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Biomedical subjects

D Ploog

Publications and source records attributed to D Ploog.

At least 19 recordsLinked to original sources
PubMed1989

Human neuroethology of emotion.

1. Based on ethological theory, the question of what is the difference between human and nonhuman primate emotionality is investigated. 2. The anatomical basis for this difference is the greater number of neurons in the anterior thalamic nuclei in humans than in monkeys and apes. This may represent an increased differentiation of the limbic message being sent to the cortex. 3. Only humans can report about experiences and subjective feelings in certain motivational states. The two most general states are wakefulness and sleep. The subjective aspect of (desynchronized) sleep is dreaming. The causal relationship between dreaming and certain lower brain stem mechanisms is analysed. 4. Whereas the motor system is usually blocked during desynchronized sleep, there are individuals who voice their emotions and speak while sleeping. As there are essential differences in the substrates for the voluntary control of the voice in the human and nonhuman primates there are essential differences in the voluntary control of emotions. 5. Similar to the motor matching theory of speech perception a motor matching process of affect perception is suggested. 6. The evolutionary change in the human motivational system is thought to be one of several prerequisites for the evolution of language.

Biological Evolution↗
PubMed1988

An outline of human neuroethology.

Neuroethology is concerned with the analysis of neural substrates and mechanisms that underlie invariant forms of species-typical behavior. The aim of this outline is to delineate in an evolutionary perspective some specific human functional brain states and mechanisms which form the foundation of homo-typical behavior and experience. Dreaming, as one example, is considered to belong to the universals of human experience. Another example is the repertoire of human emotion and mental phenomena evoked by the electrical stimulation of the human limbic system. The expression of emotions by vocal behavior gains momentum in man and is based on certain transformations of the CNS that were fundamental for the emergence of speech. The phonemes in speech are the species-typical articulatory gestures for which a special decoding device is required. This innate mechanism may have features in common with the vocal signal decoding mechanism of subhuman primates.

Behavior↗
PubMed1987

Regional cerebral glucose metabolism in anorexia nervosa measured by positron emission tomography.

Regional cerebral glucose metabolism was measured in five female anorectic patients, during the anorectic state and after weight gain, using the fluorodeoxyglucose method and positron emission tomography. In addition, these results were compared with those of 15 young male normals. During the anorectic state, significant caudate hypermetabolism was found bilaterally, unlike the finding in repeat measurements or in male normals. In some other brain structures (temporal cortex, lentiform nucleus, thalamus, and brainstem), significant hypermetabolism was also found during the anorectic state, but these results were not concordant for both sides and in both comparisons. There was no difference between patients after improvement and young male normals.

Adolescent↗
PubMed1981

Inhibition of auditory cortical neurons during phonation.

The neuronal activity of the auditory cortex in the squirrel monkey was investigated during phonation in order to study relationships between brain structures involved in phonation and audition. Responses of single cells in the superior temporal gyrus were extracellularly recorded during stimulation by self-produced vocalizations (elicited either through electrical stimulation of the central gray or uttered spontaneously), and by tape-recorded vocalizations played back together with other species-specific cells. More than half of those cells which reacted to the play-back of self-produced vocalizations responded clearly weaker or not at all during phonation. Less than half of the neurons did not differentiate between self-produced and loudspeaker-transmitted vocalizations. It is concluded that brain structures which are activated during phonation exert an inhibitory influence on parts of the auditory cortex, a fact providing evidence of a neuronal feed-forward circuit mechanism within the process of audiovocal communication.

Acoustic Stimulation↗
PubMed1981

[Anorexia nervosa in puberty (author's transl)].

The complementary somato-psychic processes are shown in relationship to the well known psycho-social constellations. The well known and here demonstrated experimental animals and human medicine investigation lead to the conclusion that the hypothalamic disorders have a direct effect on the intellectual-spiritual functioning. So far we did not yet find the lesion specific for the disease.

Adolescent↗
PubMed1979

Phonation, emotion, cognition, with reference to the brain mechanisms involved.

Phylogenetic steps in the evolution of vocal communication have a bearing on the brain mechanisms involved in the emergence of human language and speech. A schema of the neuronal organization of voicing in a hierarchical manner is presented. At the lowest mesencephalic level the movements of the vocal apparatus are coordinated and integrated into species-specific vocal gestures. At the middle level these signals are controlled by the anterior limbic cortex, which serves this function in primates only, and only in the human species is the highest level around the cortical larynx and facial area actively involved in the vocal signalling process. This functional schema is used to explain the sequential stages in the ontogenetic process of phonemicization in the human infant, and special emphasis is placed on vocal-auditory feedback mechanisms which come into play from the lowest to the highest level of the central nervous system during maturation. Even feedback loops of the lowest level enable the distinction to be made between self-produced vocalizations and those produced by others. These mechanisms are thought to be an early means for the development of self-awareness. If one grants that the human infant possesses self-awareness, one must concede that such stages of the mind were developed before the emergence of the human species.

Animals↗
PubMed1977

The effect of superior temporal lesions on the recognition of species-specific calls in the squirrel monkey.

Eleven squirrel monkeys (Saimiri sciureus) were trained to discriminate species-specific calls from non-species-specific complex sounds in a go, no-go procedure with social contact as positive reinforcement. The task required that the animals not only responded to a particular call but that this response should be generalized to any squirrel monkey call, whether or not it had been presented previously in training. After having reached a performance level of 75% correct responses in three consecutive sessions, seven animals received bilateral lesions of the auditory cortex; the other four animals served as controls. It was found that small lesions within the superior temporal gyrus did not interfere with the discrimination task. Lesions destroying about three quarters of the auditory cortex led to loss of retention; during retraining the animals did not reach criterion, but performed significantly above chance. These animals were able, however, to master a simplified version of the task where one species-specific call had to be discriminated from one non-species-specific sound. Animals with almost total ablation of the auditory cortex were capable of mastering neither the generalized task nor the simplified version. From these results, together with those of the literature, it is concluded 1) that recognition of complex sounds is not possible after complete auditory cortex ablation, probably because of interference with gestalt-formation processing, and 2) that species-specific calls are processed in the auditory system in the same way as other complex sounds.

Agnosia↗
PubMed1977

Malignant lymphoma in a squirrel monkey (Saimiri sciureus).

A juvenile male Saimiri sciureus died of a tumor diagnosed as a histiocytic type of malignant lymphoma. The neoplasm presented as a thoracic mass occupying the posterior mediastinum and infiltrating the contiguous structures without involving distant nodes, the liver or spleen. The tumor tissue consisted of sheets or poorly defined clusters of fairly large cells with a vesicular nucleus and a variably abundant cytoplasm. The tumor cells were laid out in a poorly developed stroma of fine argyrophilic fibers. This is the first report of a spontaneous malignant lymphoma in a primate of this species. The speculation is put forth that the reported tumor is probably the first known example of the long sought after correlate of squirrel monkeys to Burkitt lymphoma in man.

Animals↗
PubMed1976

[On the evolution of voice (author's transl)].

The paper gives a short survey of the phylogenetic development of the laryngeal and supralaryngeal apparatus from amphibians to man. The increasing differentiation of vocal behaviour, paralleling the differentiation of the vocal apparatus, is outlined and special reference is made to the non-verbal component in human language. It is stressed that animal vocal repertoires can be extremely rich, but in contrast to human verbal behaviour they are generated almost exclusively by laryngeal modulations and only to a minimal degree by supralaryngeal activity (i.e. articulation). A phylogenetic development can also be seen in the cerebral organization of vocal behaviour. In amphibians, reptiles and lower mammals, the dorsal midbrain-pons transitional zone seems to be the only area responsible for the production of vocal utterances. This area probably serves in integrating vocal fold movements, expiration, intra- and extra-oral muscle activity into species-specific vocal patterns; its destruction results in mutism. In higher mammals, including man, this area does not lose its original function but is brought under the control of the cortex around the anterior sulcus cinguli (supplementary motor area and anterior cingulate gyrus). The latter seems to play an essential role in the initiation of vocal utterances in situations which do not have a rigid stimulus-response characteristic, i.e. in voluntary vocal behaviour. The highest level of voice production, finally is represented by the cortical face area, the destruction of which is without consequence to the innate vocal behaviour of animals but produces dysarthria in man. This area (together with its associated structures, such as the cortex-pontine nuclei-cerebellum-thalamus-cortex circuit) seems to be essential for the production of verbal or, more generally, learned vocal behaviour.

Amphibians↗
PubMed1975

Psychobiology of partnership behaviour.

Animal experiments demonstrate that it is not only the quality of transmitted and received social signals that is important, but also their frequency and the timing of the information transmitted. In order for progress to be made in the investigation of human social behaviour and its disorders, methods must be developed which allow the transmission of verbal and non-verbal information to be measured. Experiments carried out with healthy adults and healthy and disturbed children to investigate human eye contact and distance behaviour are reported, along with experiments on the influence of gaze and body posture on spoken communication. Finally, a report on the use of behaviour therapy for an autistic child is outlined in order to explore the psychobiological correlations between social behaviour and language, which concur with extensive experiments on brain stimulation. It is suggested that there is a cerebral representation for species-specific social behaviour and a vocalization system embedded in these brain structures which is a phylogenetically-patterned prerequisite for the development of human language.

Animals↗