Biomedical subjects

Christina M. Thorpe

Publications and source records attributed to Christina M. Thorpe.

3 recordsLinked to original sources

PubMed2003

Rats have trouble associating all three parts of the time-place-event memory code.

The ability of animals to associate an event with predictable time and place information confers a major biological advantage. The current research uses a variety of procedures and paradigms (e.g. place preference, radial arm maze, Morris water maze, T-maze, go no-go) to show that rats, unlike pigeons [e.g. Anim Learn Behav 22 (1994) 143] do not readily make an event-time-place association. They do make associations between event-time and event-place information, however. These findings are in disagreement with Gallistel's (The Organization of Learning, MIT Press, Cambridge, MA ) theory that claims that animals automatically store a memory code that has these three pieces of information. The present research is in line with the work of others who also find that rats do not readily make daily time-place associations [Behav Processes 23 (1997) 232; Behav Processes 52 (2000) 11; Behav Processes 49 (2000) 21; Anim Learn Behav 28 (2000) 298]. An interesting finding that did emerge from the present research was that at least some rats can use a circadian timer to solve a time-of-day discrimination if the task is a go no-go discrimination.

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PubMed2002

Unequal interval time-place learning.

In time-place learning tasks food availability depends upon both spatial and temporal variables. For example, food might be first available at location one, then location two, then location three, and finally location four. To date, the duration of food availability at each of the locations have been identical (e.g. for 4 min). The major purpose of the present experiment was to determine if rats can successfully learn a time-place task in which four locations provided food for different durations. Lever 1 intermittently produced food for 6 min, then Lever 2 produced food for 4 min. Lever 3 and 4 provided food for 2 and 8 min, respectively. Rats were able to learn this unequal interval time-place task. However, their behavior on this unequal interval time-place task was not in agreement with Scalar Expectancy Theory/Weber's Law.

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PubMed2002

How rats process spatiotemporal information in the face of distraction.

How rats process spatiotemporal information in the face of distraction was assessed. Rats were trained on a time-place learning task in which the location of food availability depended on the amount of time elapsed since the beginning of the training session. In each training session each of four levers provided food pellets for 5 min on an intermittent schedule. In probe sessions interspersed with the final training sessions, the rats were presented with a second highly preferred food source-a piece of cheese-at various times into the session. Rats choose the correct lever after the cheese distraction, but it appeared that their internal clock had stopped during the cheese consumption period. Thus rats' internal clock, like that of pigeons, displays the properties of 'stop', 'reset', and 'restart'. Rat-pigeon differences in timing processes may be restricted to circadian or time of day timing. Present results also suggest that rats process spatial and temporal information separately.

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