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Science for Sapiens A year in research (2024)

heromone detection and social behaviour
are affected by old age and neurodegenera-
tive diseases such as Alzheimer’s. To better
understand these mechanisms, the Group
for Synaptic Neuromodulation of the Insti-
tute for Neurosciences, a joint centre of the
University Miguel Hernández (UMH) of Elche
Pand the National Spanish Research Council,
led by researcher Sandra Jurado, has carried out a new study
in collaboration with the University of Tours (France). In this
work, the social behaviour in naturally aged rodents and in
an animal model of Alzheimer’s disease have been analysed.

The researchers conducted experiments to determine how
long mice spent exploring a space with an object – with a
known mouse and another with a new congener – to analyse
the mice’s overall sociability level, as well as their ability to
react to social novelty.
The brain undergoes changes in its structure and function as
people age, which can influence the ability to relate to others.
Social impoverishment has been identified as an important
factor that decreases life expectancy and is also an indicator
of the onset of dementia and neurodegenerative disorders,
such as Alzheimer’s disease. Although social interaction
plays a central role in maintaining general well-being, the
mechanisms by which aging could alter the processing of
social information, whether by natural or pathological condi-
tion, remain unclear.
The results of the study, published in the journal Molecular
Neurobiology, showed that all aged mice, whether naturally
or animal models of Alzheimer’s, spent more time exploring
the side of the box where there was another mouse instead
of paying attention to an area with an object. However, the re-
searchers found that there was less interaction with new indivi-
duals, especially in those mice affected by pathological aging.

To delve into the causes of this lack of interest in new indivi-
duals, researchers from the Institute for Neurosciences analy-
sed the properties of the vomeronasal organ in the rodents
involved in the study. The vomeronasal organ, located in the
nasal septum, is fundamental for the detection of pheromo-
nes in most mammalian species, and although in humans it
is considered vestigial, in mice, this organ is the gateway to
Impact of natural and pathological aging on cell proliferation in the marginal ventricu-
stimuli that determine social behaviours as important as the lar-subventricular zone (VSE). Confocal images of PCNA staining in the VSE proliferative
selection of partners or the recognition of offspring. niche are presented, with additional images showing OMP and PCNA double staining.
No overlapping signal between the markers indicates different maturation stages of
cells. Dispersion plots illustrate the number of PCNA+ cells and Sox2+ cells in the margi-
During cell regeneration analysis, they identified that, as ex- nal VSE. Using two-way ANOVA with Tukey’s test, statistical analysis indicates significant
pected, natural aging reduces the ability of the vomeronasal differences. Data were collected from slices of at least three animals per condition.
Source: Portalés A. et al., Molecuar Neurobiology (2023)
organ to regenerate, suggesting that old animals may have
less ability to distinguish olfactory signals, such as pheromo-
nes, which indicate the presence of a new congener. Patients suffering from neurodegenerative diseases have
frequent episodes of aggression, apathy and social isolation,
Surprisingly, no changes in the vomeronasal organ were which greatly reduces their quality of life and that of their ca-
found in Alzheimer’s mouse models, although they did not regivers. Therefore, it is of utmost importance to understand
interact normally with new partners. The development of the changes that the brain undergoes in its structure and
neurodegenerative diseases often leads to deficits in social function as it ages, and what processes could be related to
behaviour and, as these results suggest, they may not be a di- premature or pathological aging. This study provides new
rect consequence of loss of sensory abilities as occurs during information on the different mechanisms involved in both
natural and healthy aging, but the result of deeper changes types of aging, potential targets for the development of futu-
related to the processing of social information. re therapeutic interventions.

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