The damage involved the ventral anterior thalamus, the mamillothalamic tract, and the rostroventral internal medullary lamina. In summary, the syndrome of thalamic amnesia is associated with lesions involving the anterior, dorsomedial and paramedian nuclei of the thalamus. These lesions have the effect of disrupting the fornix-mamillothalamic tract, and the ventral amygdalofugal pathway. These findings suggest functional involvement of the frontal and temporal lobe connections with the dorsomedial and anterior nuclei in patients with thalamic amnesia. In terms of neuropsychological analysis, the amnesia in these patients is characterized by severe anterograde memory loss with preservation of motor learning.
Some patients also develop retrograde memory loss with a temporal gradient.
Bilateral lesions involving the anterior thalamus have been shown to produce a lasting global amnesia. Impairment of dorsolateral pre-frontal functions has also been documented in these patients by neuropsychological testing. The neuropsychology of paramedian thalamic infarction.