The paper reviews the 20-year experience of recording impulse activity of neurons in the basal ganglia-thalamocortical circuits. These recordings were made from patients with Parkinson's disease who failed to respond to conventional medical treatment and who had undergone stereotaxic neurosurgery. When taken together, the results show that: (1) the basal ganglia-thalamocortical circuits become active only when a stimulus is attended or when a movement is voluntarily implemented, i.e. they are involved in the process of selection of an appropriate sensory stimulus for advanced processing and in the process of selection of an appropriate motor action for achieving a certain goal; (2) neuronal circuits responsible for assessment actions and for motor acts are segregated; (3) inhibitory opponent neuronal mechanisms are implemented for initiating and suppressing inappropriate actions; and (4) preparation to make different assessment actions (attentional set) is associated with different preparatory activities. To explain these findings a hypothesis of action programming has been formulated. According to it, the whole of human behavior is divided into separate sensory-motor-cognitive actions, while the brain in turn is divided into separate systems playing different roles in the organization of actions. The system for action selection that includes the basal ganglia-thalamic circuits plays a critical role in initiation of, preparation for, and suppression of these actions. The neuronal mechanisms for the system for action selection including mapping of actions, 'winner takes all' operations in the striatum, disinhibition and inhibition process in the thalamus are suggested and discussed.

The main aim of this contribution was to demonstrate a way of objectifying various aspects of musical thinking by analysing the continuously running EEG. In this respect, the determination of coherence between the brain‐electric activities at all possible recording sites (i.e., 171, for the 19 electrodes we use), together with power at these sites proved to be a useful method. For data reduction, only statistically significant differences between resting periods (usually 1 min) and periods of musical thinking were considered. This procedure was performed for each of six frequency bands between 1 and 31.5 Hz. The results of both group and individual experiments are reported. In group studies, listening to music involved mainly the temporal regions of both hemispheres, yet in different frequency ranges. The results proved to be specific and clearly differed from those obtained during tasks involving mental arithmetic, silent reading, listening to text and others. Moreover, musically trained subjects produced more increases of coherence than the untrained. While imagining music, usually more coherence increases (i.e., higher cortico‐cortical co‐operation) were found. The same is true of composing, which was found to be different from both previously mentioned manners of musical thinking and in which usually the highest degrees of cortico‐cortical co‐operation within and between the hemispheres were found. While composing, the uppermost beta band was the most involved. One sample illustrates the manner of representing the results. It is hypothesized that coherence reflects—to some extent—’differential attention’, aconditio sine qua non for conscious experience.

Probability mapping of amplitude and coherence based on spectral analysis yields information on the cooperation of brain areas in cognitive processes. The method is based on comparing these two parameters during the performance of a mental task with the respective values of the EEG at rest. For each of 6 frequency bands spanning the entire EEG spectrum the data are represented on schematic brain maps with significant changes of amplitude (entered at the sites of the 19 electrodes) and coherence (between all respective electrodes). These maps have proven to be largely task-specific in both group and individual studies. They are considered to objectify electrical manifestations of differential attention.

The impulse activity of 183 multiunits was recorded from the premotor cortex, the caudate nucleus, the globus pallidus, and the thalamus in 15 Parkinson's disease patients bearing inert gold electrodes implanted for diagnosis and therapy. The patients performed a task in which stimulus triplets (each consisting of two informational and one trigger stimulus) were presented. The patients initiated or inhibited actions (naming or counting) depending on the particular informational stimuli, thus allowing discrimination between different components of multiunit responses associated with attention and preparatory set and with disengagement from these states. The data indicate the existence of two overlapping circuits: one responsible for preparation for and assessment of the behavioral meaning of the stimulus and the other responsible for preparation for and performance of verbal action.

In order to determine the effects of attention and distraction on painful and non-painful stimuli, the amplitude changes of 3 components (N150, P200, P300) of the Somatosensory event-related potential (SERF) elicited by painful and non-painful electrical stimuli were investigated. Painful and non-painful stimuli were determined using a visual analog scale. SERPs were recorded from 16 healthy volunteers at 5 midline and 4 left and 4 right hemispheric sites. The differences between the amplitudes of attended and ignored stimuli were quantified with a baseline-to-peak measure. ANOVA results revealed no significant attention or stimulus intensity effects for N150 but highly significant differences in P200 and P300 amplitudes between attended and ignored stimuli. In addition, P200 and P300 amplitudes were larger for strong stimuli than for weak stimuli, with no significant differences between non-painful and painful stimuli. These findings are consistent with the existence of a relative, rather than an absolute, relationship between SERP component amplitudes and subjective pain reports. Furthermore, the data give evidence that attentional manipulations represent a powerful method to decrease the perception of pain and that, when used with subjective and behavioral measures, the SERP represents a valuable asset in the multidimensional approach to pain measurement and assessment.

This exploratory study deals with EEG changes in 3 professional interpreters while mentally interpreting from their mother language into foreign languages and vice versa. EEGs were recorded while interpreting and compared with the periods at rest between these periods of interpreting. Significant (P < 0.05) changes of coherence between all pairs of electrodes with respect to the averaged EEG at rest were computed for 5 frequency bands between 4 and 32 Hz. The verbal tasks were control-compared with comparable coherence measures for mental arithmetic and listening to music. Interindividual differences predominated, but certain common characteristics of the EEG measures were also found. The temporal regions were most involved in interpreting and particularly in the uppermost beta band (24-32 Hz). More coherence increases--particularly in the right hemisphere--were found while interpreting into the foreign than into the native language. Coherence changes were found to accumulate in certain regions of the scalp as pivots or focal areas which apparently have functional significance for the task in question as nodal points of information exchange and/or transfer. Such pivots were found in T3 more than in T4 (in the right-handers) and vice versa in a left-hander. Theta and alpha bands behaved differently and did not show such clear-cut differences. The results during mental arithmetic and listening to music were different from the ones while interpreting. The results give support to the conception of the cortex as a network serving the greatest possible divergence and convergence of signals.

This study was performed to test the usefulness of the EEG as a research instrument for music psychology in individuals. Measuring the degree of functional interrelatedness of brain areas by coherence estimates has turned out to be more efficient than amplitude mapping. Therefore, the method, based on the analysis of EEG periods of at least 1 min, has been expanded to estimate all possible coherence values between the 19 electrodes (i.e., 171 values) and to observe any significant changes in those values caused by different musical tasks. This report concerns observations in a total of 49 healthy subjects (29 male and 20 female). The main goal of this study was to determine the degree of engagement of either hemisphere in the processing of music. Two items were shown to indicate hemispheric involvement: (1) the topographic distribution of "focal points of coherence" (brain areas participating in coherence changes with respect to a great number of other brain areas) and (2) the number of intrahemispheric coherence increases. In most cases, both items seem to focus on the same hemisphere. Taking these as parameters for hemispheric engagement, the following principal observations were made: the beta bands (and particularly their uppermost ranges) seem to play a major role in the processing of music; the hemispheric engagement, however, need not be the same for each frequency band. No hemisphere seems to be preferred. When listening to music is shifted between different styles, laterality may change. When the same tasks are repeated at several weeks' intervals, a fairly large degree of consistency is found. Imagining music and composing clearly differs from listening by activating many more coherence increases in the beta band and by an increasing percentage of hemispheric interaction. This kind of analysis may also provide some clues as to how a piece of music is processed by an individual. The coherence changes observed may represent events taking place in a system of differential attention that selects and orders the sensory inputs before the musical material is further processed at higher order hierarchical levels.

Multiunit activity was recorded from strio-pallido-thalamic sites in parkinsonian patients bearing gold electrodes for diagnosis and therapy. The patients voluntarily participated in tasks designed to study neuronal correlates of both physical and semantic characteristics of stimuli as well as motor responses. Six modifications of the stimulus-response paradigm were used: visual odd-ball, visual and acoustic odd-ball tasks; tasks in which either the stimulus intensity or the meaning of non-target stimuli varied; single-stage delayed response and dual-stage delayed response tasks, respectively. In each task the patients had to evaluate some of the stimulus characteristics and to respond in a particular way according to the preliminary instructions. Peristimulus time histograms for each multiunit separately as well as profiles of reactions and profiles of reaction differences for the whole set of multiunits were calculated and subjected to statistical analysis. Two functional groups of subcortical neuronal reactions, stimulus-related and response-related activities, were separated. The stimulus-related activities of most multiunits were modality-unspecific. Their most striking feature was dependence on stimulus relevance and also its probability, the strongest reactions observed in response to task relevant stimuli occurring with low probability. The response-related activities occurred prior to initiation of movements, dependent upon the particular action and its probability. The data suggest at least two different and spatially overlapping subcortical channels responsible for goal-directed behaviour: the one related to stimulus assessment and the other to preparation for motor action.

Event-related potentials (ERPs) were recorded from the globus pallidus, the N. ventro-lateralis thalami and adjacent areas in parkinsonian patients bearing gold electrodes for diagnosis and therapy. The patients participated in a recognition task in which visual stimuli (digits) were presented at threshold durations. The ERPs from each single recording site, as separate histograms and then in combination as composite histograms across all recording sites (‘profiles of reactions’ and ‘profiles of reaction differences’), were computed for 3 response types (correct, non-recognition, and incorrect). Four groups of depth-ERP components (N100, P200, N300, P300) were observed. The N100 was not found to be affected by the quality of recognition, manifest in type of response, while the later components were, but each in its own way. A comparison of these data with those of multiunit activity recorded from these same sites (see Bechtereva et al. 1990) shows that the pattern of the depth N100 and P200 components with reference to the 3 types of response have no observable counterparts in the impulse activity manifestations of subcortical neuronal populations, while the depth N300 and P300 are indeed associated with the neuronal impulse activity. This in turn supports the hypothesis concerning multiple (including subcortical) generators of the P300.

Multiunit activity was recorded from 124 different subcortical sites in 10 parkinsonian patients bearing gold electrodes for diagnosis and therapy. The patients participated in a visual recognition task in which the stimuli (digits) were presented on a LED-matrix at threshold, the exposure times so chosen that in about half the trials the patient failed to recognize the digit correctly. Peristimulus time histograms (PSTHs) for each neuronal population as well as profiles of reactions for all neuronal populations were calculated and statistically analysed, separately for the cases of correct, incorrect, and non-recognition. There are at least 3 groups of neuronal populations, each associated with one temporally separate neurophysiological process involved in the performance of the psychological recognition task. They can be differentiated by the parameters' ‘onset’ and ‘peak’ latency. This in itself suggests that they may be related to different psychological processes involved in the task's performance, the earlier components in feature detection and/or evaluation operations concerning the stimulus; the later components, presumably, in processes related to initiation of the actual response. By scanning the individual PSTHs, we found one neuronal population which might be considered an error detector. This population reacted robustly in the early stages of information processing (100–500 ms post-stimulus) only in the case of non-optimal behavior, suggesting that it might somehow be related to signalling an error.

The purpose of this study is to examine speech convergence as a primitive form of socialized speech. Specifically, we examine (1) the extent of speech pattern matching by three year-old children, and (2) whether a talkativeness/reticence factor influenced degree of convergence. Four three-year-old girls individually interacted with 6 to 8 previously unfamiliar adults in free-play settings. From video recordings and verbatim transcripts, the degree of children's convergence to adult speech (i.e., moves toward similarity) is assessed on dimensions of speech rate, response latency, utterance length, and number of utterances. Three conclusions are drawn from the results. First, at age 3, speech convergence on these behaviors is evident, though the convergence mechanism is still relatively unstable. Second, only one reticent child consistently performed below the level of the talkative children. Third, adults tend to compensate for a child's lack of conversational activity by talking more to maintain the flow of interaction.

Multiunit activity was recorded from 80 different subcortical sites in 9 parkinsonian patients bearing gold electrodes for diagnosis and theraphy. The patients participated in a visual recognition task in which the stimuli (digits) were presented on a LED matrix at threshold. The exposure times were so chosen that in about half the trials the patient failed to recognized the digit correctly. Peristimulus time histograms for each neuronal population as well as profiles of reactions for the groups of neuronal populations localized in the N. ventro-laterals thalami and the globus pallidus, respectively, were analysed statistically, contrasting the cases of correct recognition with those of non-recognition. Different types of response, possibly related to different stages of task performance, were separated: an early type with onset latencies ranging from 80 to 160 msec, two middle types with onset latencies ranging from 200 to 300 msec, and a type characterized by slow shifts in the discharge rate beginning 400–600 msec post stimulus. Most of the significant differences in the discharge rate between qualities of recognition were found in the middle-type responses and in the slow shift, shorter latencies and larger amplitudes accompanying correct recognition.