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K Laughlin

Publications and source records attributed to K Laughlin.

5 recordsLinked to original sources
PubMed2000

Pigs shift too: foraging strategies and spatial memory in the domestic pig.

In a previous experiment, we showed that domestic pigs, Sus scrofa, unlike many other species, performed accurately in a spatial memory task, where visits to a previously baited food trough were rewarded (win-stay). We investigated whether pigs have a predisposition for this strategy, by comparing their performance in a radial arm maze under either win-stay (N=10) or win-shift (N=10) reward contingencies. Contrary to our earlier results, only one of the animals in the win-stay condition was able to reach the imposed criterion level of accuracy. The performances of the other win-stay pigs did not deviate from random. All pigs in the win-shift condition reached criterion by day 25 of the experiment, and performed better than expected by chance. Analysis of the types of errors made matched our a priori predictions that shift movements would occur more frequently, especially within visits to the maze. We suggest that the difference in learning rates may reflect the fact that win-stay pigs needed to use two different rules, stay between trials and shift within trials, while win-shift pigs only needed to use the shift rule. In our previous study, win-stay pigs did not experience a conflict of rules and this may have facilitated stay learning. We found evidence of a recency effect in win-shift animals and a primacy effect in the win-stay group. However, we discuss the unsuitability of these specific terms in this type of experiment, and propose an alternative interpretation of the results. Copyright 2000 The Association for the Study of Animal Behaviour.

Journal Article↗
PubMed1997

Pigs in space: spatial memory and its susceptibility to interference.

This study provided basic information about spatial memory in the domestic pig, Sus scrofa and examined how susceptible it is to disruption by environmental stimuli. Eight male pigs were tested individually in a foraging arena. Each day, they entered the arena to search for food randomly located in one of 10 enclosed areas (search trial). After finding and eating the food, they were removed from the arena for a retention interval, and then allowed back in to relocate the food in the same area as previously (relocation trial). Once pigs had achieved a criterion level of performance in relocation trials, 'disturbances' (e.g. isolation, novel food source, novel spatial environment) were presented during the retention interval. Disturbance days were separated by control days on which no disturbance was presented. During search trials, pigs did not use food-related cues to locate food, but appeared to use memory to search systematically and avoid revisits to empty areas. During relocation trials, they found food using fewer area visits than expected by chance, indicating that they could remember the location of food across both 10-min and 2-h retention intervals. Disturbances administered during 10-min retention intervals resulted in more relocation errors than on corresponding control days, indicating that spatial memory in pigs is susceptible to interference by relatively mild environmental stimuli, in contrast to that in rats, Rattus norvegicus and pigeons, Columba livia which appears to be highly resistant to retroactive interference even when potent stimuli are used. Analysis of error locations suggested that disturbances probably acted to increase the general area in which the pig remembered the food to be located, and so reduced accuracy of memory without eradicating it. There was no evidence that errors made during relocation trials represented sampling of areas not visited during the preceding search trial.Copyright 1997 The Association for the Study of Animal Behaviour

Journal Article↗
PubMed1986

Urinary polyamines in colorectal cancer.

Urine polyamine content is increased in patients with colorectal malignancy and may be a useful tumor marker in the management of these patients. Urinary excretion of putrescine and spermidine was measured preoperatively and in the first week postoperatively in nine patients with inflammatory bowel disease, eight with other benign colorectal disease, and 13 with colorectal cancer. Preoperative urine putrescine levels were elevated similarly in patients with inflammatory bowel disease and malignancy. Polyamine levels were increased in all three groups in the early postoperative period. Urinary polyamine excretion did not correlate with serum CEA levels, tumor volume, or stage of disease in patients with cancer. Because elevated levels of urinary polyamines are not specific for malignancy and do not correlate with other prognostic indicators, such measurements are unlikely to be useful in tumor detection and determining prognosis. Polyamine levels, however, may prove useful in monitoring response to therapy and detecting recurrences in individual patients.

Adult↗
PubMedDate not supplied

Relationship of jejunostomy and urine polyamine content to refeeding and intestinal structure and function.

The polyamine content of the intestinal mucosa is increased with mucosal proliferation. Our purpose was to determine if urine and jejunostomy polyamine content increases after refeeding and correlates with intestinal length and carbohydrate absorption after intestinal resection. Five patients with intestinal remnant lengths ranging from 1.5 to 8 feet after intestinal resection and jejunostomy formation were studied after refeeding of an elemental diet. Mean putrescine and spermidine levels in the jejunostomy effluent but not in the urine increased significantly after refeeding (p less than 0.05). These changes correlated with intestinal remnant length and carbohydrate absorption. Carbohydrate absorption correlated with polyamine levels in a single patient studied longitudinally. The polyamine content of intestinal fluid may serve as a marker of the status of the intestinal mucosa and may prove useful in the dietary management of individuals with the short bowel syndrome.

Adult↗