Aobs

As in RBS analysis, ERS can provide information on the atomic concentration of hydrogen as a function of depth (measured in atoms/cm ). This is derived from the height Aobs°f ERS spectrum (counts per channel), at energies corresponding to particular depths within the sample (see Figure 3c). For a sample consisting of H and another material X, with composition the spectrum height... 

S. Hirayama, H. Hiraga, K. Otsuka, N. Ikeda, M. Sasaki, Extended Abstracts of the 34th Battery Symposium in Japan, 1993, Abstract No. 1 AOb. 

The presence of the VNO and/or the AOB in the following survey is based upon confirmation by histology, occasionally with histochemistry and sometimes by TEM. A strong behavioural to vomerolfactory linkage allows the Flehmen response (Chap. 7) to be used as a non-structural indicator (Schneider, 1930-1935 Knappe, 1964). 

The numbers given below (0/0) show the estimated number of families with AOS present/total family numbers, in those orders so far investigated. The results of a survey of AOB variability generally parallel the pattern of occurrence for the organ (Meisami and Bhatnagar, 1998). The main features of the mammalian organ are evident in the primitive prototherian stock. 

PI. 2.4 Bulbar layers horizontal section of MOB + AOB (outlined) in Mouse Lemur (Microcebus murinus). g = Glomerular m = Mitral and gr = Granular layers (courtesy of Alain Schilling ). 

Fig. 2.19 Central pathways and nuclei, (a) Frog AOS Pl/Pm = lateral and medial pallium EP = post, olfactory eminence and nSm = medial Septal nucleus (from Kratskin, 1995). Reptiles and mammals-—afferent pathways from AOB to amygdala nuclei (Cortical C3 and Medial M), with tertiary connections to other central nuclei in hypothalamus (MPOA, VMH and PMN) (from Johnston, 2000). (b) Snake AOS Second-order projection of accessory fibres nAOT - nucleus of AOT AM = anterior amygdala and nSph = nucleus Sphericus. (c) Mammal AOS Projection sites of vomeronasal fibres in cortex and hypothalamus (from Johnston, 1998).

Fig. 2.20 Efferent pathways into bulb showing (a) cholinergic (ACh) fibres projecting to MOB from basal forebrain nuclei. AON = ant. olfactory nucleus, OT = olfactory tract, DB = diagonal band nuc. (from Davis et al., 1978). (b) Nor-Adrenalin input to AOB, via MFB pathway from brain stem centres (nuclei A1-2, A6) (from Keveme, 1971).

The developmental processes which produce the AOS parallel to those of the MOS and, although they become separate systems as soon as the organisation of the forebrain begins, do not differ except in the details specific to each system. The differentiation of cell types within the organ, synapse formation in the AOB and the establishment of more central tertiary connections occur in a similar but not identical sequence. In general, the differences amount to alterations in the timing of ontogenetic events, with primary olfaction usually in advance of the... 

Species differences indicate that the AOS is not invariably operational prenatally, even though most peripheral and central neural units are in place and available for activation. Variability in the timing of maturation of the Organ-to-AOB linkage could well provide the necessary flexibility of response consistently associated with higher mammalian, and especially primate, neural systems. The onset of effective accessory... 

Fig. 5.2 Recording and/or stimulation in Peripheral and Central AOS electrode/injection sites at primary (VNO), secondary (AOB) and tertiary (PMCN) levels (from Licht and Meredith, 1987).

AOB VN Input to mitral cells (MC) Fig. 5.4 Location of major neurotransmitters in aw qc) + Granule (GC) cells modified and processed by interaction with Periglomeru ventral sympathetic fibers <=> = reciprocal synapses efferent/centrifugal (CF) input p gs. 5.12(a) and (b)... 

An additional and widespread neuroactive (transmitter-like) compound is nitric oxide (NO). This gaseous secretion is a product of the action of the enzyme NO-synthase on arginine. It is implicated in at least two roles within the non-sensory tissues of the organ, and at particular synapses in the AOB. One nitric oxidergic effect is initiated by the nerve fibres supplying the smooth muscle component of the vasomotor tissues. The other effect is the expected action of NO on the output... 

Removal of the AOB is handicapped by its inaccessibility and lack of external demarcation, making it a challenging target for complete removal (Cooper, 1974 Kelche and Aron, 1984 Dudley and Moss,... 

When combined with VN-x it provides a useful parallel approach, as AOB-x leaves other nasal afferents untouched. However, in some species it may also damage MOB efferents (Beltramino and Taleisnik, 1983 Meredith, 1988). Systematic and sequential deafferentation by VN nerve section can yield additional information by examination of the consequences for local degeneration in the AOB (Roland et al.,... 

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