Towards a left MTL specialization for arbitrary-associative learning? A multiple-case study

Since the famous case of HM provided unquestionable evidence for the involvement of medial temporal lobe (MTL) structures in memory, a dominant neuropsychological model raised up in the 1970’s. Brenda Milner proposed that “the most significant variable (to explain post-surgery memory outcome in temporal lobe epilepsy) is the verbal or non-verbal character of the material to be retained” [1]. This model predicts that verbal and non-verbal memories are homogenous and independent systems, respectively relying upon left and right temporal lobes. Yet, series of cases of amnesia following unilateral temporal lobectomy have been documented, drawing a more complex picture [2]. Moreover, cases of poorer verbalmemory outcome after right TL surgery had been reported [3], and other studies underlined deficits in spatial learning after left surgery. Taken together, those data strongly challenges the dominant material-specific view. In linewith those challenging data,other authors suggested that beyond material-specificity, task-specifi-