Cholinergic mechanisms in a simple test of olfactory learning in the rat

Hunter, A. J.; Murray, Tracey K.

doi:10.1007/bf00442821

Cited by 70 publications

(44 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Thus, disruption of normal cholinergic function has frequently been implicated in interference of many forms of odor memory, such as simple habituation (Hunter and Murray 1989), perceptual learning (Fletcher and Wilson 2002;Wilson et al 2004), and odor rule or set learning (Saar et al 2001). Of significant relevance to the current study is the fact that ACh also modulates olfactory associative memory, with both lesions of the cortical cholinergic pro- Figure 4.…”

Section: Discussionmentioning

confidence: 92%

Differential effects of muscarinic receptor blockade in prelimbic cortex on acquisition and memory formation of an odor-reward task

Carballo-Márquez¹,

Vale-Martínez²,

Guillazo-Blanch³

et al. 2007

Learn. Mem.

View full text Add to dashboard Cite

The present experiments determined the consequences of blocking muscarinic cholinergic receptors of the prelimbic (PL) cortex in the acquisition and retention of an odor-reward associative task. Rats underwent a training test (five trials) and a 24-h retention test (two retention trials and two relearning trials). In the first experiment, rats were bilaterally infused with scopolamine (20 or 5 µg/site) prior to training. Although scopolamine rats showed acquisition equivalent to PBS-injected controls, they exhibited weakened performance in the 24-h retention test measured by number of errors. In the second experiment, rats were injected with scopolamine (20 µg/site) immediately or 1 h after training and tested 24 h later. Scopolamine rats injected immediately showed severe amnesia detected in two performance measures (errors and latencies), demonstrating deficits in retention and relearning, whereas those injected 1 h later showed good 24-h test performance, similar to controls. These results suggest that muscarinic transmission in the PL cortex is essential for early memory formation, but not for acquisition, of a rapidly learned odor discrimination task. Findings corroborate the role of acetylcholine in consolidation processes and the participation of muscarinic receptors in olfactory associative tasks.

show abstract

Section: Discussionmentioning

confidence: 92%

Differential effects of muscarinic receptor blockade in prelimbic cortex on acquisition and memory formation of an odor-reward task

Carballo-Márquez¹,

Vale-Martínez²,

Guillazo-Blanch³

et al. 2007

Learn. Mem.

View full text Add to dashboard Cite

show abstract

“…In concert with this change in the olfactory bulb, norepinephrine can modify/enhance piriform cortical neuron responses to odors (Bouret and Sara 2002;Best and Wilson 2004 block afferent synaptic depression to cortical neurons, perhaps via a direct interaction between noradrenergic β receptor activation and mGluRII/III receptors (Cai and others 2001). ACh has also been implicated as modulating odor habituation (Hunter and Murray 1989), although precise mechanisms have not been determined. As mentioned above, the extent of cross-adaptation between similar odors is dependent on whether those odors are familiar.…”

Section: Implicit Memorymentioning

confidence: 99%

Plasticity in the Olfactory System: Lessons for the Neurobiology of Memory

2004

View full text Add to dashboard Cite

Odor perception is situational, contextual, and ecological. Odors are not stored in memory as unique entities. Rather, they are always interrelated with other sensory perceptions . . . that happen to coincide with them.-Engen (1991, p 86-87) The field of olfaction has experienced explosive growth over the past decade toward understanding the molecular events underlying transduction, mechanisms of spatiotemporal central processing, and neural correlates of olfactory perception and cognition. A thread running through each of these broad components that define olfaction appears to be their dynamic nature. How odors are processed, at both the behavioral and neural level, is heavily dependent on past experience, current environmental context, and internal state. The neural plasticity that allows this dynamic processing is expressed nearly ubiquitously in the olfactory pathway, from olfactory receptor neurons to the higher-order cortex, and includes mechanisms ranging from changes in membrane excitability to changes in synaptic efficacy to neurogenesis and apoptosis.The olfactory system has proven to be an excellent model system for the study of the neurobiology of memory for several reasons. First, the olfactory system is phylogenetically highly conserved, and memory plays a critical role in many ecologically significant odorguided behaviors. Thus, many different animal models, ranging from Drosophila to primates, can be taken advantage of to address specific experimental questions. Second, the olfactory pathway is relatively short and perhaps simplified compared to mammalian thalamocortical systems, with second-order neurons projecting directly to a well-described trilaminar sensory cortex. Third, the olfactory system has very strong anatomical ties to the limbic system; for example, both the lateral nucleus of the amygdala and the hippocampal dentate gyrus are three synapses from olfactory receptor neurons in the nose. Finally, the olfactory system is heavily innervated by well-defined neuromodulatory systems known to be important for memory and neural plasticity.This review will describe recent findings regarding plasticity in the mammalian olfactory system that we believe have general relevance for understanding the neurobiology of memory. Following a brief overview of olfactory system functional anatomy, we will review types of neural plasticity expressed in the olfactory system and then how these mechanisms relate to the diverse components of behavioral olfactory memory. Finally, we will attempt to identify some emergent principles of the neurobiology of olfactory memory and outline some potential future directions. Olfactory System OrganizationVery simply put, the primary olfactory pathway includes the olfactory receptor neurons in the nose (or antenna in many invertebrates), second-order neurons and affiliated We are rapidly advancing toward an understanding of the molecular events underlying odor transduction, mechanisms of spatiotemporal central odor processing, and neural correlates of olfactory percept...

show abstract

“…The research presented here focuses on the olfactory system. In the olfactory system, scopolamine has been shown to reduce behavioral odor habituation (Hunter & Murray, 1989), impair short-term memory Neurobiology of Learning and Memory 80 (2003) [302][303][304][305][306][307][308][309][310][311][312][313][314] www.elsevier.com/locate/ynlme for odors (Ravel, Elaagouby, & Gervais, 1994), and cause increased interference between overlapping odors (DeRosa & Hasselmo, 2000). Scopolamine also prevents increases in odor discrimination in a conditioning task (Fletcher & Wilson, 2002), while causing greater crosshabituation in olfactory cortex activity (Wilson, 2001).…”

Section: Introductionmentioning

confidence: 99%

Enhanced cholinergic suppression of previously strengthened synapses enables the formation of self-organized representations in olfactory cortex

Linster

Maloney

Patil

et al. 2003

Neurobiology of Learning and Memory

View full text Add to dashboard Cite

Computational modeling assists in analyzing the specific functional role of the cellular effects of acetylcholine within cortical structures. In particular, acetylcholine may regulate the dynamics of encoding and retrieval of information by regulating the magnitude of synaptic transmission at excitatory recurrent connections. Many abstract models of associative memory function ignore the influence of changes in synaptic strength during the storage process and apply the effect of these changes only during a socalled recall-phase. Efforts to ensure stable activity with more realistic, continuous updating of the synaptic strength during the storage process have shown that the memory capacity of a realistic cortical network can be greatly enhanced if cholinergic modulation blocks transmission at synaptic connections of the association fibers during the learning process. We here present experimental data from an olfactory cortex brain slice preparation showing that previously potentiated fibers show significantly greater suppression (presynaptic inhibition) by the cholinergic agonist carbachol than unpotentiated fibers. We conclude that low suppression of non-potentiated fibers during the learning process ensures the formation of self-organized representations in the neural network while the higher suppression of previously potentiated fibers minimizes interference between overlapping patterns. We show in a computational model of olfactory cortex, that, together, these two phenomena reduce the overlap between patterns that are stored within the same neural network structure. These results further demonstrate the contribution of acetylcholine to mechanisms of cortical plasticity. The results are consistent with the extensive evidence supporting a role for acetylcholine in encoding of new memories and enhancement of response to salient sensory stimuli.

show abstract

Cholinergic mechanisms in a simple test of olfactory learning in the rat

Cited by 70 publications

References 24 publications

Differential effects of muscarinic receptor blockade in prelimbic cortex on acquisition and memory formation of an odor-reward task

Differential effects of muscarinic receptor blockade in prelimbic cortex on acquisition and memory formation of an odor-reward task

Plasticity in the Olfactory System: Lessons for the Neurobiology of Memory

Enhanced cholinergic suppression of previously strengthened synapses enables the formation of self-organized representations in olfactory cortex

Contact Info

Product

Resources

About