Habitual Conditions Research Articles

Electrographic activity of the mesencephalic reticular formation during conditioning in the cat

In 4 cats the electroencephalographic changes recorded in the cortex, the thalamus and the mesencephalic reticular formation during conditioning were studied. Conditioning was produced by coupling of an unconditioned light stimulus in the form of intermittent photic stimulation with a preceding conditional auditory stimulus in the form of a continuous sound. This study allows to draw the following conclusions: 1. 1. The results confirm certain findings obtained in investigations carried out in the recent years. The appearance of evoked potentials and of a desynchronization during the presentation of the conditioned stimulus characterizes the first stage of conditioning. During a second stage the desynchronization is replaced by hypersynchronous repetitive discharges which progressively tend to follow the frequency of the intermittent photic stimulation. The so-called stage of experimental neurosis is characterized by the alternation of rapid patterns with sleep patterns during which the conditioned electroencephalographic responses characterized by desynchronization or by specific rhythmic discharges disappear. 2. 2. The role played by the reticular formation in the elaboration of conditioning processes is again stressed: 3. (a) the conditioned specific responses are of earlier onset, higher amplitude and are more stable in the reticular formation; 4. (b) the daily repetition of the experiments progressively increases the relationships of phase, form and amplitude between the bursts and other electrographic elements recorded in the occipital cortex and in the reticular formation without any stimulation. 5. 3. A new finding was obtained in this, study: the spontaneous appearance without any stimulation of repetitive discharges at the frequency of the photic flashes and almost exclusively recorded from the reticular formation. These rhythmic discharges appear as soon as the animal is placed in the habitual conditions of the experiment. They could represent an elementary electrographic manifestation of a memory processes.

Interessante comportamento dos cromossômios na espermatogênese dp escorpião Isometrus maculatus De Geer

Having had the opportunity of studying a male of the species Isometrus maculatus De Qeer (Scorplones, Buthidae) the author was able to observe one of the most interesting anomalies hitherto met with in his investigations on Scorpions. This anomaly consisted in the formation by the primary spermatocyte metaphase chromosomes of a complex group of eight elements, and two independent pairs. As it is clear, the octovalent group resulted from tranlocations involving the members of four chromosome pairs. Since aside the compound group two independent bivalents were always present, 12 was estabilished as representing the diploid chromosome number of the individual, what was soon confirmed by the counts in the spermatogonia. This peculiar behavior of the chromosomes of the primary spermatocytes represents the habitual condition in the studied individual, since it was found everywhere in the whole testis. Better than any description, the figures in this, paper show what was observed. Notwithstanding the complications which may occur at anaphase, separation of the chromosomes goes normally, each pole receiving four chromosomes from the group and two from the free bivalents. Secondary spermatocytes are thus provided with six monovalents. Though not found, we may believe in the existence of secondary spermatocytes with more or lesse than six chromosomes, because it seems highly probable that lhe chromosomes of the complex may now and then passe to the wrong pole 'n consequence of an incorrect orientation. Bridge vestiges suggest that chromosomes may sometimes break. The spermatogonia have 12 short chromosomes, which bend to the poles at anaphase. The chromosomes of the present species approach, in shape and behavior, those of Tityus mattogrossensis.

On the clinical differentiation of the various forms of ambulatory automatism.

Discusses the clinical observation of ambulatory automatism in 3 forms - the toxic, the epileptic and the hysteric. The views and observations of various psychologists like Voisin, Janet, Pitres, Raymond, Colman, Grandjean, Spartling and Sweeney on the characteristics of different forms of ambulatory automatism have been given. Concludes that epileptic fugue presents no popularities which distinguish it clinically from hysteric fugue. Suggests that diagnosis between the two conditions is not to be attempted on the basis of this phenomena alone, but rather, from a study of the habitual condition of the patients. (PsycINFO Database Record (c) 2006 APA, all rights reserved)