Enhancing memory performance with rTMS in healthy subjects and individuals with Mild Cognitive Impairment: the role of the right dorsolateral prefrontal cortex

A debated question in the literature is the degree of anatomical and functional lateralization of the executive control processes sub-served by the dorsolateral prefrontal cortex (DLPFC) during recognition memory retrieval. We investigated if transient inhibition and excitation of the left and right DLPFC at retrieval by means of repetitive transcranial magnetic stimulation (rTMS) modulate recognition memory performance in 100 healthy controls (HCs) and in eight patients with Mild Cognitive Impairment (MCI). Recognition memory tasks of faces, buildings, and words were used in different experiments. rTMS-inhibition of the right DLPFC enhanced recognition memory in both HCs and MCIs. rTMS-excitation of the same region in HCs deteriorated memory performance. Inhibition of the right DLPFC could modulate the excitability of a network of brain regions, in the ipsilateral as well as in the contralateral hemisphere, enhancing function in HCs or restoring an adaptive equilibrium in MCI

Executive function and metacognitive self-awareness after severe traumatic brain injury

The objective of this study is to identify the clinical, neuropsychological, neuropsychiatric, and functional variables that correlate with metacognitive self-awareness (SA) in severe traumatic brain injury (TBI) outpatients and to assess the influence of the same variables on the sensory-motor, cognitive, and behavioral-affective indicators of SA. This cross-sectional observational study evaluated 37 outpatients from May 2006 to June 2007 in a neurorehabilitation hospital on the basis of the following inclusion criteria: (1) age 8); (3) posttraumatic amnesia (PTA) resolution; (4) capacity to undergo formal psychometric evaluation despite cognitive and sensory-motor deficits; (5) absence of aphasia; (6) availability of informed consent. A neuropsychological battery was used to evaluate attention, memory, and executive functions. SA was assessed by the awareness questionnaire (AQ), administered to both patients and relatives. Decreased metacognitive self-awareness is significantly correlated with increased problems in some components of executive system, even when the AQ subscales were considered separately. The significant correlation found between some components of executive system and metacognitive self-awareness confirmed the importance of addressing this issue to treat SA contextually in the rehabilitation of executive functions