Intact high‐resolution working memory binding in a patient with developmental amnesia and selective hippocampal damage

Abstract

Debate continues regarding the possible role of the hippocampus across short-term and working memory tasks. The current study examined the possibility of a hippocampal contribution to precise, high-resolution cognition and conjunctive memory.We administered visual working memory tasks featuring a continuous response component to a well-established developmental amnesic patient with relatively selective bilateral hippocampal damage (Jon) and healthy controls. The patient was able to produce highly accurate response judgments regarding conjunctions of color and orientation or color and location, using simultaneous or sequential presentation of stimuli, with no evidence of any impairment in working memory binding, categorical accuracy, or continuous precision. These findings indicate that hippocampal damage does not necessarily lead to deficits in high-resolution cognitive performance, even when the damage is severe and bilateral.

Anatomo-functional changes in neural substrates of cognitive memory in developmental amnesia: Insights from automated and manual MRI examinations

“…In measures of color-location memory, Jon’s recognition accuracy matched the highest achieving control participant, while his reconstruction performance was superior to 6 of the 7 controls (Allen et al, 2014). Across four tasks measuring binding between color and orientation or color and location using simultaneous or sequential presentation of stimuli, Jon’s response accuracy was high, and always numerically superior to the control mean (Allen et al, 2022).…”

“…While patient KA displayed few, if any, residual episodic abilities, this patient was able to accurately retrieve semantic memories, and show evidence of superior or even very superior access to these memories than controls. Another patient with DA, patient ‘Jon’, has often produced response accuracy levels that are at least higher than those of control participants in previous experimental explorations of visuospatial working memory (Allen et al, 2022, 2014; Baddeley et al, 2010). Jon was at least numerically superior to the control mean on recognition-based measures of shape-color binding (Baddeley et al, 2010).…”

“…This latter possibility is challenged however by the fact that patients with DA presenting with severe hippocampal damage have repeatedly shown unimpaired working memory performance (Allen et al, 2014;Baddeley et al, 2011Baddeley et al, , 2010. Recent work extended these findings by showing that high resolution working memory performance was unimpaired, and even often superior, relative to control group in a patient with DA (Allen et al, 2022). Our observation of a negative correlation between uncus volume and working memory performance suggests that the perirhinal, entorhinal, and parahippocampal cortices normally involved in the binding of information in the short term (Miyashita, 2019) may be subject to plastic changes in patients with DA and that these plastic changes may depend on the degree of hippocampal damage.…”

The integrity of dopaminergic and noradrenergic brain regions is associated with different aspects of late-life memory performance

“…While the SN–VTA has long been attributed as source of the memory-enhancing dopaminergic inputs [35,38,43], recent findings point to a denser innervation by the LC that can provide noradrenergic as well as dopaminergic signals [41,45,46]. Here we compared the association of the two catecholaminergic centers with an extensive set of tasks that are thought to depend more (episodic memory) or less (working memory) on hippocampal processing [108,115]. We observed that LC integrity was specifically related to late-life episodic memory performance (as compared to working memory or fluid intelligence) and that this association was stronger than the SN–VTA–episodic memory relationship.…”

Visual working memory phenomena based on categorical tasks replicate using a continuous measure: A simple interpretation and some methodological considerations

“…Our studies always used a limited set of colours or shapes, leading open the suggestion that Jon's problem might be with the precision of responding (Ekstrom & Yonelinas, 2020;Yonelinas, 2013). Although this proved not to be the case in this instance (Allen et al, 2022), there is evidently potential value to be gained from looking at major phenomena using both methodologies. This has been nicely illustrated by studies of visual working memory for color showing that performance reflects a combination of categorical and continuous information (Bae et al, 2015;Hardman et al, 2017), with the precise nature of the representation appearing to vary depending on the task that is implemented (Ricker et al, 2022).…”