Cortical representations of olfactory input by trans-synaptic tracing.

HHMI/Department of Biology, Stanford University, Stanford, California 94305, USA.
Nature (Impact Factor: 42.35). 12/2010; 472(7342):191-6. DOI: 10.1038/nature09714
Source: PubMed

ABSTRACT 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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Available from: Bosiljka Tasic, Jul 30, 2015
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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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    • "Furthermore, there is gross spatial organization, but many overlapping areas are observed in the anterior olfactory nucleus (Miyamichi et al., 2011) and amygdala (Miyamichi et al., 2011; Sosulski et al., 2011). The organization of the piriform cortex, which lacks clear topography, is similar to the organization of the MB calyx. "
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