Unilateral medial temporal damage, however extensive, causes, not global amnesia but rather material specific memory deficits, i.e. verbal memory deficits after left-sided and nonverbal after right-sided lesions, and this is the case in children just as in adults.  Recently, we discovered the explanation for what had at first seemed a contradictory finding, namely, verbal memory impairment in about half the patients that had received right-sided medial temporal removals for relief of epilepsy.  Quantitative MR techniques revealed the presence of subtle abnormalities in the left medial temporal region of those patients with right-sided removals who had the verbal memory deficits.  This pathology had escaped detection by other methods, including standard magnetic resonance imaging, emphasizing again the importance of applying quantitative MR techniques to neuropsychological studies of brain-injured patients.

Executive functions.  Word fluency, a form of executive function that is seriously impaired after left prefrontal damage sustained in adulthood, is substantially spared after comparable congenital lesions.  However, another form of executive function, namely card sorting, which is severely impaired after prefrontal lesions of either hemisphere in adults, is also impaired after either left or right congenital prefrontal lesions.  The latter result is surprising, in view of the considerable evidence in the literature indicating that the prefrontal cortex does not reach full functional maturity until late childhood or even adolescence.  Our finding highlights the need to examine many different abilities within and across domains in order to understand how the cerebral system underlying each one evolves functionally.

Keynote and Plenary Lectures:

Numerous invited lectures have been delivered at conferences, symposia and workshops in the UK and overseas. Recent invited lectures for 2003/2004 include:

2003

International Neuropsychology Society, plenary lecture

6-9 February, Hawaii

Title: Dissociations in cognitive memory and developmental amnesia

American Association for the Advancement of Science, Symposium Organizer

13-16 February, Denver Colorado

Title: Symposium From Gene to Speech

Cleveland Clinic, invited lecture

29 May - 1 June, Bielefeld, Germany

Title: Behavioural consequences of focal lesions

University of Gröningen, plenary lecture