Affiliations: Department of Psychology, Eleanor Rathbone Building,
University of Liverpool, Liverpool L69 3BX, UK | Departments of Clinical Physics and Clinical
Neuroradiology, Institute of Neurological Sciences, Southern General Hospital,
Glasgow, Scotland, UK
Note: [] Corresponding author: Dr. Daniela Montaldi, Department of
Psychology, Eleanor Rathbone Building, University of Liverpool, Liverpool L69
7ZA, UK. Tel.: +44 151 794 6953; Fax: +44 151 794 6955; E-mail:
[email protected]
Abstract: Brain dedicated single photon emission computed tomography (SPECT)
was used to compare the neuroactivation produced by the cued recall of response
words in a set of studied word pairs with that produced by the cued retrieval
of words semantically related to unstudied stimulus words. Six of the 12
subjects scanned were extensively trained so as to have good memory of the
studied pairs and the remaining six were minimally trained so as to have poor
memory. When comparing episodic with semantic retrieval, the well-trained
subjects showed significant left medial temporal lobe activation, which was
also significantly greater than that shown by the poorly trained subjects, who
failed to show significant medial temporal lobe activation. In contrast, the
poorly trained subjects showed significant bilateral frontal lobe activation,
which was significantly greater than that shown by the well-trained subjects
who failed to show significant frontal lobe activation. The frontal activations
occurred mainly in the dorsolateral region, but extended into the ventrolateral
and, to a lesser extent, the frontal polar regions. It is argued that whereas
the medial temporal lobe activation increased as the proportion of response
words successfully recalled increased, the bilateral frontal lobe activation
increased in proportion to retrieval effort, which was greater when learning
had been less good.
