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PubMed2005

Automatic encoding of polyphonic melodies in musicians and nonmusicians.

In music, multiple musical objects often overlap in time. Western polyphonic music contains multiple simultaneous melodic lines (referred to as "voices") of equal importance. Previous electrophysiological studies have shown that pitch changes in a single melody are automatically encoded in memory traces, as indexed by mismatch negativity (MMN) and its magnetic counterpart (MMNm), and that this encoding process is enhanced by musical experience. In the present study, we examined whether two simultaneous melodies in polyphonic music are represented as separate entities in the auditory memory trace. Musicians and untrained controls were tested in both magnetoencephalogram and behavioral sessions. Polyphonic stimuli were created by combining two melodies (A and B), each consisting of the same five notes but in a different order. Melody A was in the high voice and Melody B in the low voice in one condition, and this was reversed in the other condition. On 50% of trials, a deviant final (5th) note was played either in the high or in the low voice, and it either went outside the key of the melody or remained within the key. These four deviations occurred with equal probability of 12.5% each. Clear MMNm was obtained for most changes in both groups, despite the 50% deviance level, with a larger amplitude in musicians than in controls. The response pattern was consistent across groups, with larger MMNm for deviants in the high voice than in the low voice, and larger MMNm for in-key than out-of-key changes, despite better behavioral performance for out-of-key changes. The results suggest that melodic information in each voice in polyphonic music is encoded in the sensory memory trace, that the higher voice is more salient than the lower, and that tonality may be processed primarily at cognitive stages subsequent to MMN generation.

Acoustic Stimulation↗
PubMed1999

Accessory stimulus effects on response selection: does arousal speed decision making?

When an intense but task-irrelevant "accessory" stimulus accompanies the imperative stimulus in a choice reaction task, reaction times (RTs) are facilitated. In a similar previous study (Hackley & Valle-Inclán, 1998), we showed that this effect is not due to a reduction of the interval from onset of the lateralized readiness potential (LRP) until movement onset. In the present study, the RT task was modified to move a portion of the response selection stage into this time interval. The interval remained invariant, indicating that this late phase of the response selection process is not speeded by accessory stimulation. However, we observed amplitude modulation of the LRP on no-go trials in a condition with three alternative responses. This finding suggests that an earlier phase of response selection is influenced by accessory stimulation. In addition, a novel dependent measure was introduced to event-related potential research--the latency of spontaneous, post-trial blinking.

Acoustic Stimulation↗
PubMed2006

Reduced suppression or labile memory? Mechanisms of inefficient filtering of irrelevant information in older adults.

Cognitive aging theories emphasize the decrease in efficiency of inhibitory processes and attention control in normal aging, which, in turn, may result in reduction of working memory function. Accordingly, some of these age-related changes may be due to faster sensory memory decay or to inefficient filtering of irrelevant sensory information (sensory gating). Here, event-related brain potentials and the event-related optical signal were recorded in younger and older adults passively listening to tone trains. To determine whether age differentially affects decay of sensory memory templates over short intervals, trains were separated by delays of either 1 or 5 sec. To determine whether age affects the suppression of responses to unattended repeated stimuli, we evaluated the brain activity elicited by successive train stimuli. Some trains started with a shorter-duration stimulus (deviant trains). Results showed that both electrical and optical responses to tones were more persistent with repeated stimulation in older adults than in younger adults, whereas the effects of delay were similar in the two groups. A mismatch negativity (MMN) was elicited by the first stimulus in deviant trains. This MMN was larger for 1- than 5-sec delay, but did not differ across groups. These data suggest that age-related changes in sensory processing are likely due to inefficient filtering of repeated information, rather than to faster sensory memory decay. This inefficient filtering may be due to, or interact with, reduced attention control. Furthermore, it may increase the noise levels in the information processing system and thus contribute to problems with working memory and speed of processing.

Acoustic Stimulation↗
PubMed2006

Attentional modulation in the detection of irrelevant deviance: a simultaneous ERP/fMRI study.

Little is known about the neural mechanisms that control attentional modulation of deviance detection in the auditory modality. In this study, we manipulated the difficulty of a primary task to test the relation between task difficulty and the detection of infrequent, task-irrelevant deviant (D) tones (1,300 Hz) presented among repetitive standard (S) tones (1,000 Hz). Simultaneous functional magnetic resonance imaging (fMRI)/event-related potentials (ERPs) were recorded from 21 subjects performing a two-alternative forced-choice duration discrimination task (short and long tones of equal probability). The duration of the short tone was always 50 msec. The duration of the long tone was 100 msec in the easy task and 60 msec in the difficult task. As expected, response accuracy decreased and response time (RT) increased in the difficult compared with the easy task. Performance was also poorer for D than for S tones, indicating distraction by task-irrelevant frequency information on trials involving D tones. In the difficult task, an amplitude increase was observed in the difference waves for N1 and P3a, ERP components associated with increased attention to deviant sounds. The mismatch negativity (MMN) response, associated with passive deviant detection, was larger in the easy task, demonstrating the susceptibility of this component to attentional manipulations. The fMRI contrast D > S in the difficult task revealed activation on the right superior temporal gyrus (STG) and extending ventrally into the superior temporal sulcus, suggesting this region's involvement in involuntary attention shifting toward unattended, infrequent sounds. Conversely, passive deviance detection, as reflected by the MMN, was associated with more dorsal activation on the STG. These results are consistent with the view that the dorsal STG region is responsive to mismatches between the memory trace of the standard and the incoming deviant sound, whereas the ventral STG region is activated by involuntary shifts of attention to task-irrelevant auditory features.

Acoustic Stimulation↗
PubMed2006

Implicit, intuitive, and explicit knowledge of abstract regularities in a sound sequence: an event-related brain potential study.

Implicit knowledge has been proposed to be the substrate of intuition because intuitive judgments resemble implicit processes. We investigated whether the automatically elicited mismatch negativity (MMN) component of the auditory event-related potentials (ERPs) can reflect implicit knowledge and whether this knowledge can be utilized for intuitive sound discrimination. We also determined the sensitivity of the attention-and task-dependent P3 component to intuitive versus explicit knowledge. We recorded the ERPs elicited in an "abstract" oddball paradigm. Tone pairs roving over different frequencies but with a constant ascending inter-pair interval, were presented as frequent standard events. The standards were occasionally replaced by deviating, descending tone pairs. The ERPs were recorded under both ignore and attend conditions. Subjects were interviewed and classified on the basis of whether or not they could datect the deviants. The deviants elicited an MMN even in subjects who subsequent to the MMN recording did not express awareness of the deviants. This suggests that these subjects possessed implicit knowledge of the sound-sequence structure. Some of these subjects learned, in an associative training session, to detect the deviants intuitively, that is, they could detect the deviants but did not give a correct description of how the deviants differed from the standards. Intuitive deviant detection was not accompanied by P3 elicitation whereas subjects who developed explicit knowledge of the sound sequence during the training did show a P3 to the detected deviants.

Acoustic Stimulation↗
PubMed2006

Lapses in a prefrontal-extrastriate preparatory attention network predict mistakes.

Mistakes are common to all forms of behavior but there is disagreement about what causes errors. We recorded electrophysiological and behavioral measures in a letter discrimination task to examine whether deficits in preparatory attention predicted subsequent response errors. Error trials were characterized by decreased frontal-central preparatory attention event-related potentials (ERPs) prior to stimulus presentation and decreased extrastriate sensory ERPs during visual processing. These findings indicate that transient lapses in a prefrontal-extrastriate preparatory attention network can lead to response errors.

Adult↗
PubMed1976

The "intoxication state of consciousness": a model for alcohol and drug abuse.

The author describes a model of intoxicant use based on altered states of consciousness and reviews his own and others' research on marijuana to illustrate the utility of this model, which is derived from both introspective reports and observed data. The relationship of social behavior and cognitive functioning to the "intoxication state of consciousness" is discussed. This state of consciousness may have an adaptive value in engendering and stabilizing social cohesion. Possible treatment implications include cognitive labeling of cues that precipitate episodes of abuse, training for moderated drug use while patients are intoxicated, and providing abusers with altered consciousness through other means, such as meditation.

Alcoholic Intoxication↗
PubMed2002

Impaired cortical network for preattentive detection of change in speech sounds in schizophrenia: a high-resolution event-related potential study.

OBJECTIVE: Schizophrenia is associated with language-related dysfunction. At the most basic level, the dysfunction of schizophrenic patients in perceiving phoneme boundaries has been demonstrated in a behavioral task. The goal in this study was to obtain an electrophysiological index of preattentive detection of change in speech sounds by schizophrenic patients. METHOD: A high-density recording system was used to measure mismatch negativity, i.e., difference in electrophysiological responses between standard and deviant auditory stimuli. The amplitude of mismatch negativity was measured in 23 right-handed schizophrenic patients and in 28 healthy comparison subjects. Three types of mismatch negativity were recorded: change in duration of pure-tone stimuli, change in duration of the Japanese vowel /a/, and difference between vowels /a/ and /o/ (across-phoneme change). RESULTS: The schizophrenic patients had a lower amplitude of mismatch negativity for across-phoneme change than for change in duration of tone or vowel. For across-phoneme change, the schizophrenia group showed significantly lower bilateral amplitude of mismatch negativity than the comparison subjects. These findings coincide with those from the analysis of scalp current density, indicating that the schizophrenic patients had a significantly weaker left temporal combination of current sink (perpendicularly sinking into the scalp) and current source (arising out of the scalp) and a significantly weaker right frontal/temporal current sink than the comparison subjects. CONCLUSIONS: These results demonstrate impaired frontotemporal cortical networks for preattentive detection of change in speech sounds in schizophrenia. The language-related dysfunction in schizophrenia may be present at the early stage of auditory processing of relatively simple stimuli, such as phonemes, and not just at stages involving higher-order semantic processes.

Adult↗
PubMed2005

Behavioral and electrophysiological indices of temporal processing dysfunction in schizophrenia.

Timing deficits in schizophrenia have been noted in several behavioral studies. However, the involvement of mediating factors, such as inattention, has not been ruled out as contributing to these effects. Mismatch negativity (MMN), an electrophysiological measure, may provide a more direct index of stimulus processing ability in individuals with schizophrenia. The current study explored the relationship between behavioral time judgments and a time-based MMN paradigm. Participants were administered two MMN paradigms consisting of an "easy" or "difficult" deviant and an analogous behavioral measure of time processing. Matched against a healthy comparison group, patients exhibited decreased MMN amplitude on the "difficult" deviant interval only. However, on the behavioral paradigm, the patients made significantly more errors across all conditions. These results suggest that behavioral measures of time processing may reflect different processes than those captured by preattentive physiological measures in this population.

Acoustic Stimulation↗
PubMed1998

Biobehavioral correlates in migraine: the role of hypersensitivity and information-processing dysfunction.

In this paper we address the role of specific abnormal behavioral patterns (such as perfectionism or hypersensitivity) which have been described as psychological characteristics in migraine patients. We propose that behavioral abnormalities may be the result of a determined cortical hypersensitivity and an associated social learning process. New neuro(psycho)physiological data support the concept that migraine is a brainstem-related information-processing dysfunction that is characterized by cortical hypersensitivity and reduced habituation to stimuli. The cortical activity reflects a (time) periodicity and may be due to endogenous or exogenous factors. Based on the current understanding of behavioral and neurophysiological aspects of migraine, we postulate a two-process model of migraine aetiology: (i) a genetically determined hyperactivity of the central monoaminergic (catecholaminergic) system, which could be possibly modulated by learning processes and (ii) a homeostatic (counter) regulation and mobilization of reduced (mitochondrial) energy reserve.

Behavior↗
PubMed2006

Performance monitoring and error processing during a lexical decision task in patients with Parkinson's disease.

To evaluate performance monitoring and error processing during lexical decision tasks, event-related potentials (ERPs) obtained by time-locked to correct and error responses were studied in 17 Parkinson's disease (PD) patients without dementia and 15 healthy elderly participants. The amplitude of error negativity (Ne) obtained by averages time-locked to error response was significantly reduced in the PD patients, whereas there were no significant differences in the negative component for the correct response (Nc) between the two participant groups. The amplitude of the error positivity (Pe) and correct positivity (Pc) after the Ne and Nc components was also significantly reduced in the PD patients. The PD patients showed significantly slower reaction times and higher error rates. The reduced amplitude of the Ne, Pe, and Pc components in the PD patients suggested impaired performance and conflict monitoring as well as abnormal response strategy adjustments and deviant in later error monitoring processes associated with emotional, conscious evaluation of the error.

Aged↗
PubMed2004

Cortical neuromagnetic fields preceding voluntary jaw movements.

Slow cortical potentials (readiness potentials, RPs) reflecting the central programming of voluntary jaw movements were reported to appear preceding the movements. However, the current source producing the RP has not yet been localized. This study aimed to determine the cortical regions involved in the central programming of bilaterally symmetrical voluntary jaw movements, by locating the current source of the neuromagnetic counterpart of the RP (readiness field, RF). The RFs were found in the fronto-lateral region bilaterally, starting around 860 and 600 ms prior to the onset of masseter and digastric electromyograms (EMGs), respectively, and gradually increasing in magnitude to the peak within 100 ms before the EMG onset. Thus, the RFs appeared long before the reported onset of the excitability increase of pyramidal tract neurons. The current sources producing the RFs were located in the precentral gyrus bilaterally, with no bilateral differences in strength. We conclude that the primary motor cortex is involved bilaterally in central programming as well as in execution of bilaterally symmetrical voluntary jaw movements.

Adult↗
PubMed1980

The EEG effects of tobacco smoking--a review.

In summary, smoking does produce obvious changes in EEG activity. Human studies have been limited to surface electrodes. These have provided evidence of the alpha, evoked potential, and CNV effects of smoking. Changes in alpha and evoked potential activity have been statistically analyzed across subjects. These analyses indicated statistically significant arousal effects. However, large individual differences in responding were observed but not analyzed. Analysis of individual data in the Ashton, et. al. (1974) study indicated some arousal effects and some sedative effects, depending on the personality characteristics of the individual subject. Differential effects might have been detected in other studies had individual subject data been adequately analyzed. In research with nonhuman subjects, nicotine and tobacco smoke produced cortical arousal and sometimes a biphasic effect of arousal followed by apparent sedation. Behavioral effects accompanied the cortical arousal, including eyelid opening, head movements, and eye movements. During the synchronization phase, crouching, low mobility, and closed eyes occurred. Both the limbic and reticular activating systems seem to be affected by nicotine and smoking with the hippocampus most noticeably affected.

Alpha Rhythm↗