upper level of the OB. In other sensory systems, neuronal representations of stimuli can be reorganized or enhanced following learning. While the mammalian OB has been shown to undergo experience-dependent plasticity at the glomerular level, it is still unclear if similar representational change occurs within (M/T) cell glomerular odor representations following learning. To address this, odorant-evoked glomerular activity patterns were imaged in mice expressing a GFP-based calcium indicator (GCaMP2) in OB (M/T) cells. Glomerular odor responses were imaged before and after olfactory associative conditioning to aversive foot shock. Following conditioning, we found no overall reorganization of the glomerular representation. Training, however, did significantly alter the amplitudes of individual glomeruli within the representation in mice in which the odor was presented together with foot shock. Further, the specific pairing of foot shock with odor presentations lead to increased responses primarily in initially weakly activated glomeruli. Overall, these results suggest that associative conditioning can enhance the initial representation of odors within the OB by enhancing responses to the learned odor in some glomeruli.
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Affiliation(s)
- Max L Fletcher
- Department of Neurobiology and Anatomy, University of Texas Medical School, Houston TX, USA
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Gottfried JA, Zelano C. The value of identity: olfactory notes on orbitofrontal cortex function. Ann N Y Acad Sci 2012; 1239:138-48. [PMID: 22145883 DOI: 10.1111/j.1749-6632.2011.06268.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neuroscientific research has emphatically promoted the idea that the key function of the orbitofrontal cortex (OFC) is to encode value. Associative learning studies indicate that OFC representations of stimulus cues reflect the predictive value of expected outcomes. Neuroeconomic studies suggest that the OFC distills abstract representations of value from discrete commodities to optimize choice. Although value-based models provide good explanatory power for many different findings, these models are typically disconnected from the very stimuli and commodities giving rise to those value representations. Little provision is made, either theoretically or empirically, for the necessary cooperative role of object identity, without which value becomes orphaned from its source. As a step toward remediating the value of identity, this review provides a focused olfactory survey of OFC research, including new work from our lab, to highlight the elemental involvement of this region in stimulus-specific predictive coding of both perceptual outcomes and expected values.
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Affiliation(s)
- Jay A Gottfried
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA.
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Zelano C, Mohanty A, Gottfried JA. Olfactory predictive codes and stimulus templates in piriform cortex. Neuron 2011; 72:178-87. [PMID: 21982378 DOI: 10.1016/j.neuron.2011.08.010] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2011] [Indexed: 11/29/2022]
Abstract
Neuroscientific models of sensory perception suggest that the brain utilizes predictive codes in advance of a stimulus encounter, enabling organisms to infer forthcoming sensory events. However, it is poorly understood how such mechanisms are implemented in the olfactory system. Combining high-resolution functional magnetic resonance imaging with multivariate (pattern-based) analyses, we examined the spatiotemporal evolution of odor perception in the human brain during an olfactory search task. Ensemble activity patterns in anterior piriform cortex (APC) and orbitofrontal cortex (OFC) reflected the attended odor target both before and after stimulus onset. In contrast, prestimulus ensemble representations of the odor target in posterior piriform cortex (PPC) gave way to poststimulus representations of the odor itself. Critically, the robustness of target-related patterns in PPC predicted subsequent behavioral performance. Our findings directly show that the brain generates predictive templates or "search images" in PPC, with physical correspondence to odor-specific pattern representations, to augment olfactory perception.
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Affiliation(s)
- Christina Zelano
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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43
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Fourcaud-Trocmé N, Courtiol E, Buonviso N, Voegtlin T. Stabilisation of beta and gamma oscillation frequency in the mammalian olfactory bulb. BMC Neurosci 2011. [PMCID: PMC3240481 DOI: 10.1186/1471-2202-12-s1-p362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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FINGELKURTS ANDREWA, FINGELKURTS ALEXANDERA, NEVES CARLOSFH. PHENOMENOLOGICAL ARCHITECTURE OF A MIND AND OPERATIONAL ARCHITECTONICS OF THE BRAIN: THE UNIFIED METASTABLE CONTINUUM. ACTA ACUST UNITED AC 2011. [DOI: 10.1142/s1793005709001258] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In our contribution we will observe phenomenal architecture of a mind and operational architectonics of the brain and will show their intimate connectedness within a single integrated metastable continuum. The notion of operation of different complexity is the fundamental and central one in bridging the gap between brain and mind: it is precisely by means of this notion that it is possible to identify what at the same time belongs to the phenomenal conscious level and to the neurophysiological level of brain activity organization, and what mediates between them. Implications for linguistic semantics, self-organized distributed computing algorithms, artificial machine consciousness, and diagnosis of dynamic brain diseases will be discussed briefly.
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Affiliation(s)
- ANDREW A. FINGELKURTS
- BM-Science — Brain and Mind Technologies Research Centre, P.O. Box 77, FI-02601, Espoo, Finland
| | | | - CARLOS F. H. NEVES
- BM-Science — Brain and Mind Technologies Research Centre, P.O. Box 77, FI-02601, Espoo, Finland
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45
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Bidirectional plasticity of cortical pattern recognition and behavioral sensory acuity. Nat Neurosci 2011; 15:155-61. [PMID: 22101640 PMCID: PMC3245808 DOI: 10.1038/nn.2966] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 09/23/2011] [Indexed: 11/08/2022]
Abstract
Learning to adapt to a complex and fluctuating environment requires the ability to adjust neural representations of sensory stimuli. Through pattern completion processes, cortical networks can reconstruct familiar patterns from degraded input patterns, while pattern separation processes allow discrimination of even highly overlapping inputs. Here we show that the balance between pattern separation and completion is experience-dependent. Rats given extensive training with overlapping complex odorant mixtures show improved behavioral discrimination ability and enhanced cortical ensemble pattern separation. In contrast, behavioral training to disregard normally detectable differences between overlapping mixtures results in impaired cortical ensemble pattern separation (enhanced pattern completion) and impaired discrimination. This bidirectional effect was not found in the olfactory bulb, and may be due to plasticity within olfactory cortex itself. Thus pattern recognition, and the balance between pattern separation and completion, is highly malleable based on task demands and occurs in concert with changes in perceptual performance.
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Jacobs J, Lega B, Anderson C. Explaining how brain stimulation can evoke memories. J Cogn Neurosci 2011; 24:553-63. [PMID: 22098266 DOI: 10.1162/jocn_a_00170] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
An unexplained phenomenon in neuroscience is the discovery that electrical stimulation in temporal neocortex can cause neurosurgical patients to spontaneously experience memory retrieval. Here we provide the first detailed examination of the neural basis of stimulation-induced memory retrieval by probing brain activity in a patient who reliably recalled memories of his high school (HS) after stimulation at a site in his left temporal lobe. After stimulation, this patient performed a customized memory task in which he was prompted to retrieve information from HS and non-HS topics. At the one site where stimulation evoked HS memories, remembering HS information caused a distinctive pattern of neural activity compared with retrieving non-HS information. Together, these findings suggest that the patient had a cluster of neurons in his temporal lobe that help represent the "high school-ness" of the current cognitive state. We believe that stimulation here evoked HS memories because it altered local neural activity in a way that partially mimicked the normal brain state for HS memories. More broadly, our findings suggest that brain stimulation can evoke memories by recreating neural patterns from normal cognition.
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Chen CFF, Barnes DC, Wilson DA. Generalized vs. stimulus-specific learned fear differentially modifies stimulus encoding in primary sensory cortex of awake rats. J Neurophysiol 2011; 106:3136-44. [PMID: 21918001 DOI: 10.1152/jn.00721.2011] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Experience shapes both central olfactory system function and odor perception. In piriform cortex, odor experience appears critical for synthetic processing of odor mixtures, which contributes to perceptual learning and perceptual acuity, as well as contributing to memory for events and/or rewards associated with odors. Here, we examined the effect of odor fear conditioning on piriform cortical single-unit responses to the learned aversive odor, as well as its effects on similar (overlapping mixtures) in freely moving rats. We found that odor-evoked fear responses were training paradigm dependent. Simple association of a condition stimulus positive (CS+) odor with foot shock (unconditioned stimulus) led to generalized fear (cue-evoked freezing) to similar odors. However, after differential conditioning, which included trials where a CS- odor (a mixture overlapping with the CS+) was not paired with shock, freezing responses were CS+ odor specific and less generalized. Pseudoconditioning led to no odor-evoked freezing. These differential levels of stimulus control over freezing were associated with different training-induced changes in single-unit odor responses in anterior piriform cortex (aPCX). Both simple and differential conditioning induced a significant decrease in aPCX single-unit spontaneous activity compared with pretraining levels while pseudoconditioning did not. Simple conditioning enhanced mean receptive field size (breadth of tuning) of the aPCX units, while differential conditioning reduced mean receptive field size. These results suggest that generalized fear is associated with an impairment of olfactory cortical discrimination. Furthermore, changes in sensory processing are dependent on the nature of training and can predict the stimulus-controlled behavioral outcome of the training.
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Affiliation(s)
- Chien-Fu F Chen
- Emotional Brain Institute, Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA.
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48
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Stability of fast oscillations in the mammalian olfactory bulb: experiments and modeling. ACTA ACUST UNITED AC 2011; 105:59-70. [PMID: 21843638 DOI: 10.1016/j.jphysparis.2011.07.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 06/06/2011] [Accepted: 07/13/2011] [Indexed: 12/27/2022]
Abstract
In the rat olfactory bulb (OB), fast oscillations of the local field potential (LFP) are observed during the respiratory cycle. Gamma-range oscillations (40-90 Hz) occur at the end of inspiration, followed by beta-range oscillations (15-30 Hz) during exhalation. These oscillations are highly stereotypical, and their frequencies are stable under various conditions. In this study, we investigate the effect of stimulus intensity on activity in the OB. Using a double-cannulation protocol, we showed that although the frequency of the LFP oscillation does depend on the respiratory cycle phase, it is relatively independent of the intensity of odorant stimulation. In contrast, we found that the individual firing rate of mitral OB cells dramatically changed with the intensity of the stimulation. This suggests that OB fast oscillation parameters, particularly frequency, are fully determined by intrinsic OB network parameters. To test this hypothesis, we explored a model of the OB where fast oscillations are generated by the interplay between excitatory mitral/tufted cells and inhibitory granule cells with graded inhibition. We found that our model has two distinct activity regimes depending on the amount of noise. In a low-noise regime, the model displays oscillation in the beta range with a stable frequency across a wide range of excitatory inputs. In a high-noise regime, the model displays oscillatory dynamics with irregular cell discharges and fast oscillations, similar to what is observed during gamma oscillations but without stability of the oscillation frequency with respect to the network external input. Simulations of the full model and theoretical studies of the network's linear response show that the characteristics of the low-noise regime are induced by non-linearities in the model, notably, the saturation of graded inhibition. Finally, we discuss how this model can account for the experimentally observed stability of the oscillatory regimes.
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