The volunteer underwent 20 min periods of rest and motor activation (motor task, which involved repetitively grasping and releasing the right hand, performed during the initial 5 min of the activation period)
Hypermetabolism in the contralateral primary motor cortex, the supplementary motor area, and the ipsilateral (right) cerebellum.
FDG injection has been performed during both a force and position task (separated by 7 days, with the elbow flexor muscles at 15% maximal voluntary contraction force)
Greater metabolism in the occipital and temporal cortices of the brain during the position task compared to the force task.
PET-FDG at rest and while swallowing (20-second intervals for 30 minutes) in the erect seated position
During swallowing hypermetabolism in left sensorimotor cortex, cerebellum, thalamus, precuneus, anterior insula, left and right lateral postcentral gyrus, and left and right occipital cortex; decreased metabolism in the right premotor cortex, right and left sensory and motor association cortices, left posterior insula and left cerebellum.
Subjects underwent PET-FDG performing a complex visuospatial/motor task (the computer game Tetris), before and after 4–8 weeks of daily practice on Tetris
After practicing glucose metabolism in cortical surface regions decreased despite an increased performance: subjects who improved their Tetris performance the most after practice showed the largest glucose metabolic decreases in several areas. These results suggest that learning may result in decreased use of extraneous or inefficient brain areas.
Injection of FDG in bolus during neutral (rest) and during a pure (stimulation) olfactory condition in both papers.
At rest mainly increased glucose metabolism in left superior, inferior, middle, medial frontal, orbital gyri and anterior cingulate cortex, while during olfactory stimulation hyperactivation in the cuneus, lingual, and parahippocampal gyri, mainly in the left hemisphere in both papers.
PET-FDG have been performed while the subjects viewed videos on two occasions, tasks with no inherent reasoning or problem solving, and data have been compared to Raven’s Advanced Progressive Matrices test (RAPM) scores.
Hyperactivation in specific posterior brain areas in high RAPM scorers. Subsequent analyses revealed a high/low RAPM group difference in functional connectivity between left activity and the left anterior cingulate/medial frontal gyrus. These data provide evidence that individual differences in intelligence correlate to brain function even when the brain is engaged in nonreasoning tasks.
R. J. Haier, N. S. White and M. T. Alkire, “Individual differences in general intelligence correlate with brain function during nonreasoning tasks,” Intelligence, vol. 31, no. 5, pp. 429-441, 2003.
Visual lexical decision tasks
11 right-handed male subjects
Subjects underwent PET-FGD during rest and two versions of a visual lexical decision task ( novel or repeated stimuli performed during the 30 min FDG uptake period).
Comparisons of the tasks with the resting condition revealed significant relative activations of visual and motor areas. Novel words evoked significantly greater activation in the left and right anterior cingulate gyri and right hippocampal formation than did repeated words in the same task. Relative glucose metabolism in the left angular gyrus was significantly greater to novel words than to resting. Thus, two tasks equated in sensory, motor, and decision processes, but differing in the familiarity of the stimuli, evoke significantly different patterns of brain activation.
V. I. Nenov, E. Halgren, M. Mandelkern and M. E. Smith, “Human brain metabolic responses to familiarity during lexical decision,” Hum Brain Mapp, vol. 1, no. 4, pp. 249-268, 1994.
Car driving task (active and passive driving)
30 subjects
Subjects have been divided into three subgroups for examination by PET-FDG: active driving (10 subjects that drove for 30 minutes), passive driving (10 subjects that participated as passengers on the front seat) and control (10 subjects remained seated in a lit room) groups.
In active driving: hyperactivation in the primary and secondary visual cortices, primary sensorimotor areas, premotor area, parietal association area, cingulate gyrus, the parahippocampal gyrus, thalamus and cerebellum. In passive driving: manifested a similar-looking activation pattern, lacking activations in the premotor area, cingulate and parahippocampal gyri and thalamus. Direct comparison of the active and passive driving conditions revealed activation in the cerebellum.
M. Jeong, M. Tashiro, L. N. Singh, K. Yamaguchi, E. Horikawa, M. Miyake, S. Watanuki, R. Iwata, H. Fukuda, Y. Takahashi and M. Itoh, “Functional brain mapping of actual car-driving using FDG-PET,” Ann Nucl Med, vol. 20, no. 9, pp. 623-628, 2006.
Horizontal and vertical navigation tasks in real space
24 right-handed male subjects
Spatial orientation was tested during a horizontal and vertical real navigation task. Video tracking of eye movements was used to analyse the behavioral strategy and combined with simultaneous measurements of brain activation and metabolism.
During horizontal navigation metabolism increased in the right hippocampus, bilateral retrosplenial cortex, and pontine tegmentum; during vertical navigation in bilateral hippocampus and insula. Direct comparison revealed a relative activation in the pontine tegmentum and visual cortical areas during horizontal navigation and in the flocculus, insula, and anterior cingulate cortex during vertical navigation.
A. Zwergal, F. Schoberl, G. Xiong, C. Pradhan, A. Covic, P. Werner, C. Trapp, P. Bartenstein, C. la Fougere, K. Jahn, M. Dieterich and T. Brandt, “Anisotropy of Human Horizontal and Vertical Navigation in Real Space: Behavioral and PET Correlates,” Cereb Cortex, vol. 26, no. 11, pp. 4392-4404, 2016.
Word repetition and word cognitive association tasks
8 subjects
Two different tasks were performed in randomized order during PET FDG scanning: word repetition (after the auditory presentation of nouns) as a control condition, and word association (after the auditory presentation of nouns) as a specific semantic activation.
Word association was associated with Activation in the left prefrontal cortex, the left frontal operculum (Broca's area) and the left insula, indicating the involvement of these areas in associative language processing. decreased metabolism was found in the left posterior cingulum during word association; during word repetition, highly significant negative correlations were found between the left prefrontal cortex, the contralateral cortex areas, and the ipsilateral posterior cingulum.
M. Schreckenberger, E. Gouzoulis-Mayfrank, O. Sabri, C. Arning, G. Schulz, T. Tuttass, G. Wagenknecht, H. J. Kaiser, H. Sass, and U. Buell, “Cerebral interregional correlations of associative language processing: a positron emission tomography activation study using fluorine-18 fluorodeoxyglucose,” Eur J Nucl Med, vol. 25, no. 11, pp. 1511-1519, 1998.
Continuous emotion task
10 subjects
PET FDG performed during facial emotion recognition studies and neutral on a different day
Activation the left amygdala and activation of the emotional recognition-related areas
E. Fernandez-Egea, E. Parellada, F. Lomeña, C. Falcon, J. Pavia, A. Mane, G. Sugranyes, M. Valdes, M. Bernardo, “A continuous emotional task activates the left amygdala in healthy volunteers: (18)FDG-PET study,”Psychiatry Res. 2009 Mar 31;171(3):199-206
Long-term, free recall of emotional information
8 right-handed male subjects
Subjects viewed two videos during PET scanning, separated by 3-7 days, consisting either of emotionally arousing film clips or of neutral film clips. Three weeks after the second session, memory for the videos was assessed in a free recall test.
Glucose metabolic rate of the right amygdaloid complex while viewing the emotional films was highly correlated with the number of emotional films recalled and was not correlated with the number of neutral films recalled.
L. Cahill, R. J. Haier, J. Fallon, M. T. Alkire, C. Tang, D. Keator, J. Wu, and J. L. McGaugh, “Amygdala activity at encoding correlated with long-term, free recall of emotional information,” Proceedings of the National Academy of Sciences of the United States of America, vol. 93, no. 15, pp. 8016-8021, 1996.
