Short or long runs: An exploratory study of odor-induced fMRI design.

Objective: Functional magnetic resonance imaging (fMRI) is a non-invasive neuroimaging technique widely used in olfactory research. During a typical fMRI olfactory block-design, one functional "run" refers to a combination of multiple blocks with continuous brain image acquisition. The current study investigated the length of functional runs on odor-induced brain response signals (blood oxygen level dependent [BLOD]) within the primary and key secondary olfactory areas.

Olfactory change detection.

The human olfactory system is characterized by poor temporal and spatial resolution. When determining changes in the environment, humans rather rely on visual than on olfactory information. Against this background, we developed a test in order to investigate the human capacity to detect changes in the olfactory environment and to determine potential modulators of olfactory change detection.

Impaired brain response to odors in patients with varied severity of olfactory loss after traumatic brain injury.

Traumatic brain injury (TBI) as a major public health problem may lead to olfactory dysfunction. However, little is known about brain responses to odors in TBI olfactory loss patients. Nineteen healthy controls and forty TBI olfactory dysfunctional patients (19 with hyposmia and 21 with anosmia) underwent a functional magnetic resonance imaging scan when two odors (peach and coffee) were presented intranasally using a computerized olfactometer.

Different Neural Processing of Umami and Salty Taste Determined by Umami Identification Ability Independent of Repeated Umami Exposure.

There is a large inter-individual variation for umami taste perception. However the neural mechanism for this variability is not well understood. This study investigated brain responses to umami and salty taste among individuals with different umami identification abilities and the effect of repeated oral umami exposure on umami identification and neural processing of taste perceptions.

Alterations of Brain Gray Matter Density and Olfactory Bulb Volume in Patients with Olfactory Loss after Traumatic Brain Injury.

Olfactory loss and traumatic brain injury (TBI) both lead to anatomical brain alterations in humans. Little research has been done on the structural brain changes for TBI patients with olfactory loss. Using voxel-based morphometry, the gray matter (GM) density was examined for 22 TBI patients with hyposmia, 24 TBI patients with anosmia, and 22 age-matched controls.

Food-Related Odors Activate Dopaminergic Brain Areas.

Food-associated cues of different sensory categories have often been shown to be a potent elicitor of cerebral activity in brain reward circuits. Smells influence and modify the hedonic qualities of eating experience, and in contrast to smells not associated with food, perception of food-associated odors may activate dopaminergic brain areas. In this study, we aimed to verify previous findings related to the rewarding value of food-associated odors by means of an fMRI design involving carefully preselected odors of edible and non-edible substances.

Bimodal odor processing with a trigeminal component at sub- and suprathreshold levels.

Odors are typically bimodal in nature, interacting with the olfactory and trigeminal systems. The trigeminal component may be noticed (e.g.

The Rewarding Effect of Pictures with Positive Emotional Connotation upon Perception and Processing of Pleasant Odors-An FMRI Study.

This fMRI study was designed to investigate the effect of cross-modal conditioning in 28 female volunteers. Subjects underwent initial fMRI block design scanning during which three pleasant olfactory stimuli were presented and had to be rated with respect to intensity and pleasantness. This was followed by an odor identification task spread out over 3 days: the experimental group was rewarded for successful trials (correct odor identification) with emotionally salient photos, whilst the control group only received randomly displayed, emotionally neutral, pictures.

Olfactory Performance Can Be Influenced by the Presentation Order, Background Noise, and Positive Concurrent Feedback.

Sniffin' Sticks have become a popular procedure to measure overall olfactory functionality with 3 subtest: phenyl ethyl alcohol threshold test (T), discrimination (D), and identification (I). However, several procedural components specified by the original paper have not been tested nor has the impact of deviations been measured. The aim of the present work was to measure olfactory performance under modified testing procedures.

Cultural Adaptation of the Portuguese Version of the "Sniffin' Sticks" Smell Test: Reliability, Validity, and Normative Data.

The cross-cultural adaptation and validation of the Sniffin`Sticks test for the Portuguese population is described. Over 270 people participated in four experiments. In Experiment 1, 67 participants rated the familiarity of presented odors and seven descriptors of the original test were adapted to a Portuguese context.

Peripheral adaptive filtering in human olfaction? Three studies on prevalence and effects of olfactory training in specific anosmia in more than 1600 participants.

Selective processing of environmental stimuli improves processing capacity and allows adaptive modulation of behavior. The thalamus provides an effective filter of central sensory information processing. As olfactory projections, however, largely bypass the thalamus, other filter mechanisms must consequently have evolved for the sense of smell.

Characteristics of chemosensory disorders--results from a survey.

This survey was undertaken to investigate the nature of chemosensory dysfunction in relation to the underlying cause, severity, and course of the disease and to elucidate their clinical significance. A total of 269 patients (116 men and 149 women) with chemosensory disorders participated in the survey. Approximately 89 % had olfactory loss, either alone or in combination with taste loss and 2 % had gustatory loss alone; 7.

Human olfactory lateralization requires trigeminal activation.

Rats are able to lateralize odors. This ability involves specialized neurons in the orbitofrontal cortex which are able to process the left, right and bilateral presentation of stimuli. However, it is not clear whether this function is preserved in humans.

Olfaction as a marker for depression in humans.

Background: Animal studies show a strong link between the loss of olfactory function and depressive behavior. We analyzed, whether olfactory function is a marker for depression in humans. If so, reduced olfactory function can be expected in depression that improves to level of normality after successful antidepressive treatment.

A salty-congruent odor enhances saltiness: functional magnetic resonance imaging study.

Excessive intake of dietary salt (sodium chloride) may increase the risk of chronic diseases. Accordingly, various strategies to reduce salt intake have been conducted. This study aimed to investigate whether a salty-congruent odor can enhance saltiness on the basis of psychophysical (Experiment 1) and neuroanatomical levels (Experiment 2).

The influence of olfactory loss on dietary behaviors.

Objectives: To assess dietary behavior and possible changes in food selection in patients with smell loss.

Patients And Methods: A total of 176 patients (114 women and 62 men) age 17 to 86 years were classified into three diagnostic groups (normosmia, n = 12; hyposmia, n = 75; functional anosmia, n = 89) according to their olfactory test scores obtained with "Sniffin' Sticks." Group differences in food intake and dietary behaviors were investigated with a specifically designed questionnaire providing a dietary alterations score (DAS).

Lateralized differences in olfactory function.

Background: Birhinal testing of odor identification will not allow the detection of unilateral olfactory loss. The aim of the presented study was to evaluate side differences of odor identification in large groups of healthy subjects and in patients with nasal symptoms.

Participants And Method: Self-assessment of olfactory function and evaluation of olfactory function by means of a validated test were performed in 479 healthy subjects, in 765 patients with chronic rhinosinusitis (CRS), and in 53 patients with a tumor.

Olfactory loss may be a first sign of idiopathic Parkinson's disease.

Recent studies support the idea of olfactory dysfunction as a very early sign of idiopathic Parkinson's disease (IPD). Aim of the present study was to clinically follow-up patients with idiopathic hyposmia to find out the percentage of patients developing IPD after 4 years time. At baseline, olfactory tests had been combined with transcranial sonography of the substantia nigra and (123)I-FP-CIT SPECT imaging.

Spatial relationship of source localizations in patients with focal epilepsy: Comparison of MEG and EEG with a three spherical shells and a boundary element volume conductor model.

Epilepsy surgery is an option for patients with pharmacoresistant focal epilepsies, but it requires a precise focus localization procedure. Magnetoencephalography (MEG) and electroencephalography (EEG) can be used for analysis of interictal activity. The aim of this prospective study was to compare clusters of source localization results with MEG and EEG using a three spherical shells (3SS) and a boundary element method (BEM) volume conductor model.

Post-apoplectic reorganization of cortical areas processing passive movement and tactile stimulation--a neuromagnetic case study.

Magnetoencephalography (MEG) was used in a patient with right centro-parietal stroke to investigate the cortical processing of tactile pneumatic stimulation and passive movement of the impaired left and unaffected right-hand index finger. Source localization of somatosensory evoked magnetic fields (SEF) recorded 2 weeks after infarction demonstrated a spatial displacement of the contralateral SI generators in the affected hemisphere. The distance between SI sources activated by either stimulation technique was noticeably enlarged in comparison to the left hemisphere and to previous data from 12 healthy subjects.

Somatotopic organization of the ventral and dorsal finger surface representations in human primary sensory cortex evaluated by magnetoencephalography.

Cortical reorganization of the subtly differentiated hand map after peripheral nerve injury might be better understood if there was a topographic conception of the homuncular representation of the dorsal finger surfaces in humans, in addition to the well-established sequential rostrocaudal array of the ventral finger aspects in cortical area 3b. In the present magnetoencephalographic study, tactile pneumatic stimulation was delivered to the fingertip and to the ventral and dorsal proximal phalanx of each digit of the dominant hand in 20 right-handed volunteers. Source localization of equivalent current dipoles underlying the recorded somatosensory evoked magnetic field was performed using a Cartesian coordinate system established by the anatomical landmarks nasion and preauricular points.