scholarly journals NMDA spikes mediate amplification of odor pathway information in the piriform cortex

2018 ◽  
Author(s):  
Amit Kumar ◽  
Oded Schiff ◽  
Edi Barkai ◽  
Bartlett W. Mel ◽  
Alon Poleg-Polsky ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Pyramidal Neurons ◽  
Piriform Cortex ◽  
Receptive Fields ◽  
Odor Recognition ◽  
Olfactory Glomeruli ◽  
Direct Input ◽  
Main Station ◽  
First Time ◽  
Prevailing View

AbstractThe piriform cortex (PCx) receives direct input from the olfactory bulb (OB) and is the brain’s main station for odor recognition and memory. The transformation of the odor code from OB to PCx is profound: mitral and tufted cells in olfactory glomeruli respond to individual odorant molecules, whereas pyramidal neurons (PNs) in the PCx responds to multiple, apparently random combinations of activated glomeruli. How these “discontinuous” receptive fields are formed from OB inputs remains unknown. Counter to the prevailing view that olfactory PNs sum their inputs passively, we show for the first time that NMDA spikes within individual dendrites can both amplify OB inputs and impose combination selectivity upon them, while their ability to compartmentalize voltage signals allows different dendrites to represent different odorant combinations. Thus, the 2-layer integrative behavior of olfactory PN dendrites provides a parsimonious account for the nonlinear remapping of the odor code from bulb to cortex.

scholarly journals NMDA spikes mediate amplification of inputs in the rat piriform cortex

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Amit Kumar ◽  
Oded Schiff ◽  
Edi Barkai ◽  
Bartlett W Mel ◽  
Alon Poleg-Polsky ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Pyramidal Neurons ◽  
Piriform Cortex ◽  
Receptive Fields ◽  
Odor Recognition ◽  
Olfactory Glomeruli ◽  
Direct Input ◽  
Main Station ◽  
First Time ◽  
Prevailing View

The piriform cortex (PCx) receives direct input from the olfactory bulb (OB) and is the brain's main station for odor recognition and memory. The transformation of the odor code from OB to PCx is profound: mitral and tufted cells in olfactory glomeruli respond to individual odorant molecules, whereas pyramidal neurons (PNs) in the PCx responds to multiple, apparently random combinations of activated glomeruli. How these ‘discontinuous’ receptive fields are formed from OB inputs remains unknown. Counter to the prevailing view that olfactory PNs sum their inputs passively, we show for the first time that NMDA spikes within individual dendrites can both amplify OB inputs and impose combination selectivity upon them, while their ability to compartmentalize voltage signals allows different dendrites to represent different odorant combinations. Thus, the 2-layer integrative behavior of olfactory PN dendrites provides a parsimonious account for the nonlinear remapping of the odor code from bulb to cortex.

Comparison of Odor Receptive Field Plasticity in the Rat Olfactory Bulb and Anterior Piriform Cortex

2000 ◽  
Vol 84 (6) ◽  
pp. 3036-3042 ◽  
Author(s):  
Donald A. Wilson
Keyword(s):  
Receptive Field ◽  
Olfactory Bulb ◽  
Piriform Cortex ◽  
Receptive Fields ◽  
Odor Discrimination ◽  
Unit Recording ◽  
Anterior Piriform Cortex ◽  
Carbon Chains ◽  
Rapid Changes ◽  
Tufted Cells

Recent work in the anterior piriform cortex (aPCX) has demonstrated that cortical odor receptive fields are highly dynamic, showing rapid changes of both firing rate and temporal patterning within relatively few inhalations of an odor, despite relatively maintained, patterned input from olfactory bulb mitral/tufted cells. The present experiment examined the precision (odor-specificity) of this receptive field plasticity and compared it with the primary cortical afferent, olfactory bulb mitral/tufted cells. Adult Long-Evans hooded rats, urethan anesthetized and freely breathing, were used for single-unit recording from mitral/tufted and aPCX layer II/III neurons. Partial mapping of receptive fields to alkane odors (pentane, heptane, and nonane) was performed before and immediately after habituation (50-s exposure) to one of the alkanes. The results demonstrated that odor habituation of aPCX responses was odor specific, with minimal cross-habituation between alkanes differing by as few as two carbons. Mitral/tufted cells, however, showed strong cross-habituation within the odor set with the most profound cross effects to carbon chains shorter than the habituating stimulus. The results suggest that although mitral/tufted cells and aPCX neurons have roughly similar odor receptive fields, aPCX neurons have significantly better odor discrimination within their receptive field. The results have important implications for understanding the underlying bases of receptive fields in olfactory system neurons and the mechanisms of odor discrimination and memory.

scholarly journals Binaral Interactions in the Rat Piriform Cortex

1997 ◽  
Vol 78 (1) ◽  
pp. 160-169 ◽  
Author(s):  
Donald A. Wilson
Keyword(s):  
Olfactory Bulb ◽  
Piriform Cortex ◽  
Receptive Fields ◽  
Isoamyl Acetate ◽  
Response Patterns ◽  
Bilateral Stimulation ◽  
Contralateral Stimulation ◽  
Anterior Piriform Cortex ◽  
Single Unit Recordings ◽  
Ipsilateral Stimulation

Wilson, Donald A. Binaral interactions in the rat piriform cortex. J. Neurophysiol. 78: 160–169, 1997. Single-unit recordings were made from layer II/III anterior piriform cortex (aPCX) neurons in adult Wistar rats to examine odor response patterns to unilaterally and bilaterally delivered stimuli. Isoamyl acetate odor stimulation was presented either unilaterally through tubes inserted into the external nares, or bilaterally during unilateral olfactory bulb lidocaine infusions. Olfactory bulb multiunit or slow-wave activity was recorded simultaneously bilaterally to monitor selectivity of unilateral odor stimulation. The results demonstrate that 1) commissural input to aPCX neurons is sufficient to drive odor responses, and 2) aPCX neurons can be classified on the basis of spatial receptive field type. These receptive fields include cells that respond 1) selectively to ipsilateral stimulation, 2) selectively to contralateral stimulation, 3) to either ipsilateral or contralateral stimulation, and 4) selectively to bilateral stimulation. The potential functions of binaral convergence in the piriform cortex are discussed, and may include enhancement of perceived odor intensity and bilateral access to olfactory memory.

scholarly journals Functional relevance of dual olfactory bulb in olfactory coding

2019 ◽  
Author(s):  
Praveen Kuruppath ◽  
Li Bai ◽  
Leonardo Belluscio
Keyword(s):  
Olfactory Bulb ◽  
Receptive Fields ◽  
Behavioral Experiments ◽  
Olfactory Bulbs ◽  
Olfactory Coding ◽  
Olfactory Information ◽  
Functional Relevance ◽  
Stimulus Localization ◽  
External Stimuli ◽  
First Time

AbstractBilateral convergence of external stimuli is a common feature of vertebrate sensory systems. This convergence of inputs from the bilateral receptive fields allows higher order sensory perception, such as depth perception in the vertebrate visual system and stimulus localization in the auditory system. The functional role of such bilateral convergence in the olfactory system is mostly unknown. To test whether each olfactory bulb contributes a separate piece of olfactory information, and whether information from the bilateral olfactory bulb is integrated, we synchronized the activation of olfactory bulbs with blue light in mice expressing channelrhodopsin in the olfactory sensory neurons and behaviorally assessed the relevance of dual olfactory bulb in olfactory perception. Our findings suggest that each olfactory bulb contributes separate components of olfactory information and mice integrate the olfactory information from each olfactory bulb to identify an olfactory stimulus.Significance statementIdentifying an odor is the first step in olfactory coding, as it is critical for the survival of most animals. Previous studies have shown that bilateral olfactory bulbs help rodents to localize the odor source and navigate accordingly. But It is still unclear whether the bilateral olfactory information plays any role in determining odor identity. Here for the first time, using optogenetics and behavioral experiments, we demonstrate that each olfactory bulb provides distinct olfactory information, and rodents integrate information from the two bulbs to identify an odor.

scholarly journals Functional changes in piriform cortex pyramidal neurons in the chronic methamphetamine-treated rat

2015 ◽  
Vol 34 (01) ◽  
pp. 5-12 ◽  
Author(s):  
Nobuaki Hori ◽  
Tomoko Kadota ◽  
Norio Akaike
Keyword(s):  
Pyramidal Neurons ◽  
Piriform Cortex ◽  
Functional Changes

scholarly journals Neurodegeneration, Myelin Loss and Glial Response in the Three-Vessel Global Ischemia Model in Rat

2020 ◽  
Vol 21 (17) ◽  
pp. 6246
Author(s):  
Tatiana Anan’ina ◽  
Alena Kisel ◽  
Marina Kudabaeva ◽  
Galina Chernysheva ◽  
Vera Smolyakova ◽  
...  
Keyword(s):  
Pyramidal Neurons ◽  
Brain Slices ◽  
Global Cerebral Ischemia ◽  
Hippocampal Damage ◽  
Sham Operation ◽  
Ischemic Brain ◽  
Stratum Pyramidale ◽  
Male Wistar Rats ◽  
First Time ◽  
The Brain

(1) Background: Although myelin disruption is an integral part of ischemic brain injury, it is rarely the subject of research, particularly in animal models. This study assessed for the first time, myelin and oligodendrocyte loss in a three-vessel model of global cerebral ischemia (GCI), which causes hippocampal damage. In addition, we investigated the relationships between demyelination and changes in microglia and astrocytes, as well as oligodendrogenesis in the hippocampus; (2) Methods: Adult male Wistar rats (n = 15) underwent complete interruption of cerebral blood flow for 7 min by ligation of the major arteries supplying the brain or sham-operation. At 10 and 30 days after the surgery, brain slices were stained for neurodegeneration with Fluoro-Jade C and immunohistochemically to assess myelin content (MBP+ percentage of total area), oligodendrocyte (CNP+ cells) and neuronal (NeuN+ cells) loss, neuroinflammation (Iba1+ cells), astrogliosis (GFAP+ cells) and oligodendrogenesis (NG2+ cells); (3) Results: 10 days after GCI significant myelin and oligodendrocyte loss was found only in the stratum oriens and stratum pyramidale. By the 30th day, demyelination in these hippocampal layers intensified and affected the substratum radiatum. In addition to myelin damage, activation and an increase in the number of microglia and astrocytes in the corresponding layers, a loss of the CA1 pyramidal neurons, and neurodegeneration in the neocortex and thalamus was observed. At a 10-day time point, we observed rod-shaped microglia in the substratum radiatum. Parallel with ongoing myelin loss on the 30th day after ischemia, we found significant oligodendrogenesis in demyelinated hippocampal layers; (4) Conclusions: Our study showed that GCI-simulating cardiac arrest in humans—causes not only the loss of pyramidal neurons in the CA1 field, but also the myelin loss of adjacent layers of the hippocampus.

scholarly journals Recurrent cortical circuits implement concentration-invariant odor coding

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

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

Cortical Processing of Odorants

2017 ◽  
Author(s):  
Yaniv Cohen ◽  
Emmanuelle Courtiol ◽  
Regina M. Sullivan ◽  
Donald A. Wilson
Keyword(s):  
Olfactory Bulb ◽  
Sensory Neurons ◽  
Perceptual Experience ◽  
Spatial Organization ◽  
Piriform Cortex ◽  
Olfactory Sensory Neurons ◽  
Anterior Olfactory Nucleus ◽  
Molecular Features ◽  
Cortical Nucleus ◽  
Local Circuitry

Odorants, inhaled through the nose or exhaled from the mouth through the nose, bind to receptors on olfactory sensory neurons. Olfactory sensory neurons project in a highly stereotyped fashion into the forebrain to a structure called the olfactory bulb, where odorant-specific spatial patterns of neural activity are evoked. These patterns appear to reflect the molecular features of the inhaled stimulus. The olfactory bulb, in turn, projects to the olfactory cortex, which is composed of multiple sub-units including the anterior olfactory nucleus, the olfactory tubercle, the cortical nucleus of the amygdala, the anterior and posterior piriform cortex, and the lateral entorhinal cortex. Due to differences in olfactory bulb inputs, local circuitry and other factors, each of these cortical sub-regions appears to contribute to different aspects of the overall odor percept. For example, there appears to be some spatial organization of olfactory bulb inputs to the cortical nucleus of the amygdala, and this region may be involved in the expression of innate odor hedonic preferences. In contrast, the olfactory bulb projection to the piriform cortex is highly distributed and not spatially organized, allowing the piriform to function as a combinatorial, associative array, producing the emergence of experience-dependent odor-objects (e.g., strawberry) from the molecular features extracted in the periphery. Thus, the full perceptual experience of an odor requires involvement of a large, highly dynamic cortical network.

1908 Spatial-temporal patterns of electrical and optical signals in the piriform cortex evoked by olfactory bulb stimulation

1997 ◽  
Vol 28 ◽  
pp. S230
Author(s):  
Takaaki Sato ◽  
Ichiro Takashima ◽  
Kaoru Tsukada ◽  
Toshio Iijima
Keyword(s):  
Olfactory Bulb ◽  
Piriform Cortex ◽  
Temporal Patterns ◽  
Optical Signals
Sign in / Sign up

Export Citation Format

Share Document