Profound loss of general knowledge in retrograde amnesia: evidence from an amnesic artist

Abstract

Studies of retrograde amnesia have focused on autobiographical memory, with fewer studies examining how non-autobiographical memory is affected. Those that have done so have focused primarily on memory for famous people and public events—relatively limited aspects of memory that are tied to learning during specific times of life and do not deeply tap into the rich and extensive knowledge structures that are developed over a lifetime. To assess whether retrograde amnesia can also cause impairments to other forms of general world knowledge, we explored losses across a broad range of knowledge domains in a newly-identified amnesic. LSJ is a professional artist, amateur musician and history buff with extensive bilateral medial temporal and left anterior temporal damage. We examined LSJ's knowledge across a range of everyday domains (e.g., sports) and domains for which she had premorbid expertise (e.g., famous paintings). Across all domains tested, LSJ showed losses of knowledge at a level of breadth and depth never before documented in retrograde amnesia. These results show that retrograde amnesia can involve broad and deep deficits across a range of general world knowledge domains. Thus, losses that have already been well-documented (famous people and public events) may severely underestimate the nature of human knowledge impairment that can occur in retrograde amnesia.

The Necessity of the Medial Temporal Lobe for Statistical Learning

“…Consistent with her extensive MTL damage and the neuropsychological profile of other cases of herpes encephalitis (e.g., Kapur et al, 1994), LSJ exhibits profound retrograde and anterograde memory impairment (see Gregory, McCloskey, & Landau, 2014, for a more detailed neuropsychological profile). The retrograde memory impairment encompasses both episodic (autobiographical) and semantic information.…”

“…In testing of semantic memory, LSJ was severely impaired in identifying famous faces (2 of 60 correct) and famous landmarks (2 of 26; see Duchaine, Germine, & Nakayama, 2007; Duchaine, Nieminen-von Wendt, New, & Kulomaki, 2003, for control means). In testing with recall and recognition tasks developed to probe knowledge across a broad range of domains (e.g., commercial logos, familiar songs), including areas of premorbid expertise for LSJ (e.g., famous artworks, classical music), LSJ was uniformly and severely impaired (Gregory et al, 2014). …”

The Necessity of the Hippocampus for Statistical Learning

“…Patient L. S. J. had complete loss of hippocampus bilaterally as well as a more extensive damage to surrounding MTL cortex and left anterior temporal lobe as a result of herpes simplex encephalitis (HSE). This significant MTL damage resulted in profound declarative memory impairment (Wechsler Memory Scale–General Memory Index [WMS GMI] = 47) as well as working memory impairment (Wechsler Memory Scale–Working Memory Index [WMS WMI] = 76), in the context of preserved intelligence (Wechsler Adult Intelligence Scale–Full Scale Intelligence Quotient [WAIS FSIQ] = 92), perception, language, and world knowledge (Gregory, McCloskey, & Landau, 2014). L. S. J. completed four versions of two experiments in which she was passively exposed to continuous sequences of shapes, syllables, scenes, or tones.…”

Functions of ventral visual cortex after bilateral hippocampal loss

“…We asked whether the hippocampus is necessary for long-lag adaptation, and in particular what role it plays in cortical adaptation for individual stimuli. To establish necessity, we examined patient LSJ (25)(26)(27)(28) who has complete bilateral hippocampal loss ( Figure 1A). We hypothesized that if the lag between repetitions extends beyond the timescale at which local physiological changes can produce (immediate) adaptation, LSJ will differ from healthy control participants and fail to show adaptation in visual cortex due to the lack of hippocampal feedback.…”