Transection of the lateral olfactory tract does not produce anosmia

Slotnick, Burton M.; Berman, Eric J.

doi:10.1016/0361-9230(80)90186-0

Cited by 28 publications

(8 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Basic odor discrimination is notoriously robust in the face of severe damage to the central olfactory system, including massive lesions of the OB and other regions [46]-[49] although very fine olfactory acuity can be more sensitive to damage or circuit function disruption [44], [50]-[53]. Why then is odor perceptual impairment such an early and strong predictor of transition from mild cognitive impairment to AD [2], [9], [10], [54]?…”

Section: Discussionmentioning

confidence: 99%

Spared Piriform Cortical Single-Unit Odor Processing and Odor Discrimination in the Tg2576 Mouse Model of Alzheimer's Disease

Xu¹,

Lopez-Guzman

Schoen

et al. 2014

PLoS ONE

View full text Add to dashboard Cite

Alzheimer's disease is a neurodegenerative disorder that is the most common cause of dementia in the elderly today. One of the earliest reported signs of Alzheimer's disease is olfactory dysfunction, which may manifest in a variety of ways. The present study sought to address this issue by investigating odor coding in the anterior piriform cortex, the primary cortical region involved in higher order olfactory function, and how it relates to performance on olfactory behavioral tasks. An olfactory habituation task was performed on cohorts of transgenic and age-matched wild-type mice at 3, 6 and 12 months of age. These animals were then anesthetized and acute, single-unit electrophysiology was performed in the anterior piriform cortex. In addition, in a separate group of animals, a longitudinal odor discrimination task was conducted from 3–12 months of age. Results showed that while odor habituation was impaired at all ages, Tg2576 performed comparably to age-matched wild-type mice on the olfactory discrimination task. The behavioral data mirrored intact anterior piriform cortex single-unit odor responses and receptive fields in Tg2576, which were comparable to wild-type at all age groups. The present results suggest that odor processing in the olfactory cortex and basic odor discrimination is especially robust in the face of amyloid β precursor protein (AβPP) over-expression and advancing amyloid β (Aβ) pathology. Odor identification deficits known to emerge early in Alzheimer's disease progression, therefore, may reflect impairments in linking the odor percept to associated labels in cortical regions upstream of the primary olfactory pathway, rather than in the basic odor processing itself.

show abstract

Section: Discussionmentioning

confidence: 99%

Spared Piriform Cortical Single-Unit Odor Processing and Odor Discrimination in the Tg2576 Mouse Model of Alzheimer's Disease

Xu¹,

Lopez-Guzman

Schoen

et al. 2014

PLoS ONE

View full text Add to dashboard Cite

show abstract

“…Whereas both receptor neurons and olfactory bulb mitral cells have odor-receptive fields that imply a high degree of odor discrimination near the periphery, both behavioral (Slotnick and Berman 1980;Staubli et al 1987) and physiological (Wilson 2000a,b) data indicate that the piriform cortex is critically involved in discrimination and memory of complex and/or very similar odorants. The piriform cortex has been hypothesized to be involved in synthesizing odorant features, extracted by more peripheral olfactory structures, into perceptual odor wholes and perhaps including multi-modal associations, similar to the higher-order cortical processing of complex visual stimuli (Hasselmo et al 1990;Haberly 2001).…”

Section: Discussionmentioning

confidence: 99%

Scopolamine Enhances Generalization between Odor Representations in Rat Olfactory Cortex

Wilson¹

2001

Learn. Mem.

View full text Add to dashboard Cite

Acetylcholine (ACh) has a critical, modulatory role in plasticity in many sensory systems. In the rat olfactory system, both behavioral and physiological data indicate that ACh may be required for normal odor memory and synaptic plasticity. Based on these data, neural network models have hypothesized that ACh muscarinic receptors reduce interference between learned cortical representations of odors within the piriform cortex. In this study, odor receptive fields of rat anterior piriform cortex (aPCX) single-units for alkane odors were mapped before and after either a systemic injection of the muscarinic receptor antagonist scopolamine (0.5 mg/kg) or aPCX surface application of 500 µM scopolamine (or saline/ACSF controls). Cross-habituation between alkanes differing by two to four carbons was then examined following a 50-sec habituating stimulus. The results demonstrate that neither aPCX spontaneous activity nor odor-evoked activity (receptive field) was affected by scopolamine, but that cross-habituation in aPCX neurons was enhanced significantly by either systemic or cortical scopolamine. These results indicate that scopolamine selectively enhances generalization between odor representations in aPCX in a simple memory task. Given that ACh primarily affects intracortical association fibers in the aPCX, the results support a role for the association system in odor memory and discrimination and indicate an important ACh modulatory control over this basic sensory process.Central cholinergic systems have been implicated in attention and memory, and degeneration of these systems may partially underlie aging/dementia-associated declines in cognitive ability (Olton and Wenk 1987;Fibiger 1991;Everitt and Robbins 1997). Cortical acetylcholine release is elevated during arousal and/or attention (Acquas et al. 1996), and lesions or pharmacological blockade of central cholinergic synapses impairs cognitive functions (Cheal 1981;Coyle et al. 1983).The olfactory system has been an especially useful model system for studying the role of acetylcholine in memory. Disruption of normal cholinergic function has been implicated in disruption of many forms of odor memory, including simple odor habituation (Hunter and Murray 1989;Paolini and McKenzie 1993), associative odor memory (Roman et al. 1993;Ravel et al. 1994;Ferreira et al. 1999;DeRosa and Hasselmo 2000;Winters et al. 2000; see also Wirth et al. 2000), and odor rule or set learning (Saar et al. 2001). The mechanisms of cholinergic modulation of olfactory memory, however, are unknown.The olfactory system primarily receives cholinergic input from the basal forebrain (Wenk et al. 1977;Shipley and Ennis 1996), although there is also a small population of intrinsic cholinergic neurons within the olfactory bulb and cortex (Phelps et al. 1992). The major source of acetylcholine (ACh) to the olfactory system is the horizontal limb of the diagonal band of Broca (HLDB), which also receives olfactory input. In fact, activity within the HLDB and ACh release are enhanced by olfactory sys...

show abstract

“…Lesion work in rodent models has demonstrated that basic olfactory perception, that is, detection and simple discrimination, is very robust in the face of large-scale structural damage (McBride and Slotnick, 2006; Slotnick, 1985; Slotnick and Berman, 1980; Slotnick and Risser, 1990). However, local changes in circuit function, for example, through manipulations of local inhibition (Abraham et al, 2010; Lepousez and Lledo, 2013; Nusser et al, 2001), changes in neuromodulatory tone (Chapuis et al, 2013; Doucette et al, 2007; Hellier et al, 2010; Mandairon et al, 2006), or changes in top-down signaling (Chapuis et al, 2013) can impact fine odor discrimination.…”

Section: Olfactory Cortex and Pathologymentioning

confidence: 99%

Cortical Odor Processing in Health and Disease

Wilson

Sadrian

et al. 2014

Progress in Brain Research

View full text Add to dashboard Cite

The olfactory system has a rich cortical representation, including a large archicortical component present in most vertebrates, and in mammals neocortical components including the entorhinal and orbitofrontal cortices. Together, these cortical components contribute to normal odor perception and memory. They help transform the physicochemical features of volatile molecules inhaled or exhaled through the nose into the perception of odor objects with rich associative and hedonic aspects. This chapter focuses on how olfactory cortical areas contribute to odor perception and begins to explore why odor perception is so sensitive to disease and pathology. Odor perception is disrupted by a wide range of disorders including Alzheimer’s disease, Parkinson’s disease, schizophrenia, depression, autism, and early life exposure to toxins. This olfactory deficit often occurs despite maintained functioning in other sensory systems. Does the unusual network of olfactory cortical structures contribute to this sensitivity?

show abstract

Transection of the lateral olfactory tract does not produce anosmia

Cited by 28 publications

References 10 publications

Spared Piriform Cortical Single-Unit Odor Processing and Odor Discrimination in the Tg2576 Mouse Model of Alzheimer's Disease

Spared Piriform Cortical Single-Unit Odor Processing and Odor Discrimination in the Tg2576 Mouse Model of Alzheimer's Disease

Scopolamine Enhances Generalization between Odor Representations in Rat Olfactory Cortex

Cortical Odor Processing in Health and Disease

Contact Info

Product

Resources

About