The metabolic signature of C9ORF72-related ALS: FDG PET comparison with nonmutated patients

Purpose Recently, a GGGGCC hexanucleotide repeat expansion in the C9ORF72 gene, located on chromosome 9p21 has been demonstrated to be the commonest cause of familial amyotrophic lateral sclerosis (ALS) and to account for 5 to 10 % of apparently sporadic ALS. Relatively little is known about the brain metabolism profile of patients carrying the expansion. Our aim was to identify the [18F]FDG PET profile in ALS patients with the C9ORF72 expansion (C9ORF72-ALS). Methods Fifteen C9ORF72-ALS patients were compared with 12 patients with ALS and comorbid frontotemporal dementia (FTD) without the C9ORF72 expansion (ALSFTD) and 30 cognitively normal patients with ALS without mutations of ALS-related genes (sALS). The three groups were then cross-matched to 40 neurologically normal controls. All patients underwent FDG PET within 4 months of diagnosis. Results The C9ORF72-ALS patients compared with the sALS patients showed significant hypometabolism in the anterior and posterior cingulate cortex, insula, caudate and thalamus, the left frontal and superior temporal cortex, and hypermetabolism in the midbrain, bilateral occipital cortex, globus pallidus and left inferior temporal cortex. The ALS FTD patients compared with the sALS patients showed more limited hypometabolic areas, including the orbitofrontal, prefrontal, anterior cingulate and insular cortex, and hypermetabolic areas, including the bilateral occipital cortex, the left precentral and postcentral cortex and superior temporal gyrus. The C9ORF72-ALS patients compared with the ALS-FTD patients showed hypometabolism in the left temporal cortex. Conclusion ALS patients with the C9ORF72 hexanucleotide repeat expansion had a more widespread central nervous system involvement than ALS patients without genetic mutations, with or without comorbid FTD, consistent with their more severe clinical picture

Brain hypermetabolism in amyotrophic lateral sclerosis: A FDG PET study in ALS of spinal and bulbar onset.

Abstract Purpose To identify the neurobiological traits of amyotrophic lateral sclerosis (ALS) and to elucidate functional differences between ALS of spinal and bulbar onset. We hypothesized that glucose metabolism distribution might vary between groups. Methods The study groups comprised 32 patients with ALS of either bulbar (n=13) or spinal (n=19) onset and 22 subjects as controls. They were investigated by [ 18 F]fluorodeoxyglucose (FDG) positron emission tomography (FDG PET), comparing the patient groups with each other and with the controls by statistical parametric mapping. Results Highly significant relative increases in glucose metabolism distribution were found in the group comprising all 32 ALS patients as compared with the controls in the bilateral amygdalae, midbrain, pons and cerebellum. Relative hypermetabolism was also found in patients with spinal onset as compared with the controls in the right midbrain. In patients with bulbar onset compared with the controls and with patients with spinal onset, large relatively hypometabolic areas were found in the bilateral frontal cortex, right insula, anterior cingulate, precuneus and inferior parietal lobe. Patients with spinal onset had significantly higher scores in a neuropsychological test assessing verbal fluency compared with patients with bulbar onset. Conclusion This large FDG PET investigation provided unprecedented evidence of relatively increased metabolism in the amygdalae, midbrain and pons in ALS patients as compared with control subjects, possibly due to local activation of astrocytes and microglia. Highly significant relative decreases in metabolism were found in large frontal and parietal regions in the bulbar onset patients as compared with the spinal onset patients and the controls, suggesting a differential metabolic and neuropsychological state between the two conditions

Group Membership Modulates the Neural Circuitry Underlying Third Party Punishment.

This research aims to explore the neural correlates involved in altruistic punishment, parochial altruism and anti-social punishment, using the Third-Party Punishment (TPP) game. In particular, this study considered these punishment behaviors in in-group vs. out-group game settings, to compare how people behave with members of their own national group and with members of another national group. The results showed that participants act altruistically to protect in-group members. This study indicates that norm violation in in-group (but not in out-group) settings results in increased activity in the medial prefrontal cortex and temporo-parietal junction, brain regions involved in the mentalizing network, as the third-party attempts to understand or justify in-group members' behavior. Finally, exploratory analysis during anti-social punishment behavior showed brain activation recruitment of the ventromedial prefrontal cortex, an area associated with altered regulation of emotions

An example of a trial used in the present study.

<p>In this case Players A and B belonged to the <i>out-out group condition</i> (OUT- OUT).</p

FMRI results: Antisocial punishment.

<p>Brain activation recruitment of the ventromedial prefrontal cortex during antisocial punishment behavior for the <i>punishment vs</i>. <i>no punishment</i> contrast in the in-group and out-group settings.</p

FMRI results: Parochial altruism.

<p>When player C observes unfair behavior in the <i>in-in group condition</i> (IN-IN) the recruitment of the mentalizing system, the medial prefrontal cortex (MPFC), and the right and left temporal-parietal junction (rTPJ and lTPJ) and, in addition, of the caudate nucleus (CN) were observed.</p

FMRI results: Altruistic Punishment.

<p>Brain activation maps during altruistic punishment behavior for the <i>punishment vs</i>. <i>no punishment</i> contrast: (A) ventral tegmental area (VTA), anterior cingulate cortex (ACC);(B) right and left insula (rAI; lAI), ventromedial prefrontal cortex (VMPFC).</p

Brain regions revealed by contrasts of interest.

<p>Brain regions revealed by contrasts of interest.</p