[Thalamo-cortical system and consciousness]. / El sistema tálamo-cortical y la consciencia.

After reviewing the concept of the specific and non specific thalamo-cortical systems, the connectivity of the relay and intralaminar nuclei is analyzed as well as the recent data concerning the chemical identity of thalamic neurones, the concept and distribution of "matrix" and "core" neurones and its functional role. The intrinsic electrical properties of thalamic neurones, its mode of discharge--depending of the membrane potential level--and its functional significance in the context of the brain's global activity are discussed. Of special interest are the studies on the effects of lesion of the relay and intralaminar nuclei as well as its repercussion in the interpretation of the sensory perception. After intralaminar nuclei lesion the individual is not aware of the nformation conveyed through the specific channels. It follows a discussion on the importance of the temporal and spatial mapping in the elaboration of perception and cognition. Due to the intrinsic electrical properties and the connectivity of thalamic neurones two groups of corticothalamic loops are generated, which resonate at a frequency of 40 Hz. The specific thalamo-cortical loops give the content of cognition and the no specific loop, the temporal binding required for the unity of the cognitive experience. Consciousness is then, a product of the resonant thalamo-cortical activity, and the dialogue between the thalamus and cortex, the process that generates subjectivity, the unique experience we all recognized as the existence of the "self".

[Gregorio Marañón and Walter B. Cannon]. / Gregorio Marañón y Walter B. Cannon.

The story of a friendly relationship between two great scientists, Gregorio Marañón (G.M.) and Walter B. Cannon (W.B.C.), is reported. Both share a common interest for the biology of emotion. In the early twenties they had already made important contributions to the nature of the emotional processes. The meeting point was in the interpretation of the somato-visceral response elicited by the injection of adrenaline in humans (G.M.) and of the emergency reaction (W.B.C.). The relevant moment in their relationship was the utilization by W.B.C. of the G.M.'s results concerning the artificial induction of the visceral changes typical of strong emotions as the main argument against the James-Lange theory of emotion, as no specific emotion was generated by the adrenaline; instead, only "as if" subjective feelings were reported by patients. A clear distinction then was drawn by G.M. between perception of the vegetative changes and the physical emotion proper. Since then it was clearly defined the cognitive component as essential and primary as concerns to the nature of emotion. The visceral changes are not determinant of the emotional quality. Its role was restricted to the strength and duration of the emotional experience.