Modeling object recognition under semantic impairment: The impact of conceptual regularities on perceptual decisions

2001 ◽  
Author(s):  
Timothy T. Rogers ◽  
Matthew A. Lambon Ralph ◽  
John R. Hodges ◽  
Karalyn Patterson
Keyword(s):  
Object Recognition ◽  
The Impact ◽  
Semantic Impairment

scholarly journals NATURAL SELECTION: THE IMPACT OF SEMANTIC IMPAIRMENT ON LEXICAL AND OBJECT DECISION

2004 ◽  
Vol 21 (2-4) ◽  
pp. 331-352 ◽  
Author(s):  
Timothy T. Rogers ◽  
Matthew A. Lambon Ralph ◽  
John R. Hodges ◽  
Karalyn Patterson
Keyword(s):  
Natural Selection ◽  
Object Decision ◽  
The Impact ◽  
Semantic Impairment

scholarly journals Dopamine D3 receptor and GSK3β signaling mediate deficits in novel object recognition memory within dopamine transporter knockdown mice

2020 ◽  
Vol 27 (1) ◽  
Author(s):  
Pi-Kai Chang ◽  
Jung Chu ◽  
Ya-Ting Tsai ◽  
Yan-Heng Lai ◽  
Jin-Chung Chen
Keyword(s):  
Object Recognition ◽  
Recognition Memory ◽  
Dopamine Transporter ◽  
Neural Plasticity ◽  
Brain Regions ◽  
Novel Object Recognition ◽  
Novel Object ◽  
Novel Objects ◽  
Dopamine Signaling ◽  
The Impact

Abstract Background Over-stimulation of dopamine signaling is thought to underlie the pathophysiology of a list of mental disorders, such as psychosis, mania and attention-deficit/hyperactivity disorder. These disorders are frequently associated with cognitive deficits in attention or learning and memory, suggesting that persistent activation of dopamine signaling may change neural plasticity to induce cognitive or emotional malfunction. Methods Dopamine transporter knockdown (DAT-KD) mice were used to mimic a hyper-dopamine state. Novel object recognition (NOR) task was performed to assess the recognition memory. To test the role of dopamine D3 receptor (D3R) on NOR, DAT-KD mice were treated with either a D3R antagonist, FAUC365 or by deletion of D3R. Total or phospho-GSK3 and –ERK1/2 signals in various brain regions were measured by Western blot analyses. To examine the impact of GSK3 signal on NOR, wild-type mice were systemically treated with GSK3 inhibitor SB216763 or, micro-injected with lentiviral shRNA of GSK3β or GSK3α in the medial prefrontal cortex (mPFC). Results We confirmed our previous findings that DAT-KD mice displayed a deficit in NOR memory, which could be prevented by deletion of D3R or exposure to FAUC365. In WT mice, p-GSK3α and p-GSK3β were significantly decreased in the mPFC after exposure to novel objects; however, the DAT-KD mice exhibited no such change in mPFC p-GSK3α/β levels. DAT-KD mice treated with FAUC365 or with D3R deletion exhibited restored novelty-induced GSK3 dephosphorylation in the mPFC. Moreover, inhibition of GSK3 in WT mice diminished NOR performance and impaired recognition memory. Lentiviral shRNA knockdown of GSK3β, but not GSK3α, in the mPFC of WT mice also impaired NOR. Conclusion These findings suggest that D3R acts via GSK3β signaling in the mPFC to play a functional role in NOR memory. In addition, treatment with D3R antagonists may be a reasonable approach for ameliorating cognitive impairments or episodic memory deficits in bipolar disorder patients.

scholarly journals Deregulated Semantic Cognition Follows Prefrontal and Temporo-parietal Damage: Evidence from the Impact of Task Constraint on Nonverbal Object Use

2011 ◽  
Vol 23 (5) ◽  
pp. 1125-1135 ◽  
Author(s):  
Faye Corbett ◽  
Elizabeth Jefferies ◽  
Matthew A. Lambon Ralph
Keyword(s):  
Conceptual Knowledge ◽  
Case Series ◽  
Semantic Knowledge ◽  
Regulatory Control ◽  
Task Constraint ◽  
Semantic Cognition ◽  
Object Use ◽  
Task Conditions ◽  
The Impact ◽  
Semantic Impairment

Semantic cognition, which encompasses all conceptually based behavior, is dependent on the successful interaction of two key components: conceptual representations and regulatory control. Qualitatively distinct disorders of semantic knowledge follow damage to the different parts of this system. Previous studies have shown that patients with multimodal semantic impairment following CVA—a condition referred to as semantic aphasia (SA)—perform poorly on a range of conceptual tasks due to a failure of executive control following prefrontal and/or temporo-parietal infarction [Jefferies, E., & Lambon Ralph, M. A. Semantic impairment in stroke aphasia versus semantic dementia: A case-series comparison. Brain, 129, 2132–2147, 2006]. Although a deficit of core semantic control would be expected to impair all modalities in parallel, most research exploring this condition has focused on tasks in the verbal domain. In a novel exploration of semantic control in the nonverbal domain, therefore, we assessed eight patients with SA on two experiments that examined object use knowledge under different levels of task constraint. Patients exhibited three key characteristics of semantic deregulation: (a) difficulty using conceptual knowledge flexibly to support the noncanonical uses of everyday objects; (b) poor inhibition of semantically related distractor items; and (c) improved object use with the provision of more tightly constraining task conditions following verbal and pictorial cues. Our findings are consistent with the notion that a neural network incorporating the left inferior prefrontal and temporo-parietal areas (damaged in SA) underpins regulation of semantic activation across both verbal and nonverbal modalities.

The impact of semantic impairment on word stem completion in Alzheimer's disease

2001 ◽  
Vol 39 (3) ◽  
pp. 302-314 ◽  
Author(s):  
M. Beauregard ◽  
H. Chertkow ◽  
D. Gold ◽  
S. Bergman
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Stem Completion ◽  
Word Stem Completion ◽  
The Impact ◽  
Semantic Impairment

scholarly journals Insights into the role of diet and dietary flavanols in cognitive aging: results of a randomized controlled trial

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Richard P. Sloan ◽  
Melanie Wall ◽  
Lok-Kin Yeung ◽  
Tianshu Feng ◽  
Xinyang Feng ◽  
...  
Keyword(s):  
Object Recognition ◽  
Dentate Gyrus ◽  
Diet Quality ◽  
Cognitive Aging ◽  
Recognition Task ◽  
Healthy Eating Index ◽  
Learning Performance ◽  
Age Related ◽  
List Learning ◽  
The Impact

AbstractWith the world's population aging, age-related memory decline is an impending cognitive epidemic. Assessing the impact of diet on cognitive aging, we conducted a controlled, randomized, parallel-arm dietary intervention with 211 healthy adults (50–75 years) investigating effects of either a placebo or 260, 510 and 770 mg/day of cocoa flavanols for 12-weeks followed by 8-weeks washout. The primary outcome was a newly-developed object-recognition task localized to the hippocampus’ dentate gyrus. Secondary outcomes included a hippocampal-dependent list-learning task and a prefrontal cortex-dependent list-sorting task. The alternative Healthy Eating Index and a biomarker of flavanol intake (gVLM) were measured. In an MRI substudy, hippocampal cerebral blood volume was mapped. Object-recognition and list-sorting performance did not correlate with baseline diet quality and did not improve after flavanol intake. However, the hippocampal-dependent list-learning performance was directly associated with baseline diet quality and improved after flavanol intake, particularly in participants in the bottom tertile of baseline diet quality. In the imaging substudy, a region-of-interest analysis was negative but a voxel-based-analysis suggested that dietary flavanols target the dentate gyrus. While replication is needed, these findings suggest that diet in general, and dietary flavanols in particular, may be associated with memory function of the aging hippocampus and normal cognitive decline.

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