OBJECTIVE: To observe the effects of moxa smoke through olfactory pathway on learning and memory ability in rapid aging (SAMP8) mice, and to explore the action pathway of moxa smoke. METHODS: Forty-eight six-month-old male SAMP8 mice were randomly divided into a model group, an olfactory dysfunction group, a moxa smoke group and an olfactory dysfunction + moxa smoke group, with 12 mice in each group. Twelve age-matched male SAMR1 mice were used as the blank group. The olfactory dysfunction model was induced in the olfactory dysfunction group and the olfactory dysfunction + moxa smoke group by intraperitoneal injection of 3-methylindole (3-MI) with 300 mg/kg, and the moxa smoke group and the olfactory dysfunction + moxa smoke group were intervened with moxa smoke at a concentration of 10-15 mg/m³ for 30 min per day, with a total of 6 interventions per week. After 6 weeks, the emotion and cognitive function of mice was tested by open field test and Morris water maze test, and the neuronal morphology in the CAI area of the hippocampus was observed by HE staining. The contents of neurotransmitters (glutamic acid [Glu], gamma-aminobutyric acid [GABA], dopamine [DA], and 5-hydroxytryptamine [5-HT]) in hippocampal tissue of mice were detected by ELISA. RESULTS: The mice in the blank group, the model group and the moxa smoke group could find the buried food pellets within 300 s, while the mice in the olfactory dysfunction group and the olfactory dysfunction + moxa smoke group took more than 300 s to find them. Compared with the blank group, the model group had increased vertical and horizontal movements (P<0.05) and reduced central area residence time (P<0.05) in the open field test, prolonged mean escape latency on days 1-4 (P<0.05), and decreased search time, swimming distance and swimming distance ratio in the target quadrant of the Morris water maze test, and decreased GABA, DA and 5-HT contents (P<0.05, P<0.01) and increased Glu content (P<0.05) in hippocampal tissue. Compared with the model group, the olfactory dysfunction group had increased vertical movements (P<0.05), reduced central area residence time (P<0.05), and increased DA content in hippocampal tissue (P<0.05); the olfactory dysfunction + moxa smoke group had shortened mean escape latency on days 3 and 4 of the Morris water maze test (P<0.05) and increased DA content in hippocampal tissue (P<0.05); the moxa smoke group had prolonged search time in the target quadrant (P<0.05) and increased swimming distance ratio, and increased DA and 5-HT contents in hippocampal tissue (P<0.05, P<0.01) and decreased Glu content in hippocampal tissue (P<0.05). Compared with the olfactory dysfunction group, the olfactory dysfunction + moxa smoke group showed a shortened mean escape latency on day 4 of the Morris water maze test (P<0.05). Compared with the moxa smoke group, the olfactory dysfunction + moxa smoke group had a decreased 5-HT content in the hippocampus (P<0.05). Compared with the blank group, the model group showed a reduced number of neurons in the CA1 area of the hippocampus with a disordered arrangement; the olfactory dysfunction group had similar neuronal morphology in the CA1 area of the hippocampus to the model group. Compared with the model group, the moxa smoke group had an increased number of neurons in the CA1 area of the hippocampus that were more densely packed. Compared with the moxa smoke group, the olfactory dysfunction + moxa smoke group had a reduced number of neurons in the CA1 area of the hippocampus, with the extent between that of the moxa smoke group and the olfactory dysfunction group. CONCLUSION The moxa smoke could regulate the contents of neurotransmitters Glu, DA and 5-HT in hippocampal tissue through olfactory pathway to improve the learning and memory ability of SAMP8 mice, and the olfactory is not the only effective pathway.
Male ; Animals ; Mice ; Olfactory Pathways ; Smoke/adverse effects* ; Serotonin ; Aging ; Dopamine ; Olfaction Disorders/etiology*

Objective: To retrospectively analysely the electrophysiological and imaging features of isolated congenital anosmia (ICA) and to assess the clinical phenotypic characteristics and classification of ICA. Methods: Clinical data of 30 ICA patients in Beijing Anzhen Hospital from 2012 to 2019 was retrospectively reviewed, including 13 males and 17 females, aged (35±19) years. The control group consisted of 30 healthy people from medical examination center, including 13 males and 17 females, aged (39±14) years. The clinical characteristics of ICA were analyzed using Sniffin' Sticks test, olfactory event-related potentials (oERPs), trigeminal event-related potentials (tERP) and olfactory pathway MRI. SPSS 17.0 software was used to compare the difference of olfactory function between the two groups. The correlation between olfactory bulb, olfactory sulcus structure and age was observed, and the clinical phenotype characteristics of ICA patients were analyzed. Results: The subjective olfactory function was completely lost in ICA patients. oERP was absent in all of the ICA patients, but showed normal N₁ and P₂ waves in controls. tERP could be evoked in 63.3% (19/30) of ICA patients, and signals in these patients showed higher amplitude in the N₁ ((-10.33±6.93) μV vs (-5.11±2.71) μV, t=-10.113, P<0.01) and P₂ ((+17.25±8.51) μV vs (+7.31±3.46) μV, t=5.443, P<0.01) waves than that of the controls. Olfactory bulbs were aplastic in 80.0% (24/30) of patients and hypoplastic in 20.0% (6/30) of patients. Fifty-six point seven percent (17/30) of patients had bilateral olfactory sulcus deletion while 43.3% (13/30) had dysplasia, and all of the patients exhibited a depth of olfactory sulcus less than 8 mm. Both the structure of olfactory bulbs and olfactory sulcus were not associated with age for ICA patients (r value was -0.174 and 0.325, respectively, all P>0.05). Conclusions: ICA patients show neurophysiologic deficits and some anatomic differences compared with healthy controls. The absence of oERP combining with a depth of olfactory sulcus less than 8 mm is the important indicator for clinical diagnosis of ICA. The structure of olfactory bulb may be a critical factor for clinical classification of ICA.
Adolescent ; Adult ; Anosmia ; Female ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Olfaction Disorders/diagnosis* ; Olfactory Bulb/diagnostic imaging* ; Olfactory Pathways ; Retrospective Studies ; Smell ; Young Adult

The hippocampus and olfactory bulb incorporate new neurons migrating from neurogenic regions in the brain. Hippocampal atrophy is evident in numerous neurodegenerative disorders, and altered hippocampal neurogenesis is an early pathological event in Alzheimer's disease. We hypothesized that hippocampal neurogenesis is affected by olfactory stimuli through the neural pathway of olfaction-related memory. In this study, we exposed mice to novel pleasant odors for three weeks and then assessed the number of neurons, non-neuronal cells (mainly glia) and proliferating cells in the hippocampus and olfactory bulb, using the isotropic fractionator method. We found that the odor enrichment significantly increased the neuronal cell numbers in the hippocampus, and promoted cell proliferation and neurogenesis in the olfactory bulb. In contrast, the glial cell numbers remained unchanged in both of the regions. Our results suggest that exposure to novel odor stimuli promotes hippocampal neurogenesis and support the idea that enriched environments may delay the onset or slow down the progression of neurodegenerative disorders.
Alzheimer Disease ; Animals ; Atrophy ; Brain ; Cell Count ; Cell Proliferation ; Hippocampus ; Memory ; Methods ; Mice* ; Neural Pathways ; Neurodegenerative Diseases ; Neurogenesis ; Neuroglia ; Neurons* ; Odors* ; Olfactory Bulb

Olfaction plays an important role to detect environmental risk, taste the food, and performs various additional roles crucial to the nutrition, mood and memory. But it has been overlooked compared with other sensory organs, such as vision or hearing function. Recently, a variety of studies associated with olfactory system are in progress from periphery to central area. This review shows the brief summary of the recent ongoing study on olfaction.
Hearing ; Memory ; Olfactory Bulb ; Olfactory Pathways ; Smell*

The olfactory epithelium is the main end organ for the sense of smell in humans and vertebrates. Specially differenciated neuronal cells called olfactory receptor neurons (ORNs) play a key role in the olfactory epithelium by expressing the olfactory receptors (ORs) on their apical surface membrane. The ORs are G-protein coupled receptors that transmit signals from odorants to ORNs by molecular cascades using cyclic adenosine monophosphate, calcium ions and other molecules, which result in the depolarization of ORN. Unlike other mammalian animals, only about 30% of OR genes in the human genome are expressed. The Nobel Prize was awarded to the scientists who cloned these ORs for the first time. Each ORN expresses only a single type of OR, and ORNs which express the same type of OR converge together into the same glomeruli in the olfactory bulb. A single OR recognizes multiple odorants, and a single odorant is recognized by multiple ORs with varying affinities. At the higher neurons beyond the bulb, neuronal connections are divergent. The combinatorial model of odor identification and discrimination is well established at the convergence level, but little is known about the action mechanisms of neuronal divergence for odor identification and discrimination and further study is required.
Adenosine Monophosphate ; Animals ; Awards and Prizes ; Calcium ; Clone Cells ; Discrimination (Psychology) ; Genome, Human ; GTP-Binding Proteins ; Humans ; Ions ; Membranes ; Neurons ; Nobel Prize ; Odors ; Olfactory Bulb ; Olfactory Mucosa ; Olfactory Pathways ; Olfactory Receptor Neurons ; Receptors, Odorant ; Smell* ; Vertebrates

OBJECTIVES: Patients with smell loss after craniocerebral trauma are known to have some brain abnormalities, but there was no study to analyze the findings according to the time interval between injury and evaluation. We aimed to identify whether the time interval may influence on the findings in the brain. METHODS: Medical records of 19 patients with posttraumatic olfactory dysfunction were reviewed. All of them underwent a magnetic resonance imaging and olfactory function tests. The patients were divided into early (n=10) and delayed (n=9) groups according to the time interval. RESULTS: Magnetic resonance imaging was taken at a mean time of 2.2 and 59.6 months after trauma in the early and delayed groups, respectively. Abnormal findings in the brain were found in 6 and 8 patients in the early and delayed groups, respectively. The olfactory bulb and orbitofrontal cortex were commonly affected olfactory pathways in both groups. In the early group, the abnormalities were brain tissue defect, hemorrhage, and focal edema whereas tissue defect was the only finding in the delayed group. In the early group, 5 of 6 patients with severe olfactory dysfunction showed brain abnormality while 1 of 4 patients with mild dysfunction had abnormality. In the delayed group, all the patients had severe dysfunction and 8 of 9 patients showed brain abnormality. CONCLUSION: Most patients with traumatic olfactory dysfunction had abnormality in the brain, and brain abnormality might be different according to the timing of evaluation. Furthermore, there might be an association between the severity of olfactory dysfunction and radiological abnormalities.
Brain ; Craniocerebral Trauma ; Edema ; Hemorrhage ; Humans ; Magnetic Resonance Imaging* ; Medical Records ; Olfactory Bulb ; Olfactory Pathways ; Smell

MRI scanning is an important technique to evaluate the olfactory system, special scanning parameters could reveal the fine structures of the olfactory pathway. Olfactory cleft, olfactory bulb/tract, olfactory sulcus and olfactory center are the main targets of the scanning. Chronic rhino-sinusitis, head trauma, congenital dysplasia and neural degenerative diseases are the primary causes of the olfactory dysfunction and have particular imaging presentations respectively. Besides indicating the olfactory pathway lesions, MRI could also present the etiology and the prognosis of the olfactory disorder.
Humans ; Magnetic Resonance Imaging ; Olfaction Disorders ; diagnosis ; Olfactory Bulb ; Olfactory Pathways

External tufted (ET) cells are the major excitatory elements coordinating the activities of glomerulars and mediating the input from the olfactory neurons to mitral cells. The ET cells participate in inter-and intra-glomerular microcircuits in the olfactory bulb, link the isofunctional odor columns within the same olfactory bulb, and play an important role in olfactory information processing. This paper reviews the research progress of the anatomy and physiological properties and electrophysiological modeling of ET cells, elaborate the problems and defects in the field. And then it further gives some proposals for the future research of electrophysiological properties, development of olfactory information coding and performance of modeling of ET cells.
Electrophysiological Phenomena ; physiology ; Humans ; Olfactory Bulb ; cytology ; physiology ; Olfactory Pathways ; physiology ; Olfactory Receptor Neurons ; cytology

OBJECTIVE: The purpose of this study is to compare the surgical outcomes of pterional-subolfactory approach for the high positioned anterior communicating artery (ACoA) aneurysm with the conventional pterional approach. METHODS: Between February 2005 and December 2012, 463 ACoA aneurysms were surgically treated in our institution. Forty eight high positioned ACoA aneurysms were treated with pterional-subolfactory or conventional pterional approach. High positioned ACoA aneurysms were defined as aneurysms located higher than 10 mm above the anterior clinoid process. Pterional-subolfactory approach is a procedure including dissection of olfactory tract and resection of the gyrus rectus inferior and medial to the olfactory tract. Thirty-four of the 48 cases were treated with pterional-subolfactory approach and 14 were treated conventionally. RESULTS: There were 2 postoperative cerebral infarction with the conventional pterional approach, but none with the pterional-subolfactory approach group (p = 0.026). Postoperative digital subtraction angiography revealed significant remnant aneurysm in the conventional pterional approach group. All patients with unruptured aneurysms had good clinical outcomes with Glasgow outcome score of 5. Among ruptured ACoA aneurysm patients, 2 patients with conventional pterional approach had postoperative cerebral infarctions but permanent neurologic deficit was found in only 1 patient. Three patients treated with the pterional-subolfactory approach, who had preoperative ruptured aneurysms had poor clinical outcomes. The mean operation time for the conventional pterional approach was 58 minutes longer than for the pterional-subolfactory approach (p = 0.001). CONCLUSION: We concluded that pterional-subolfactory approach is highly preferable for cases of high positioned ACoA aneurysm, giving a wide and effective operation view.
Aneurysm ; Aneurysm, Ruptured ; Angiography, Digital Subtraction ; Arteries ; Cerebral Infarction ; Humans ; Intracranial Aneurysm ; Neurologic Manifestations ; Olfactory Pathways

OBJECTIVE: The purpose of this study is to compare the surgical outcomes of pterional-subolfactory approach for the high positioned anterior communicating artery (ACoA) aneurysm with the conventional pterional approach. METHODS: Between February 2005 and December 2012, 463 ACoA aneurysms were surgically treated in our institution. Forty eight high positioned ACoA aneurysms were treated with pterional-subolfactory or conventional pterional approach. High positioned ACoA aneurysms were defined as aneurysms located higher than 10 mm above the anterior clinoid process. Pterional-subolfactory approach is a procedure including dissection of olfactory tract and resection of the gyrus rectus inferior and medial to the olfactory tract. Thirty-four of the 48 cases were treated with pterional-subolfactory approach and 14 were treated conventionally. RESULTS: There were 2 postoperative cerebral infarction with the conventional pterional approach, but none with the pterional-subolfactory approach group (p = 0.026). Postoperative digital subtraction angiography revealed significant remnant aneurysm in the conventional pterional approach group. All patients with unruptured aneurysms had good clinical outcomes with Glasgow outcome score of 5. Among ruptured ACoA aneurysm patients, 2 patients with conventional pterional approach had postoperative cerebral infarctions but permanent neurologic deficit was found in only 1 patient. Three patients treated with the pterional-subolfactory approach, who had preoperative ruptured aneurysms had poor clinical outcomes. The mean operation time for the conventional pterional approach was 58 minutes longer than for the pterional-subolfactory approach (p = 0.001). CONCLUSION: We concluded that pterional-subolfactory approach is highly preferable for cases of high positioned ACoA aneurysm, giving a wide and effective operation view.
Aneurysm ; Aneurysm, Ruptured ; Angiography, Digital Subtraction ; Arteries ; Cerebral Infarction ; Humans ; Intracranial Aneurysm ; Neurologic Manifestations ; Olfactory Pathways