Conditions Of Auditory Stimulation Research Articles

Side effects of monaural beat stimulation during sustained mental work on mind wandering and performance measures.

Excessive mind wandering (MW) contributes to the development and maintenance of psychiatric disorders. Previous studies have suggested that auditory beat stimulation may represent a method enabling a reduction of MW. However, little is known about how different auditory stimulation conditions are subjectively perceived and whether this perception is in turn related to changes in subjective states, behavioral measures of attention and MW. In the present study, we therefore investigated MW under auditory beat stimulation and control conditions using experience sampling during a sustained attention to response task (SART). The subjective perception of the stimulation conditions, as well as changes in anxiety, stress and negative mood after versus before stimulation were assessed via visual-analog scales. Results showed that any auditory stimulation applied during the SART was perceived as more distracting, disturbing, uncomfortable and tiring than silence and was related to more pronounced increases of stress and negative mood. Importantly, the perception of the auditory conditions as disturbing was directly correlated with MW propensity. Additionally, distracting, disturbing and uncomfortable perceptions predicted negative mood. In turn, negative mood was inversely correlated with response accuracy for target stimuli, a behavioral indicator of MW. In summary, our data show that MW and attentional performance are affected by the adverse perception of auditory stimulation, and that this influence may be mediated by changes in mood.

Gamma (60 Hz) auditory stimulation improves intrusions but not recall and working memory in healthy adults

Gamma-band (> 30 Hz) brain oscillations (γ) play a crucial role in memory and long-term potentiation, and their disruptions have been consistently documented in patients with Alzheimer's Disease (AD). Gamma-band oscillation entrainment through 60 Hz transcranial alternating stimulation (tACS) and 40 Hz tACS/sensory stimulation has been shown to enhance memory performance in healthy adults and patients with AD, respectively. However, the impact of gamma auditory stimulation on healthy adults' memory remains uncertain. In this balanced crossover study, 36 healthy subjects (27 Females) underwent three auditory stimulation conditions: no auditory stimulation (NO_AS), 40 Hz, and 60 Hz. Long-term verbal memory (LTM) and verbal working memory (WM) were assessed using, respectively, the Ray Auditory Verbal Test (RAVLT) and Digit Span Backward test (DS-B). We hypothesized that 60 Hz would improve LTM (as compared to NO_AS), but not WM; no specific effects were hypothesized for 40 Hz. We found that gamma-band auditory stimulation (40 Hz and 60 Hz) did not significantly affect RAVLT recall or WM. However, 60 Hz stimulation reduced RAVLT immediate recall intrusion; this outcome negatively correlated with DS-B performance, suggesting a positive impact of 60 Hz on executive functions. In summary, gamma-band auditory stimulation did not enhance memory in healthy adults, but 60 Hz stimulation potentially benefits executive functions. Further investigation is needed to understand gamma oscillation's role in cognitive processes for both healthy and clinical populations.

The effect of auditory stimulation on pet dogs’ reactions to owner separation

The domestic dog has attracted notable attention in relation to the welfare benefits of auditory stimulation. Studies carried out in rescue kennels, an environment in which dogs are prone to chronic stress, have pointed to a calming influence of both classical music and audiobooks. The benefits of auditory stimulation for dogs experiencing more immediate types of stress, however, are still unknown. This investigation thus examined the effect of classical music and the spoken voice in the form of an audiobook on the behaviour of pet dogs in response to separation from their owners, a known short-term stressor. Three conditions of auditory stimulation were employed: (1) a control (the normal environment of the university research room), (2) classical music (Mozart’s Sonata K.448) and (3) an audiobook (Harry Potter and the Philosopher’s Stone). The effect of these conditions was explored using two approaches. Study 1 explored the effects of auditory stimulation using a between-subjects design. Sixty dogs were assigned to one of the 3 conditions and exposed to the relevant auditory stimulus for 1-hour. Each dog’s behaviour was recorded every 10 s using a purpose-designed ethogram. Latency data were recorded by video. Results revealed a significant effect of auditory condition on latency to lie down, latency to settle (i.e., lie down for >30 s) and speaker-directed gaze. Dogs exposed to classical music were significantly faster to lie down than animals in the audiobook condition and quicker to settle than animals in the audiobook and control conditions. Subjects in the audiobook condition spent significantly more time gazing at the speaker than animals in the classical music and control conditions. Dogs in the classical music condition also spent significantly more time looking towards the speaker than control animals. Study 2 examined the effects of auditory stimulation using a repeated measures design. Twenty-two dogs were exposed to each condition of auditory stimulation for 30 min, with a period of 10 min between conditions. Each animal’s behaviour was recorded as per Study 1. Only speaker-directed gaze differed significantly between conditions, with animals spending more time looking at the speaker in the audiobook and classical music conditions than the control. Overall, findings point to only a moderately calming effect of classical music, and no apparent welfare benefits of an audiobook, on dogs separated from their owners. The research points to auditory stimulation having little value to dogs in situations of short-term acute stress. Further research is recommended in this field, ideally in a wider variety of contexts than studied thus far.

Multivariate analysis of the systemic response to auditory stimulation: An integrative approach.

What is the central question of this study? Auditory stimulation produces a response in different physiological systems: cardiac, peripheral blood flow, electrodermal, cortical and peripheral haemodynamic responses and auditory event-related potentials. Do all these subsystems covary when responding to auditory stimulation, suggesting a unified locus of control, or do they not covary, suggesting independent loci of control for these physiological responses? What is the main finding and its importance? Auditory sensory gating reached a fixed level of neural activity independently of the intensity of auditory stimulation. The use of multivariate techniques revealed the presence of different regulatory mechanisms for the different physiologically recorded signals. We studied the effects of an increasing amplitude of auditory stimulation on a variety of autonomic and CNS responses and their possible interdependence. The subjects were stimulated with an increasing amplitude of auditory tones while the auditory event-related potentials (ERPs), the cortical and extracerebral functional near-infrared spectroscopy (fNIRS) signal of standard and short separation channel recordings, the peripheral pulse measured by photoplethysmography, heart rate and electrodermal responses were recorded. Trials with eight tones of equal amplitude were presented. The results showed a parallel increase of activity in ERPs, fNIRS and peripheral responses with the increase in intensity of auditory stimulation. The ERPs, measured as peak-to-peak N1-P2, showed an increase in amplitude with auditory stimulation and a high attenuation from the first presentation with respect to the second to eighth presentations. Peripheral signals and standard and short channel fNIRS responses showed a decrease in amplitude in the high-intensity auditory stimulation conditions. Principal components analysis showed independent sources of variance for the recorded signals, suggesting independent control of the recorded physiological responses. The present results suggest a complex response associated to the increase of auditory stimulation with a fixed amplitude for ERPs, and a decrease in the peripheral and cortical haemodynamic response, possibly mediated by activation of the sympathetic nervous system, constituting a defensive reflex to excessive auditory stimulation.

Prediction of Acoustic Residual Inhibition of Tinnitus Using a Brain-Inspired Spiking Neural Network Model.

Auditory Residual Inhibition (ARI) is a temporary suppression of tinnitus that occurs in some people following the presentation of masking sounds. Differences in neural response to ARI stimuli may enable classification of tinnitus and a tailored approach to intervention in the future. In an exploratory study, we investigated the use of a brain-inspired artificial neural network to examine the effects of ARI on electroencephalographic function, as well as the predictive ability of the model. Ten tinnitus patients underwent two auditory stimulation conditions (constant and amplitude modulated broadband noise) at two time points and were then characterised as responders or non-responders, based on whether they experienced ARI or not. Using a spiking neural network model, we evaluated concurrent neural patterns generated across space and time from features of electroencephalographic data, capturing the neural dynamic changes before and after stimulation. Results indicated that the model may be used to predict the effect of auditory stimulation on tinnitus on an individual basis. This approach may aid in the development of predictive models for treatment selection.

Patterned auditory stimulation and suck dynamics in full-term infants.

To determine whether patterned auditory stimuli, designed to mimic the natural burst-pause pattern evident in non-nutritive suck (NNS) with variations to the intraburst frequency, alter infants' NNS and cardiorespiratory patterning. Sixteen healthy full-term infants participated in this study. Infants were fitted with electrocardiogram electrodes and a respiratory belt to measure cardiorespiratory patterning. Infants were offered a custom pacifier attached to a pressure transducer to measure NNS. Prior to the start of the study, a two-minute NNS and cardiorespiratory baseline was attained. Next, three auditory stimulation conditions were presented in the form of sucking clicks at interburst frequencies of 1, 2 and 4Hz. Each of the three frequencies was played for two minutes. Separate repeated-measures ANOVAs revealed significant differences in NNS burst duration (p=0.013), NNS cycles/burst (p=0.010) and NNS bursts/minute (p=0.005) across auditory stimulation conditions. No significant differences were evident in the cardiorespiratory outcomes. We found that patterned auditory stimulation significantly reduced NNS dynamics and had no effect on cardiorespiratory patterning. The findings further suggest that infants attempted to modulate their suck pattern to the patterned acoustic stimuli by shortening their burst durations with fewer cycles per burst.

The effect of binaural beats on verbal working memory and cortical connectivity

Objective. Synchronization in activated regions of cortical networks affect the brain’s frequency response, which has been associated with a wide range of states and abilities, including memory. A non-invasive method for manipulating cortical synchronization is binaural beats. Binaural beats take advantage of the brain’s response to two pure tones, delivered independently to each ear, when those tones have a small frequency mismatch. The mismatch between the tones is interpreted as a beat frequency, which may act to synchronize cortical oscillations. Neural synchrony is particularly important for working memory processes, the system controlling online organization and retention of information for successful goal-directed behavior. Therefore, manipulation of synchrony via binaural beats provides a unique window into working memory and associated connectivity of cortical networks. Approach. In this study, we examined the effects of different acoustic stimulation conditions during an N-back working memory task, and we measured participant response accuracy and cortical network topology via EEG recordings. Six acoustic stimulation conditions were used: None, Pure Tone, Classical Music, 5 Hz binaural beats, 10 Hz binaural beats, and 15 Hz binaural beats. Main results. We determined that listening to 15 Hz binaural beats during an N-Back working memory task increased the individual participant’s accuracy, modulated the cortical frequency response, and changed the cortical network connection strengths during the task. Only the 15 Hz binaural beats produced significant change in relative accuracy compared to the None condition. Significance. Listening to 15 Hz binaural beats during the N-back task activated salient frequency bands and produced networks characterized by higher information transfer as compared to other auditory stimulation conditions.

The effect of auditory enrichment, rearing method and social environment on the behavior of zoo-housed psittacines (Aves: Psittaciformes); implications for welfare

The psychological and physiological effects of different genres of music are well documented in humans. These concepts have also been studied in kenneled dogs and some exotic animals, implying that animals may experience benefits similar to those of humans. This study tested the hypothesis that auditory enrichment changed the behavior of ten zoo-housed psittacines. All animals were exposed to six conditions of auditory stimulation; a ‘control’ (no auditory stimulation), and ‘experimental’ conditions, during which animals were presented with commercially-available CDs of classical music, pop music, natural rainforest sounds, parrot sounds and a talking radio. Each type of stimulation lasted two days, with a wash-out day between different stimulation conditions. We recorded key parameters relating to the birds’ social environment – whether they were group or single-housed and whether they had been hand or parent-reared. The parrots’ behaviour was recorded every minute for a 25min period seven times a day using instantaneous sampling. The incidence of calm vocalisations and the level of preening changed with the different conditions. Birds exposed to rainforest and talking radio preened more than control birds. Birds exposed to several genres of auditory stimulation expressed fewer calm vocalisations than control birds. A further finding from this study was that hand-reared birds exhibited dramatically increased incidences of stereotypic behavior, more learned vocalisation and interacted less with enrichment than parent-reared and the implications of hand rearing for welfare are discussed. Similarly solo housed birds showed changes in behavior compared to group housed, such as less preening and more stereotypic behaviour. Hand reared, solo housed parrots express less normal behavior and maybe at risk of impaired welfare.

FMRI as a Preimplant Objective Tool to Predict Postimplant Oral Language Outcomes in Children with Cochlear Implants.

Despite the positive effects of cochlear implantation, postimplant variability in speech perception and oral language outcomes is still difficult to predict. The aim of this study was to identify neuroimaging biomarkers of postimplant speech perception and oral language performance in children with hearing loss who receive a cochlear implant. The authors hypothesized positive correlations between blood oxygen level-dependent functional magnetic resonance imaging (fMRI) activation in brain regions related to auditory language processing and attention and scores on the Clinical Evaluation of Language Fundamentals-Preschool, Second Edition (CELF-P2) and the Early Speech Perception Test for Profoundly Hearing-Impaired Children (ESP), in children with congenital hearing loss. Eleven children with congenital hearing loss were recruited for the present study based on referral for clinical MRI and other inclusion criteria. All participants were <24 months at fMRI scanning and <36 months at first implantation. A silent background fMRI acquisition method was performed to acquire fMRI during auditory stimulation. A voxel-based analysis technique was utilized to generate z maps showing significant contrast in brain activation between auditory stimulation conditions (spoken narratives and narrow band noise). CELF-P2 and ESP were administered 2 years after implantation. Because most participants reached a ceiling on ESP, a voxel-wise regression analysis was performed between preimplant fMRI activation and postimplant CELF-P2 scores alone. Age at implantation and preimplant hearing thresholds were controlled in this regression analysis. Four brain regions were found to be significantly correlated with CELF-P2 scores. These clusters of positive correlation encompassed the temporo-parieto-occipital junction, areas in the prefrontal cortex and the cingulate gyrus. For the story versus silence contrast, CELF-P2 core language score demonstrated significant positive correlation with activation in the right angular gyrus (r = 0.95), left medial frontal gyrus (r = 0.94), and left cingulate gyrus (r = 0.96). For the narrow band noise versus silence contrast, the CELF-P2 core language score exhibited significant positive correlation with activation in the left angular gyrus (r = 0.89; for all clusters, corrected p < 0.05). Four brain regions related to language function and attention were identified that correlated with CELF-P2. Children with better oral language performance postimplant displayed greater activation in these regions preimplant. The results suggest that despite auditory deprivation, these regions are more receptive to gains in oral language development performance of children with hearing loss who receive early intervention via cochlear implantation. The present study suggests that oral language outcome following cochlear implant may be predicted by preimplant fMRI with auditory stimulation using natural speech.

Effects of Emotionally Charged Auditory Stimulation on Gait Performance in the Elderly: A Preliminary Study

ObjectivesTo evaluate the effect of a novel divided attention task—walking under auditory constraints—on gait performance in older adults and to determine whether this effect was moderated by cognitive status. DesignValidation cohort. SettingGeneral community. ParticipantsAmbulatory older adults without dementia (N=104). InterventionsNot applicable. Main Outcome MeasuresIn this pilot study, we evaluated walking under auditory constraints in 104 older adults who completed 3 pairs of walking trials on a gait mat under 1 of 3 randomly assigned conditions: 1 pair without auditory stimulation and 2 pairs with emotionally charged auditory stimulation with happy or sad sounds. ResultsThe mean age of subjects was 80.6±4.9 years, and 63% (n=66) were women. The mean velocity during normal walking was 97.9±20.6cm/s, and the mean cadence was 105.1±9.9 steps/min. The effect of walking under auditory constraints on gait characteristics was analyzed using a 2-factorial analysis of variance with a 1-between factor (cognitively intact and minimal cognitive impairment groups) and a 1-within factor (type of auditory stimuli). In both happy and sad auditory stimulation trials, cognitively intact older adults (n=96) showed an average increase of 2.68cm/s in gait velocity (F1.86,191.71=3.99; P=.02) and an average increase of 2.41 steps/min in cadence (F1.75,180.42=10.12; P<.001) as compared with trials without auditory stimulation. In contrast, older adults with minimal cognitive impairment (Blessed test score, 5–10; n=8) showed an average reduction of 5.45cm/s in gait velocity (F1.87,190.83=5.62; P=.005) and an average reduction of 3.88 steps/min in cadence (F1.79,183.10=8.21; P=.001) under both auditory stimulation conditions. Neither baseline fall history nor performance of activities of daily living accounted for these differences. ConclusionsOur results provide preliminary evidence of the differentiating effect of emotionally charged auditory stimuli on gait performance in older individuals with minimal cognitive impairment compared with those without minimal cognitive impairment. A divided attention task using emotionally charged auditory stimuli might be able to elicit compensatory improvement in gait performance in cognitively intact older individuals, but lead to decompensation in those with minimal cognitive impairment. Further investigation is needed to compare gait performance under this task to gait on other dual-task paradigms and to separately examine the effect of physiological aging versus cognitive impairment on gait during walking under auditory constraints.

Facilitating access to emotions: neural signature of EMDR stimulation.

BackgroundEye Movement Desensitisation and Reprocessing (EMDR) is a method in psychotherapy effective in treating symptoms of posttraumatic stress disorder. The client attends to alternating bilateral visual, auditory or sensory stimulation while confronted with emotionally disturbing material. It is thought that the bilateral stimulation as a specific element of EMDR facilitates accessing and processing of negative material while presumably creating new associative links. We hypothesized that the putatively facilitated access should be reflected in increased activation of the amygdala upon bilateral EMDR stimulation even in healthy subjects.MethodsWe investigated 22 healthy female university students (mean 23.5 years) with fMRI. Subjects were scanned while confronted with blocks of disgusting and neutral picture stimuli. One third of the blocks was presented without any additional stimulation, one third with bilateral simultaneous auditory stimulation, and one third with bilateral alternating auditory stimulation as used in EMDR.ResultsContrasting disgusting vs. neutral picture stimuli confirmed the expected robust effect of amygdala activation for all auditory stimulation conditions. The interaction analysis with the type of auditory stimulation revealed a specific increase in activation of the right amygdala for the bilateral alternating auditory stimulation. Activation of the left dorsolateral prefrontal cortex showed the opposite effect with decreased activation.ConclusionsWe demonstrate first time evidence for a putative neurobiological basis of the bilateral alternating stimulation as used in the EMDR method. The increase in limbic processing along with decreased frontal activation is in line with theoretical models of how bilateral alternating stimulation could help with therapeutic reintegration of information, and present findings may pave the way for future research on EMDR in the context of posttraumatic stress disorder.

Auditory stimulation as enrichment for zoo-housed Asian elephants (Elephas maximus)

AbstractThis study explored the effect of auditory stimulation on the behaviour and welfare of four zoo-housed, female Asian elephants(Elephas maximus). All animals were exposed, in an ABA design, to two conditions of auditory stimulation: a ‘control’ (no auditory stimulation), and an ‘experimental’ condition, during which the animals were presented with a commercially-available CD of classical music. Each condition lasted for five days, with an interim period of two days between each condition (Study 1). The elephants’ behaviour was recorded every minute for four hours a day for the full five days of each condition using instantaneous scan-sampling. The procedure was repeated four months later (Study 2), for a shorter period of time (one day per condition, again using an ABA design) to assess whether the results are generalisable. Analysis of both studies revealed that the elephants spent significantly less of their time stereotyping during the experimental conditions than the control. None of the other behaviours recorded were influenced significantly by auditory stimulation. Overall, the findings from this study suggest that auditory stimulation, in the form of classical music, may be a useful method of reducing stereotypic behaviour in zoo-housed Asian elephants, although more long-term work with a larger number of animals is needed before firm conclusions can be drawn.

A note on the effect of auditory stimulation on the behaviour and welfare of zoo-housed gorillas

Auditory stimulation has long been employed as a form of therapy for humans and animals housed in institutions. Its effect on one of our closest-living relatives, the gorilla, however, is largely unknown. This study explored the effect of auditory stimulation on the behaviour and welfare of six gorillas housed in Belfast Zoo. All animals were exposed to three conditions of auditory stimulation: a control (no auditory stimulation), an ecologically relevant condition (rainforest sounds) and an ecologically non-relevant condition (classical music). The gorillas’ behaviour was recorded in each condition using a scan-sampling technique. There was no significant effect of the auditory environment on the gorillas’ behaviour, although animals tended to show more behaviours suggestive of relaxation (i.e. resting, sitting) and fewer behaviours typically associated with stress (i.e. aggression, abnormal behaviour) during the ecologically relevant, and, in particular, the non-relevant, conditions than the control. Overall, findings suggest that certain types of auditory stimulation may hold some merit as a method of enrichment for zoo-housed gorillas, although more long-term work with a larger number of animals is needed before firm conclusions can be drawn.

Accessibility of spoken, written, and sign language in Landau‐Kleffner syndrome: a linguistic and functional MRI study

ABSTRACT Landau‐Kleffner syndrome (LKS) is an acquired aphasia which begins in childhood and is thought to arise from an epileptic disorder within the auditory speech cortex. Although the epilepsy usually subsides at puberty, a severe communication impairment often persists. Here we report on a detailed study of a 26‐year old, left‐handed male, with onset of LKS at age 5 years, who is aphasic for English but who learned British Sign Language (BSL) at age 13. We have investigated his skills in different language modalities, recorded EEGs during wakefulness, sleep, and under conditions of auditory stimulation, measured brain stem auditory‐evoked potentials (BAEP), and performed functional MRI (fMRI) during a range of linguistic tasks. Our investigation demonstrated severe restrictions in comprehension and production of spoken English as well as lip‐reading, while reading was comparatively less impaired. BSL was by far the most efficient mode of communication. All EEG recordings were normal, while BAEP showed minor abnormalities. fMRI revealed: 1) powerful and extensive bilateral (R &gt; L) activation of auditory cortices in response to heard speech, much stronger than when listening to music; 2) very little response to silent lip‐reading; 3) strong activation in the temporo‐parieto‐occipital association cortex, exclusively in the right hemisphere (RH), when viewing BSL signs. Analysis of these findings provides novel insights into the disturbance of the auditory speech cortex which underlies LKS and its diagnostic evaluation by fMRI, and underpins a strategy of restoring communication abilities in LKS through a natural sign language of the deaf ( with Video ).

Infants′ Visual Preferences in the Presence and Absence of Auditory Stimulation

Two experiments were conducted to explore the hypothesis that altering rate of change of an auditory stimulus will affect infants′ fixation of changing visual stimuli. Experiment 1 revealed that average percent time that infants preferred looking at the less stimulating of two meaningless visual displays was highest under conditions of auditory stimulation. Experiment 2 demonstrated a significant inverse linear relation between rate of change of loudness in auditory stimulation and attentiveness to rapidly changing visual stimulation, due largely to decreased looking at the most stimulating display under conditions of auditory stimulation. In addition, the heart rates of a significant number of subjects were found to be accelerated in the presence of auditory stimulation. The results are interpreted as indicating that this type of sensory interaction is mediated, at least in part, by a subject′s level of arousal.

An on-line program to calculate respiratory sinus arrhythmia amplitude

A variety of evidence shows that the amplitude of respiratory sinus arrhythmia (RSA)—the peak-to-peak variations in heart rate caused by respiration—is a valid and reliable index of para-sympathetic cardiac control. An on-line program to calculate RSA amplitude on a breath-by-breath basis is described. The validity of the RSA amplitude values obtained through the computer pro-gram were tested in two studies. From the first one, the correlations between RSA amplitude and a set of cardiorespiratory variables, under both rest and auditory stimulation conditions, are reported. In the second study, the effect of atropine administration on the RSA amplitude, under both rest and mental load conditions, was examined. The results of both studies are con-gruent with predictions and suggest the usefulness of the software.

Anatomical evidence of synaptic plasticity in the cochlear nuclei of white-deaf cats

Synapses are dynamic structures reflecting environmental events. It was observed that densities associated with apposing synaptic membranes were altered in response to changing conditions of auditory stimulation ( Gulley et al. 1978 . J. Comp. Neurol. 180: 707–742). Synapses also exhibit plasticity during early development of the auditory system ( Larsen and Pappas, 1985. Proceedings: 43rd Annual Meeting of the Electron Microscopy Society of America, pp. 493–494). Larsen and Pappas reported that, in young kittens, the end bulb of Held (EBH) terminal was distinguished by excessive density at apposing synaptic membranes which assume gradually the pattern observed in adult cats. The maturation of synapses parallels emerging function and may depend upon auditory stimulation ( Larsen and Kirchhoff, 1987. Neurosci. Abstr. 13: 1260). Larsen and Kirchhoff found that EBH synapses on large spherical cells of white-deaf cats resembled the immature synapses found in young kittens (Fig. 1). They also found terminals that had an increased number and length of the membrane densities associated with synapses. Because the number of synaptic vesicles in these presynaptic terminals was equivalent to the number of vesicles found in normal-hearing cats, Larsen and Kirchhoff (1987) suggest that this is evidence of synaptic plasticity. We have completed a quantitative study of the synapses of EBH terminals found in adult cats that had been deaf for at least 3 years.

Global brain asymmetries in regional cerebral blood flow (rCBF) observed during resting conditions with positron emission tomography (PET): Establishing a baseline for experiments on brain asymmetries and complex sounds in the CNS Project

During 1981–1985, the first author and colleagues at the Mallinckrodt Institute of Radiology at Washington University in St. Louis collected a series of 29 PET-scan studies of the brains of 16 normal young adult subjects using the PETT VI and intravenous oxygen-15 to test each subject in multiple 40-s scans, comparing rCBF topography during session-initial and session-final control scans, and under a variety of auditory stimulation conditions. Global hemispheric rCBF in all control scans are currently being measured in this library. Results will be presented for work to date, detailing between- and within-subject comparisons, including patterns to within- and between-session replications. These measurements will provide a baseline for the Coordinated Noninvasive Studies (CNS) Project, in which subjects first examined behaviorally for processing asymmetries (e.g., ear advantages), are then tested with PET to determine the degree of correlation between behavioral and physiological asymmetries. [Work supported by AFOSR.]

Physical Anhedonia and Future Psychopathology: An Electrocortical Continuity?

ABSTRACTDuring the past decade, a great deal of effort has been focused on the identification of subjects who may be at “high‐risk” for the development of psychopathology. Chapman, Chapman, and Raulin (1976) suggested that college students who report pervasive physical anhedonia may comprise a group of subjects vulnerable to the development of schizophrenia. The present study provides cortical evoked potential data consistent with this relationship.Auditory event‐related potentials (ERPs) were collected from anhedonic subjects and normal controls under two conditions of auditory stimulation. In the first condition (nonsignal orienting), anhedonic and normal control subjects did not differ on any measure of the ERP. However, under signal conditions, reliable group differences emerged which were strikingly apparent in the late positive (P3) component. These group differences were maximal when the auditory signal predicted a high‐interest event. Similar observations of reduced P3 activity have been frequently reported in studies with schizophrenic patients. In conjunction with previous investigations of anhedonic subjects, the present data continue to support the hypothesis that these subjects may constitute a psychosis‐prone population.

The EEG's of chronic schizophrenic patients in hospital and in the community

EEG's were recorded from chronic schizophrenic impatients, remitted patients living in the community and normal controls, during resting and auditory stimulation conditions. Chronic inpatients had more energy in the slower and fastest wave bands than either remitted patients or normal controls. No differences were found in overall EEG energy and variability between groups of subjects or between sides of the head. It was concluded that any abnormalities were associated with behavioural differences and not with schizophrenic process changes.