Unlike peripheral nervous system neurons and certain groups of nerve cells in the CNS, cortical projection neurons are tolerant of axonal lesions. This resistance is incongruent with the massive death of pyramidal neurons in age-associated neurodegenerative diseases that proceed along corticocortical connections. Some insights have emerged from our previous work showing that pyramidal cells in ...

We examined brain-derived neurotrophic factor (BDNF) mRNA expression across the olfactory system following fear conditioning. Mice received 10 pairings of odor with footshock or equivalent unpaired odors and shocks. We found increased BDNF mRNA in animals receiving paired footshocks in the multiple regions examined including the posterior piriform cortex (PPC) and basolateral amygdala (BLA). Th...

Olfaction is a principal sensory modality in rodents, and rats quickly learn to discriminate between odors and to associate odor with reward. Here we show that such olfactory discrimination (OD) learning consists of two phases with distinct cellular mechanisms: an initial NMDAR-sensitive phase in which the animals acquire a successful behavioral strategy (rule learning), followed by an NMDAR-in...

Meaningful social interactions modify behavioral responses to sensory stimuli. The neural mechanisms underlying the entrainment of neutral sensory stimuli to salient social cues to produce social learning remain unknown. We used odor-driven behavioral paradigms to ask if oxytocin, a neuropeptide implicated in various social behaviors, plays a crucial role in the formation of learned association...

The olfactory bulb receives rich glutamatergic projections from the piriform cortex. However, the dynamics and importance of these feedback signals remain unknown. Here, we use multiphoton calcium imaging to monitor cortical feedback in the olfactory bulb of awake mice and further probe its impact on the bulb output. Responses of feedback boutons were sparse, odor specific, and often outlasted ...

Cortical organization in the Etruscan shrew is of comparative interest because of its small size and because the Etruscan shrew is an amazing tactile hunter. Here we investigated cortical organization in Etruscan shrews by electrophysiological mapping. We developed an anesthesia protocol for this very small mammal in which we combined massive application of local anesthesia, very slow induction...

Neurogenesis in the rat primary olfactory cortex was examined with [3H]thymidine autoradiography. The experimental animals were the offspring of pregnant females given an injection of [3H]thymidine on two consecutive gestation days. Nine groups of embryos were exposed to [3H]thymidine on E13-E14, E14-E15....E21-E22, respectively. On P60, the percentage of labeled cells and the proportion of cel...

Alzheimer's disease is a neurodegenerative disorder that is the most common cause of dementia in the elderly today. One of the earliest reported signs of Alzheimer's disease is olfactory dysfunction, which may manifest in a variety of ways. The present study sought to address this issue by investigating odor coding in the anterior piriform cortex, the primary cortical region involved in higher ...

Oligodendrocyte progenitor cells (OPCs) in the postnatal mouse corpus callosum (CC) and motor cortex (Ctx) reportedly generate only oligodendrocytes (OLs), whereas those in the piriform cortex may also generate neurons. OPCs have also been subdivided based on their expression of voltage-gated ion channels, ability to respond to neuronal activity, and proliferative state. To determine whether OP...