Johann Lehrner

Ambient odor of orange in a dental office reduces anxiety and improves mood in female patients.

Essential oils have been used as remedies for a long time in different cultures across the world. However, scientific proof of such application is scarce. We included 72 patients between the ages of 22 and 57 while waiting for dental treatment in our study. The participants were assigned to either a control group (14 men, 23 women) or to an odor group (18 men and 17 women). Ambient odor of orange was diffused in the waiting room through an electrical dispenser in the odor group whereas in the control group no odor was in the air. We assessed by means of self-report demographic and cognitive variables, trait and state anxiety, and current pain, mood, alertness, and calmness. In this study, we report that exposure to ambient odor of orange has a relaxant effect. Specifically, compared to the controls, women who were exposed to orange odor had a lower level of state anxiety, a more positive mood, and a higher level of calmness. Our data support the previous notion of sedative properties of the natural essential oil of orange (Citrus sinensis).

Different forms of human odor memory: a developmental study

Recognizing odors is an important biological function, both in the animal kingdom as well as for humans. It has been debated whether there exist different forms of human odor memory. For verbal memory, the concept of recollection and familiarity for conscious and unconscious recognition is widely accepted. Here we introduce a similar model for human odor memory. We use a combination of an odor naming and odor recognition memory task to estimate the relationship between depth of processing and retention of olfactory information. A developmental approach with children, young adults, middle aged adults and elderly subjects was chosen in order to study the influence of age. Our results indicate the existence of two separable forms of odor memory depending on whether the odors were correctly or incorrectly named during the naming task. These two forms of odor memory were differently represented across the human age range. Intact familiarity-based memory was found in all age groups, whereas memory based on recollection was impaired in the elderly and not yet fully developed in children. Our data show, for the first time, two different forms of human odor memory across the human life span.

Does modification of olfacto-gustatory stimulation diminish sensory-specific satiety in humans?

UNLABELLED Alimentary sensory pleasure is an important factor in ingestive behavior. Renewal of olfacto-gustatory pleasure by introducing new foods or through seasoning of previously consumed food might increase intake. OBJECTIVES To explore whether sensory-specific satiety (SSS) for a food could be modulated, either by introducing a novel food or by a modification of sensory stimulation via seasoning the food just eaten. METHODS 180 out of 242 subjects were distributed over 3 experiments involving ad libitum intake of one of 6 fresh foods (cucumber, tomato, pineapple, banana, peanut, pistachio). Blindfolded subjects reported their sensations for the foods on 3 parameters before and after intake of an olfactorily chosen food: Olfactory pleasure (OP), Specific appetite (SA) and Stimulus-Induced Salivation (SIS). EXP. 1: One chosen food was repeatedly presented orthonasally and rated before and after it was eaten. EXP. 2: A second food was olfactorily chosen and ingested after the first one. EXP. 3: The same food was offered again after seasoning. RESULTS 2 min after ingestion, food intake was limited by SSS. OP, SA, SIS correlated with each other for eaten and non-eaten foods. OP for non-eaten foods increased (p<0.01) after ingestion of the chosen food to specific satiety. When the food just eaten was seasoned, OP increased (p<0.01) and led to additional intake (80% of first intake). CONCLUSION A reduction in SSS after introduction of a new flavor or after seasoning an ingested food was observed. Such a reduction has not previously been reported. This could hint at how food sensory variation leads to over-consumption.

Depth of word processing in Alzheimer patients and normal controls: a magnetoencephalographic (MEG) study

Summary.Effects related to depth of verbal information processing were investigated in probable Alzheimer’s disease patients (AD) and age matched controls. During word encoding sessions 10 patients and 10 controls had either to decide whether the letter “s” appeared in visually presented words (alphabetical decision, shallow encoding), or whether the meaning of each presented word was animate or inanimate (lexical decision, deep encoding). These encoding sessions were followed by test sessions during which all previously encoded words were presented again together with the same number of new words. The task was then to discriminate between repeated and new words. Magnetic field changes related to brain activity were recorded with a whole cortex MEG.5 probable AD patients showed recognition performances above chance level related to both depths of information processing. Those patients and 5 age matched controls were then further analysed. Recognition performance was poorer in probable AD patients compared to controls for both levels of processing. However, in both groups deep encoding led to a higher recognition performance than shallow encoding. We therefore conclude that the performance reduction in the patient group was independent of depth of processing. Reaction times related to false alarms differed between patients and controls after deep encoding which perhaps could already be used for supporting an early diagnosis.The analysis of the physiological data revealed significant differences between correctly recognised repetitions and correctly classified new words (old/new-effect) in the control group which were missing in the patient group after deep encoding. The lack of such an effect in the patient group is interpreted as being due to the respective neuropathology related to probable AD. The present results demonstrate that magnetic field recordings represent a useful tool to physiologically distinguish between probable AD and age matched controls.

Olfaction and depth of word processing: a magnetoencephalographic study.

Using a whole-cortex magnetoencephalograph, magnetic field changes were recorded to describe brain activities related to simultaneous visual and olfactory processing and to detect odor-related influences on verbal information processing. Words had to be either shallowly (nonsemantic) or deeply (semantic) encoded by healthy young subjects, each of these tasks under two different kinds of olfactory stimulation. After each encoding phase, word recognition performance was tested. First, the odor was randomly associated with some of the study words (simultaneous stimulation; same duration as for words) for both depths of word processing conditions, and second, continuous olfactory stimulation (permanent stimulation) was provided during the whole study phases of both depths of word processing conditions. The statistical analysis of the physiological data revealed evidence of a specific odor-induced effect depending on depth of word processing and kind of olfactory stimulation. Brain activity between about 250 and 450 ms as well as between about 650 and 1000 ms after stimulus onset was found to vary as a function of odor delivery and depth of word processing. In addition, a significant effect of odor stimulation on subsequent word recognition performance occurred in case of simultaneous odor stimulation and semantic word encoding. It is interpreted that in this case, word recognition performance significantly decreased because of the presence of the odor during prior word encoding. Such a behavioral effect was missing in all other conditions. The present psychological and physiological findings support the idea that semantic word encoding is specifically affected by simultaneous olfactory information processing. It is concluded that this phenomenon is due to a competition with cortical regions related to language and olfactory information processing, as suggested by T. S. Lorig (1999, Neurosci. Biobehav. Rev. 23, 391-398).

Event-related potentials in patients with temporal lobe epilepsy reveal topography specific lateralization in relation to the side of the epileptic focus

Event-related potentials (ERPs) were recorded during a continuous recognition memory paradigm in patients with left-sided (LTLE; n = 8) or right-sided temporal lobe epilepsy (RTLE; n = 6), and in healthy control subjects (n = 24). Control subjects and both patient groups exhibited consistent OLD/NEW ERP-differences from 200-600 ms after stimulus onset. ERPs did not differ significantly between LTLE and RTLE patients, with respect to OLD/NEW distinction or the type of presented material (verbal vs. non-verbal). However, ERP topography showed significant differences between LTLE and RTLE patients: in lateral fronto-temporal recordings, patients showed larger negativities contralateral to the seizure focus, whereas we found larger negativities ipsilateral to the seizure focus in parietal recordings. Differences between the groups were significant from 300 to 600 ms post-stimulus. As a consequence, the amplitude gradient from fronto-temporal to parietal recordings was higher on the right side in LTLE patients and on the left side in RTLE patients. Again, differences between LTLE and RTLE patients were highly significant. We assume that ERPs reflect disturbances of a cortico-cortical network dependent on the side of the seizure focus in temporal lobe epilepsy. Furthermore, scalp-recorded ERPs might be a useful tool in the prediction of the side of the seizure focus in patients with temporal lobe epilepsy.

Preserved memory traces within diencephalic amnesia

Summary. A male patient with bilateral thalamic lesions (medio-ventral nuclei) was investigated. Despite explicit memory impairments his lexical ability was normal. We recorded magnetic field changes (magnetoencephalography, MEG) during the performance of an animate/inanimate discrimination task in which some words where repeated after long delays. Normally, repeated items are classified significantly faster than their first presentations which is accomplished by an unconscious process called priming. The patient did not show any behavioural evidence of priming but the physiological data indicated preservation of this robust form of memory. Brain activation associated with repetitions was attenuated at early stages. The activity difference was posteriorly distributed which is consistent with previous reports about repetition priming. The present study indicated that the bilateral thalamic lesions of our patient disconnected the information processing stream between the primed information and the behavioural response.