Characterizing cardiac autonomic dynamics of fear learning in humans

Understanding transient dynamics of the autonomic nervous system during fear learning remains a critical step to translate basic research into treatment of fear-related disorders. In humans, it has been demonstrated that fear learning typically elicits transient heart rate deceleration. However, classical analyses of heart rate variability (HRV) fail to disentangle the contribution of parasympathetic and sympathetic systems, and crucially, they are not able to capture phasic changes during fear learning. Here, to gain deeper insight into the physiological underpinnings of fear learning, a novel frequency-domain analysis of heart rate was performed using a short-time Fourier transform, and instantaneous spectral estimates extracted from a point-process modeling algorithm. We tested whether spectral transient components of HRV, used as a noninvasive probe of sympathetic and parasympathetic mechanisms, can dissociate between fear conditioned and neutral stimuli. We found that learned fear elicited a transient heart rate deceleration in anticipation of noxious stimuli. Crucially, results revealed a significant increase in spectral power in the high frequency band when facing the conditioned stimulus, indicating increased parasympathetic (vagal) activity, which distinguished conditioned and neutral stimuli during fear learning. Our findings provide a proximal measure of the involvement of cardiac vagal dynamics into the psychophysiology of fear learning and extinction, thus offering new insights for the characterization of fear in mental health and illness

Long-latency modulation of motor cortex excitability by ipsilateral posterior inferior frontal gyrus and pre-supplementary motor area

The primary motor cortex (M1) is strongly influenced by several frontal regions. Dual-site transcranial magnetic stimulation (dsTMS) has highlighted the timing of early (<40 ms) prefrontal/premotor influences over M1. Here we used dsTMS to investigate, for the first time, longer-latency causal interactions of the posterior inferior frontal gyrus (pIFG) and pre-supplementary motor area (pre-SMA) with M1 at rest. A suprathreshold test stimulus (TS) was applied over M1 producing a motor-evoked potential (MEP) in the relaxed hand. Either a subthreshold or a suprathreshold conditioning stimulus (CS) was administered over ipsilateral pIFG/pre-SMA sites before the TS at different CS-TS inter-stimulus intervals (ISIs: 40-150 ms). Independently of intensity, CS over pIFG and pre-SMA (but not over a control site) inhibited MEPs at an ISI of 40 ms. The CS over pIFG produced a second peak of inhibition at an ISI of 150 ms. Additionally, facilitatory modulations were found at an ISI of 60 ms, with supra-but not subthreshold CS intensities. These findings suggest differential modulatory roles of pIFG and pre-SMA in M1 excitability. In particular, the pIFG-but not the pre-SMA-exerts intensity-dependent modulatory influences over M1 within the explored time window of 40-150 ms, evidencing fine-tuned control of M1 output

Visual, sensorimotor and cognitive routes to understanding others' enjoyment: An individual differences rTMS approach to empathic accuracy

Functional imaging studies suggest that accurate understanding of others' emotional feelings (i.e., empathic accuracy, EA) recruits high-order visual, sensorimotor and mentalizing brain networks. However, the behavioral relevance of these findings is unclear. To fill in this gap, we used repetitive transcranial magnetic stimulation (rTMS) to interfere with the right superior temporal sulcus (STS), inferior frontal gyrus (IFG) and temporoparietal junction (TPJ) during an EA task requiring participants to infer the enjoyment felt by a social target while smiling/laughing. Relative to a baseline condition (sham rTMS), active rTMS of STS, IFG and TPJ (but not of a control site) disrupted the efficiency of EA task performance, mainly by lowering task accuracy; rTMS of IFG and TPJ also slowed down response speeds. Importantly, the effects of rTMS on EA task efficiency were predicted by baseline EA performance, with high-performers showing a performance decrease when the TPJ was targeted, and low-performers showing a performance decrease when the STS or the IFG was targeted. The double dissociation in the effect of rTMS between low- and high-performers suggests distinct roles of STS, IFG and TPJ in efficient understanding of the enjoyment felt by others. These findings provide causal evidence of distinct visual, sensorimotor and cognitive routes to EA and suggest that individual differences in EA are underpinned by differential recruitment of these routes

Visual, sensorimotor and cognitive routes to understanding others' enjoyment: An individual differences rTMS approach to empathic accuracy

Functional imaging studies suggest that accurate understanding of others' emotional feelings (i.e., empathic accuracy, EA) recruits high-order visual, sensorimotor and mentalizing brain networks. However, the behavioral relevance of these findings is unclear. To fill in this gap, we used repetitive transcranial magnetic stimulation (rTMS) to interfere with the right superior temporal sulcus (STS), inferior frontal gyrus (IFG) and temporoparietal junction (TPJ) during an EA task requiring participants to infer the enjoyment felt by a social target while smiling/laughing. Relative to a baseline condition (sham rTMS), active rTMS of STS, IFG and TPJ (but not of a control site) disrupted the efficiency of EA task performance, mainly by lowering task accuracy; rTMS of IFG and TPJ also slowed down response speeds. Importantly, the effects of rTMS on EA task efficiency were predicted by baseline EA performance, with high-performers showing a performance decrease when the TPJ was targeted, and low-performers showing a performance decrease when the STS or the IFG was targeted. The double dissociation in the effect of rTMS between low- and high-performers suggests distinct roles of STS, IFG and TPJ in efficient understanding of the enjoyment felt by others. These findings provide causal evidence of distinct visual, sensorimotor and cognitive routes to EA and suggest that individual differences in EA are underpinned by differential recruitment of these routes

New “CAPE” solutions for olefins plants. Detailed dynamic simulation and dynamic real-time optimization

This paper deals with certain novel and appealing computer-aided process engineering (CAPE) solutions to improve flexibility, controllability, and operability of olefins plants. It shows the use of detailed kinetic schemes, developed and validated by Professor Sauro Pierucci and his colleagues at the Chemical Engineering group at Politecnico di Milano, to produce new effective tools for reliable and accurate dynamic simulation and dynamic real-time optimization methodologies. Preliminary results and tangible benefits are explained for a steam cracking furnace

Anxiety dissociates the adaptive functions of sensory and motor response enhancements to social threats

International audienceEfficient detection and reaction to negative signals in the environment is essential for survival. In social situations, these signals are often ambiguous and can imply different levels of threat for the observer, thereby making their recognition susceptible to contextual cues – such as gaze direction when judging facial displays of emotion. However, the mechanisms underlying such contextual effects remain poorly understood. By computational modeling of human behavior and electrical brain activity, we demonstrate that gaze direction enhances the perceptual sensitivity to threat-signaling emotions – anger paired with direct gaze, and fear paired with averted gaze. This effect arises simultaneously in ventral face-selective and dorsal motor cortices at 200 ms following face presentation, dissociates across individuals as a function of anxiety, and does not reflect increased attention to threat-signaling emotions. These findings reveal that threat tunes neural processing in fast, selective, yet attention-independent fashion in sensory and motor systems, for different adaptive purposes