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Author (up) Merchant, H.; Fortes, A.F.; Georgopoulos, A.P. doi  openurl
  Title Short-term memory effects on the representation of two-dimensional space in the rhesus monkey Type Journal Article
  Year 2004 Publication Animal Cognition Abbreviated Journal Anim. Cogn.  
  Volume 7 Issue 3 Pages 133-143  
  Keywords Analysis of Variance; Animals; Discrimination Learning/*physiology; Macaca mulatta; Male; Memory, Short-Term/*physiology; Mental Processes/*physiology; Pattern Recognition, Visual/*physiology; Space Perception/*physiology  
  Abstract Human subjects represent the location of a point in 2D space using two independent dimensions (x-y in Euclidean or radius-angle in polar space), and encode location in memory along these dimensions using two levels of representation: a fine-grain value and a category. Here we determined whether monkeys possessed the ability to represent location with these two levels of coding. A rhesus monkey was trained to reproduce the location of a dot in a circle by pointing, after a delay period, on the location where a dot was presented. Five different delay periods (0.5-5 s) were used. The results showed that the monkey used a polar coordinate system to represent the fine-grain spatial coding, where the radius and angle of the dots were encoded independently. The variability of the spatial response and reaction time increased with longer delays. Furthermore, the animal was able to form a categorical representation of space that was delay-dependent. The responses avoided the circumference and the center of the circle, defining a categorical radial prototype around one third of the total radial length. This radial category was observed only at delay durations of 3-5 s. Finally, the monkey also formed angular categories with prototypes at the obliques of the quadrants of the circle, avoiding the horizontal and vertical axes. However, these prototypes were only observed at the 5-s delay and on dots lying on the circumference. These results indicate that monkeys may possess spatial cognitive abilities similar to humans.  
  Address Brain Sciences Center (11B), Veterans Affairs Medical Center, One Veterans Drive, MN 55417, Minneapolis, USA  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1435-9448 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:14669074 Approved no  
  Call Number Equine Behaviour @ team @ Serial 2548  
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Author (up) Zentall, T.R.; Clement, T.S.; Bhatt, R.S.; Allen, J. openurl 
  Title Episodic-like memory in pigeons Type Journal Article
  Year 2001 Publication Psychonomic bulletin & review Abbreviated Journal Psychon Bull Rev  
  Volume 8 Issue 4 Pages 685-690  
  Keywords Animals; Behavior, Animal/physiology; Columbidae; Memory, Short-Term/*physiology; Teaching  
  Abstract It has been proposed that memory for personal experiences (episodic memory, rather than semantic memory) relies on the conscious review of past experience and thus is unique to humans. In an attempt to demonstrate episodic-like memory in animals, we first trained pigeons to respond to the (nonverbal) question “Did you just peck or did you just refrain from pecking?” by training them on a symbolic matching task with differential responding required to the two line-orientation samples and reinforcing the choice of a red comparison if they had pecked and the choice of a green comparison if they had not pecked. Then, in Experiment 1, after providing the conditions for (but not requiring) the pigeons to peck at one new stimulus (a yellow hue) but not at another (a blue hue), we tested them with the new hue stimuli and the red and green comparisons. In Experiment 2, we tested the pigeons with novel stimuli (a circle, which they spontaneously pecked, and a dark response key, which they did not peck) and the red and green comparisons. In both experiments, pigeons chose the comparison appropriate to the response made to the test stimulus. Thus, the pigeons demonstrated that they could remember specific details about their past experiences, a result consistent with the notion that they have the capacity for forming episodic-like memories.  
  Address Department of Psychology, University of Kentucky, Lexington 40506-0044, USA. zentall@pop.uky.edu  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1069-9384 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:11848586 Approved no  
  Call Number refbase @ user @ Serial 243  
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