Discrimination In Pigeons Research Articles

The influence of hippocampal lesions on the discrimination of structure and on spatial memory in pigeons (Columba livia).

Pigeons (Columba livia) were trained with a spatial structural discrimination, which was based on the spatial relationship among the components of a pattern, and a feature-binding structural discrimination, which was based on how different visual features within a pattern were combined. Neither discrimination was impaired by damage to the hippocampus and area parahippocampalis. The lesions impaired performance on a spatial working memory and a spatial reference memory task in open field. The results indicate an intact hippocampus is not essential for the solution of structural discriminations in pigeons and the hippocampus is important for processing some types of spatial information--that used in navigation, but not other types--that used in spatial structural discriminations.

Effects of Wulst and ectostriatum lesions on repeated acquisition of spatial discrimination in pigeons

The avian telencephalon has two visual areas, (1) a ‘Wulst’ that consists of hyperstriatum accessorium, hyperstriatum intercalatus superior and hyperstriatum dorsale, and (2) the ectostriatum. Deficits in visual discrimination have been observed after ectostratal lesions but not after Wulst lesions. In the present experiments, the cognitive functions of the Wulst in pigeons were examined. Pigeons were trained on repeated acquisition of a three key discrimination. Every time the subjects reached the criterion of discrimination, they were trained on different discriminations in which one of two previously incorrect keys became the correct key. The Wulst lesions disrupted the acquisition of discrimination, while the ectostriatal lesions did not.

Effects of hippocampal lesions on conditional spatial discrimination in pigeons

Pigeons were trained on a conditional spatial discrimination with a three-key operant chamber. The position of the correct key was left when all the keys were red, center when all the keys were green, and right when all the keys were white. Pigeons with hippocampal damages could learn the task, as well as intact birds and those that received hippocampal lesions after acquisition of the task. These results suggest that the pigeon hippocampus does not play a role in conditional spatial discrimination.

Imitation of conditional discriminations in pigeons ( Columba livia).

Imitation of conditional discriminations in pigeons ( Columba livia).

Imitation of conditional discriminations in pigeons (Columba livia).

In the present experiments, the 2-action method was used to determine whether pigeons could learn to imitate a conditional discrimination. Demonstrator pigeons (Columba livia) stepped on a treadle in the presence of 1 light and pecked at the treadle in the presence of another light. Demonstration did not seem to affect acquisition of the conditional discrimination (Experiment 1) but did facilitate its reversal of the conditional discrimination (Experiments 2 and 3). The results suggest that pigeons are not only able to learn a specific behavior by observing another pigeon, but they can also learn under which circumstances to perform that behavior. The results have implications for proposed mechanisms of imitation in animals.

Four-choice drug discrimination in pigeons.

(+)Amphetamine was added as a training stimulus for pigeons previously trained to discriminate among pentobarbital, morphine and saline using a three-choice procedure. Pigeons quickly learned the four-choice drug discrimination. Generalization from the training drugs was similar to that established with simpler drug discriminations; pentobarbital generalized to chlordiazepoxide, morphine generalized to methadone, and (+)amphetamine generalized to cocaine and methamphetamine. Low doses of phencyclidine generalized to saline, while higher doses partially generalized to pentobarbital and (+)amphetamine. When dose-response curves were redetermined with a cumulative-dosing procedure, the same pattern of generalization occurred as under single-dose procedures. Dose-response curves were quantal under both the single-dose and the cumulative-dosing procedures. The four-choice procedure offers some important advantages for studying the discriminative stimulus effects of drugs that interact with multiple receptor subtypes and for studying drug mixtures.

Van Gogh, Chagall and pigeons: picture discrimination in pigeons and humans.

The author has previously reported that pigeons can discriminate paintings by different artists. Here, I replicated the previous findings, carried out additional tests and compared discrimination by pigeons with that of humans. In Experiment 1, pigeons were trained to discriminate between paintings by Van Gogh and Chagall. After training, the subjects were tested with different paintings by the same artists. The subjects showed generalization to these paintings. The subjects maintained their discriminative ability for black-and-white paintings and partially occluded paintings. When they were tested with mosaic paintings, the number of correct responses decreased, depending on the level of processing needed. In Experiment 2, human subjects were tested with the same paintings. The subjects showed generalization and decrement of correct responses depending on the degree of mosaic processing. These observations suggest that the visual cognitive function of pigeons is comparable to that of humans. The convergence of higher visual cognition between the two species may stem from similar selection pressures on avian ancestors and our ancestors through their evolution.

Three-choice discrimination in pigeons is based on relative efficacy differences among opioids.

Drug discrimination assays can provide important information on receptor selectivity and relative efficacy to guide the classification and characterization of opioid agonists. A three-choice discrimination was established among high efficacy opioid agonist morphine, low efficacy opioid agonist nalbuphine, and saline to examine the conditions under which differences in relative efficacy might serve as a basis for stimulus control. Seven White Carneau pigeons were trained to discriminate among 5.6 mg/kg nalbuphine, 3.2 mg/kg morphine, and saline under fixed ratio 30 (FR30) schedules of food reinforcement. Substitution and antagonism experiments were then conducted with mu, kappa, and delta opioids and naltrexone, respectively and the percent responding appropriate to the training stimuli was determined. Low, intermediate, and high doses of morphine produced > or = 80% saline-, > or = 60% nalbuphine-, and > or = 96% morphine-appropriate responding, respectively. Low and high doses of nalbuphine produced > or = 80% saline- and nalbuphine-appropriate responding, respectively. In substitution tests, low doses of fentanyl and etorphine produced partial nalbuphine-appropriate responding (20-60%) and high doses produced > or = 60-80% morphine-appropriate responding. Intermediate doses of buprenorphine and dezocine produced > or = 60-80% nalbuphine-appropriate responding and high doses produced > or = 80% morphine-appropriate responding. The lower efficacy agonists butorphanol, nalorphine, and levallorphan produced > or = 40-80% nalbuphine-appropriate responding. The kappa agonists spiradoline and U50,488 produced approximately > or = 50% nalbuphine-appropriate responding whereas d-amphetamine, saline, and delta agonists BW373U86 and SNC 80 produced > or = 80% saline-appropriate responding. Naltrexone produced > or = 80% saline-appropriate responding and reversed the stimulus effects of morphine and nalbuphine. The discrimination between morphine and nalbuphine in pigeons is predominantly based on the relative efficacy differences between morphine, a higher-efficacy mu agonist and nalbuphine, a lower-efficacy mu agonist.

Effects of hippocampal lesions on repeated acquisition of spatial discrimination in pigeons

Anatomical studies of avian hippocampus suggest this structure is a counterpart of that of mammals, and allometric studies of food storing birds support the idea that the avian hippocampus has spatial cognitive functions. In the present study, the spatial cognitive function of hippocampus in pigeons was examined by lesion experiments. Pigeons were trained on either a spatial discrimination, or a spatial discrimination with an added color cue, using a repeated acquisition procedure. In the spatial task, the pigeons were trained to discriminate the position of three keys. Each time the subjects reached the criterion, they were trained on different discriminations in which one out of two previously incorrect keys became the correct key. In the task with color added, each key had its own color, so the subject had both spatial and color cues for the discrimination. The hippocampal lesions disturbed the acquisition of the spatial discrimination, but not in the task in which color cues were added. These results suggest that the avian hippocampus have a crucial role in acquisition of spatial discriminations.

Effects of Lobus parolfactorius Lesions on Repeated Acquisition of Spatial Discrimination in Pigeons

The basal part of the avian telencephalon can be divided into the paleostriatum augmentatum, paleostriatum primitivum and lobus parolfactorius (LPO). In the present experiments, the cognitive functions of the LPO in pigeons were examined. Pigeons were trained on spatial discrimination with or without added color cues using a repeated acquisition procedure. The discrimination task was a choice of three keys in an operant chamber. Every time the subjects reached the criterion, they were trained on a different discrimination in which one of two previously incorrect keys became the correct key. In the task with added color each key had a unique color (i.e., color discrimination). The LPO lesions disrupted the acquisition of both the spatial discrimination and the discrimination with added color. Birds with LPO damage emitted many errors in the first trial indicating the preservation of a previously correct response. Thus, the LPO lesions caused cognitive rigidity. These results are consistent with clinical observations of patients with basal ganglia disorders.

The pigeon's discrimination of shape and location information

Two groups of pigeons (n = 4) were trained with 16 line drawings portraying a fixed shape and a variable shape. The four variable shapes (a wedge, a cone, a cylinder, and a handle) appeared to the left of, to the right of, above, or below the fixed shape (a cube). Group Shape (S) was required to discriminate the identity of the variable shape that was mated with the cube, whereas Group Location (L) was required to discriminate where the variable shape appeared relative to the cube. Three of the four pigeons in each group mastered their respective tasks. Later tests revealed that the two groups of pigeons had attended to different aspects of the shape pairs, even though the visual stimuli and general procedures they had been given were the same. Group S had attended to the identity of the variable shape and had ignored the identity and location of the cube, whereas Group L had attended to the configuration of the two shapes. The methods and stimuli could be useful in delineating the biological bases of shape and location perception.

Display variability and spatial organization as contributors to the pigeon's discrimination of complex visual stimuli.

Three experiments assessed the contributions of display variability and spatial organization to the pigeon's discrimination of 16-icon visual displays. After training to discriminate 4 x 4 arrays of same and different computer icons, 4 pigeons were shown testing displays that systematically manipulated the variability of the depicted icons and their spatial organization on the display screen. Display variability and spatial organization each reliably controlled the pigeon's behavior. These seemingly separate effects could be collectively explained by the pigeon's discriminating the amount of variability or entropy in localized regions of the display.

Display variability and spatial organization as contributors to the pigeon's discrimination of complex visual stimuli.

Display variability and spatial organization as contributors to the pigeon's discrimination of complex visual stimuli.

Effects of hippocampal lesions on spatial operant discrimination in pigeons

In experiment 1, pigeons were trained on spatial or color autodiscrimination. Presentation of one of two keys or one of two colors was followed by food presentation. However, the other side of the keys or the other color was not. The hippocampal lesions disturbed the acquisition of spatial discrimination but not of color discrimination. In experiment 2, pigeons were preoperatively trained the spatial autodiscrimination, then received the hippocampal lesions. The subjects maintained the discrimination. These results suggest that the avian hippocampus plays a crucial role in acquisition of spatial discrimination.

Discrimination of “Four” and “Two” by Pigeons

Two pigeons learned to respond to four objects while withholding response to two objects. The birds maintained their numerical discrimination when new objects were introduced. They also maintained the discrimination when large and small objects were used to construct "2" and "4," and when different kinds of objects were mixed to make "2" and "4 ." The subjects responded most often to four objects when tested with one, two, three, four, and five objects in the generalization test after fourth discrimination task. These results suggest the ability of numerical discrimination in pigeons. Two other birds that were trained to peck two objects but not to peck four objects showed, however, severe difficulty in learning this task. Thus, pigeons' ability for numerical discrimination is affected by training procedure.

Visual Discrimination in Pigeons Impaired by Glutamatergic Blockade of Nucleus Accumbens

Gargiulo, P. A., M. Siemann and J. D. Delius. Visual discrimination in pigeons impaired by glutamatergic blockade of nucleus accumbens. Physiol. Behav. 63(4) 705–709, 1998. The nucleus accumbens septi (Acc) is thought to be involved in the control of cognitive processes and to be implicated in the pathophysiology of schizophrenia. Because perceptual-cognitive distortions are a core symptom in schizophrenia, any evidence that the Acc intervenes in a sensory recognition task in an animal species would be of interest. Pigeons were instrumentally trained to discriminate visual shapes. The acute effects of drug microinjections into the Acc on the discrimination of the training shapes, on the correction responding after errors, and on the generalisation to different shapes were examined. The effects of conduction blockade with lidocaine, glutamatergic blockade with 7-aminophosphonoheptanoic acid, and dopaminergic stimulation with apomorphine on behavioural performance were tested. No effects were observed with lidocaine and apomorphine. A significant and reversible performance disruption to near chance levels was obtained after aminophosphonoheptanoic acid injections into the Acc. It appears that a glutamatergic blockade of the Acc interferes with the visual discrimination processes of pigeons.

Effects of number of items on the pigeon's discrimination of same from different visual displays.

The pigeon's discrimination of visual displays comprising from 2 to 16 computer icons that were either the same as or different from one another was studied. Discrimination of Same from Different displays improved when the displays contained more icons, both after training with just 16-icon displays (Experiment 1) and after training with 2-, 4-, 8-, 12-, and 16-icon displays (Experiment 2). That improvement was specific to displays of different icons; accuracy to displays of same icons did not differ as a function of icon number. These results were well described by the degree of variability or entropy in multielement visual displays.

Same–different texture discrimination in pigeons: Testing competing models of discrimination and stimulus integration.

Same–different texture discrimination in pigeons: Testing competing models of discrimination and stimulus integration.

Effects of number of items on the pigeon's discrimination of same from different visual displays.

Effects of number of items on the pigeon's discrimination of same from different visual displays.

Error factors in pigeon discrimination and delayed matching.

Error factors in pigeon discrimination and delayed matching.