Cortical representation of olfactory input by trans-synaptic tracing

HHMI/Department of Biology, Stanford University, Stanford, California 94305, USA.
Nature (Impact Factor: 41.46). 12/2010; 472(7342):191-6. DOI: 10.1038/nature09714
Source: PubMed


In the mouse, each class of olfactory receptor neurons expressing a given odorant receptor has convergent axonal projections to two specific glomeruli in the olfactory bulb, thereby creating an odour map. However, it is unclear how this map is represented in the olfactory cortex. Here we combine rabies-virus-dependent retrograde mono-trans-synaptic labelling with genetics to control the location, number and type of 'starter' cortical neurons, from which we trace their presynaptic neurons. We find that individual cortical neurons receive input from multiple mitral cells representing broadly distributed glomeruli. Different cortical areas represent the olfactory bulb input differently. For example, the cortical amygdala preferentially receives dorsal olfactory bulb input, whereas the piriform cortex samples the whole olfactory bulb without obvious bias. These differences probably reflect different functions of these cortical areas in mediating innate odour preference or associative memory. The trans-synaptic labelling method described here should be widely applicable to mapping connections throughout the mouse nervous system.

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    • "There is evidence that some of the OT does not reach the bulbs directly via these neural projections (Yu et al., 1996a; Yu et al., 1996b), and transport of OT via the cerebrospinal fluid is possibly one of the mechanisms involved (Veening et al., 2010; Veening and Olivier, 2013). OT can directly affect neuronal processing in the bulb itself and in addition many amygdaloid and other limbic brain areas contain OT-receptors (Ghosh et al., 2011; Gimpl and Fahrenholz, 2001; Kang et al., 2009; 2011; Miyamichi et al., 2011; Nagayama et al., 2010; Sosulski et al., 2011) and may be influenced by a local release of OT. Similar mechanisms have been studied extensively in sheep (Kendrick, 2000; Kendrick et al., 1997; Kendrick et al., 1986; Kendrick et al., 1991). "
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    ABSTRACT: Oxytocin (OT) is a nonapeptide with an impressive variety of physiological functions. Among them, the 'prosocial' effects have been discussed in several recent reviews, but the direct effects on male and female sexual behavior did receive much less attention so far. As our contribution to honor the lifelong interest of Berend Olivier in the control mechanisms of sexual behavior, we decided to explore the role of OT in the present review. In the successive sections, some physiological mechanisms and the 'pair-bonding' effects of OT will be discussed, followed by sections about desire, female appetitive and copulatory behavior, including lordosis and orgasm. At the male side, the effects on erection and ejaculation are reviewed, followed by a section about 'premature ejaculation' and a possible role of OT in its treatment. In addition to OT, serotonin receives some attention as one of the main mechanisms controlling the effects of OT. In the succeeding sections, the importance of OT for 'the fruits of labor' is discussed, as it plays an important role in both maternal and paternal behavior. Finally, we pay attention to an intriguing brain area, the ventrolateral part of the ventromedial hypothalamic nucleus (VMHvl), apparently functioning in both sexual and aggressive behavior, which are at first view completely opposite behavioral systems.
    European Journal of Pharmacology 07/2014; 753. DOI:10.1016/j.ejphar.2014.07.045 · 2.53 Impact Factor
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    • "The diverse cortical projections of a single mitral cell, the broad distribution of mitral cells axons and the overlapping of their information at their target neurons provide the basis for a diversification and combinatorial integration of the olfactory information processing (Ghosh et al., 2011). Recent work using anatomical and physiological techniques demonstrated that individual neurons in the piriform cortex receive convergent input from mitral/tufted cells connected to multiple glomeruli located all over the OB (Apicella et al., 2010; Davison and Ehlers, 2011; Miyamichi et al., 2011). The precise scheme of the olfactory pathway displayed by Cajal (Figure 1A) opened the door to the anatomical basis of olfactory processing (Gire et al., 2013). "
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    ABSTRACT: authors have contributed equally to this work. The olfactory system has a highly regular organization of interconnected synaptic circuits from the periphery. It is therefore an excellent model for understanding general principles about how the brain processes information. Cajal revealed the basic cell types and their interconnections at the end of the XIX century. Since his original descriptions, the observation and analysis of the olfactory system and its components represents a major topic in neuroscience studies, providing important insights into the neural mechanisms. In this review, we will highlight the importance of Cajal contributions and his legacy to the actual knowledge of the olfactory system.
    Frontiers in Neuroanatomy 07/2014; 8. DOI:10.3389/fnana.2014.00055 · 3.54 Impact Factor
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    • "M/T cells project their axons to the olfactory cortex to covey odor information to higher brain areas in the forebrain. Mitral cells project their axons to nearly all areas of the olfactory cortex with a dispersed manner, while tufted cells target densely only to the anterior regions of the olfactory cortex (Ghosh et al., 2011; Miyamichi et al., 2011; Sosulski et al., 2011; Igarashi et al., 2012). "
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    ABSTRACT: The olfactory bulb (OB) is the first central processing center for olfactory information connecting with higher areas in the brain, and this neuronal circuitry mediates a variety of odor-evoked behavioral responses. In the adult mammalian brain, continuous neurogenesis occurs in two restricted regions, the subventricular zone (SVZ) of the lateral ventricle and the hippocampal dentate gyrus. New neurons born in the SVZ migrate through the rostral migratory stream and are integrated into the neuronal circuits of the OB throughout life. The significance of this continuous supply of new neurons in the OB has been implicated in plasticity and memory regulation. Two decades of huge investigation in adult neurogenesis revealed the biological importance of integration of new neurons into the olfactory circuits. In this review, we highlight the recent findings about the physiological functions of newly generated neurons in rodent OB circuits and then discuss the contribution of neurogenesis in the brain function. Finally, we introduce cutting edge technologies to monitor and manipulate the activity of new neurons.
    Frontiers in Neuroscience 05/2014; 8(8):121. DOI:10.3389/fnins.2014.00121 · 3.66 Impact Factor
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