***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND The brain plays a crucial role in the decision to eat , integrating multiple hormonal and neural signals . A key factor controlling food intake is selective satiety , ie , the phenomenon that the motivation to eat more of a food decreases more than does the motivation to eat foods not eaten . OBJECTIVE We investigated the effect of satiation with chocolate on the brain activation associated with chocolate taste in men and women . DESIGN Twelve men and 12 women participated . Subjects fasted overnight and were scanned by use of functional magnetic resonance imaging while tasting chocolate milk , before and after eating chocolate until they were satiated . RESULTS In men , chocolate satiation was associated with increased taste activation in the ventral striatum , insula , and orbitofrontal and medial orbitofrontal cortex and with decreased taste activation in somatosensory areas . Women showed increased taste activation in the pre central gyrus , superior temporal gyrus , and putamen and decreased taste activation in the hypothalamus and amygdala . Sex differences in the effect of chocolate satiation were found in the hypothalamus , ventral striatum , and medial prefrontal cortex ( all P < 0.005 ) . CONCLUSIONS Our results indicate that men and women differ in their response to satiation and suggest that the regulation of food intake by the brain may vary between the sexes . Therefore , sex differences are a covariate of interest in studies of the brain 's responses to food Does the structure of an adult human brain alter in response to environmental dem and s ? Here we use whole-brain magnetic-resonance imaging to visualize learning-induced plasticity in the brains of volunteers who have learned to juggle . We find that these individuals show a transient and selective structural change in brain areas that are associated with the processing and storage of complex visual motion . This discovery of a stimulus-dependent alteration in the brain 's macroscopic structure contradicts the traditionally held view that cortical plasticity is associated with functional rather than anatomical changes BACKGROUND Food intake fluctuates throughout the menstrual cycle ; it is greater during the early follicular and luteal phases than in the late follicular ( periovulatory ) phase . Ovarian steroids can influence brain areas that process food-related information , but the specific contribution of individual hormones and the importance of the pr and ial state remain unknown . OBJECTIVE The objective was to examine whether brain activation during food visualization is affected by changes in estradiol concentration in the fasted and fed conditions . DESIGN Nine eumenorrheic , lean young women [ mean ( ±SD ) age : 26.2 ± 3.2 y ; body mass index ( in kg/m(2 ) ) : 22.4 ± 1.2 ] completed 2 visits , one in the early ( low estradiol ) and one in the late ( high estradiol ) follicular phase of their menstrual cycle . At each visit , subjects underwent functional magnetic resonance imaging while they viewed food and nonfood images , before and after a st and ardized meal . Region-of-interest analysis was used to examine the effect of follicular phase and pr and ial state on brain activation ( food > nonfood contrast ) and its association with estradiol concentration . RESULTS Differences were identified in the inferior frontal and fusiform gyri . In these areas , visualization of food elicited greater activation in the fed state than during fasting but only in the late follicular phase , when estradiol concentration was high . The change in estradiol concentration across the follicular phase ( late minus early ) was inversely correlated with the change in fusiform gyrus activation in the fasted state but not in the fed state . CONCLUSION Our findings suggest that estradiol may reduce food intake by decreasing sensitivity to food cues in the ventral visual pathway under conditions of energy deprivation . This trial was registered at clinical trials.gov as NCT00130117 To maintain nutritional homeostasis , external food-related stimuli have to be evaluated in relation to the internal states of hunger or satiety . To examine the neural circuitry responsible for integration of internal and external determinants of human eating behaviour , brain responses to visual and complex gustatory food-related stimuli were measured using functional magnetic resonance imaging in 18 healthy non-smokers ( 10 women , 8 men ) . Each individual was studied on two occasions , the order of which was counterbalanced ; after eating as usual and after 24 h fasting . Raised plasma free fatty acids and lower insulin and leptin concentrations confirmed that participants fasted as requested . When fasted , participants reported more hunger , nervousness and worse mood and rated the visual ( but not gustatory ) food-related stimuli as more pleasant . The effect of fasting on hunger was stronger in women than in men . No circuitry was identified as differentially responsive in fasting compared to satiety to both visual and gustatory food-related stimuli . The left insula response to the gustatory stimuli was stronger during fasting . The inferior occipito-temporal response to visual food-related stimuli also tended to be stronger during fasting . The responses in the occipito-temporal cortex to visual and in the insula to gustatory stimuli were stronger in women than in men . There was no interaction between gender and fasting . In conclusion , food reactivity in modality-specific sensory cortical areas is modulated by internal motivational states . The stronger reactivity to external food-related stimuli in women may be explored as a marker of gender-related susceptibility to eating disorders Building on findings related to physiological and psychological motivations of food preference , this research develops a framework to examine preferences toward comfort foods . Study 1 used a North American survey of 411 people to determine favored comfort foods , and Study 2 quantified the preferences for these foods across gender and across age groups using a stratified sample of 1005 additional people . Consistent with hypotheses , the findings showed different comfort food preferences across gender and across age . Males preferred warm , hearty , meal-related comfort foods ( such as steak , casseroles , and soup ) , while females instead preferred comfort foods that were more snack related ( such as chocolate and ice cream ) . In addition , younger people preferred more snack-related comfort foods compared to those over 55 years of age . Associations with guilty feelings underscored how these different preferences between males and females may extend to areas of application Although impaired inhibitory control is linked to a broad spectrum of health problems , including obesity , the brain mechanism(s ) underlying voluntary control of hunger are not well understood . We assessed the brain circuits involved in voluntary inhibition of hunger during food stimulation in 23 fasted men and women using PET and 2-deoxy-2[18F]fluoro-D-glucose ( 18FDG ) . In men , but not in women , food stimulation with inhibition significantly decreased activation in amygdala , hippocampus , insula , orbitofrontal cortex , and striatum , which are regions involved in emotional regulation , conditioning , and motivation . The suppressed activation of the orbitofrontal cortex with inhibition in men was associated with decreases in self-reports of hunger , which corroborates the involvement of this region in processing the conscious awareness of the drive to eat . This finding suggests a mechanism by which cognitive inhibition decreases the desire for food and implicates lower ability to suppress hunger in women as a contributing factor to gender differences in obesity We have previously shown that propensity for weight gain , energy balance state and sex are important determinants of the neuronal response to visual food cues . It is not clear , though , whether these factors also impact the neuronal response to taste . The objective of this study was to examine the neuronal response to sweet taste during energy imbalance in men and women recruited to be obesity-prone ( OP ) or obesity-resistant ( OR ) . OP ( 13 men and 12 women ) and OR ( 12 men and 12 women ) subjects were studied after 1 day of eucaloric , overfed and underfed conditions in a r and omized crossover design . On each test day , fMRI was performed in the respective acute fed state while subjects received in r and om order 60 trials each of 1 M sucrose solution ( SU ) , or artificial saliva ( AS ) following a visual cue predicting the taste . The neuronal response to SU versus AS expectation was significantly greater in the amygdala , orbitofrontal cortex , putamen and insula in OR versus OP ; SU receipt was not different between groups . There were also sex-based differences with men having greater neuronal response to SU versus AS receipt in the cau date than women . The results , however , were not impacted by the state of energy balance . In summary , response to expectation but not receipt of basic sweet taste was different in OR compared to OP , highlighting the importance of learning and conditioning in the propensity to gain weight . Response to sucrose taste receipt was stronger in men than women , raising questions about the effect of sex hormones on brain response to food Sex-based differences in food intake related behaviors have been observed previously . The objective of this study was to examine sex-based differences in the behavioral and neuronal responses to food . 22 women and 21 men were studied . After 6 days of controlled eucaloric feeding , ad libitum energy intake ( EI ) was measured for 3 days . Appetite ratings using visual analog scales were obtained before and after each meal . Functional magnetic resonance imaging was performed in the overnight fasted state on the last day of eucaloric feeding while subjects were presented visual stimuli of food and neutral non-food objects . While hunger and prospect i ve consumption were not different between sexes , women had higher post-meal satiety ratings and dietary restraint than men . Images of hedonic foods result ed in significantly greater activation of lateral and dorsolateral prefrontal cortex ( DLPFC ) and parietal cortex in women as compared to men . No brain regions were more activated in men as compared to women . Men increased their EI during the ad libitum diet phase . While measures of appetite or feeding behaviors did not correlate with either neuronal activation or subsequent EI , DLPFC activation in response to hedonic foods was negatively correlated with EI . In summary , greater prefrontal neuronal responses to food cues in women may suggest increased cognitive processing related to executive function , such as planning , guidance or evaluation of behavior . Finally , increased DLPFC activation , perhaps relating to inhibitory cognitive control in response to food cues may be a better predictor of food intake than behavioral measures 
    Output:
    
In response to visual food cues , women , compared with men , showed increased activation in the frontal , limbic and striatal areas of the brain as well as the fusiform gyrus while fasted .
This suggests that women may be more reactive to visual food stimuli , especially when hungry .