Several Days Of Training Research Articles

Transient suppression of processing during rapid serial visual presentation: Acquired distinctiveness of probes modulates the attentional blink

The attentional blink is revealed in studies of rapid serial visual processing, in which observers view a stream of letters presented sequentially at the same location in a visual display. Reporting the identity of a specially marked letter (the target) amidst distractors causes a transient loss of accuracy for detection of another prespecified symbol (the probe). In two experiments, observers viewed lists of letters, identified a randomly selected letter as a target, and detected the presence of a probe from a different category (a digit or a Greek letter). After several days of training, probe detection following a target had improved markedly. Posttarget probe detection was again impaired when the distractor set included members of the probe set. These results are compatible with an explanation of the attentional blink as an act of suppression aimed at the current set of distractors, but additional mechanisms are needed to account for the effects of training.

Flavor preference produced by intragastric polycose infusions in rats using a concurrent conditioning procedure

Prior studies demonstrate that nondeprived rats learn to prefer a flavor (the CS+) paired with intragastric (IG) nutrient infusions over another flavor (the CS−) paired with IG water infusions when the flavors are presented on alternate days. The present experiment determined if a nutrient-based preference could be established when both flavors were concurrently available. Adult female rats were fitted with two chronic gastric catheters and were given ad lib access to chow and two flavored solutions (a bitter sucrose octaacetate solution and a sour citric acid solution). Using an automated infusion system, consumption of the CS+ flavor was paired with IG infusions of 32% Polycose, and consumption of the CS− flavor was paired with IG infusions of water. Seven of the eight rats tested developed a strong flavor preference for the CS+ over the CS−; their CS+ preference increased from 53% on day 1 to 95% on day 8. (The remaining animal eventually displayed a 97% CS+ preference after it received one-bottle training with the CS flavors.) During the first several days of training, the rats tended to drink primarily one flavor per day, and consumed primarily one flavor per drinking bout. This provided them with relatively discrete flavor-consequence experiences that presumably facilitated flavor preference conditioning.

Auditory evoked responses to names for different objects: Cross-modal processing as a basis for infant language acquisition.

Evoked potential techniques were used to study the acquisition of names for different objects in 14-month-old infants. Auditory evoked responses (AERs) were recorded from each infant by scalp electrodes positioned over frontal, temporal, and parietal regions of each hemisphere before and after several days of training in which nonsense consonant-vowel-consonant-vowel bisyllables were used by parents to consistently name novel objects. Analyses of the AERs collected during the posttraining session indicated that two portions of the brain response discriminated a versus a occurring between the auditorily presented names and the objects held by the infants. Specifically, an early occurring portion of the AER recorded from bilaterally placed frontal electrodes and a late occurring response detected at only the left hemisphere electrode sites discriminated between situations when a match occurred between the object and its name versus those in which there was a mismatch between the name and object. No such differences were found in the pretraining AER data. Results are viewed as a preliminary step in the neuropsychological study of word concept development using electrophysiological measures.

Olfactory discrimination learning is blocked by Leupeptin, a thiol protease inhibitor

Rats were trained on successive two-odor discriminations with the cues randomly located in an 8-arm radial maze. After several days of training using different odor pairs, the thiol protease inhibitor leupeptin was infused into the ventricles and testing continued. Leupeptin caused a pronounced, dose-dependent and reversible deficit in performance in this task. Previous studies have shown that these drug concentrations do not influence spontaneous activity, feeding and drinkin, or the acquisition and retention of avoidance conditioning. The results are interpreted as supporting the hypothesis that a calcium-sensitive proteinase is involved in certain forms of memory that require modification of telencephalic circuitries.

Gradual increase vs. constant-intensity shock during rabbit heart rate conditioning

In an attempt to delineate some aspects of heart rate conditioning anomolies, 40 New Zealand albino rabbits were subjects in a classical discrimination conditioning study employing a pulsed tone for a conditioned stimulus and an electric shock as an unconditioned stimulus. A 2 by 2 factorial design used two different shock intensities of 6 and 14 mA and two different conditions of shock administration, gradual increase of intensity, and constant intensity. The conditioned heart rate response was measured by comparing the heart rate for 10 beats preceding the tone onset with the rate for 10 beats following the tone onset during interpolated test trials. No differences among the four groups were found in discrimination ability, nor were there any differences between the 6- and 14-mA groups for either shock administration condition. Both constant shock groups, however, showed significantly larger decelerator heart rate responding during the first several days of training, but this responding decreased rapidly to the same relatively stable level of responding exhibited by the gradual increase groups.

Temperature-dependent learning in goldfish: A multi-trial active avoidance situation

Two experiments examined the rate of acquisition of a conditioned avoidance response in goldfish ( Carassius auratus ) over several days of training (3), temperatures (12.8–24.9°C), and intertrial interval conditions (10–60 sec). In the first experiment ( n = 543) avoidance rate was found to vary positively with temperature and days of training, but not with intertrial interval. But general activity rate also was related to the same variables. Experiment 2 ( n = 270) shows that the acquisition of the conditioned avoidance response in the first experiment cannot be interpreted as a pseudoconditioning effect.

Serum glycoproteins and physical exercise

Changes in serum levels of protein-bound hexoses, α 2-macroglobulins, transferrin and γM-globulins were studied after one hour of physical stress, after a night's rest, following several days of training in athletes and in normal controls. A significant rise in the levels of the proteins studied (with the exception of the γM-globulins) was observed following one hour of work on the ergometer (170 W). During the training period and competitions, aihletes had elevated serum values of the bound hexoses, transferrin and α 2-macroglobulins.

The positive and negative learning process in Octopus vulgaris Lamarck. Influence of the vertical and median superior frontal lobes

1. A hypothesis for the function of the vertical and the median superior frontal lobes of Octopus vulgaris has been investigated, using new methods for analysing the attacks upon a prey (a crab or a figure). The advance of the animal towards its prey and the total time taken to attack have been divided into three parts: a) when the animal leaves its home (first time delay, FTD). b) when it crosses the mid-way line (D1 time) and c) when it catches the prey (D2 time). 2. The animals were taught to attack one figure and also a crab attached to a bar (CAB) but to avoid another figure. After several days of training the animals underwent an operation. In one group of animals the vertical lobe was removed (NVL group), and in the other group the median superior frontal lobe (NMF group). 3. From the results obtained before operation some characteristic features of the performance of the normal octopus became apparent. The crab attached to a bar is a more positive complex than the positive figure and this superiority was not overcome during training. The performance with positive complexes (figures or crabs) is very “sensitive” to shocks received when the animals attacked negative complexes. A long positive training (without negative trials) led to a high general level of attack, irrespective of the complex presented. 4. After removal of either the vertical or the median superior frontal lobe the performance with the crab attached to a bar was impaired. The NVL group showed a better performance than the NMF group. The NVL group attacked more often and more quickly, with shorter FTD and D1 time and revealed a complete insensivity to punishment. No difference between the groups appeared either with the positive or the negative figure. The correlation between these results and the hypothesis on the function of the lobes put forward elsewhere is discussed. 5. Animals in which the subvertical or lateral superior frontal lobes were damaged during the operation did not attack any complex. They were able to take a prey when placed between their arms or extremely close to their home. 6. The distance home-goal has been shown to be a very important factor in eliciting an attack. Reduction of this distance seems to be good method to reveal a real content of memory that would otherwise remain masked. Further studies on the way in which this parameter influences the attack are necessary.