Even in the presence of irrelevant stimuli, word production is a highly accurate and fluent process. But how do speakers prevent themselves from naming the wrong things? One possibility is that an ...attentional system inhibits task-irrelevant representations. Alternatively, a verbal self-monitoring system might check speech for accuracy and remove errors stemming from irrelevant information. Because self-monitoring is sensitive to social appropriateness, taboo errors should be intercepted more than neutral errors are. To prevent embarrassment, speakers might also speak more slowly when confronted with taboo distractors. Our results from two experiments are consistent with the self-monitoring account: Examining picture-naming speed (Experiment 1) and accuracy (Experiment 2), we found fewer naming errors but longer picture-naming latencies for pictures presented with taboo distractors than for pictures presented with neutral distractors. These results suggest that when intrusions of irrelevant words are highly undesirable, speakers do not simply inhibit these words: Rather, the language-production system adjusts itself to the context and filters out the undesirable words.
In awake cats trained to perform a food-procuring conditioned operant reflex (placing movement), we studied impulse reactions of 86 neurons of the motor cortex (field 4) related to realization of the ...above movements. As conditioning stimuli (CS) initiating the reflex, we used either non-noxious electrocutaneous stimulation (ECS) of the contralateral forelimb or an acoustic stimulus (sound click). Impulsation of cortical neurons was recorded under conditions of (i) isolated presentation of the CS (control), (ii) presentation of the CS (either ECS or acoustic stimulus) combined with thermostimulation (heating with a miniature electric bulb) of the skin of the working forelimb, and (iii) the same, but with stimulation of the resting forelimb. When we recorded spike activity of neurons within the projection motor zone of the resting limb subjected to ESC, alternating thermostimulation of both forelimbs resulted in considerable intensification and an increase in the duration of neuronal responses, especially in cases where thermostimulation was applied to the working limb ipsilateral to the recording site (a two- to threefold increase). When spike reactions were recorded within the motor cortex of the working forelimb, thermostimulation resulted in a considerable increase in the intensity of these reactions and a decrease in their latency, but only when such stimulation was applied to the working forelimb. Thermostimulation of the resting (ipsilateral, subjected to ESC) limb evoked opposite effects (the intensity of neuronal reactions dropped). In both situations, placing movements remained within the control limits. When sound click was used as a distant CS, thermostimulation of the working limb enhanced neuronal responses, increased their duration by 50-100%, and also increased the time of forestalling of the movement initiation by spike neuronal reactions. Thermostimulation of the resting forelimb in this situation also suppressed neuronal reactions. We conclude that "foreign" stimulations directed toward modifications of the receptor model of the operant reflex experimental situation formed in the animal result in a decrease in the intensity of the spike responses of field-4 neurons and prolongation of the latencies of these responses, while stimulations promoting the inflow of afferent information to the cortical projection of the working limb evoke opposite effects, an increase in the intensity of neuronal spike responses and a decrease in their latencies.
Auditory and visual distraction in hippocampectomized Riddell, William I; Rothblat, Lawrence A; Wilson, William A
Journal of comparative & physiological psychology,
02/1969, Letnik:
67, Številka:
2p1
Journal Article
Investigated the effect of visual and auditory distracting stimuli upon the runway performance of 24 hippocampectomized rats. Although the distracting stimuli affected the controls significantly more ...than the hippocampectomized Ss, the latter also showed a decrement in performance. The results supported a response-inhibition theory of hippocampal function.
The authors recorded contingent negative variation (CNV) in a group of subjects affected by presenile dementia, at the onset of the symptoms, with a slight degree of intellectual deterioration. ...Recordings were carried out in rest basal conditions and upon administration of an insignificant distracting stimulus. Results were compared with data obtained in a group of normal subjects of the same age under the same experimental conditions. In the patients a marked decrease of the wave was observed upon the administration of a distracting stimulus.
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