Medial temporal lobe damage impairs representation of simple stimuli

David E Warren, Melissa C. Duff, Daniel Tranel, Neal J. Cohen

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Medial temporal lobe (MTL) damage in humans is typically thought to produce a circumscribed impairment in the acquisition of new enduring memories, but recent reports have documented deficits even in short-term maintenance. We examined possible maintenance deficits in a population of MTL amnesics, with the goal of characterizing their impairments as either representational drift or outright loss of representation over time. Patients and healthy comparisons performed a visual search task in which the similarity of various lures to a target was varied parametrically. Stimuli were simple shapes varying along one of several visual dimensions. The task was performed in two conditions, one presenting a sample target simultaneously with the search array and the other imposing a delay between sample and array. Eye-movement data collected during search revealed that the duration of fixations to items varied with lure-target similarity for all participants, i.e., fixations were longer for items more similar to the target. In the simultaneous condition, patients and comparisons exhibited an equivalent effect of similarity on fixation durations. However, imposing a delay modulated the effect differently for the two groups: in comparisons, fixation duration to similar items was exaggerated; in patients, the original effect was diminished. These findings indicate that MTL lesions subtly impair short-term maintenance of even simple stimuli, with performance reflecting not the complete loss of the maintained representation but rather a degradation or progressive drift of the representation over time.

Original languageEnglish (US)
Pages (from-to)1-9
Number of pages9
JournalFrontiers in Human Neuroscience
Volume4
DOIs
StatePublished - Jan 1 2010

Fingerprint

Temporal Lobe
Eye Movements
Maintenance
Population

Keywords

  • Amnesia
  • Decay
  • Delay
  • Hippocampus
  • MTL
  • Memory
  • STM
  • WM

ASJC Scopus subject areas

  • Psychiatry and Mental health
  • Neurology
  • Biological Psychiatry
  • Behavioral Neuroscience
  • Neuropsychology and Physiological Psychology

Cite this

Medial temporal lobe damage impairs representation of simple stimuli. / Warren, David E; Duff, Melissa C.; Tranel, Daniel; Cohen, Neal J.

In: Frontiers in Human Neuroscience, Vol. 4, 01.01.2010, p. 1-9.

Research output: Contribution to journalArticle

Warren, David E ; Duff, Melissa C. ; Tranel, Daniel ; Cohen, Neal J. / Medial temporal lobe damage impairs representation of simple stimuli. In: Frontiers in Human Neuroscience. 2010 ; Vol. 4. pp. 1-9.
@article{0f22f4da149140f1ab6dccd0ed73b98a,
title = "Medial temporal lobe damage impairs representation of simple stimuli",
abstract = "Medial temporal lobe (MTL) damage in humans is typically thought to produce a circumscribed impairment in the acquisition of new enduring memories, but recent reports have documented deficits even in short-term maintenance. We examined possible maintenance deficits in a population of MTL amnesics, with the goal of characterizing their impairments as either representational drift or outright loss of representation over time. Patients and healthy comparisons performed a visual search task in which the similarity of various lures to a target was varied parametrically. Stimuli were simple shapes varying along one of several visual dimensions. The task was performed in two conditions, one presenting a sample target simultaneously with the search array and the other imposing a delay between sample and array. Eye-movement data collected during search revealed that the duration of fixations to items varied with lure-target similarity for all participants, i.e., fixations were longer for items more similar to the target. In the simultaneous condition, patients and comparisons exhibited an equivalent effect of similarity on fixation durations. However, imposing a delay modulated the effect differently for the two groups: in comparisons, fixation duration to similar items was exaggerated; in patients, the original effect was diminished. These findings indicate that MTL lesions subtly impair short-term maintenance of even simple stimuli, with performance reflecting not the complete loss of the maintained representation but rather a degradation or progressive drift of the representation over time.",
keywords = "Amnesia, Decay, Delay, Hippocampus, MTL, Memory, STM, WM",
author = "Warren, {David E} and Duff, {Melissa C.} and Daniel Tranel and Cohen, {Neal J.}",
year = "2010",
month = "1",
day = "1",
doi = "10.3389/fnhum.2010.00035",
language = "English (US)",
volume = "4",
pages = "1--9",
journal = "Frontiers in Human Neuroscience",
issn = "1662-5161",
publisher = "Frontiers Research Foundation",

}

TY - JOUR

T1 - Medial temporal lobe damage impairs representation of simple stimuli

AU - Warren, David E

AU - Duff, Melissa C.

AU - Tranel, Daniel

AU - Cohen, Neal J.

PY - 2010/1/1

Y1 - 2010/1/1

N2 - Medial temporal lobe (MTL) damage in humans is typically thought to produce a circumscribed impairment in the acquisition of new enduring memories, but recent reports have documented deficits even in short-term maintenance. We examined possible maintenance deficits in a population of MTL amnesics, with the goal of characterizing their impairments as either representational drift or outright loss of representation over time. Patients and healthy comparisons performed a visual search task in which the similarity of various lures to a target was varied parametrically. Stimuli were simple shapes varying along one of several visual dimensions. The task was performed in two conditions, one presenting a sample target simultaneously with the search array and the other imposing a delay between sample and array. Eye-movement data collected during search revealed that the duration of fixations to items varied with lure-target similarity for all participants, i.e., fixations were longer for items more similar to the target. In the simultaneous condition, patients and comparisons exhibited an equivalent effect of similarity on fixation durations. However, imposing a delay modulated the effect differently for the two groups: in comparisons, fixation duration to similar items was exaggerated; in patients, the original effect was diminished. These findings indicate that MTL lesions subtly impair short-term maintenance of even simple stimuli, with performance reflecting not the complete loss of the maintained representation but rather a degradation or progressive drift of the representation over time.

AB - Medial temporal lobe (MTL) damage in humans is typically thought to produce a circumscribed impairment in the acquisition of new enduring memories, but recent reports have documented deficits even in short-term maintenance. We examined possible maintenance deficits in a population of MTL amnesics, with the goal of characterizing their impairments as either representational drift or outright loss of representation over time. Patients and healthy comparisons performed a visual search task in which the similarity of various lures to a target was varied parametrically. Stimuli were simple shapes varying along one of several visual dimensions. The task was performed in two conditions, one presenting a sample target simultaneously with the search array and the other imposing a delay between sample and array. Eye-movement data collected during search revealed that the duration of fixations to items varied with lure-target similarity for all participants, i.e., fixations were longer for items more similar to the target. In the simultaneous condition, patients and comparisons exhibited an equivalent effect of similarity on fixation durations. However, imposing a delay modulated the effect differently for the two groups: in comparisons, fixation duration to similar items was exaggerated; in patients, the original effect was diminished. These findings indicate that MTL lesions subtly impair short-term maintenance of even simple stimuli, with performance reflecting not the complete loss of the maintained representation but rather a degradation or progressive drift of the representation over time.

KW - Amnesia

KW - Decay

KW - Delay

KW - Hippocampus

KW - MTL

KW - Memory

KW - STM

KW - WM

UR - http://www.scopus.com/inward/record.url?scp=77953448776&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=77953448776&partnerID=8YFLogxK

U2 - 10.3389/fnhum.2010.00035

DO - 10.3389/fnhum.2010.00035

M3 - Article

VL - 4

SP - 1

EP - 9

JO - Frontiers in Human Neuroscience

JF - Frontiers in Human Neuroscience

SN - 1662-5161

ER -