Ultrastructure and synaptic connectivity of main and accessory olfactory bulb efferent projections terminating in the rat anterior piriform cortex and medial amygdala

2013 ◽  
Vol 219 (5) ◽  
pp. 1603-1613 ◽  
Author(s):  
Sook Kyung Park ◽  
Jong Ho Kim ◽  
Eun Sun Yang ◽  
Dong Kuk Ahn ◽  
Cheil Moon ◽  
...  
Keyword(s):  
Olfactory Bulb ◽  
Piriform Cortex ◽  
Synaptic Connectivity ◽  
Medial Amygdala ◽  
Accessory Olfactory Bulb ◽  
Anterior Piriform Cortex ◽  
Efferent Projections

Habituation of Odor Responses in the Rat Anterior Piriform Cortex

1998 ◽  
Vol 79 (3) ◽  
pp. 1425-1440 ◽  
Author(s):  
Donald A. Wilson
Keyword(s):  
Olfactory Bulb ◽  
Respiration Rate ◽  
Single Unit ◽  
Piriform Cortex ◽  
Firing Frequency ◽  
Respiratory Cycle ◽  
Intracellular Recordings ◽  
Main Olfactory Bulb ◽  
Anterior Piriform Cortex ◽  
Initial Basis

Wilson, Donald A. Habituation of odor responses in the rat anterior piriform cortex. J. Neurophysiol. 79: 1425–1440, 1998. Simultaneous recordings of main olfactory bulb (MOB) and anterior piriform cortex (aPCX) neuron responses to repeated and prolonged odor pulses were examined in freely breathing, urethan-anesthetized rats. Comparisons of odor responses were made between multi-unit recordings of MOB activity and single-unit extracellular and intracellular recordings of Layer II/III aPCX neurons. Odor stimuli consisted of either 2-s pulses repeated at 30-s intervals or a single, prolonged 50-s stimulus. Respiration rate was monitored throughout. MOB and aPCX neuron responses to odor were quantified both through firing frequency and through the temporal patterning of firing over the respiratory cycle. The results demonstrate that aPCX neurons habituate significantly more (faster) than MOB neurons with both repeated and prolonged stimulation paradigms. This enhanced habituation is expressed as both a decrease in aPCX firing despite maintained odor-evoked MOB input and as a decrease in aPCX respiratory cycle entrainment despite maintained MOB cyclic input. Intracellular aPCX recordings suggest that several mechanisms may be involved in this experience-induced change in aPCX function, including 1) decreased excitatory driveof aPCX neurons, 2) decreased excitability of aPCX neurons,and/or 3) enhancement in odor-evoked inhibition of aPCX neurons. These studies provide the initial basis for understanding the mechanisms of nonassociative plasticity in olfactory 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.

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