Ventilatory conditioning by self-stimulation in rats: A pilot study

International audience; This article describes an experimental attempt to condition breathing pattern in rats. In this experiment, a freely moving rat was first rewarded by an electrical stimulation of the medial forebrain bundle whenever inspiratory duration (TI) exceeded 300 ms. A bidirectional control was then used: TIs longer than 400 ms were rewarded, and then TIs shorter than 300 ms were rewarded. The frequency of TIs longer than 300 ms increased when this event was rewarded, further increased when TIs above 400 ms were rewarded, and decreased during reversal conditioning (TI < 300 ms). At the beginning of the experiment, stimulation caused increased arousal and motor activity, but af…

Implicit learning shapes new conscious percepts and representations

We present here the lineaments of a new account of implicit learning, an account that does not rely on the notion of “implicit knowledge.” In this account, improved performance depends on the action of unconscious mechanisms that structure the phenomenal, conscious experience of the world. This integrative view makes groundless the search for dissociations between conscious and unconscious influences that has been at the core of the research on implicit learning and memory. We contrast this view, on the one hand, to Dienes and Berry’s (1997) proposal, which defines implicit learning by analogy with subliminal perception, and, on the other, to Neal and Hesketh’s (1997) episodic account, in w…

Abstraction of covariations in incidental learning and covariation bias

Experiment 1 was devised to distinguish, in a given set of features composing drawn robots, those whose variations were related a priori for participants from those whose variations were a priori independent. In Expt 2, correlations were experimentally induced between a priori-related features for one group of participants (pre-primed group), and between a priori-independent features for another group {arbitrary group), in incidental learning conditions. A subsequent transfer phase revealed that participants' performances were sensitive to experimentally induced correlations in both groups. However, only the performances of the pre-primed group accurately matched the predictions of a statis…

The effect of attentional load on the breathing pattern in children.

Abstract Experiments designed to establish the effects of video games on breathing patterns have led to contradictory results. Several authors reported that video games tended to increase breathing frequency (i.e. to reduce breath duration), whereas others reported the opposite. We postulated that video games contain different psychophysiological components which may have opposite effects on breathing pattern. On the one hand, arousal and emotion may tend to stimulate breathing. On the other, focusing attention on the game may prompt subject to inhibit any movement — including breathing — which might be a potential nuisance variable. The aim of this study was to assess the specific effects …

Carbohydrate Antigen-125–Guided Therapy in Acute Heart Failure

Abstract Objectives This study sought to evaluate the prognostic effect of carbohydrate antigen-125 (CA125)–guided therapy (CA125 strategy) versus standard of care (SOC) after a hospitalization for acute heart failure (AHF). Background CA125 has emerged as a surrogate of fluid overload and inflammatory status in AHF. After an episode of AHF admission, elevated values of this marker at baseline as well as its longitudinal profile relate to adverse outcomes, making it a potential tool for treatment guiding. Methods In a prospective multicenter randomized trial, 380 patients discharged for AHF and high CA125 were randomly assigned to the CA125 strategy (n = 187) or SOC (n = 193). The aim in th…

Do Dogs Know Related Rates Rather than Optimization?

(2006). Do Dogs Know Related Rates Rather than Optimization? The College Mathematics Journal: Vol. 37, No. 1, pp. 16-19.

Effects of voluntary changes in breathing frequency on respiratory comfort

Previous experiments on voluntary breathing have suggested that spontaneous breathing is partly determined by the minimization of respiratory sensations. However, during instructed breathing, respiratory sensations may be confounded with difficulty in achieving the prescribed pattern. In the present experiment, we tested the hypothesis that the subjective assessment of respiratory comfort and the difficulty in following breathing instructions are closely related. A total of 15 subjects adjusted breathing frequency to prescribed values ranging from 40 to 250% of individual spontaneous levels. Then, they scored the difficulty of this task and the discomfort associated with the target frequenc…

Ventilatory responses to imagined exercise.

We studied whether the ventilatory responses to imagined exercise are influenced by automatic processes. Twenty-nine athletes produced mental images of a sport event with successive focus on the environment, the preparation, and the exercise. Mean breathing frequency increased from 15 to 22 breaths/min. Five participants reported having voluntarily controlled breathing, two of them during preparation. Twenty participants reported that their breathing pattern changed during the experiment: 11 participants were unable to correctly report on the direction of changes in frequency, and 13 incorrectly reported changes in amplitude. This finding suggests that these changes were not voluntary in mo…

Classic conditioning of the ventilatory responses in rats

Nsegbe, Elise, Guy Vardon, Pierre Perruchet, and Jorge Gallego. Classic conditioning of the ventilatory responses in rats. J. Appl. Physiol. 83(4): 1174–1183, 1997.—Recent authors have stressed the role of conditioning in the control of breathing, but experimental evidence of this role is still sparse and contradictory. To establish that classic conditioning of the ventilatory responses can occur in rats, we performed a controlled experiment in which a 1-min tone [conditioned stimulus (CS)] was paired with a hypercapnic stimulus [8.5% CO2, unconditioned stimulus (US)]. The experimental group ( n = 9) received five paired CS-US presentations, followed by one CS alone to test conditioning. Th…

The formation of structurally relevant units in artificial grammar learning

A total of 78 adult participants were asked to read a sample of strings generated by a finite state grammar and, immediately after reading each string, to mark the natural segmentation positions with a slash bar. They repeated the same task after a phase of familiarization with the material, which consisted, depending on the group involved, of learning items by rote, performing a short term matching task, or searching for the rules of the grammar. Participants formed the same number of cognitive units before and after the training phase, thus indicating that they did not tend to form increasingly large units. However, the number of different units reliably decreased, whatever the task that…

What about unconscious processing during the test?