KC: The Role of Visual Imagery Deficits within Autobiographical Memory Rosenbaum, R.S., McKinnon, M.C., Levine, B., & Moscovitch, M. (2004). Visual imagery deficits, impaired strategic retrieval, or memory loss: disentangling the nature of an amnesic person ’ s autobiographical memory deficit. Neuropsychologia, 42(12), Presented by : Juliana Peters

This puzzling problem arises when we ask, "Who is the I that knows the bodily me, who has an image of myself and a sense of identity over time, who knows that I have propriate strivings?" I know all these things, and what is more, I know that I know them. But who is it who has this perspectival grasp? … It is much easier to feel the self than to define the self. -Gordon Allport

KC 50-year-old, right-handed man 15 years of education Suffered irreversible amnesia from traumatic brain injury caused during a motorcycle accident in 1981.

Damage Complete devastation to right hippocampus Atrophy to right parahippocampal gyrus. Also in mammillary bodies, the septal area, and the fornices.

Damage cont. Lesion in left occipital-temporal cortex, and slightly in retrosplenial cortex; lesions in medial occipital-temporal- parietal, and left frontal-parietal regions. du/AANLIB/cases/caseN A/pb9.htm

Memory Impairment Severe Anterograde and Retrograde Amnesia for autobiographical memory. Inability to place images within a temporal- spatial context. Impairment seen on standardized tests of memory. –WASI: IQ of 99 (2003 assessment) –WMS-R: 5th percentile on logical memory –Autobiographical Memory Interview

Sustained Memory Abilities Semantic Memory World Knowledge Remained Schematic Cognitive Map Executive Function Tests –WASI similarities and matrix reasoning subtests Abstract Reasoning Concept Formation/Mental Flexibility –Wisconsin Card Sorting test/Concept Generation Test

Rosenbaum et al.’s Tests Main purpose: to see if K.C.’s memory loss was due to malfunctioning of posterior neocortex or to malfunctioning of frontal neocortex. Experiment One: Visual imagery of object identity and spatial location –Wanted to see if visual imagery loss was at all an important aspect of K.C.’s inability to recall his personal past. –Tested K.C.’s ability to segment, combine and rotate mental images –Tests included: Imagery for Object Size Imagery of Object Color Mental Clock Test Recreated Images

Experiment One Findings K.C. maintains functional imagery system. –Was able to make accurate judgements of size, shape, and spatial relations of tested objects. –Showed ability to dismantle, rotate, and reorganize visual representations Shows that the imagery system is “necessary but…not sufficient for autobiographical memory retrieval.”

Experiment Two: Autobiographical Interview Wanted to distinguish if deficit was result of problems in memory storage or shows deficit in executive functioning to retreive details. Tested KC through Autobiographical Interview (Moscovitch et al.& Levine et al.) –Categorized retrievals as episodic or non-episodic. -Categorized as internal or external -Free Recall versus Specific Probe

Experiment 2 Findings The Autobiographical Interview reinstated that K.C. had severe retrograde amnesia for internal details. –Unable to retrieve a single memory through free recall. –Specific Cue Retrieval provided only a slight improvement for details Information provided lacked significant richness

Findings Suggest? As stated by Nadel and Moscovitch (1997), the hippocampus plays a major role in the retreival of autobiographical memories throughout the life. –Role of the hippocampal-neocortical interactions These studies do suggest that degeneration of the neocortex and damage to the hippocamal area are not the sole areas responsible for the severe anterograde amnesia

Future Research Scores from cued recall may be misleading due to previous exposure. –Future research needed to see the defining role of cued recall on autobiographical memory retrieval. More research needed in recognition of past events. –Does not depend on strategic search and just the identification of a particular event Rosenbaum, although found that no relationship between visual imagery deficits and memory loss, he suggests that future research focus on other types of neocortically mediated functions and their effects on amnesia.