膳食营养与抑郁症的关系

近十几年, 膳食营养与抑郁症的关系受到了研究者越来越多的重视。早期的研究主要考察单一营养元素或食物对于抑郁症的影响, 其中研究最多的是n-3多不饱和脂肪酸和叶酸, 近期的研究开始关注整体膳食模式与抑郁症的联系。膳食营养与抑郁症关联的内在机制涉及炎症反应、氧化应激和脑源性神经营养因子等。以流行病学为主的研究现状限制了膳食营养影响抑郁症的因果解释, 未来的研究应强化对两者关联的内在机制以及现实价值的考察。     

Monogeusia for fructose,glucose, sucrose,and maltose

We investigated the ability of subjects to discriminate sugars with a whole-mouth forced-choice paradigm, in which a standard solution was compared with a test solution of varied concentration. Discrimination probabilities were U-shaped functions of test concentration: for 6 subjects and pairwise combinations of fructose, glucose, and sucrose, discriminability always declined to chance over a narrow range of test concentrations. At concentrations ≦ 100 mM, maltose was indiscriminable from fructose but discriminable at higher concentrations for 4 subjects. By analogy with themonochromacy of night vision, whereby any two lights are indiscriminable when their relative intensities are suitably adjusted, we call the gustatory indiscriminability of these sugarsmonogeusia. The simplest account of monogeusia is that all information about the indiscriminable sugars is represented by a single neural signal that varies only in magnitude. The discriminability of maltose from the other sugars at higher concentrations is consistent with the hypothesis that maltose also activates a second gustatory code.     

Gustatory plasticity in C. elegans involves integration of negative cues and NaCl taste mediated by serotonin, dopamine, and glutamate

While na?ve Caenorhabditis elegans individuals are attracted to 0.1-200 mM NaCl, they become strongly repelled by these NaCl concentrations after prolonged exposure to 100 mM NaCl. We call this behavior gustatory plasticity. Here, we show that C. elegans displays avoidance of low NaCl concentrations only when pre-exposure to NaCl is combined with a negative stimulus, e.g., a repellent, or in the absence of food. By testing serotonin and/or dopamine signaling mutants and rescue by exogenously supplying these neurotransmitters, we found that serotonin and dopamine play a role during the plasticity response, while serotonin is also required during development. In addition, we also show that glutamate plays an important role in the response to NaCl, both in chemoattraction to NaCl and in gustatory plasticity. Thus, C. elegans can associate NaCl with negative stimuli using dopaminergic, serotonergic, and glutamatergic neurotransmission. Finally, we show that prolonged starvation enhances gustatory plasticity and can induce avoidance of NaCl in most gustatory plasticity mutants tested. Only mutation of the glutamate-gated Cl(-) channel gene avr-15 affected starvation-enhanced gustatory plasticity. These results suggest that starvation induces avoidance of NaCl largely independent of the normal gustatory plasticity mechanism.     

Learning and memory impairment in rats fed a high saturated fat diet

At the age of 1 month, three separate groups of Long-Evans rats were placed on 20% (w/w) fat (40% of calories) diets high in either saturated fatty acids (lard-based) or polyunsaturated fatty acids (soybean oil-based) or standard laboratory chow (Purina, 4.5% (w/w) fat). After 3 months, all rats were administered three tests of learning and memory--Olton's radial arm maze, a variable-interval delayed alternation task, and the Hebb-Williams maze series. The lard-fed group was impaired on all tests. The soybean oil-fed group was slightly impaired on some measures, relative to the chow-fed group, but consistently performed better than the lard-fed group. The results indicate that a diet high in saturated fatty acids can impair a wide range of learning and memory functions and are in line with biochemical and physiological evidence showing widespread effects of such diets on brain function.     

Perceptual Experience Norms for 506 Russian Nouns: Modality Rating,Spatial Localization,Manipulability, Imageability and Other Variables

A number of new psycholinguistic variables has been proposed during the last years within embodied cognition framework: modality experience rating (i.e., relationship between words and images of a particular perceptive modality—visual, auditory, haptic etc.), manipulability (the necessity for an object to interact with human hands in order to perform its function), vertical spatial localization. However, it is not clear how these new variables are related to each other and to such traditional variables as imageability, AoA and word frequency. In this article, normative data on the modality (visual, auditory, haptic, olfactory, and gustatory) ratings, vertical spatial localization of the object, manipulability, imageability, age of acquisition, and subjective frequency for 506 Russian nouns are presented. Strongest correlations were observed between olfactory and gustatory modalities (.81), visual modality and imageability (.78), haptic modality and manipulability (.7). Other modalities also significantly correlate with imageability: olfactory (.35), gustatory (.24), and haptic (.67). Factor analysis divided variables into four groups where visual and haptic modality ratings were combined with imageability, manipulability and AoA (the first factor); word length, frequency and AoA formed the second factor; olfactory modality was united with gustatory (the third factor); spatial localization only is included in the fourth factor. Present norms of imageability and AoA are consistent with previous as correlation analysis has revealed. The complete database can be downloaded from supplementary material.     

Taste,traits, and tendencies

Philosophical Studies - Many experiential properties are naturally understood as dispositions such that e.g. a cake tastes good to you iff you are disposed to get gustatory pleasure when you eat...     

Comparison of taste qualities elicited by tactile,electrical, and chemical stimulation of single human taste papillae

Taste quality responses elicited by chemical, electrical, and tactile stimulation of 40 single fungiform papillae in four subjects were examined. A comparison of responses revealed differences in taste quality mediation for the three different classes of stimuli. Chemical stimulation elicited multiple taste qualities from a greater proportion of papillae than did either electrical or tactile stimulation. In addition, the chemical data revealed the presence of consistent bitter-sour and sour-salty confusions. Both tactile and electrical stimulation elicited relatively few bitter and sweet responses, as compared with either sour or salty responses. However, correct quality identification in these papillae for bitter and sweet compounds was no different from that for sour or salty compounds. In addition, electrical stimulation elicited a greater proportion of salty responses than did tactile stimulation. Comparison of the taste quality elicited by either tactile or electrical stimulation of a papilla with the taste quality exhibiting the greatest relative chemical sensitivity in the papilla also revealed independence of responding, and it was observed that both electrical and tactile stimulation elicited consistent taste quality responses from papillae in which these taste qualities could not be elicited by any concentration of any chemical test compound. The observed differences in quality judgments are discussed as possibly being the result of cross-modal gustatory associations resulting from nongustatory components of inadequate stimulation.     

Psychophysics of taste lateralization on anterior tongue

There have been very few investigations of the spatial properties of taste stimuli localized to specific areas of the oral cavity. This is surprising, since the spatial localization of taste sensations may contribute to the overall taste percept, much as do quality, intensity, and the temporal characteristics of tastes. The difficulty in eliminating the confounding factor of a tactile sensation may partially account for the paucity of such studies, since a gustatory stimulus cannot be presented as a liquid without a tactile component. As a step toward understanding the localizability of gustatory sensations, we designed a yoked stimulator and an experimental procedure to control for tactile cues. Lateral discrimination was evaluated at the tip of the tongue with four taste stimuli (sodium saccharin, sodium chloride, citric acid, and quinine hydrochloride) by presenting a taste and a blank solution simultaneously at two locations on the tongue. We found that subjects could lateralize all four taste stimuli in the absence of any discriminative tactile cues. Subjects' ability to lateralize varied as a psychometric function of the stimulus concentration. Detection thresholds, measured in a forced-choice two-interval staircase procedure with the same yoked stimulator that was used in the lateralization task, were always lower than lateralization thresholds, and both lateralization and detection thresholds were correlated within subjects. Subjects were unable to lateralize taste cues on a nongustatory surface under the upper lip at the highest tested concentrations, at which performance was 100% on a gustatory surface (dorsal anterior tongue). These results show that (1) taste compounds can be lateralized in the absence of any discriminative mechanical cue (but only on the gustatory epithelium) and (2) although the localization of a compound does not logically require conscious detection of the taste (cf. blind sight), subjects always detected a taste when they were able to lateralize.     

Interrelations of perceptual reports of smell,taste and irritance over the near-threshold range,for members of the N-aliphatic monohydric alcohol series

Many compounds are psychophysically complex because they stimulate all three chemical senses; smell, taste, and irritance.3 Interrelations among these three modalities are reported over the near-threshold range, and comparisons are made for three such compounds; methanol, ethanol, and propanol. Eighteen Ss were tested over 16 sessions each under a range of conditions: a combined task condition that approximated normal drinking, in which thresholds for all three modalities were determined simultaneously, and three conditions, in each of which only one threshold in one modality was determined. Pooled results over Ss gave significant shifts in olfactory thresholds between conditions, whereas changes in gustatory and irritant acuity were less marked. Individual results yielded significant correlations between psychophysical behavior and personality measures. Factor analysis of Ss indicated the existence of subgroups of Ss, each typified by different patterns of relative sensitivity over modalities and over alcohols.     

Cation and anion contributions to gustatory quality of simple salts

Curves of mean percentages of the four gustatory quality responses as a function of concentration of solutions of LiCl, KCl, lithium sulfate, and potassium sulfate were evaluated as to the relative contributions of the cation and anion to the quality. It was concluded that chloride ion, and sulfate ion to a lesser degree, were responsible for the salty quality. In the mid-range concentrations, potassium ion was responsible for the bitter quality, and lithium ion, by means of an ion-soliient interaction; was responsible for the sour quality reported. At the very low concentrations, at which all salts tested evoked sweet responses, a structure produced by a solvent-cation interaction was assumed to be responsible. The details of the presumed structure are still to be clarified. Although one ion in each salt is primarily responsible for a particular quality over a given concentration, the other ion usually modifies the effect.     

Sensory responsiveness and the effects of equal subjective rewards on tactile learning and memory of honeybees

In tactile learning, sucrose is the unconditioned stimulus and reward, which is usually applied to the antenna to elicit proboscis extension and which the bee can drink when it is subsequently applied to the extended proboscis. The conditioned stimulus is a tactile object that the bee can scan with its antennae. In this paper we describe the quantitative relationships between gustatory antennal stimulation, gustatory proboscis stimulation, and tactile learning and memory. Bees are 10-fold more responsive to sucrose solutions when they are applied to the antenna compared to proboscis stimulation. During tactile conditioning, the sucrose solution applied to the proboscis determines the level of acquisition, whereas antennal input is of minor importance. Bees differing in their gustatory responsiveness measured at the antenna differ strongly in their tactile acquisition and memory. We demonstrate how these differences in tactile acquisition and memory can be greatly reduced by calculating equal subjective rewards, based on individual gustatory responsiveness.     

Taste and Acquaintance

The analogy between gustatory taste and critical or aesthetic taste plays a recurring role in the history of aesthetics. Our interest in this article is in a particular way in which gustatory judgments are frequently thought to be analogous to critical judgments. It appears obvious to many that to know how a particular object tastes we must have tasted it for ourselves; the proof of the pudding, we are all told, is in the eating. And it has seemed just as obvious to many philosophers that aesthetic judgment requires first‐person experience. In this article we argue that, despite its initial appeal, the claim that gustatory and critical judgments are analogous in this way is mistaken. The two sorts of judgments are, as a matter of fact, similar in their epistemology, but earlier theorists have got things entirely backward—neither gustatory judgment nor aesthetic judgment requires first‐hand acquaintance with their objects. Our particular focus in this article is on arguing that first‐person experience is not required to know how an item of food or drink tastes. In fact, there are a wide variety of ways in which we can acquire this knowledge.     

Event‐related potential differences in children supplemented with long‐chain polyunsaturated fatty acids during infancy

Long‐chain polyunsaturated fatty acids (LCPUFA) have been shown to be necessary for early retinal and brain development, but long‐term cognitive benefits of LCPUFA in infancy have not been definitively established. The present study sought to determine whether LCPUFA supplementation during the first year of life would result in group differences in behavior and event‐related potentials (ERPs) while performing a task requiring response inhibition (Go/No‐Go) at 5.5 years of age. As newborns, 69 children were randomly assigned to infant formulas containing either no LCPUFA (control) or formula with 0.64% of total fatty acids as arachidonic acid (ARA; 20:4n6) and various concentrations of docosahexaenoic acid (DHA; 22:6n3) (0.32%, 0.64% or 0.96%) for the first 12 months of life. At 5.5 years of age, a task designed to test the ability to inhibit a prepotent response (Go/No‐Go) was administered, yielding both event‐related potentials (ERPs) and behavioral data. Behavioral measures did not differ between groups, although reaction times of supplemented children were marginally faster. Unsupplemented children had lower P2 amplitude than supplemented children to both Go and No‐Go conditions. N2 amplitude was significantly higher on No‐Go trials than Go trials, but only for supplemented children, resulting in a significant Group × Condition interaction. Topographical analysis of the ERPs revealed that the LCPUFA‐supplemented group developed a novel period of synchronous activation (microstate) involving wider anterior brain activation around 200 ms; this microstate was not present in controls. These findings suggest that LCPUFA supplementation during the first 12 months of life exerts a developmental programming effect that is manifest in brain electrophysiology. A video abstract of this article can be viewed at: https://www.youtube.com/watch?v=oM2leg4sevs .     

Prostaglandins and endogenous psychoses

The authors refer to the biochemical investigation of the occurrence and metabolism of essential fatty acids in the CNS and to significant differences in results between those obtained in animal experiments and those involving human beings, taking into account hypotheses that have not yet met with general acceptance. Discussed is the possible connection between eicosanic acid and schizophrenia, notably Horrobin's hypothesis of PGE1 deficiency in schizophrenic patients. The probability of a pathogenetic connection between changes in the metabolism of fatty acids and the occurrence of endogenous psychoses is assumed.     

Time-dependent recovery of taste aversion learning by fetal brain transplants in gustatory neocortex-lesioned rats.

We recently showed that fetal brain transplants produced a significant recovery in the ability of gustatory neocortex-lesioned rats to learn a conditioned taste aversion. In this report we assessed the capability of gustatory neocortex fetal brain transplants to produce behavioral recovery at different times. Four groups of male Wistar rats showing disrupted taste aversions due to gustatory neocortex lesions were studied. The lesioned animals received fetal cortical grafts, obtained from 16-day-old fetuses, and were retrained in the behavioral procedure after 15, 30, 45, or 60 days postgraft. Behavioral results showed a very good functional recuperation at 60 days, slight recovery at 45 and 30 days, and a poor recovery at 15 days postgraft. Results with HRP histochemistry revealed that at 30, 45, and 60 days postgrafting there were increased connections with the ventromedial nucleus of the thalamus and with the amygdala. At 15 days postgrafting there was an absence of HRP-labeled cells. In addition, behavioral recovery was correlated with increased acetylcholinesterase activity, detected histochemically, and with morphological neuronal maturation, revealed by Golgi staining. These results suggest that morphological maturity and reconnectivity between grafts and host tissue are important for behavioral recovery in gustatory neocortex-lesioned rats.     

Shifting gustatory thresholds and food cravings during pregnancy as expanding uterine-induced steady potential shifts within the insula: an hypothesis

A logical extrapolation from the principle that structure dictates function is that transient or anomalous experiences are consequences of simultaneous stimulations of proximal brain regions not typically co-activated. In this paper the occasional shifts in gustatory threshold during the menstrual cycle, the craving for unusual tastes experienced by some during pregnancies, and, the reports by postmenopausal women of the "burning mouth syndrome" are hypothesized to be artifacts of the proximity of gustatory and uterine representations within the female insula. Transient (menstrual) or tonic (pregnancy) stimulation within the uterus might shift the locus of neuronal activity within the insula to include adjacent gustatory neurons and consequently alter taste experiences. Specific tests of this hypothesis are suggested.     

The neurobiology of postpartum depression

Postpartum psychiatric changes can range from maternity blues to psychosis. Causality is still undetermined, but explanations for these disturbances often focus on hormonal changes and dysregulation. Researchers have begun the process of delineating what neurobiological factors may be associated with depressive disorders in pregnancy and the postpartum. This article reviews the current literature on the roles of gonadal and pituitary hormones in the psychopathophysiology of postpartum mood disorders. Other biological factors, such as biogenic amines, neuroactive steroids, cholesterol, and fatty acids, are also discussed. The potential benefits of neuroimaging to aid in understanding neuropsychiatric changes that occur in the context of postpartum depression are also considered.     

Contextual effects in difference judgments

Manipulating stimulus spacing, stimulus frequency, or stimulus range usually affects intensity judgments. In six experiments, I investigated the locus of analogues of these contextual effects in a “difference” estimation task. When all stimuli elicited the same taste quality, stimulus distribution affected the scale values only when water was included in the stimulus set (Experiments 1–3). When the subjective ranges of two taste qualities were manipulated, different scale values were obtained for the separate qualities in the two conditions (Experiment 4). Manipulation of the expected response distribution did not affect the scale values or the responses (Experiments 5–6). It is concluded that shifts in stimulus distributions or stimulus ranges result in shifts in subjective scale values. The contextual effects can be interpreted as relative shifts of a number of gustatory continua, with water lying on a separate continuum. Proposed is a model for context-dependent judgments, consisting of four stages: stimulus classification, stimulus placement, continuum placement, and continuum projection.     

Salivary conditioning with antennal gustatory unconditioned stimulus in an insect

Classical conditioning of olfactory conditioning stimulus (CS) with gustatory unconditioned stimulus (US) in insects has been used as a pertinent model for elucidation of neural mechanisms underlying learning and memory. However, a conditioning system in which stable intracellular recordings from brain neurons are feasibly obtained while monitoring the conditioning effect has remained to be established. Recently, we found classical conditioning of salivation in cockroaches Periplaneta americana, in which an odor was associated with sucrose solution applied to the mouth, and this conditioning could be monitored by activities of salivary neurons. Application of gustatory US to the mouth, however, leads to feeding movement accompanying a movement of the brain that prevents stable recordings from brain neurons. Here we investigated whether a gustatory stimulus presented to an antenna could serve as an effective US for producing salivary conditioning. Presentation of sucrose or sodium chloride solution to an antenna induced salivation and also increased activities of salivary neurons. A single pairing trial of an odor with antennal presentation of sucrose or sodium chloride solution produced conditioning of salivation or of activities of salivary neurons. Five pairing trials led to a conditioning effect that lasted for one day. Water or tactile stimulus presented to an antenna was not effective for producing conditioning. The results demonstrate that gustatory US presented to an antenna is as effective as that presented to the mouth for producing salivary conditioning. This conditioning system provides a useful model for studying the neural basis of learning at the level of singly identifiable neurons.     

Bidirectional lexical-gustatory synesthesia

In developmental lexical–gustatory synesthesia, specific words (inducers) can trigger taste perceptions (concurrents) and these synesthetic associations are generally stable. We describe a case of multilingual lexical–gustatory synesthesia for whom some synesthesias were bidirectional as some tastes also triggered auditory word associations. Evoked concurrents could be gustatory but also tactile sensations. In addition to words and pseudowords, many voices were effective inducers, suggesting increased connections between cortical taste areas and both voice-selective and language-selective areas. Lasting changes in some evoked tastes occurred during childhood suggesting that some plasticity can be present after the initial learning of associations. Inducers were often linked to taste concurrents phonologically or semantically, but also through identifiable childhood episodes (persons or events). Several inducers were phonologically linked to episodic inducers suggesting a process of secondary acquisition for many inducers. Implications of these observations are discussed.