Caterina Padulo

GABA content within the ventromedial prefrontal cortex is related to trait anxiety

The ventromedial prefrontal cortex (vmPFC) plays a key role in emotion processing and regulation. vmPFC dysfunction may lead to disinhibition of amygdala causing high anxiety levels. γ-Aminobutyric acid (GABA) inter-neurons within vmPFC shape the information flow to amygdala. Thus, we hypothesize that GABA content within vmPFC could be relevant to trait anxiety. Forty-three healthy volunteers aged between 20 and 88 years were assessed for trait anxiety with the Subscale-2 of the State-Trait-Anxiety Inventory (STAI-Y2) and were studied with proton magnetic resonance spectroscopy to investigate GABA and Glx (glutamate+glutamine) contents within vmPFC. Total creatine (tCr) was used as internal reference. Partial correlations assessed the association between metabolite levels and STAI-Y2 scores, removing the effect of possible nuisance factors including age, educational level, volumes of gray matter and white matter within magnetic resonance spectroscopy voxel. We observed a positive relationship between GABA/tCr and STAI-Y2 scores. No significant relationships were found between Glx/tCr and STAI-Y2 and between tCr/water and STAI-Y2. No differences were found between males and females as regards to age, STAI-Y2, GABA/tCr, Glx/tCr, tCr/water, gray matter and white matter volumes. We suggest a close relationship between GABA content within vmPFC and trait anxiety providing new insights in the physiology of emotional brain.

GABA levels in the ventromedial prefrontal cortex during the viewing of appetitive and disgusting food images.

Characterizing how the brain appraises the psychological dimensions of reward is one of the central topics of neuroscience. It has become clear that dopamine neurons are implicated in the transmission of both rewarding information and aversive and alerting events through two different neuronal populations involved in encoding the motivational value and the motivational salience of stimuli, respectively. Nonetheless, there is less agreement on the role of the ventromedial prefrontal cortex (vmPFC) and the related neurotransmitter release during the processing of biologically relevant stimuli. To address this issue, we employed magnetic resonance spectroscopy (MRS), a non-invasive methodology that allows detection of some metabolites in the human brain in vivo, in order to assess the role of the vmPFC in encoding stimulus value rather than stimulus salience. Specifically, we measured gamma-aminobutyric acid (GABA) and, with control purposes, Glx levels in healthy subjects during the observation of appetitive and disgusting food images. We observed a decrease of GABA and no changes in Glx concentration in the vmPFC in both conditions. Furthermore, a comparatively smaller GABA reduction during the observation of appetitive food images than during the observation of disgusting food images was positively correlated with the scores obtained to the body image concerns sub-scale of Body Uneasiness Test (BUT). These results are consistent with the idea that the vmPFC plays a crucial role in processing both rewarding and aversive stimuli, possibly by encoding stimulus salience through glutamatergic and/or noradrenergic projections to deeper mesencephalic and limbic areas.

Sex-specific effects of posture on the attribution of handedness to an imagined agent

In a series of previous studies, we found that when participants were required to imagine another person performing a manual action, they imagined a significantly higher proportion of actions performed with their dominant rather than non-dominant hand, which indicates that shared motor representations between the self and the other are involved also during the imagination of others’ actions. Interestingly, the activation of lateralized body-specific motor representations (as indexed by the congruence between the participant’s handedness and the imagined person’s handedness) appeared to be affected by the visual perspective adopted and participants’ handedness. Given that past literature indicates that incongruent or unnatural postures interfere with motor imagery, we tested 480 right-handed participants to investigate whether subjects holding their right hand behind their back would have imagined right-handed actions less frequently than those holding their left hand behind their back. Moreover, we examined the effects of participant’s sex, action category (simple or complex) and hand shape (open or fist). Contrary to our prediction, female participants holding their right hand behind their back imagined right-handed actions more frequently than those holding their left hand behind their back, whereas no significant effect was observed in male participants. We propose that the muscle contraction needed to keep a hand behind the back could activate the motor representations of that hand so as to increase the likelihood of imagining an action performed with the corresponding hand. Moreover, the sex difference observed is consistent with the greater use of embodied strategies by females than by males.

Involvement of ordinary what and where auditory cortical areas during illusory perception

The focus of the present study is on the relationships between illusory and non-illusory auditory perception analyzed at a biological level. To this aim, we investigate neural mechanisms underlying the Deutsch’s illusion, a condition in which both sound identity (“what”) and origin (“where”) are deceptively perceived. We recorded magnetoencephalogram from healthy subjects in three conditions: (a) listening to the acoustic sequence eliciting the illusion (ILL), (b) listening to a monaural acoustic sequence mimicking the illusory percept (MON), and (c) listening to an acoustic sequence similar to (a) but not eliciting the illusion (NIL). Results show that the areas involved in the illusion were the Heschl’s gyrus, the insular cortex, the inferior frontal gyrus, and the medial-frontal gyrus bilaterally, together with the left inferior-parietal lobe. These areas belong to the two main auditory streams known as the what and where pathways. The neural responses there observed indicate that the sound sequence eliciting the illusion is associated to larger activity at early and middle latencies and to a dynamic lateralization pattern net in favor of the left hemisphere. The present findings extend to illusory perception the well-known what–where auditory processing mechanism, especially as regards tardy latency activity.

Gender Differences in Food Choice: Effects of Superior Temporal Sulcus Stimulation

The easy availability of food has caused a shift from eating for survival to hedonic eating. Women, compared to men, have shown to respond differently to food cues in the environment on a behavioral and a neural level, in particular to energy rich (compared to low energy) foods. It has been demonstrated that the right posterior superior temporal sulcus (STS) is the only region exhibiting greater activation for high vs. low calorie food choices. In order to test for a possible causal role of STS in food choice, we applied high frequency transcranial random noise stimulation (tRNS) on STS assuming a different response pattern between males and females. Our participants (18 females, 17 males) performed a forced choice task between food pairs matched for individual liking but differed in calorie, during the left STS, right STS stimulation and sham condition. Male participants showed a general preference for low calorie (LC) foods compared to females. In addition, we observed in males, but not in females, an increase of high calorie (HC) food choice during right STS tRNS compared to sham condition and left STS tRNS. Finally, we found an increase of missed choices during right STS stimulation compared to sham condition and left STS stimulation. In conclusion, thanks to tRNS evidence, we both confirm the involvement and suggest a causal role of right posterior STS in feeding behavior. Moreover, we suggest that gender differences exist in STS mechanisms underlying food choice.

Inversion Reveals Perceptual Asymmetries in the Configural Processing of Human Body

Ambiguous human bodies performing unimanual/unipedal actions are perceived more frequently as right-handed/footed rather than left-handed/footed, which suggests a perceptual and attentional bias toward the right side of others’ body. A bias toward the right arm of human bodies could be adaptive in social life, most social interactions occurring with right-handed individuals, and the implicit knowledge that the dominant hand of humans is usually placed on their right side might also be included in body configural information. Given that inversion disrupts configural processing for human bodies, we investigated whether inversion reduces the bias toward the right side of human bodies. Consistent with our hypothesis, when presented with ambiguous stimuli depicting humans performing lateralized actions or movements, participants perceived a greater proportion of right-handed figures when the stimuli were shown upright than when the stimuli were shown inverted. The present findings seem to confirm our hypothesis that body configural information may include some form of knowledge about the probable handedness of other individuals, although alternative accounts involving the role of experience cannot be ruled out.

Assessment of late-life depression via self-report measures: a review

Depression in later life is a significant and growing problem. Age-related differences in the type and severity of depressive disorders continue to be questioned and necessarily question differential methods of assessment and treatment strategies. A host of geropsychiatric measures have been developed for diagnostic purposes, for rating severity of depression, and monitoring treatment progress. This literature review includes the self-report depression measures commonly and currently used in geropsychological practice. Each of the included measures is considered according to its psychometric properties. In particular, information about reliability; convergent, divergent, and factorial validity evidence based on data from clinical and nonclinical samples of older adults; and availability of age-appropriate norms was provided along with the strengths and weaknesses of each measure. Results highlighted that in cognitively intact or mildly impaired patients over 65 years, the Geriatric Depression Scale and the Geriatric Depression Scale-15 currently seem to be the preferred instruments. The psychometric functioning of the Beck Depression Inventory-II and the Center for Epidemiological Studies Depression Scale, instead, is mixed in this population. Most importantly, this review may be a valuable resource for practicing clinicians and researchers who wish to develop state-of-the-science assessment strategies for clinical problems and make informed choices about which instruments best suit their purposes in older populations.

Author Correction: Emotional faces influence evaluation of natural and transformed food

This article unfortunately contained two mistakes.

Hemispheric asymmetries in the processing of body sides: A study with ambiguous human silhouettes

When required to indicate the perceived orientation of pictures of human silhouettes with ambiguous front/back orientation and handedness, both right- and left-handed participants perceive the figures more frequently as right-handed than as left-handed, which seems to indicate an attentional bias towards the right arm of human bodies. Given that past research exploiting the divided visual field paradigm indicated a processing advantage for contralateral body parts in both hemispheres, we tested whether human silhouettes with ambiguous handedness presented in the right visual field would be interpreted more frequently as right-handed compared with those presented in the left visual field. We confirmed the expected lateralised embodiment of ambiguous human bodies, in line with previous studies showing that right and left limbs are processed faster and/or more accurately when presented in the right and left hemifield, respectively.