Most Read Articles
Jackey Suen, 04 Jul 2018

The risk of stroke remains elevated 5 years after a transient ischaemic attack (TIA) or minor ischaemic stroke, with around half of the cardiovascular (CV) events occurring during years 2–5, data from the TIAregistry.org project have shown.

Pank Jit Sin, 12 Jun 2018

A reduction as small as 2 mm Hg can lower cardiovascular risks among patients with cardiovascular disease (CVD), says an expert.

04 Mar 2018
Less than 20 percent of elderly adults in immediate care facilities are discharged to their homes, a recent Japan study reports. Older age, need for greater care and the presence of several medical conditions are among the factors that appear to be significantly related to discharge to home.

Hippocampal GABA helps suppress unwanted thoughts

10 Nov 2017
Depression has become the leading cause of morbidity and disability in the world.

Inhibition of hippocampal retrieval processes through gamma-aminobutyric acid (GABA) enables the suppression of intrusive thoughts, a recent study shows.

Thirty right-handed participants (mean age 24.7±4.3 years; males n=7) were subjected to two behavioural tasks. The first was a stop signal (SS) task, where participants were made to press a specific button in response to a coloured circle stimulus flashed on-screen. If the stimulus came with a beeping sound, participants were asked to prevent their response.

The second was a Think/No-Think (TNT) task, where they were shown reminders of unwanted thoughts and instructed to suppress retrieval. Functional magnetic resonance imaging (fMRI) was performed during each task and 1H magnetic resonance spectroscopy (1H-MRS) was used to measure GABA.

The researchers found that No-Think trial elicited significantly reduced activity both in right (p=0.003) and left (p=0.001) hippocampus. Retrieval suppression also resulted in impaired memory of the items, with No-Think items being recalled significantly less in a postscan recall test than the Think items (59±3 vs 65±3 percent; p=0.04).

Moreover, hippocampal GABA showed a significantly negative correlation with hippocampal blood-oxygen level-dependent activity signals during Think and No-Think (p<0.05 for both) conditions but not during Go or Stop conditions.

Finally, those with higher hippocampal GABA also showed stronger negative coupling between the hippocampus and dorsolateral prefrontal cortex, while those with lower hippocampal GABA did not show this negative coupling during retrieval suppression. The difference in connectivity between the two groups reached statistical significance (p=0.03).

“The present findings raise the possibility that GABAergic disinhibition in the hippocampus contributes to reduced fronto-hippocampal connectivity, hippocampal hyperactivity and intrusive symptomatology,” researchers said.

Editor's Recommendations
Most Read Articles
Jackey Suen, 04 Jul 2018

The risk of stroke remains elevated 5 years after a transient ischaemic attack (TIA) or minor ischaemic stroke, with around half of the cardiovascular (CV) events occurring during years 2–5, data from the TIAregistry.org project have shown.

Pank Jit Sin, 12 Jun 2018

A reduction as small as 2 mm Hg can lower cardiovascular risks among patients with cardiovascular disease (CVD), says an expert.

04 Mar 2018
Less than 20 percent of elderly adults in immediate care facilities are discharged to their homes, a recent Japan study reports. Older age, need for greater care and the presence of several medical conditions are among the factors that appear to be significantly related to discharge to home.