Characterization of Antennal Sensilla and Immunolocalization of Odorant-Binding Proteins on Spotted Alfalfa Aphid, Therioaphis trifolii (Monell)

The spotted alfalfa aphid [Therioaphis trifolii (Monell), Homoptera, Drepanosiphidae] is a well-known destructive pest that can significantly reduce alfalfa yields. Herein, the morphology of antennal sensilla of T. trifolii has been examined by using scanning electron microscopy and the ultrastructure of sensilla stellate and placoidea was described by transmission electron microscopy. Stellate sensilla, placoid sensilla, and coeloconic sensilla were found on the 6th segment, and a single sensillum placoidea was located on the 5th segment. Placoid sensilla were also present on the 3rd antennal segment of alate and apterous aphids, and the number was similar between two morphs. Two types of trichoid sensilla and coeloconic sensilla were found on the antennae, respectively. The results of ultrastructure showed that stellate sensilla are innervated by three neurons, while placoid sensilla present three groups of neurons, equipped with 2–3 dendrites in each neuron group. Immunocytochemical localization of odorant-binding proteins (OBPs) was performed on ultrathin sections of sensilla stellate and placoidea, and we observed that the antiserum against OBP6 intensively labeled all placoid sensilla from both primary and secondary rhinaria. OBP7 and OBP8 could also be detected in placoid sensilla, but less strongly than OBP6. In addition, OBP6, OBP7, and OBP8 were densely labeled in stellate sensilla, suggesting OBP6, OBP7, and OBP8 may sense alarm pheromone germacrene A in T. trifolii.

Macroscopic Cluster Organizations Change the Complexity of Neural Activity

In this study, simulations are conducted using a network model to examine how the macroscopic network in the brain is related to the complexity of activity for each region. The network model is composed of multiple neuron groups, each of which consists of spiking neurons with different topological properties of a macroscopic network based on the Watts and Strogatz model. The complexity of spontaneous activity is analyzed using multiscale entropy, and the structural properties of the network are analyzed using complex network theory. Experimental results show that a macroscopic structure with high clustering and high degree centrality increases the firing rates of neurons in a neuron group and enhances intraconnections from the excitatory neurons to inhibitory neurons in a neuron group. As a result, the intensity of the specific frequency components of neural activity increases. This decreases the complexity of neural activity. Finally, we discuss the research relevance of the complexity of the brain activity.

Integration mechanism and transcendental semiosis

Cognition consists of multiple layers. Each neuron group in layers processes information and transmits it to other layers. The more information is integrated, the more obvious and usable signs become. Horizontally, signs in semiosis are associated and mediated with each other. Vertically, they collaborate beyond the horizon; from sensory neuron to reflective consciousness. Semiosis involves trying to reach final interpretant through following a possible interpretation-course by the force of a guiding principle. Whereas, in trans-semiosis, we attempt to integrate two semioses despite their conceptual gap. In that situation, transcendence occurs. If integration is impossible, semiosis would rev up excessively. Accordingly, intense neural stimulations are generated. Once probable routes of interpretation have rapidly accumulated in quantity, they cross a threshold where restrictions are broken or do not exist. Then, we jump to a stable belief, attaining trans-interpretance that has competence for casually suturing a conceptual gap without any adequate foundation. The overflow of stimulation integrates into transcendence feelings that deviate from cognitive boundaries. That momentary strong feelings and trans-interpretance are connected with each other by a memory mechanism. Trans-interpretance creation leaves some unresolved surplus, reminding us of the once ignored gap and reactivate semiosis. However, if trans-interpretance is reformed and semiosis comes to a lull again, they can be strengthened.

Brain stem representation of thermal and psychogenic sweating in humans

Functional MRI was used to identify regions in the human brain stem activated during thermal and psychogenic sweating. Two groups of healthy participants aged 34.4 ± 10.2 and 35.3 ± 11.8 years (both groups comprising 1 woman and 10 men) were either heated by a water-perfused tube suit or subjected to a Stroop test, while they lay supine with their head in a 3-T MRI scanner. Sweating events were recorded as electrodermal responses (increases in AC conductance) from the palmar surfaces of fingers. Each experimental session consisted of two 7.9-min runs, during which a mean of 7.3 ± 2.1 and 10.2 ± 2.5 irregular sweating events occurred during psychogenic (Stroop test) and thermal sweating, respectively. The electrodermal waveform was used as the regressor in each subject and run to identify brain stem clusters with significantly correlated blood oxygen level-dependent signals in the group mean data. Clusters of significant activation were found with both psychogenic and thermal sweating, but a voxelwise comparison revealed no brain stem cluster whose signal differed significantly between the two conditions. Bilaterally symmetric regions that were activated by both psychogenic and thermal sweating were identified in the rostral lateral midbrain and in the rostral lateral medulla. The latter site, between the facial nuclei and pyramidal tracts, corresponds to a neuron group found to drive sweating in animals. These studies have identified the brain stem regions that are activated with sweating in humans and indicate that common descending pathways may mediate both thermal and psychogenic sweating.

Blockade of orexin receptors with Almorexant reduces cardiorespiratory responses evoked from the hypothalamus but not baro- or chemoreceptor reflex responses

Orexin neurons form a restricted group in the dorsal hypothalamus. The group is centered on the perifornical area within the classic hypothalamic defense area, an area which when activated produces marked cardiovascular and respiratory effects. Central administration of orexin can produce cardiorespiratory effects, but the extent to which orexin contributes to such responses evoked from the perifornical hypothalamus is not clear. To determine this, we used the dual orexin receptor antagonist Almorexant to challenge the cardiorespiratory effects evoked by disinhibition of the perifornical hypothalamus. Bicuculline (10 and 20 pmol) was microinjected in the perifornical area before and after administration of Almorexant (15 mg/kg iv) or vehicle in urethane-anesthetized rats. Almorexant significantly reduced the pressor, tachycardic, renal sympathoexcitatory, and tachypneic responses to bicuculline (10 pmol, by 55%, 53%, 28%, 77%; 20 pmol, by 54%, 27%, 51%, 72%, respectively). Reductions of similar magnitude were observed with bicuculline microinjections centered on more caudal sites just peripheral to the orexin neuron group, which would likely have activated fewer orexin neurons. In contrast, Almorexant had no effect on the cardiorespiratory response of the chemoreflex (sodium cyanide injection) or the sympathetic component of the baroreflex. Thus orexin makes a major contribution to the cardiorespiratory response evoked from the perifornical area even though orexin neurons represent only a fraction of the output of this area. Orexin neurons may also mediate cardiorespiratory responses from non-orexin neurons in the caudal hypothalamus. However, under resting conditions, blockade of orexin receptors does not affect the chemo- and baroreflexes.