The Journal of Neuroscience, November 1, 2002, 22(21):9573-9580
Nonspatial and Subdivision-Specific Working Memory Deficits after
Selective Lesions of the Avian Prefrontal Cortex
Bettina
Diekamp1,
Anna
Gagliardo2, and
Onur
Güntürkün1
1 Biopsychology, Department of Psychology,
Ruhr-University Bochum, 44780 Bochum, Germany, and 2
Department of Ethology, Ecology, and Evolution, University of Pisa,
I-56126 Pisa, Italy
Association areas in the avian forebrain are shown to subserve
higher cognitive functions, including working memory. One of these
areas, the neostriatum caudolaterale (NCL) of pigeons, has been
functionally compared with the mammalian prefrontal cortex (PFC)
because of its prominent role in spatial delay and reversal tasks and
its innervation by the dopaminergic system that modulates these
functions. However, whereas the PFC maintains in working memory
information of different domains, the essential role of the NCL in
working memory has been demonstrated only for spatial tasks. To
investigate whether the avian NCL is also crucial for nonspatial
working memory functions, pigeons were tested in an object-related
(color) delayed matching-to-sample (DMTS) task. Bilateral lesions were
placed in the entire, dorsal, or ventral NCL to test for possible
functional subdivisions that were proposed to exist on the basis of
neurochemical and behavioral data. Pigeons with total, dorsal, and
ventral NCL lesions showed significant deficits in their DMTS
performance, whereas controls were not impaired. Thus, the avian NCL is
critically involved in nonspatial working memory processes. Recovery
from performance deficits was observed in animals with ventral or total
NCL lesions, whereas animals with dorsal NCL lesions showed no
improvement. Ventral NCL may mediate perseverative behavior, whereas
dorsal NCL might be involved in active working memory. Differences in
the connections of these subdivisions with striatal areas and other
association areas in the frontomedial forebrain underline functional
differences. The data indicate a possible segregation of functions in
the avian NCL.
Key words:
delayed matching to sample; working memory; prefrontal
cortex; perseveration; birds; association area
Copyright © 2002 Society for Neuroscience 0270-6474/02/22219573-08$05.00/0