Abnormal Functional Connectivity of Hippocampus During Episodic Memory Retrieval Processing Network in Amnestic Mild Cognitive Impairment.

BACKGROUND: Functional connectivity magnetic resonance imaging technique has revealed the importance of distributed network structures in higher cognitive processes in the human brain. The hippocampus has a key role in a distributed network supporting memory encoding and retrieval. Hippocampal dysfunction is a recurrent finding in memory disorders of aging such as amnestic mild cognitive impairment (aMCI) in which learning- and memory-related cognitive abilities are the predominant impairment. The functional connectivity method provides a novel approach in our attempts to better understand the changes occurring in this structure in aMCI patients. METHODS: Functional connectivity analysis was used to examine episodic memory retrieval networks in vivo in twenty 28 aMCI patients and 23 well-matched control subjects, specifically between the hippocampal structures and other brain regions. RESULTS: Compared with control subjects, aMCI patients showed significantly lower hippocampus functional connectivity in a network involving prefrontal lobe, temporal lobe, parietal lobe, and cerebellum, and higher functional connectivity to more diffuse areas of the brain than normal aging control subjects. In addition, those regions associated with increased functional connectivity with the hippocampus demonstrated a significantly negative correlation to episodic memory performance. CONCLUSIONS: aMCI patients displayed altered patterns of functional connectivity during memory retrieval. The degree of this disturbance appears to be related to level of impairment of processes involved in memory function. Because aMCI is a putative prodromal syndrome to Alzheimer's disease (AD), these early changes in functional connectivity involving the hippocampus may yield important new data to predict whether a patient will eventually develop AD.

How many processes underline category-based induction? Effect of conclusion specificity and cognitive ability

Two studies investigated participants' sensitivity to the amount and diversity of the evidence when reasoning inductively about categories. Both showed that participants are more sensitive to characteristics of the evidence for arguments with general rather than specific conclusions. Both showed an association between cognitive ability and sensitivity to these evidence characteristics, particularly when the conclusion category was general. These results suggest that a simple associative process may not be sufficient to capture some key phenomena of category-based induction. They also support the claim that the need to generate a superordinate category is a complicating factor in category-based reasoning and that adults' tendency to generate such categories while reasoning has been overestimated.

Enlargement and the European Union’s Absorption Capacity: ‘oft-forgotten’ condition or additional obstacle to membership?

The Austrian government may have failed in its efforts in 2005 to have ‘privileged partnership' inserted into the European Union's framework for accession negotiations with Turkey, but this did not prevent the country's Chancellor, Wolfgang Schussel, from claiming that ‘for the first time ever, we have set an extra condition which will yet be very important in the future for Europe, namely the ability of the Union to take in new members'. Indeed, since its inclusion in the framework for negotiations, the EU's ‘capacity to absorb' new members is referred to as a new criterion for further enlargement of the European Union (EU). When opponents of Turkey 's membership, like Schussel, celebrate the emphasis on the EU's ‘absorption capacity', Turks generally regard it as specially-designed extra obstacle to their membership aspirations even if the EU's ‘absorption capacity' is a permanent agenda item whenever the EU discusses enlargement. This article explores the origins of this – supposedly new – condition and argues that the increased emphasis on the EU's ‘absorption capacity' can be explained by the shifts in the dynamics of EU enlargement.