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Topic: Piriform cortex


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In the News (Fri 21 Jun 19)

  
 [No title]
Since the piriform is one of the phylogenetically oldest cortical structures, and the prefrontal one of the newest, it seems likely that similar mechanisms exist in the other cortical and cortex-related structures that are innervated by 5-HT-2 axons.
Sheldon, P.W. and Aghajanian, G.K. Serotonin (5-HT) induces IPSPs in pyramidal layer of rat piriform cortex: evidence for the involvement of a 5-HT-2-activated interneuron.
Sherk, H. The claustrum and the cerebral cortex.
www.erowid.org /archive/rhodium/pharmacology/visualdistortions.html   (4151 words)

  
  Piriform cortex - Wikipedia, the free encyclopedia
In anatomy of animals, the piriform cortex, or pyriform cortex is a region in the brain.
The piriform cortex is among three areas that emerge in the telencephalon of amphibians, situated caudally to a dorsal area, which is caudal to a hippocampal area.
The piriform cortex continues to occupy a consistent albeit small and declining proportion of the increasingly large telencephalon in the most recent primate species while the volume of the olfactory bulb becomes less in proportion.
en.wikipedia.org /wiki/Piriform_cortex   (307 words)

  
 Piriform cortex -- Facts, Info, and Encyclopedia article   (Site not responding. Last check: 2007-10-09)
The piriform cortex is part of the (A center in the cerebral hemispheres that governs the sense of smell in lower animals; in humans it seems to mediate complex emotional behavior) rhinencephalon situated in the (The anterior division of the forebrain; the cerebrum and related parts of the hypothalamus) telencephalon.
The piriform cortex is among three areas that emerge in the (The anterior division of the forebrain; the cerebrum and related parts of the hypothalamus) telencephalon of amphibians, situated (Click link for more info and facts about caudal) caudally to a dorsal area, which is caudal to a hippocampal area.
The piriform cortex continues to occupy a consistent albeit small and declining proportion of the increasingly large (The anterior division of the forebrain; the cerebrum and related parts of the hypothalamus) telencephalon in the most recent primate species while the volume of the olfactory bulb becomes less in proportion.
www.absoluteastronomy.com /encyclopedia/p/pi/piriform_cortex.htm   (295 words)

  
 Cerebral Cortex   (Site not responding. Last check: 2007-10-09)
In botany, the cortex is the outer portion of the stem or root of a plant.
In anatomy and zoology, the cortex is the outermost (or "superficial") layer of an organ.
In lithic analysis in archaeology, the cortex is the outer layer of rock formed on the exterior of raw materials by chemical and mechanical weathering processes.
www.awonky.com /pages2/16/cerebral-cortex.html   (1283 words)

  
 UIC, Dept. of Psychiatry   (Site not responding. Last check: 2007-10-09)
Piriform cortex is the main central target of the olfactory bulb and plays a critical role in the identification and recollection of smells.
The physiological operation of the piriform cortex circuit has been described in detail in normal (young), adult animals; however, there have been no reports of changes in function with aging.
The present proposal addresses this issue and seeks to investigate aging effects on the cellular and synaptic physiology of piriform cortex neurons in the rat.
www.psych.uic.edu /research/rat_olfactory_cortex.htm   (156 words)

  
 Piriform cortex - Information from Reference.com
In anatomy of animals, the piriform cortex, or pyriform cortex is a region in
The piriform cortex is part of the rhinencephalon situated in the...
in slices of piriform cortex induces persistent epileptiform EPSPs in...
www.reference.com /search?q=Piriform%20cortex&db=web   (284 words)

  
 Encyclopedia: Brain
Vertebrates are characterized by increasing complexity in the cerebral cortex as one moves up the phylogenetic and evolutionary tree.
In the neocortex, prefrontal cortex is the most advanced area, and it is the largest in humans.
In mammals these sections are usually considered to be the cerebrum (a large, dorsal section with a convoluted surface), cerebellum (smaller, ventral structure with a rippled surface), and the brain stem.
www.nationmaster.com /encyclopedia/Brain   (10619 words)

  
 Stimulation of the Parasubiculum Modulates Entorhinal Cortex Responses to Piriform Cortex Inputs In Vivo -- Caruana and ...
B: mean amplitudes of responses evoked by piriform cortex stimulation at various intervals after stimulation of the parasubiculum are expressed as a percentage of the amplitudes of responses evoked by single-pulses delivered to the piriform cortex.
Piriform cortex efferents to the entorhinal cortex in vivo: kindling induced potentiation and the enhancement of long-term potentiation by low-frequency piriform cortex or medial septal stimulation.
Synaptic responses of neurones in layer II of the rat medial entorhinal cortex to stimulation of the para-subiculum in vitro.
jn.physiology.org /cgi/content/full/92/2/1226   (6653 words)

  
 12.23.2004 - How the brain tunes out odors
The most active areas during this experiment were in the piriform cortex, located behind the eyes at the bottom of the temporal lobe.
The piriform cortex is a portion of the primary olfactory cortex -- the brain's grey matter that receives input from the olfactory bulb, which is the hub of information coming from the nose.
The frontal piriform cortex, which is the attention gate, actually became active before the subjects sniffed, showing that the brain actually anticipates an odor, Sobel said.
www.berkeley.edu /news/media/releases/2004/12/23_sobel.shtml   (972 words)

  
 Mechanisms
In the case of the piriform cortex model, they showed that the time constant of inhibition "tuned" the frequency of the gamma rhythm, so that longer open times for the chloride channels resulted in slower rhythms (and also a loss of power).
In their model of the primary visual cortex Wilson and Bower [15] note in passing that local mutual inhibition between the interneurons "...improved frequency locking and produced auto- and cross-correlations with more pronounced oscillatory characteristics".
In both the visual cortex and the piriform cortex versions of this model, gamma rhythms: arose from interactions between networks of excitatory neurons, could depend on the conduction velocities of intrinsic cortical connections (Fig.
web-us.com /40hz/ww122.htm   (1221 words)

  
 Lysetskiy   (Site not responding. Last check: 2007-10-09)
The circuits of pyramidal cells of piriform cortex are an example of a neural system that may need such balancing, as these neurons are known to be sensitive to the relative timing of the afferent and association input signals.
Not only piriform cortex is likely to be in need of such STDP-based balancing, it also is, in a sense, an ideal "hardware" for its implementation.
We develop a model of piriform cortex, which employs recently proposed principle of synaptic balancing, based on the STDP learning rule with a larger window of synaptic weakening.
culture.neurobio.ucla.edu /NIC03/abstracts/lysetskiy.html   (191 words)

  
 The role of metabotropic glutamate receptors and cortical adaptation in habituation of odor-guided behavior -- Yadon ...
Both cannula tips had to be in the piriform cortex to be included in the main data set.
Habituation of odor responses in the rat anterior piriform cortex.
Synaptic correlates of odor habituation in the rat anterior piriform cortex.
www.learnmem.org /cgi/content/full/12/6/601   (3062 words)

  
 APStracts 3:0077N, 1996.   (Site not responding. Last check: 2007-10-09)
The present study tested the hypothesis that kindled epileptiform events in piriform cortex are initiated in the underlying endopiriform nucleus.
Both stimulus-evoked and spontaneous interictal-like epileptiform events were observed in most slices from the anterior piriform cortex, but in few slices from the posterior piriform cortex.
Epileptiform EPSPs in slices of piriform cortex from kindled rats displayed similarities in properties, locus of origin, and mechanism of generation to those previously studied in slices from normal rats in which epileptiform activity was induced by a brief period of bursting activity.
www.uth.tmc.edu /apstracts/1996/jn/May/77n.html   (485 words)

  
 Rapid Alterations in Diffusion-weighted Images with Anatomic Correlates in a Rodent Model of Status Epilepticus -- Wall ...
It is readily apparent that at 12 and 24 hours there are widespread changes in signal intensity in the hippocampus and piriform cortex.
The piriform cortex (and amygdala) show significant ADC decreases as early as 12 hours that are still present at 24 hours.
Histologic assessment of neuronal damage in the piriform cortex and amygdala 12 hours after pilocarpine-induced seizures.
www.ajnr.org /cgi/content/figsonly/21/10/1841   (710 words)

  
 Neurotechniques : Neuroscience Gateway
The authors did whole-cell recordings in the barrel cortex contralateral to the side that was electroporated and illuminated the region surrounding the recording electrode.
The authors recorded excitatory postsynaptic currents in these same layers of the ipsilateral cortex, suggesting that pyramidal neurons in the barrel cortex synapse in the same cortical layers on both sides of the brain.
Unlike pyramidal cells, the connections between mitral cells in the olfactory bulb and neurons in the piriform cortex have been mapped, but the processing of signals in these structures is controversial.
www.brainatlas.org /aba/2007/070503/full/aba1740.shtml   (559 words)

  
 Kurt R. Illig, PhD  Homepage   (Site not responding. Last check: 2007-10-09)
However, studies with anatomical tracers have shown that axons leaving the olfactory bulb are highly distributed, and do not appear to project to piriform cortex in any organized fashion.
A dissociation appears between the anterior and posterior subdivisions of piriform cortex, with activity in anterior piriform cortex distributed within subregions, and activity in posterior piriform cortex highly distributed without evidence of subregions.
This question is important for deciphering the functional significance of associational connections: a spatially restricted pattern would suggest that odor processing occurs by way of specific connections among subsets of neurons, while a widely distributed pattern of connections would suggest that odor processing occurs by a spatially distributed "ensemble" code.
faculty.virginia.edu /krillig/work.htm   (635 words)

  
 Sniffing and Smelling
Researchers have determined that the piriform cortex at the base of the temporal lobe is activated during olfaction in a variety of animals, including rats, rabbits, dogs, monkeys, and hedgehogs.
There was no piriform activation when she sniffed with her left nostril but there was significant activation when she sniffed through her right nostril.
concluded that piriform activation is due to the sensation of air flow in the nostrils.
web.psych.ualberta.ca /~varn/bc/Sobel.htm   (997 words)

  
 Receptive Fields in the Rat Piriform Cortex -- Wilson 26 (5): 577 -- Chemical Senses
Datiche, F. and Cattarelli, M. Catecholamine innervation of the piriform cortex: a tracing and immunohistochemical study in the rat.
Haberly, L.B. Structure of the piriform cortex of the opossum.
Wilson, D.A. (1998a) Habituation of odor responses in the rat anterior piriform cortex.
chemse.oxfordjournals.org /cgi/content/full/26/5/577   (4359 words)

  
 The ChemoReception Web   (Site not responding. Last check: 2007-10-09)
Young homing pigeons were subjected to ablations of the piriform cortex or left intact and allowed to learn a navigational map.
In contrast, piriform cortex ablated pigeons consistently oriented east, took more time to return home and were more likely to get lost.
The data support the conclusion that participation of the piriform cortex is necessary for navigational map learning, and its role in navigational learning cannot be substituted for by other telencephalic olfactory processing regions.
md1.csa.com /crw/1998/vbeh16.html   (177 words)

  
 Research: Olfaction
Wilson, D.A. A comparison of odor receptive field plasticity in the rat olfactory bulb and anterior piriform cortex.
Kadohisa, M. and Wilson, D.A. Separate encoding of identity and similarity of complex familiar odors in piriform cortex.
Rennaker, R.L., Chen, C.-F. F, Ruyle, A., Sloan, A.M. and Wilson, D.A. Spatial and temporal distribution of odorant-evoked activity in the piriform cortex.
faculty-staff.ou.edu /W/Donald.A.Wilson-1/sensory.html   (384 words)

  
 ScienceDaily: How The Brain Tunes Out Odors
The most active areas during this experiment were in the piriform cortex, located behind the eyes at the bottom of the temporal lobe.
The piriform cortex is a portion of the primary olfactory cortex -- the brain's grey matter that receives input from the olfactory bulb, which is the hub of information coming from the nose.
The frontal piriform cortex, which is the attention gate, actually became active before the subjects sniffed, showing that the brain actually anticipates an odor, Sobel said.
www.sciencedaily.com /releases/2005/01/050104105049.htm   (1111 words)

  
 New Features of Connectivity in Piriform Cortex Visualized by Intracellular Injection of Pyramidal Cells Suggest that ...
The borders of piriform cortex and the insular-perirhinal border are indicated by solid lines; the dashed line outlines the lateral olfactory tract; the dotted line is the rhinal sulcus.
Burwell RD, Amaral DG (1998) Cortical afferents of the perirhinal, postrhinal, and entorhinal cortices of the rat.
Pandya DN (1995) Anatomy of the auditory cortex.
www.jneurosci.org /cgi/content/full/20/18/6974   (6173 words)

  
 NCAMs in the HD mice
They found that the number of neurons expressing polysialylated neural cell adhesion molecules was reduced in both the dentate gyrus of the hippocampus and in layer II of the piriform cortex of mouse models R6/1 and R6/2.
During adulthood, it is most abundantly expressed in the hippocampus and the piriform cortex, which are involved in cognition and olfaction, respectively.
We show that the numbers of PSA-NCAM-positive cells in the hippocampus and piriform cortex are dramatically reduced in the R6/1 and the R6/2 mouse models of HD.
hdlighthouse.org /research/brain/updates/1352ncam.php   (834 words)

  
 Age-related remodeling of glutamic-acid decarboxylase-labeled elements in deafferented piriform cortex of rats.   (Site not responding. Last check: 2007-10-09)
Age-related remodeling of glutamic-acid decarboxylase-labeled elements in deafferented piriform cortex of rats.
Olfactory bulb (OB) removal has been shown to result in plasticity in the piriform cortex (PC) that is age dependent.
We are studying this phenomenon using immunoelectron microscopy of glutamic acid decarboxylase immunoreactivity (GAD, the enzymatic precursor for GABA) at selected postnatal ages and in adults with emphasis on short survival times of 4-7 days after OB ablation.
www.arclab.org /medlineupdates/abstract_1871680.html   (230 words)

  
 APStracts 2:0094N, 1995.   (Site not responding. Last check: 2007-10-09)
Neural firing patterns were examined in relation to task events on the current trial and variables associated with current sensory processing, events of recent past trials, and long-term associations involving the odor cues.
At a minimum, these findings indicate that piriform cortex performs functions beyond the role of odor recognition traditionally ascribed to it.
These observations, coupled with similar findings from studies of visuo-spatial processing in primate dorsolateral prefrontal and posterior parietal cortex, suggest the existence of distinct prefrontal-cortical systems that process the temporal stream of events in modality specific informational domains.
www.uth.tmc.edu /apstracts/1995/jn/April/94n.html   (617 words)

  
 MR Volumetric Analysis of The Piriform Cortex and Cortical Amygdala in Drug-Refractory Temporal Lobe Epilepsy -- ...
MR Volumetric Analysis of The Piriform Cortex and Cortical Amygdala in Drug-Refractory Temporal Lobe Epilepsy -- Pereira et al.
MR Volumetric Analysis of The Piriform Cortex and Cortical Amygdala in Drug-Refractory Temporal Lobe Epilepsy
measure the combined volume of the human piriform cortex and
www.ajnr.org /cgi/content/abstract/26/2/319   (443 words)

  
 Voltage Imaging of Epileptiform Activity in Slices From Rat Piriform Cortex: Onset and Propagation -- Demir et al. 80 ...
Voltage Imaging of Epileptiform Activity in Slices From Rat Piriform Cortex: Onset and Propagation -- Demir et al.
The piriform cortex is a temporal lobe structure with a
cortex, in slices from anterior and posterior piriform cortex,
jn.physiology.org /cgi/content/abstract/80/5/2727   (647 words)

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