fMRI measures blood flow to determine activation and deactivation of the specific brain regions associated with particular tasks.

What is the evidence for fMRI findings in people with bipolar disorder?

Compared to controls, moderate quality evidence finds decreased activation in adults with bipolar disorder in the inferior frontal gyrus during cognitive and emotion tasks, and during a mania phase. There were also decreases in the lingual gyrus during cognitive tasks and euthymia, and in the putamen during cognitive tasks. There were increases in activation in the medial temporal lobe, putamen, pallidum, and caudate during cognitive tasks.

In children and adolescents with bipolar disorder, there was decreased activation in the right ventrolateral prefrontal cortex, right dorsolateral prefrontal cortex, right superior frontal gyrus, right dorsal cingulate cortex, and right dorsal striatum compared to age-matched controls. There was increased activation in the right amygdala, right limbic lobe, right parahippocampal gyrus, right medial prefrontal cortex, right subgenual cingulate cortex, right somatosensory association cortex, left ventral striatum, left ventrolateral prefrontal cortex, left cerebellum, left lentiform nucleus, putamen, and lateral globus pallidus.

There was increased activation in children with a parent with bipolar disorder in the right dorsolateral prefrontal cortex, right insula, right inferior parietal lobule, and left cerebellum compared to age-matched controls. Compared to children and adolescents with a parent with bipolar disorder, there was decreased activation in children and adolescents with bipolar disorder in the right dorsolateral prefrontal cortex, right insula, and left cerebellum.

Moderate to low quality evidence suggests more hypoactivation in the putamen of people with bipolar disorder than in the putamen of people with major depressive disorder, post-traumatic stress disorder, or an anxiety disorder. There were similar levels of hypoactivation across diagnoses in the prefrontal/insula and the inferior parietal clusters and similar levels of hyperactivation in the left amygdala/parahippocampal gyrus, the left thalamus, and the perigenual/dorsal anterior cingulate cortex.

During facial affect processing tasks

Compared to controls, moderate quality evidence suggests decreased activation in people with bipolar disorder in the bilateral ventrolateral prefrontal cortex, and increased activation in bilateral parahippocampal gyrus (including the amygdala), left putamen and left pulvinar. With fear-face stimuli, people with bipolar disorder showed decreased activation in bilateral inferior frontal gyri and the left anterior cingulated gyrus, and increased activation in the left parahippocampal gyrus, left putamen, and left pulvinar thalamus. With happy-face stimuli, people with bipolar disorder showed decreased activation in the right anterior cingulated gyrus and increased activation in bilateral caudate and the left parahippocampal gyrus.

Compared to age-matched controls, moderate to low quality evidence suggests decreased activation in children or adolescents in the left middle occipital gyrus, and the right inferior frontal gyrus, with increased activity in the right amygdala, right parahippocampal gyrus, left inferior frontal gyrus, and left putamen.

Compared to adults with bipolar disorder, moderate to low quality evidence suggests increased activation in children or adolescents with bipolar disorder in the right amygdala.

Compared to people with major depression, moderate quality evidence suggests decreased activation in people with bipolar disorder in the dorsal anterior cingulate gyrus, and increased activation in the parahippocampal gyrus (including the amygdala), bilateral ventral anterior cingulate gyri, and left pulvinar.

Compared to people with schizophrenia moderate quality evidence suggests decreased activation in people with bipolar disorder in bilateral occipital cunei, and increased activation in the left thalamus pulvinar.

During cognitive control tasks (perceived task difficulty and effort)

Compared to controls, moderate quality evidence suggests decreased activation in people with bipolar disorder in the right inferior frontal gyrus, the right caudate nucleus, the right angular gyrus, the left inferior temporal gyrus, the left inferior frontal gyrus and the left posterior cingulate gyrus. There was also increased activation in the left precentral, left superior frontal, and the right superior temporal gyrus of patients.

During executive functioning tasks

Compared to controls, moderate quality evidence suggests reduced activation in the striatum, supplementary motor area, precentral gyrus, left cerebral hemisphere, and left cerebellum and more activation in the left gyrus rectus and right middle temporal gyrus. During euthymia there was reduced activation in the striatum, left supplementary motor area, and right inferior parietal gyrus, and more activation in the left gyrus rectus, and right middle and superior temporal lobe. People with bipolar I disorder showed hypoactivation in the putamen, insula, amygdala, supplementary motor area, and left caudate nucleus, and hyperactivation the right superior temporal lobe and left superior frontal gyrus.

During response inhibition tasks

Compared to controls, moderate quality evidence suggests decreased activation in the right inferior frontal gyrus, left lentiform nucleus, left precuneus, and left postcentral gyrus, with no evidence of increased activation. During euthymia, patients showed decreased activation in the striatum, left supplementary motor area, right anterior cingulate cortex, left lentiform nucleus/putamen, right inferior frontal gyrus, left inferior parietal lobule, right inferior parietal lobule, and the left precuneus. Euthymic patients showed increased activation in the left superior temporal gyrus, right middle frontal gyrus, and in rostral parts of the right inferior frontal gyrus. During mania, patients showed decreased activation in the right inferior frontal gyrus, left medial frontal gyrus, and the anterior cingulate cortex, and increased activation in the right insula and bilateral basal ganglia

During attention tasks

Compared to age-matched controls, moderate quality evidence suggests decreased activation in children and adolescents with bipolar disorder in the right anterior cingulate cortex, right limbic areas (including the amygdala), right dorsolateral prefrontal cortex, right lentiform nucleus and right globus pallidus. Increased activation was found in the right middle frontal gyrus, left insula, and bilateral ventrolateral prefrontal cortex of patients.

During working memory tasks

Compared to controls, moderate quality evidence suggests decreased activation in the left precentral gyrus and left cerebellum, and increased activation in the left gyrus rectus, and right middle and superior temporal lobe. People with bipolar disorder in the euthymic state showed hypoactivation in the left precuneus, right inferior occipital gyrus, and dorsolateral prefrontal cortex, and hyperactivation in the left ventromedial prefrontal cortex and right superior temporal gyrus.

December 2021

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The post Functional magnetic resonance imaging appeared first on NeuRA Library.

PET and SPECT are nuclear-based imaging techniques that utilise radioactive tracers to visualise functional brain activity. The radioisotopes tracers are coupled with a biological molecule such as glucose, which is used during cellular metabolism and can be used to highlight areas with changes in metabolic activity. While SPECT offers more limited spatial and temporal resolution than PET, it is less expensive as it does not require a cyclotron in close proximity.

What is the evidence for PET and SPECT anomalies in people with bipolar disorder?

Moderate to low quality evidence finds increased cerebral glucose metabolism in bipolar disorder in the right precentral gyrus, right supplementary motor area, right rolandic operculum, left anterior cingulate / paracingulate gyri and the left optic radiations. There was decreased cerebral glucose metabolism in bipolar disorder in the middle cerebellar peduncles, left superior temporal gyrus, and left middle temporal gyrus.

December 2021

Image: ©momius – stock.adobe.com

The post Positron emission tomography / single-photon emission computed tomography appeared first on NeuRA Library.