The olfactory bulb is a neural structure of the vertebrate forebrain involved in olfaction, the sense of smell. It sends olfactory information to be further processed in the amygdala, the orbitofrontal cortex (OFC) and the hippocampus where it plays a role in emotion, memory and learning. The bulb is divided into two distinct structures: the main olfactory bulb and the accessory olfactory bulb. The main olfactory bulb connects to the amygdala via the piriform cortex of the primary olfactory cortex and directly projects from the main olfactory bulb to specific amygdala areas. The accessory olfactory bulb resides on the dorsal-posterior region of the main olfactory bulb and forms a parallel pathway. Destruction of the olfactory bulb results in ipsilateral anosmia, while irritative lesions of the uncus can result in olfactory and gustatory hallucinations.
The olfactory system, or sense of smell, is the sensory system used for smelling (olfaction). Olfaction is one of the special senses, that have directly associated specific organs. Most mammals and reptiles have a main olfactory system and an accessory olfactory system. The main olfactory system detects airborne substances, while the accessory system senses fluid-phase stimuli.
An olfactory receptor neuron (ORN), also called an olfactory sensory neuron (OSN), is a sensory neuron within the olfactory system.
The glomerulus is a spherical structure located in the olfactory bulb of the brain where synapses form between the terminals of the olfactory nerve and the dendrites of mitral, periglomerular and tufted cells. Each glomerulus is surrounded by a heterogeneous population of juxtaglomerular neurons and glial cells.
Mitral cells are neurons that are part of the olfactory system. They are located in the olfactory bulb in the mammalian central nervous system. They receive information from the axons of olfactory receptor neurons, forming synapses in neuropils called glomeruli. Axons of the mitral cells transfer information to a number of areas in the brain, including the piriform cortex, entorhinal cortex, and amygdala. Mitral cells receive excitatory input from olfactory sensory neurons and external tufted cells on their primary dendrites, whereas inhibitory input arises either from granule cells onto their lateral dendrites and soma or from periglomerular cells onto their dendritic tuft. Mitral cells together with tufted cells form an obligatory relay for all olfactory information entering from the olfactory nerve. Mitral cell output is not a passive reflection of their input from the olfactory nerve. In mice, each mitral cell sends a single primary dendrite into a glomerulus receiving input from a population of olfactory sensory neurons expressing identical olfactory receptor proteins, yet the odor responsiveness of the 20-40 mitral cells connected to a single glomerulus is not identical to the tuning curve of the input cells, and also differs between sister mitral cells. Odorant response properties of individual neurons in an olfactory glomerular module. The exact type of processing that mitral cells perform with their inputs is still a matter of controversy. One prominent hypothesis is that mitral cells encode the strength of an olfactory input into their firing phases relative to the sniff cycle. A second hypothesis is that the olfactory bulb network acts as a dynamical system that decorrelates to differentiate between representations of highly similar odorants over time. Support for the second hypothesis comes primarily from research in zebrafish.
The olfactory tubercle (OT), also known as the tuberculum olfactorium, is a multi-sensory processing center that is contained within the olfactory cortex and ventral striatum and plays a role in reward cognition. The OT has also been shown to play a role in locomotor and attentional behaviors, particularly in relation to social and sensory responsiveness, and it may be necessary for behavioral flexibility. The OT is interconnected with numerous brain regions, especially the sensory, arousal, and reward centers, thus making it a potentially critical interface between processing of sensory information and the subsequent behavioral responses.
Rachel Wilson is a professor of neurobiology at Harvard Medical School and is a Howard Hughes Medical Institute Investigator. Wilson's work integrates electrophysiology, neuropharmacology, molecular genetics, functional anatomy, and behavior to explore how neural circuits are organized to react and sense a complex environment.
The sense of smell, or olfaction, is the special sense through which smells are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste.
Olfactory memory refers to the recollection of odors. Studies have found various characteristics of common memories of odor memory including persistence and high resistance to interference. Explicit memory is typically the form focused on in the studies of olfactory memory, though implicit forms of memory certainly supply distinct contributions to the understanding of odors and memories of them. Research has demonstrated that the changes to the olfactory bulb and main olfactory system following birth are extremely important and influential for maternal behavior. Mammalian olfactory cues play an important role in the coordination of the mother infant bond, and the following normal development of the offspring. Maternal breast odors are individually distinctive, and provide a basis for recognition of the mother by her offspring.
Lawrence C. Katz was an American neurobiologist. He was an investigator at the Howard Hughes Medical Institute. His lab was located in Duke University Medical Center, where he was the James B. Duke Professor of Neurobiology.
Leslie Birgit Vosshall is an American neurobiologist and currently an Howard Hughes Medical Institute (HHMI) Investigator and the Robin Chemers Neustein Professor of Neurogenetics and Behavior at The Rockefeller University. In 2022 she was appointed Chief Scientific Officer and vicepresident of HHMI. She is also the director of the Kavli Neural Systems Institute at The Rockefeller University. Vosshall, a member of the National Academy of Sciences, is known for her contributions to the field of olfaction, particularly for the discovery and subsequent characterization of the insect olfactory receptor family, and the genetic basis of chemosensory behavior in mosquitoes. She has also extended her research into the study of human olfaction, revealing parts of human genetic olfactory architecture, and finding variations in odorant receptors that determine individuals’ abilities to detect odors.
The Journal of Neurophysiology is a monthly peer-reviewed scientific journal established in 1938. It is published by the American Physiological Society with Jan "Nino" Ramirez as its editor-in-chief. Ramirez is the Director for the Center for Integrative Brain Research at the University of Washington.
Gordon Murray Shepherd was an American neuroscientist who carried out basic experimental and computational research on how neurons are organized into microcircuits to carry out the functional operations of the nervous system. Using the olfactory system as a model that spans multiple levels of space, time and disciplines, his studies have ranged from molecular to behavioral, recognized by an annual lecture at Yale University on "integrative neuroscience". At the time of his death, he was professor of neuroscience emeritus at the Yale School of Medicine. He graduated from Iowa State University with a BA, Harvard Medical School with a MD, and the University of Oxford with a DPhill.
Sniffing is a perceptually-relevant behavior, defined as the active sampling of odors through the nasal cavity for the purpose of information acquisition. This behavior, displayed by all terrestrial vertebrates, is typically identified based upon changes in respiratory frequency and/or amplitude, and is often studied in the context of odor guided behaviors and olfactory perceptual tasks. Sniffing is quantified by measuring intra-nasal pressure or flow or air or, while less accurate, through a strain gauge on the chest to measure total respiratory volume. Strategies for sniffing behavior vary depending upon the animal, with small animals displaying sniffing frequencies ranging from 4 to 12 Hz but larger animals (humans) sniffing at much lower frequencies, usually less than 2 Hz. Subserving sniffing behaviors, evidence for an "olfactomotor" circuit in the brain exists, wherein perception or expectation of an odor can trigger brain respiratory center to allow for the modulation of sniffing frequency and amplitude and thus acquisition of odor information. Sniffing is analogous to other stimulus sampling behaviors, including visual saccades, active touch, and whisker movements in small animals. Atypical sniffing has been reported in cases of neurological disorders, especially those disorders characterized by impaired motor function and olfactory perception.
The lateral horn is one of the two areas of the insect brain where projection neurons of the antennal lobe send their axons. The other area is the mushroom body. Several morphological classes of neurons in the lateral horn receive olfactory information through the projection neurons.
Christiane Linster is a Luxembourg-born behavioral neuroscientist and a professor in the Department of Neurobiology and Behavior at Cornell University. Her work focuses on neuromodulation along with learning and memory, using the olfactory system of rodents as a model. Her lab integrates behavioral, electrophysiological, and computational work. Linster was the founding President of the Organization for Computational Neurosciences (OCNS), which was created to coordinate and lead the annual meeting of aspiring and senior computational neuroscientists. Linster served as president of the OCNS from 2003 until 2005 when she was replaced by her successor Ranu Jung.
Li Zhaoping, born in Shanghai, China, is a neuroscientist at the University of Tübingen in Germany. She is the only woman to win the first place in CUSPEA, an annual national physics competition in China, during CUSPEA's 10-year history (1979–1989). She proposed V1 Saliency Hypothesis (V1SH), and is the author of Understanding vision: theory, models, and data published by Oxford University Press.
Mala Murthy is an American neuroscientist who serves as the Director of the Princeton Neuroscience Institute, and is the Karol and Marnie Marcin ’96 Professor of Neuroscience at Princeton University. Her work centers around how the brain extracts important information from the sensory world and utilises that information to modulate behavior in a social context. She is most known for her work in acoustic communication and song production in courting Drosophila fruit flies. Murthy and colleagues have also published an automated system for measuring animal pose in movies with one or more animal.
Jessica Cardin is an American neuroscientist who is an associate professor of neuroscience at Yale University School of Medicine. Cardin's lab studies local circuits within the primary visual cortex to understand how cellular and synaptic interactions flexibly adapt to different behavioral states and contexts to give rise to visual perceptions and drive motivated behaviors. Cardin's lab applies their knowledge of adaptive cortical circuit regulation to probe how circuit dysfunction manifests in disease models.
Dayu Lin is a neuroscientist and Associate Professor of Psychiatry, Neuroscience and Physiology at the New York University Grossman School of Medicine in New York City. Lin discovered the neural circuits in the hypothalamus that give rise to aggression in mice. Her lab at NYU now probes the neural circuits underlying innate social behaviors, with a focus on aggressive and defensive behaviors.
