The Human Memory Lab has two principal aims: 1) to understand how and why we store and retrieve memories, and 2) to apply this knowledge to our development of more effective ways to improve cognition and everyday functioning. The clinical and cognitive neuroscience research conducted in our lab combines neuropsychological, cognitive, social psychological, and neuroimaging approaches. In our research we draw insight from individuals with memory disorders and healthy adults.
Current lines of research include:
How do you store knowledge about yourself and your social life?
Much of one's autobiographical memory is composed of personal semantics, which is knowledge about the self that contextualizes experiences and adds meaning to the life story. Despite the importance of personal semantics to one's sense of self, how such knowledge is organized and retrieved remains underspecified. In the Human Memory Lab, we have attempted to close this gap in knowledge by studying personal semantics in individuals with lesions to core regions of the autobiographical memory neural network. We have proposed that personal semantics can be viewed as consisting of subtypes of content that place distinct computational demands on regions in the autobiographical memory network. Personal semantics can be bound to events, in which case they are supported by bilateral medial temporal lobe structures (Grilli & Verfaellie, 2014; 2016). They also can be associated with personally known people, places, and objects and critically depend on the left anterior ventrolateral temporal lobe (Grilli et al., in press). Or, they can represent categorical knowledge about the self, such as personality traits and social roles, in which case they are supported by neural regions that are implicated in basic level categorical knowledge or schema-like knowledge, including the medial prefrontal cortex (Marquine, Grilli, et al., 2016). This cognitive neuroscience model reflects a comprehensive attempt to explain the neural bases of personal semantics. Clinically, this model highlights the need for research on disorders of memory in the context of isolated lesions and dementias, because different patterns of autobiographical memory impairment could emerge depending on the localization of lesions and neurodegeneration.
Can studying autobiographical memory increase sensitivity to preclinical Alzheimer's disease?
Alzheimer's disease (AD) typically eludes clinical detection for years, if not decades. The identification of subtle cognitive decline associated with preclinical AD would not only advance understanding of the disease, but also provide cognitive outcome measures for preventive/early intervention clinical trials. In the Human Memory Lab, we recently proposed that disrupted retrieval of detailed episodic autobiographical memories may be a sensitive indicator of subtle cognitive decline, because this type of memory taxes a core neural network affected by preclinical AD neuropathology (Grilli et al., in press). Ongoing projects are seeking to better understand the precise autobiographical memory retrieval mechanisms that might be compromised very early by AD.
How is autobiographical memory used to ground one's personal identity?
Autobiographical memory has long been thought to ground one's conceptualization of the self, which cognitively we can think of as the traits and roles that you believe define you. Research in the Human Memory Lab has supported this idea and applied this framework to understand the benefits of talk therapy (Grilli & Ryan, forthcoming). For instance, we have shown that individuals with medial temporal lobe amnesia rely entirely on abstract personal semantic memories to ground their traits and roles, which comes at a cost: they cannot retrieve as many self-defining traits as healthy adults do (Grilli & Verfaellie, 2015). Also, we have shown that healthy adults use different types of autobiographical memory to ground longstanding/stable traits and roles versus traits and roles that were recently included in one's self-concept (Grilli, 2017).
How can we improve memory in individuals with memory impairment?
Although much of the research in the Human Memory Lab focuses on advancing cognitive neuroscience and neuropsychological models, we always consider how insights from basic research can inform new interventions for memory disorders. Dr. Grilli's first line of research merged two largely separate literatures on self-referential processing and imagination to establish a new cognitive strategy for improving episodic memory in individuals with brain lesions. In a series of studies, we demonstrated that this new strategy is a highly effective intervention for adults with traumatic brain injury, capable of enhancing recognition, cued recall, free recall, and prospective memory across various delays and over and above a variety of other cognitive strategies.