Beyond olfaction: Beneficial effects of olfactory training extend to aging-related cognitive decline.

Studies on olfactory training (OT) outcomes have mostly been limited to olfactory performance, while direct neural connections between olfactory system and amygdala-hippocampal complex allow expecting OT to have psychological effects. To address this hypothesis, we examined olfactory, cognitive and emotional effects of OT in the group of 68 subjects aged between 50 and 88 years (Mage = 62.8 ± 8.9 years; 28 males) who are likely to experience an age-related decline in olfactory and cognitive performance. We diversified stimuli used in the OT to verify whether odor mixtures result in more effective activation of olfactory receptor neurons than single molecule odors. Subjects were randomly assigned to one of the experimental conditions: (a) simple OT utilizing single-molecule odors; (b) mixtures OT using odor mixtures; (c) control group without OT. Results indicate beneficent effects of the simple OT on cognitive assessment, cognitive decline symptoms, and olfactory sensitivity. OT can be adapted from otorhinolaryngological practice to successfully serve neurocognitive research and in supporting the cognitive-related aging process. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Short-time dynamics of a packing of polyhedral grains under horizontal vibrations.

We analyze the dynamics of a 3D granular packing composed of particles of irregular polyhedral shape confined inside a rectangular box with a retaining wall subjected to horizontal harmonic forcing. The simulations are performed by means of the contact dynamics method for a broad set of loading parameters. We explore the vibrational dynamics of the packing, the evolution of solid fraction and the scaling of dynamics with the loading parameters. We show that the motion of the retaining wall is strongly anharmonic as a result of jamming and grain rearrangements. It is found that the mean particle displacement scales with inverse square of frequency, the inverse of the force amplitude and the square of gravity. The short-time compaction rate grows in proportion to frequency up to a characteristic frequency, corresponding to collective particle rearrangements between equilibrium states, and then it declines in inverse proportion to frequency.