Alex Fradera - Academia.edu (original) (raw)
Papers by Alex Fradera
The Wiley Blackwell Handbook of the Psychology of the Internet at Work
Http Dx Doi Org 10 1080 09658210600747241, Feb 17, 2007
Human Brain Mapping, 2012
Despite advances in the treatment of patients with human immunodeficiency virus (HIV), HIVassocia... more Despite advances in the treatment of patients with human immunodeficiency virus (HIV), HIVassociated neurocognitive disorder occurs in 15-50% of HIV-infected individuals, and may become more apparent as ageing advances. In the present study we investigated regional cerebral blood flow (rCBF) and regional cerebral metabolic rate of glucose uptake (rCMRglc) in medically and psychiatrically stable HIV-1-infected participants in two age-groups. Positron emission tomography (PET) and magnetic resonance imaging (MRI)based arterial spin labeling (ASL) were used to measure rCMRglc and rCBF, respectively, in 35 HIV-infected participants and 37 HIV-negative matched controls. All participants were currently asymptomatic with undetectable HIV-1 viral loads, without medical or psychiatric comorbidity, alcohol or substance misuse, stable on medication for at least 6 months before enrolment in the study. We found significant age effects on both ASL and PET with reduced rCBF and rCMRglc in related frontal brain regions, and consistent, although small, reductions in rCBF and rCMRglc in the anterior cingulate cortex (ACC) in HIV, a finding of potential clinical significance. There was no significant interaction between HIV status and the ageing process, and no significant HIV-related changes elsewhere in the brain on PET or ASL. This is the first paper to combine evidence from ASL and PET method in HIV participants. These finding provide evidence of crossvalidity between the two techniques, both in ageing and a clinical condition (HIV). Hum Brain Mapp 00:000-000,
Episodic experience is argued to be rich in temporal information, but it remains unclear whether ... more Episodic experience is argued to be rich in temporal information, but it remains unclear whether temporal information is directly coded in the event memory or is reconstructed at retrieval. The two experiments reported here emphasise the role of reconstructive processes of autobiographical context in establishing the date of memories. Younger and older participants were presented with famous public events, although only the latter had actually lived through them. Participants were asked to make forcedchoice judgements about the date of the event and other event-related facts. Overall, while the older group showed better fact knowledge of the events, this did not translate into better dating performance. This older group showed similar dating performance across events with high and low factual knowledge. In contrast, the younger group's dating accuracy was determined by their level of knowledge. This suggests that older individuals who have direct episodic experience of an event may perform the task in a qualitatively different manner, eschewing semantic facts in favour of other sources of information. Crucially, this process does not appear to enhance performance. A second experiment addressed the issue of whether older participants date events based on general qualities of the event memory (e.g., vividness), the availability of other event-related semantic facts, or autobiographical context. It was found that the ability to place an event in autobiographical context is related to dating accuracy, but not to other aspects of memory.
The Wiley Blackwell Handbook of the Psychology of the Internet at Work
Http Dx Doi Org 10 1080 09658210600747241, Feb 17, 2007
Human Brain Mapping, 2012
Despite advances in the treatment of patients with human immunodeficiency virus (HIV), HIVassocia... more Despite advances in the treatment of patients with human immunodeficiency virus (HIV), HIVassociated neurocognitive disorder occurs in 15-50% of HIV-infected individuals, and may become more apparent as ageing advances. In the present study we investigated regional cerebral blood flow (rCBF) and regional cerebral metabolic rate of glucose uptake (rCMRglc) in medically and psychiatrically stable HIV-1-infected participants in two age-groups. Positron emission tomography (PET) and magnetic resonance imaging (MRI)based arterial spin labeling (ASL) were used to measure rCMRglc and rCBF, respectively, in 35 HIV-infected participants and 37 HIV-negative matched controls. All participants were currently asymptomatic with undetectable HIV-1 viral loads, without medical or psychiatric comorbidity, alcohol or substance misuse, stable on medication for at least 6 months before enrolment in the study. We found significant age effects on both ASL and PET with reduced rCBF and rCMRglc in related frontal brain regions, and consistent, although small, reductions in rCBF and rCMRglc in the anterior cingulate cortex (ACC) in HIV, a finding of potential clinical significance. There was no significant interaction between HIV status and the ageing process, and no significant HIV-related changes elsewhere in the brain on PET or ASL. This is the first paper to combine evidence from ASL and PET method in HIV participants. These finding provide evidence of crossvalidity between the two techniques, both in ageing and a clinical condition (HIV). Hum Brain Mapp 00:000-000,
Episodic experience is argued to be rich in temporal information, but it remains unclear whether ... more Episodic experience is argued to be rich in temporal information, but it remains unclear whether temporal information is directly coded in the event memory or is reconstructed at retrieval. The two experiments reported here emphasise the role of reconstructive processes of autobiographical context in establishing the date of memories. Younger and older participants were presented with famous public events, although only the latter had actually lived through them. Participants were asked to make forcedchoice judgements about the date of the event and other event-related facts. Overall, while the older group showed better fact knowledge of the events, this did not translate into better dating performance. This older group showed similar dating performance across events with high and low factual knowledge. In contrast, the younger group's dating accuracy was determined by their level of knowledge. This suggests that older individuals who have direct episodic experience of an event may perform the task in a qualitatively different manner, eschewing semantic facts in favour of other sources of information. Crucially, this process does not appear to enhance performance. A second experiment addressed the issue of whether older participants date events based on general qualities of the event memory (e.g., vividness), the availability of other event-related semantic facts, or autobiographical context. It was found that the ability to place an event in autobiographical context is related to dating accuracy, but not to other aspects of memory.