In terrestrial locomotion, active touch sensing is an important source of near-range information. Walking stick insects show active tactile exploration behaviour by continuously sampling the ambient space with their antennae. Here, we identify central and proprioceptive contributions to the control of this behaviour. First, we investigate the potential role of synaptic drive to central neural networks using pilocarpine, an agonist of muscarinic acetylcholine receptors. In an in situ preparation, pilocarpine induced rhythmic antennal movements with a persisting pattern of inter-joint coordination, matching that seen in intact walking animals, albeit with lower cycle frequency. After de-cerebration, stick insects were still able to walk but no longer moved their antennae during walking. Here, pilocarpine still induced antennal movement, suggesting that synaptic drive to central neural networks involved in antennal movement generation occurred in the brain and not in the suboesophageal ganglion. During intact walking, these networks are likely to receive activation by ascending input. Second, we show persistent coupling of both antennal joints during intact walking, with the distal scape-pedicel joint (SP) always leading the proximal head-scape joint (HS). Ablation of joint proprioceptors had no effect on this overall pattern of inter-joint coordination but could affect the magnitude of the phase-lag. Third, we revise the description of antennal hair fields and show that complete ablation of all seven hair fields strongly affects antennal movements. Ablating dorsal hair fields mainly affected the working-ranges of antennal joints: Ablation of the dorso-medial pedicellar hair plate caused a ventral shift of the SP working-range. Ablation of the dorsal scapal hair plate considerably expanded the dorsal HS working-range, and, in combination with ablation of pedicellar hair fields, increased the SP working-range, too. We conclude that the working-ranges of both joints are under proprioceptive control of dorsal antennal hair fields. Thus, both synaptic drive to central neural networks and proprioceptive feedback are involved in the control of active tactile exploration behaviour in stick insects.

The theoretical concept concerning informational aspects of systemic cerebration was proved based on the theory of functional systems formulated by P.K. Anokhin. It has been postulated that informational models of discrete informational systemoquantum in the form of holographic images of mentality were constructed. They are constructed for the dynamics of formation of functional systems of cerebral architectonics, which determine behavior and mentality on morphofunctional structures of acceptors of the outcome of action. The successive steps of formation of informational systemoquamtums of action outcome acceptors are presented. The leading role of the dominant motivations in building and rapid retrieval of informational systemoquamtums of mentality from the memory was underlined.

During regional anesthesia for carotid endarterectomy (CEA), 10% to 15% of patients develop signs of cerebral hypoxia after cross-clamping, manifested as changes in speech, cerebration or contralateral motor power. Reversal of such neurological deficits using administration of 100% O2 has been described. We used near-infrared cerebral oximetry to assess whether 100% O2 reliably improves regional cerebral oxygenation (rSO2) during carotid cross-clamping.Sixteen patients undergoing awake CEA were studied. Bilateral rSO2 optodes were applied before the initiation of sedation and the conduct of the regional blockade. Patients received 28% oxygen by Venturi facemask. Perioperative blood pressure was maintained at or within 10% above the patient's normal limits during carotid cross-clamping. After cross-clamping, 100% O2 was administered for 5 min by a close-fitting anesthetic facemask. The O2 mask was then removed and the patient breathed room air. The effects on rSO2 readings and arterial blood gases were observed after each intervention.Data were analyzed for 15 patients. Ipsilateral rSO2 values decreased by 7.4% +/- 5% after carotid cross-clamping. Administration of 100% O2 resulted in an increase in ipsilateral rSO2 in all patients of 6.9% +/- 3.3% (range, 1%-12%) (paired t-test, P < 0.001) over the cross-clamped value while receiving 28% O2. Hemodynamic variables and arterial PaCO2 values were unaltered.With the carotid cross-clamped, ipsilateral rSO2 was reliably increased by the administration of 100% O(2) compared with 28% O2. The etiology of this increase is unclear, but may relate to the associated increase in O2 content of the blood or to an improvement in cerebral blood flow. Thus administration of 100% O2 during carotid cross-clamping may be beneficial for all patients undergoing CEA.

Psychiatric symptoms attributable to vitamin B12 deficiency have been described for decades. The earlier reports are for the most part in accord with more recent ones, despite being diagnostically less specific in psychiatric and hematologic terms. These symptoms seem to fall into several clinically separate categories: slow cerebration; confusion; memory changes; delirium, with or without hallucinations and/or delusions; depression; acute psychotic states; and (more rarely) reversible manic and schizophreniform states. While there still remain abundant hematologic, psychiatric, neurologic, or nutritional reasons for obtaining a serum vitamin B12 level, its use in the investigation of the etiology of a patient's dementia seems unjustified. However, acute or subacute changes in a demented patient's mental status, specifically a clouding of their consciousness, may make such testing advisable as part of the complete workup of their delirium regardless of a normal hematologic picture.

Eighty-one patients admitted for minor surgery were followed with questionnaires and self-rating scales in the pre- and post-anesthetic period to evaluate the effect of giving either routine or detailed information. The patients were randomly allocated to two groups and received either routinely given information by the anesthetist for about 5 min or more detailed information for at least 20 min. The patients' experience of the effect of the preanesthetic visit was tranquillizing and adequate in both groups. The most significant difference with detailed information was a smaller number of side-effects like slow cerebration, nausea and a general feeling of discomfort compared to the routinely informed patients. Repetitive ratings on Spielberger's State of Anxiety Scale showed that the patients who had had previous anesthetic experience were less influenced by the degree of information given. In view of the considerable numbers of parameters investigated, there were relatively few significant differences between the groups, and it was concluded that there was no convincing benefit from expanding routine to detailed information.

We studied the effects of acute, isovolemic hemodilution on the exercise ability and mental function of four polycythemic mountain climbers (mean hematocrit 58 +/- 1.25%) during the American Medical Research Expedition to Mt. Everest (AMREE). The subjects were studied at 5400 m (PB = 400 mm Hg). Approximately 15% of their blood volume was removed and replaced with an equal volume of 5% human albumin solution. Final hematocrits were 50.5 +/- 1.5%. Before and after hemodilution, the subjects performed psychological and exercise tests. Maximum work level, oxygen uptake, minute ventilation, and blood oxygen saturation did not change. After hemodilution, heart rate increased slightly at all work levels, and there was a small but significant improvement on the psychological tests. It is concluded that this degree of hemodilution was well tolerated and that a hematocrit of greater than 50% conferred no advantage for exercise and may have impaired cerebral function. Although, in these circumstances, isovolemic hemodilution improved cerebration, we feel that this potentially hazardous maneuver is rarely indicated.

Cardiopulmonary resuscitation and rewarming were successful in a 5-year-old boy who had been submerged for 40 minutes in ice-cold fresh water. Severe metabolic acidosis was corrected by intravenous infusion of sodium bicarbonate solution before spontaneous circulation could be re-established. Fulminant pulmonary oedema developed after re-establishment of spontaneous circulation. This was efficiently reversed by positive-end-expiratory-pressure ventilation. During 2 days of treatment of a respiratory the patient gradually regained consciousness; the endotracheal tube was then removed and the patient immediately started talking intelligently. The patient went through a period of slow cerebration and motor dysfunction but recovered rapidly, and on examination 13 months after the accident all findings were normal.