Do medial temporal lobe regions play a domain-specific or domain-independent role in perceptual learning performance?
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1
Monash University, Australia
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2
Bangor University, United Kingdom
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3
Cardiff University, United Kingdom
Background
It is contentious whether structures in the human medial temporal lobe (MTL) play a domain-specific or domain-independent role in learning and memory. Perceptual learning has been used as a tool to investigate this critical cognitive junction.
Methods
In a series of event related fMRI experiments, participants made repeated same/different judgements to previously seen and initially novel confusable pairs of dot patterns, faces and complex scenes. Using a series of orthogonal, and independent, functional localisers, clusters of stimulus-selective, novelty-sensitive voxels were identified in two medial temporal regions (perirhinal cortex and posterior hippocampus), and two extrastriate regions (fusiform face area, FFA, and parahippocampal place area, PPA). We asked how activity in these regions was influenced by discrimination accuracy and by trial repetition (e.g., adaptation).
Results
In contrast to FFA and PPA, which only cared about preferred category, activity in perirhinal cortex and posterior hippocampus predicted discrimination accuracy for faces and scenes, respectively. MTL regions also adapted less rapidly than extrastriate areas over trial repetition, with difference emerging between extrastriate and MTL regions after 8 repetitions. Structural differences were also recorded in these regions, along with caudate and thalamic areas; the size of these differences correlated with performance.
Discussion
These findings, supported by our recent work with MTL lesioned patients and a second fMRI investigation directly modulating stimulus ambiguity, show that domain-specific patterns of responding in the human brain are not just restricted to extrastriate cortex, and highlight a key role for perirhinal cortex and posterior hippocampus, but not FFA and PPA, in storing feature ambiguous representations of faces and scenes, respectively.
Keywords:
faces,
scenes,
Perceptual Learning,
Memory,
Amnesia,
Medial Temporal Lobes,
fMRI
Conference:
ACNS-2013 Australasian Cognitive Neuroscience Society Conference, Clayton, Melbourne, Australia, 28 Nov - 1 Dec, 2013.
Presentation Type:
Oral
Topic:
Memory
Citation:
Mundy
ME,
Downing
P,
Honey
R,
Dwyer
D and
Graham
K
(2013). Do medial temporal lobe regions play a domain-specific or domain-independent role in perceptual learning performance?.
Conference Abstract:
ACNS-2013 Australasian Cognitive Neuroscience Society Conference.
doi: 10.3389/conf.fnhum.2013.212.00192
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Received:
15 Oct 2013;
Published Online:
25 Nov 2013.
*
Correspondence:
Dr. Matthew E Mundy, Monash University, Melbourne, Australia, matthew.mundy@monash.edu