Mouse nose nerve cells mature after birth, allowing bonding, recognition with mother

Mar 12, 2011

For rodent pups, bonding with mom isn't hard-wired in the womb. It develops over the first few weeks of life, which is achieved by their maturing sense of smell, possibly allowing these mammals a survival advantage by learning to identify mother, siblings, and home.

Blending electrophysiological, biochemical, and behavioral experiments, Minghong Ma, PhD, an associate Professor of Neuroscience at the University of Pennsylvania School of Medicine, led a study published in a recent issue of the . With students Anderson Lee and Jiwei He, she demonstrated that in the noses of mature after birth.

Using patch-clamping – a technique that measures electrical signals at the cellular level -- Ma's team found that between birth and day 30 of development, normal neurons become six times more sensitive to their sibling's scent, in this case, a fragrance called lyral. In addition, the mice transition from a relative indiscriminate response to different odors to being highly attuned to one specific smell. They also respond to that specific odor with a faster speed over time.

The olfactory marker protein (OMP) likely mediates this developmental maturation. In olfactory sensory neurons lacking OMPs, response fails to speed up over 30 days as compared to normal neurons. The authors suggest this could be due to altered intracellular communication, since loss of the protein is associated with decreased phosphorylation of an associated enzyme called adenylate cyclase, a key player in the chemical signaling underlying the sense of smell.

The team also used a novel behavioral assay to illustrate one consequence of mistakes in this cellular maturation process. Normal mouse pups, given the choice between their mother and an unrelated, lactating female, will choose to huddle with or suckle their mother 78 percent of the time. But in the absence of OMP, newborn mice fail to make that distinction.

According to Ma, the maturation of olfaction in early development could offer animals that need nursing and care for a long time before maturing (altricial species, including some mammals) a survival advantage. Rather than being hard-wired at birth, Ma says, they learn to identify their surroundings and their family. "They actually learn to find their mother, home, and siblings, and to stay alive," she says. But whether the same is true of human infants, of course, remains an open question.

One key question yet to be addressed, Ma says, is the mechanism underlying this olfactory tuning process. How, for instance, do the cells develop a faster response speed? How do they get so good at focusing on just one odorant to the exclusion of all others? And can this process be modulated by early experience? The answers to those questions, she says, could possibly provide tools to influence the bonding between mother and child in early development, and even promote social interactions in autistic children.

Explore further: Long-term memories are maintained by prion-like proteins

Related Stories

How a baby's nose knows Mom's scent

Jul 06, 2005

For newborn mammals, including humans, identifying Mom by her odor can be critical to maternal bonding and survival. However, researchers have not understood how this odor identification develops. Now, Kevin Franks and Jeffry ...

Recommended for you

Long-term memories are maintained by prion-like proteins

9 hours ago

Research from Eric Kandel's lab at Columbia University Medical Center (CUMC) has uncovered further evidence of a system in the brain that persistently maintains memories for long periods of time. And paradoxically, ...

Water to understand the brain

10 hours ago

To observe the brain in action, scientists and physicians use imaging techniques, among which functional magnetic resonance imaging (fMRI) is the best known. These techniques are not based on direct observations ...

Scientists reveal more about how memories are formed

14 hours ago

Researchers at the University of Leicester working alongside colleagues in the US, have found that nerve cells in a brain region called the medial temporal lobe play a key role in the rapid formation of new memories about ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.