Perceptual context and the selective attention effect on auditory event-related brain potentials.

Two experiments examined the effect of the perceptual context established through tonal grouping on neuroelectric responses during selective listening. Subjects monitored one of the extreme pitches in four-pitch tone sequences and detected rare longer tones of the designated pitch. In the first study, tonal grouping was manipulated by changing the tonal separation between the extreme pitches and their nearest neighbor, keeping the extreme pitches constant.

Distractor clustering enhances detection speed and accuracy during selective listening.

The effects of distractor clustering on target detection were examined in two experiments in which subjects attended to binaural tone bursts of one frequency while ignoring distracting tones of two competing frequencies. The subjects pressed a button in response to occasional target tones of longer duration (Experiment 1) or increased loudness (Experiment 2). In evenly spaced conditions, attended and distractor frequencies differed by 6 and 12 semitones, respectively (e.

Feature processing during high-rate auditory selective attention.

Auditory event-related brain potentials (ERPs) and reaction times were analyzed in a selective attention task in which subjects attended to tone pips presented at high rates (interstimulus intervals [ISIs] of 40-200 msec). Subjects responded to infrequent target tones of a specified frequency (250 or 4000 Hz) and location (left or right ear) that were louder than otherwise identical tones presented randomly to the left and right ears. Negative difference (Nd) waves were isolated by subtracting ERPs to tones with no target features from ERPs to the same tones when they shared target location, frequency, or both frequency and location cues.

Same-hand and different-hand finger pairings in two-choice reaction time: presence or absence of response competition?

Several two-choice reaction time experiments have compared conditions in which the two possible responses were from the same hand (same-hand pairing) or from different hands (different-hand pairing). Studies that used only the two relevant fingers on response keys reported shorter reaction times for the different-hand pairing. In other studies, two additional but irrelevant fingers were also in contact with response keys.

Frequency-related differences in the speed of human auditory processing.

Three experiments were performed, two comparing the peak latencies of auditory evoked potentials (AEPs) elicited by 250 Hz and 4000 Hz tone pips and a third comparing simple reaction times (RTs) to the same stimuli. In the AEP experiments, the latencies of brainstem, middle and long-latency components were delayed following 250 Hz tone pips in comparison with the latencies of the same components evoked by loudness-matched 4000 Hz tones. Frequency-related latency differences increased with component latency, ranging from less than 1.

Study of decision-making in squash competition: a computer simulation approach.

This paper describes how a computer simulation approach was used to specify some of the cognitive processes underlying decision-making in squash competition. The work presented in this article focused on the cognitive strategy of the defending player when choosing among three categories of preparation. (Total preparation for one particular event, partial preparation in favor of one event, and absence of biased preparation.

Additive latency effects of selective and nonselective restricted priming types.

The purpose of this investigation was to examine further the contention of Alain et al. (1988) that a third priming type exists, called nonselective restricted (NSR) and controlled by response probability, which is distinct from those types influenced by foreperiod duration (nonselective general priming) and prediction probability (selective priming). In a four-choice reaction time (RT) task, prediction probability (.

Intracerebral amplitude distributions of the auditory evoked potential.

Intracerebral auditory evoked potentials were recorded from multi-contact electrodes chronically implanted in frontal, temporal, and parietal regions of the brains of 10 epileptic patients. Binaurally presented tones produced a large widely distributed biphasic potential with a close latency correspondence to the scalp vertex response. In each hemisphere, this intracerebral response inverted in polarity from posterior temporal to frontal sites.

Human intracerebral potentials associated with target, novel, and omitted auditory stimuli.

We recorded late auditory potentials from lateral and medial regions in the frontal, temporal and parietal lobes of patients with temporal lobe epilepsy implanted with horizontal depth electrodes. Tone sequences were presented in three tasks: 1) auditory target detection in a tone sequence, 2) target detection with interspersed novel stimuli, and 3) detection of stimulus omissions. At frontal sites, potentials to targets showed a triphasic response with peak latencies around 200, 270 and 350 ms.

[Decision strategy as a function of uncertainty of the result: I. Latency of the decision].

Until now, the decision strategy used by human beings faced with a dichotomous situation was studied considering that speed of reaction was the main dependent variable. It was found that, in a two choice reaction time (CRT) task, subjects used a very conservative decision strategy. That is, when compared with events of 0.