Search results

Search:
in the keywords: OLFACTORY PERCEPTION

Sort By:

Limit search:

Reduction of the number of new cells reaching olfactory bulbs impairs olfactory perception in the adult opossum

100%

Grabiec M., Turlejski K., Djavadian R.

Acta Neurobiologiae Experimentalis

2009

vol. 69

issue 2

168-176

In adult mammals cells generated in the subventricular zone (SVZ) migrate to olfactory bulbs (OB). Functional significance of this continuous neurogenesis is not clear. We injected opossums (Monodelphis domestica) for seven consecutive days with a 5HT1A agonist (8-OH-DPAT or buspirone), or its antagonist WAY100635. One hour after each of these injections bromodeoxyuridine (BrdU), a marker of dividing cells was also injected. Two months later, when newly generated neurons settled in the OB and matured the ability of these opossums to detect hidden food by olfactory cues was tested. Afterwards, numbers of BrdU-labeled cell nuclei in their OB were counted and a phenotype of labeled cells established. In all groups investigated the majority of new cells differentiated into neurons (55-76%) and a lower proportion into astroglia (6-12%). Numbers of BrdU-labeled cells differed depending on the applied treatment: both agonists of the 5HT1A receptor increased these numbers, while its antagonist decreased them. The increased number of new OB interneurons did not change the time required for finding all three food items and therefore did not improve the opossums' performance in this test of the olfactory perception. However, opossums that had the reduced number of new generated OB cells searched longer for each food item and in consequence took three times longer to find all three crickets, than did opossums from other groups. In conclusion, lower numbers of new neurons in the opossums OB correlated with their worse behavioral performance in a test based on olfactory perception.

Gamma activity in the piriform cortex and behavioral thresholds for electrical stimulation in the olfactory bulb

100%

Jirsa R. a. R. T.

Acta Neurobiologiae Experimentalis

1997

vol. 57

issue 1

11-20

The olfactory bulb was stimulated by trains of electrical pulses in freely moving rats. Evoked responses resembling damped oscillations at the gamma frequency of 30 60 Hz were recorded in the anterior and posterior piriform cortex. Different types of unconditioned sniffing were induced by stimulation of the olfactory bulb. They were similar to those evoked by an odorant (amylacetate) but differed from the behavioral patterns evoked by non olfactory (auditory) stimulation. Rats were trained to avoid foot shocks following electrical pulses into the olfactory bulb as conditioned stimulus in a two way shuttle box paradigm. Threshold electrical intensities for inducing evoked responses in piriform cortex, unconditioned behavior, and learned avoidance were compared. Thresholds for unconditioned and conditioned behavior were significantly higher in comparison with those for evoking gamma discharges in anterior and posterior piriform cortex. The results suggest that fast time locked synchronization in the gamma range in the piriform cortex induced by synaptic input from theolfactory bulb is not sufficient for inducing corresponding behavior. Thus behavioral detection and probably also olfactory recognition do not seem to be direct consequences of this fast time locked neural synchronization. Additional neuronal processes that are connected with further elevation of stimulation intensity seem to be necessary for that.

Refine search results

2 Acta Neurobiologiae Experimentalis

1 2009

1 1997

1 Djavadian R.

1 Grabiec M.

1 Jirsa R. a. R. T.

1 Turlejski K.

Search results

Reduction of the number of new cells reaching olfactory bulbs impairs olfactory perception in the adult opossum

Gamma activity in the piriform cortex and behavioral thresholds for electrical stimulation in the olfactory bulb