Sensory Intake Research Articles

Effect of Brainwave Entrainment Using Binaural Beat Stimulation on Short-Term Memory

Auditory brain entrainment is a response to a rhythmic stimulus that increases the amount of a single brainwave frequency. It has been proposed to act as a key mechanism to heighten sensory intake. Auditory brain entrainment can be induced by listening to binaural beat stimulation. It has been shown that there is a positive effect on memory caused by using binaural beat stimulation. There has been research done on memory in young adults using binaural beat stimulation, but little in adolescents. Due to the lack of research on the effects of brain entrainment on memory in adolescents, this study attempts to show that a teen's working memory will improve after listening to a 40 Hz binaural beat for five minutes as compared to 0 Hz and 4 Hz. Participants were randomly assigned into three groups (0Hz, 4Hz, 40Hz) prior to the experiment. Participants completed the Sternberg Short-term memory test.The participants then listened to a binaural beat of their designated group for 5 minutes, after which they completed the second trial of the Sternberg Short-term memory test. The average change of speed recall and errors from no binaural beat to after the binaural beat stimulus was analyzed using a T-test of independent means. The results do not support the hypothesis that listening to binaural beat stimulation of 40Hz would improve short-term memory compared to 4Hz and 0Hz.

Defense mechanisms: A guide to brain functioning?

ABSTRACT This paper draws on the writings of Sigmund Freud, Anna Freud, George Vaillant and other sources in an attempt to derive an exhaustive list of potential defense mechanisms, including some adaptive behaviors conventionally regarded as coping strategies. It then analyses them collectively as a set of well-evidenced patterns of human behavior that might be traceable to common mental operations. It organizes them by whether they modulate attention, affect or data and by whether they negate it or divert it externally or internally. From this, three distinct categories of defense are identified, each of which, it is hypothesized, operates to override a different (anoetic, noetic or autonoetic) layer of consciousness by effecting a mental enactment in substitution for a conditioned primary-process behavioral response associated with one of the negative basic emotions PANIC/GRIEF, FEAR and RAGE, or a diversion of one such behavioral response to another context. These, it is suggested, operate homeostatically to attempt to limit sensory intake (PANIC/GRIEF), modify hedonic valencing (FEAR), or fabricate causal data (RAGE) to reduce the prediction work of consciousness so that emotions remain within viable bounds and automaticity can be resumed. The paper concludes with a discussion of the implications, including the potential for greater diagnostic precision and efficacy of treatment.

Wrinkles in subsecond time perception are synchronized to the heart.

The role of the heart in the experience of time has been long theorized but empirical evidence is scarce. Here, we examined the interaction between fine-grained cardiac dynamics and the momentary experience of subsecond intervals. Participants performed a temporal bisection task for brief tones (80-188 ms) synchronized with the heart. We developed a cardiac Drift-Diffusion Model (cDDM) that embedded contemporaneous heart rate dynamics into the temporal decision model. Results revealed the existence of temporal wrinkles-dilation or contraction of short intervals-in synchrony with cardiac dynamics. A lower prestimulus heart rate was associated with an initial bias in encoding the millisecond-level stimulus duration as longer, consistent with facilitation of sensory intake. Concurrently, a higher prestimulus heart rate aided more consistent and faster temporal judgments through more efficient evidence accumulation. Additionally, a higher speed of poststimulus cardiac deceleration, a bodily marker of attention, was associated with a greater accumulation of sensory temporal evidence in the cDDM. These findings suggest a unique role of cardiac dynamics in the momentary experience of time. Our cDDM framework opens a new methodological avenue for investigating the role of the heart in time perception and perceptual judgment.

How does fatty mouthfeel, saltiness or sweetness of diets contribute to dietary energy intake?

As “taste” is a primary driver of food choice, the objective of this study was to understand how the sensory properties of diets relate to energy intake (EI). A database of 720 frequently consumed foods, described by a trained panel for basic tastes (sweetness, saltiness) and fatty mouthfeel, was systematically applied to all foods reportedly consumed in 24hr recalls as part of the 2011–2012 Australian National Nutrition and Physical Activity Survey (n = 12,153 adults and children). Food groups were classified according to the Australian Guide to Healthy Eating, and their contribution to total nutrient and sensory intake estimated. There were significant positive correlations between the nutrient and sensory properties of diets, for example, for adults, EI and fatty mouthfeel r = 0.740; EI and saltiness r = 0.623 and EI and sweetness r = 0.517 (all p < 0.01). Core foods (e.g. fruits, vegetables, grains, dairy) can provide similar sensory stimulation whilst being of lower energy content than discretionary foods (e.g. confectionary, snacks). Regression models in adults, controlling for age, sex and BMI, revealed that fatty mouthfeel (β = 0.492), saltiness (β = 0.161) and sweetness (β = 0.138) were significant predictors of EI, explaining 56% variance (p < 0.01). Similar results were found for children. Fatty mouthfeel was the primary driver of energy intake but such sensory stimulation can be derived from core (e.g. dairy foods), rather than discretionary foods, at lower energy content.

The effect of mild acute psychological stress on attention processing: an ERP study.

We aimed to investigate the effect of mild acute psychological stress on attention processing by adopting a consecutive task paradigm. In each trial, a probe stimulus (left or right arrow) was presented immediately after a mental arithmetic task (psychological stressor). Participants were asked to estimate whether the product of a multiplication term was above 10 or not, either with (stress block) or without (control block) time pressure and social-evaluative threat. When the probe was presented, participants were asked to judge the direction of the arrows. Increased subjective stress and negative affect were found for the stress versus control trials. For the probe task, reaction times were faster in the stress block than in the control block. Event-related potentials locked to the arrows revealed that (a) fronto-central N1 was enhanced in the stress block compared to the control block. This finding might indicate that stress amplified processes of early perception and that vigilance and sensory intake were augmented. (b) fronto-central N2 was enhanced in the stress block compared to the control block. This finding might reflect increased effort to control selective attention in completing the probe task. (c) less positive P3 was evoked in the stress block than in the control block. This finding potentially reflects the fact that fewer attentional resources were engaged in processing the probe, or that the activity associated with the process of response evaluation was decreased. In sum, mild acute psychological stress exerts a dissociable effect on the neural subprocesses of attention.

Assimilation of healthy and indulgent impressions from labelling influences fullness but not intake or sensory experience

Recent evidence suggests that products believed to be healthy may be over-consumed relative to believed indulgent or highly caloric products. The extent to which these effects relate to expectations from labelling, oral experience or assimilation of expectations is unclear. Over two experiments, we tested the hypotheses that healthy and indulgent information could be assimilated by oral experience of beverages and influence sensory evaluation, expected satiety, satiation and subsequent appetite. Additionally, we explored how expectation-experience congruency influenced these factors. Results supported some assimilation of healthiness and indulgent ratings—study 1 showed that indulgent ratings enhanced by the indulgent label persisted post-tasting, and this resulted in increased fullness ratings. In study 2, congruency of healthy labels and oral experience promoted enhanced healthiness ratings. These healthiness and indulgent beliefs did not influence sensory analysis or intake—these were dictated by the products themselves. Healthy labels, but not experience, were associated with decreased expected satiety. Overall labels generated expectations, and some assimilation where there were congruencies between expectation and experience, but oral experience tended to override initial expectations to determine ultimate sensory evaluations and intake. Familiarity with the sensory properties of the test beverages may have resulted in the use of prior knowledge, rather than the label information, to guide evaluations and behaviour.

Parents' explanatory models and hopes for outcomes of occupational therapy using a sensory integration approach.

PURPOSE. To describe parents' concerns and hopes for their children who would be receiving occupational therapy using a sensory integration approach. METHOD. Content analysis of 275 parental responses to three open-ended questions on developmental-sensory history intake forms. FINDINGS. Parents' descriptions of why they sought for their children were categorized into four overarching concerns about their children's challenges: self-regulation, interacting with peers, participating in skilled motor activities, and self-confidence. Parents often linked these concerns together, revealing explanatory models of how they make sense of potential relationships among their children's challenges and how these challenges affect occupational performance. Parents hoped occupational therapy would help their children develop self-understanding and frustration tolerance to self-regulate their behavior in socially acceptable ways. IMPLICATIONS. Assessment and intervention should explicitly focus on links among self-regulation, social participation, skills, and perceived competence to address parents' expectations.

The effect of ice cream formulation on palatability and rate of eating

Current commercial ice cream formulations vary greatly in both ingredients and price but few published studies have reported the effect of ice cream formulation on consumer responses. The aim of this study was to use a microstructural approach to examine eating behaviour and responses to two ice creams that differed in their microstructures and physical properties. Participants ate ice cream ad libitum in the laboratory, during which the amounts eaten were covertly recorded using the Sussex Eating Pattern Monitor (SIPM) and appetite and sensory ratings were taken. Participants consumed either a high fat or low fat ice cream that was presented without labels and they attended three test days to assess the possibility that learning about the properties of the ice cream might occur. There were no main effects of either ice cream or test day for any of the variables tested: sensory ratings, total intake, appetite and pleasantness ratings during the session. The results suggest that from a consumers perspective there is very little that separates ostensibly very different ice cream formulations on oral properties (taste and mouth feel) and that these assessments of consumers are not modified by learning over three days.

Facial expression form and function

From an evolutionary perspective, facial expressions would serve adaptive functions that promote genetic fitness. While many ideas have been proposed,1 the specific adaptive functions of expressing emotion on the face have largely remained untested since Darwin proposed a set of expressive functional principles over 130 years ago.2 Recently, we showed that expressions of fear and disgust alter the biomechanical properties of the face, such that fear increases while disgust decreases sensory exposure.3 Additional vector flow analyses presented here reveal that anger and surprise expressions may similarly be shaped by sensory contraction and expansion action tendencies. An examination of the temporal dynamics of sensory modulation may reveal a general principle shaping expressive form rather than a specific adaptation shaping fear and disgust. Furthermore, if sensory modulation is a general principle, this function should be present across species rather than only in humans. Although facial morphology differs across species, detailed examination of sensory intake in different species may reveal the origins of facial expressions inherited by humans.

The effects of modified sham feeding and variety on sensory specific satiety and food intake in humans

The effects of modified sham feeding and variety on sensory specific satiety and food intake in humans

Inhibition of pericranial muscle activity, respiration, and heart rate enhances auditory sensitivity

We investigated whether previously observed inhibition of pericranial electromyographic (EMG) activity, respiration, and heart rate during sensory intake processes improves auditory sensitivity. Participants had to detect weak auditory stimuli. We found that EMG activity in masticatory and lower facial muscles, respiration, and heart rate were more strongly inhibited when stimulus intensity was gradually lowered to threshold level whereas EMG of upper facial muscles progressively increased. Detection of near-threshold stimuli was inversely related to prestimulus EMG levels in masticatory and lower facial muscles. In two additional experiments, it was investigated whether steady, voluntary contractions negatively influence auditory sensitivity. As expected, contraction of zygomaticus produced an increase in auditory threshold in comparison with contraction of corrugator or first dorsal interosseus. It is concluded that attention to external stimuli is accompanied by quieting of those somatic activities that produce internal noise or are accompanied by impaired middle ear transmission of auditory stimuli.

Inhibition of pericranial muscle activity, respiration, and heart rate enhances auditory sensitivity

We investigated whether previously observed inhibition of pericranial electromyographic (EMG) activity, respiration, and heart rate during sensory intake processes improves auditory sensitivity. Participants had to detect weak auditory stimuli. We found that EMG activity in masticatory and lower facial muscles, respiration, and heart rate were more strongly inhibited when stimulus intensity was gradually lowered to threshold level whereas EMG of upper facial muscles progressively increased. Detection of near-threshold stimuli was inversely related to prestimulus EMG levels in masticatory and lower facial muscles. In two additional experiments, it was investigated whether steady, voluntary contractions negatively influence auditory sensitivity. As expected, contraction of zygomaticus produced an increase in auditory threshold in comparison with contraction of corrugator or first dorsal interosseus. It is concluded that attention to external stimuli is accompanied by quieting of those somatic activities that produce internal noise or are accompanied by impaired middle ear transmission of auditory stimuli.

Attentional modulation of the cardiac defense response in humans.

How cardiac components of the defense reaction are modulated by attentional factors related to sensory intake versus sensory rejection was examined. Forty-eight men participated in a test of the heart rate response to three presentations of an intense auditory stimulus while performing one of three attentional tasks during the 80 s following stimulus onset: (a) internal (rejection) task, (b) external (intake) task, and (c) no task. Results showed a potentiation of the defense response only under the external attention condition. We concluded that defensive reactions, far from provoking the rejection of the aversive stimulus, require allocation of attention to processing that stimulus in detail.

Muscle tension patterns during auditory attention

Although there is much evidence demonstrating muscle tension changes during mental work, there are few data concerning muscle tension patterns during effortful attention to simple sensory stimuli. In the present study, sensory attention was evoked by a pitch discrimination task at three levels of difficulty, with a digit retention task administered for comparison. Twenty-four females each performed both tasks at all levels of difficulty, while the EKG, and the corrugator supercilii, frontalis, lip, jaw, chin, and forearm area EMG were recorded. As expected, heart rate decreased significantly with increasing difficulty of the pitch task. A pattern of facial EMG responses accompanied the pitch task, which included significant increases in corrugator and frontalis, and decreases in the jaw as a function of difficulty, and time within trials. The tension pattern observed during sensory intake is discussed in terms of its relation to emotional expressions and motor theories of attention.

Biobehavioral basis of coronary-prone behavior in middle-aged men. Part I: Evidence for chronic SNS activation in Type As.

In previous research using young male subjects, the Type A behavior pattern was linked with cardiovascular and neurohormonal hyperresponsivity to laboratory stressors. The main objective of the present study was to determine whether the positive association between the Type A pattern and such physiological hyperreactivity is also present among healthy middle-aged men. Subjects were 28 middle-aged (35-50 years) white males who were classified as Type A (n = 16) or Type B (n = 12) on both the Structured Interview and the Jenkins Activity Survey. In two laboratory sessions, one week apart, subjects participated in either a mental arithmetic task or a sensory intake task. Twenty-four-hour urine collection was completed on a third day. Results showed that while no A/B differences in reactivity to either task were found, Type A subjects exhibited chronic elevation of plasma neurohormones on both laboratory days. The catecholamine elevations found across experimental periods on two laboratory days among Type A men generalized to more naturalistic settings, as indexed by 24-hr urinary excretion rates. The chronic elevations in both sympathetic nervous system and hypothalamic-pituitary-adrenal axis function we observed in middle-aged Type A men could account for epidemiological findings of increased coronary risk in this group.

Cardiovascular and sympathoadrenal responses to mental stress: a study of sensory intake and rejection reactions

Cardiovascular, sympathoadrenal and subjective responses to mental stress induced by two mental challenges eliciting sensory intake (word identification test = WIT) and sensory rejection (colour word conflict test = CWT) reactions were studied in 10 healthy males. Pressor responses to these stressors have been proposed to differ haemodynamically. Sympathoadrenal activity was assessed by arterial and femoral venous plasma catecholamine determinations and direct recordings of muscle sympathetic activity in the right peroneal nerve (MSA). Basal measurements differed little from those made during an active relaxation procedure, with the exception of MSA, which decreased. Both stress tasks elicited increases in heart rate, cardiac output, calf blood flow and brachial and pulmonary arterial blood pressures. WIT and CWT elicited qualitatively similar responses, but the amplitudes of the circulatory responses were lower with WIT, which also was rated as a weaker stressor. MSA increased during CWT, while marginal increases were seen during WIT. Arterial adrenaline showed a transient increase by 0.14 nmol l-1 during WIT. During CWT arterial adrenaline increased significantly by 50%. Increases in arterial adrenaline and subjective stress ratings were related to increases in cardiac output and reductions of systemic vascular resistance. Arterial and femoral venous noradrenaline increased during CWT, while changes during WIT were small. MSA and noradrenaline responses did not correlate to local vascular responses in the calf. Differences in the responses to mental challenges evoking sensory intake or rejection seem to be of a quantitative rather than a qualitative character.

Effects of intake and rejection tasks on auditory fatigue

The effects of sensory intake and rejection tasks on auditory fatigue were examined in 14 male subjects. Auditory thresholds, psychophysical tuning curves and physiological measures of cardiovascular function were obtained before, during, and following a 7 min 110 dB SPL white noise exposure. Acceleration of heart rate was observed under the sensory rejection (mental arithmetic) condition, and poorer post-exposure auditory thresholds and larger Q10 tip values (measured during late post-exposure intervals) were seen when the task required counting of interruptions in the noise. However, Q10 tip values obtained 1 to 2 min post-exposure, when cochlear effects are maximal, failed to confirm a significant difference as a function of task.

Forearm blood flow responding prior to voluntary isometric contraction.

ABSTRACTSrain‐gauge plethysmography was used to study phasic forearm blood flow (FBF) responding, which has been presumed to occur in human subjects prior to voluntary muscular contraction. In a two‐group design, 10 subjects performed a 7‐s, fixed‐foreperiod, reaction‐time (RT) task in which static handgrip was the required RT response; 10 additional subjects in a High Incentive (HI) condition performed a more stressful delayed avoidance task. Bilateral FBF and HR were computer‐sampled over the preparatory interval (PI) and transformed into second‐by‐second measures. Mean FBF estimates were also obtained by averaging over the entire PI. HI subjects were found to manifest significantly greater mean FBF prior tro motor responding than did subjects performing the nonstressful RT taks. Such preparatory FBF responding was task‐specific, occurring only in the Arm to be performing the signalled RT response. Furthermore, this task‐specific, phasic increase in averaged mean FBF was observed to occur in subjects' left and right arms. Trend analysis and visual inspection of second‐by‐second FBF waveforms demonstrated a gradual decline in flow rate over the course of the preparatory interval under all experimental conditions. HR responding manifested the characteristic triphasic waveforms, with higher heart rate and augmentation of acceleratory and terminal deceleratory components exhibited by the HI group. the findings suggest that human phasic FBF responding can be influenced by motoric and motivational factors as well as by demands for sensory intake behavior.

Type A behavior and elevated physiological and neuroendocrine responses to cognitive tasks.

Qualitatively distinct patterns of cardiovascular and neuroendocrine responses were observed in male college students during mental work and during sensory intake task performance. During mental work, Type A (coronary-prone) subjects showed greater muscle vasodilatation and more enhanced secretion of norepinephrine, epinephrine, and cortisol than Type B subjects. During sensory intake, Type A hyperresponsivity was found for testosterone and, among those subjects with a positive family history of hypertension, for cortisol. As a demonstration of combined cardiovascular, sympathetic nervous system, and neuroendocrine hyperresponsivity to specific cognitive tasks in Type A subjects, this study breaks ground in the search for mechanisms mediating the increased coronary disease risk among Type A persons.

Visual evoked potentials change as heart rate and carotid pressure change.

ABSTRACTThe relationship between cardiovascular activity and the brain was explored by recording visual evoked potentials from the occipital regions of the scalp during systolic and diastolic pressure (Experiment I) and during fast and slow heartbeats at systolic and diastolic pressure (Experiment II). Visual evoked potentials changed significantly as heart rate and carotid pressure fluctuated normally, and these changes were markedly different in the right and left cerebral hemispheres. Evoked potentials recorded from the right hemisphere during various cardiac events differed significantly, whereas those recorded from the left did not. In both experiments, differences in the right hemisphere were due primarily to the P1 component, which was larger at diastolic than at systolic pressure. The present findings are consistent with formulations from behavioral studies suggesting that baroreceptor activity can influence sensory intake, and suggest that hemispheric specialization may play an important role in the relationship between cardiac events, the brain and behavior.