Stefano Massaccesi

Infant cortex responds to other humans from shortly after birth

A significant feature of the adult human brain is its ability to selectively process information about conspecifics. Much debate has centred on whether this specialization is primarily a result of phylogenetic adaptation, or whether the brain acquires expertise in processing social stimuli as a result of its being born into an intensely social environment. Here we study the haemodynamic response in cortical areas of newborns (1–5 days old) while they passively viewed dynamic human or mechanical action videos. We observed activation selective to a dynamic face stimulus over bilateral posterior temporal cortex, but no activation in response to a moving human arm. This selective activation to the social stimulus correlated with age in hours over the first few days post partum. Thus, even very limited experience of face-to-face interaction with other humans may be sufficient to elicit social stimulus activation of relevant cortical regions.

Heart Rate Differences between Targets and Nontargets in Intuitive Tasks

This study reports the results of one experiment and a replication, aimed at investigating heart rate changes related to a purely intuitive task. In each experiment, 12 subjects were required to guess which of four pictures presented in sequence for about 10 s was the target. Each subject performed 20 trials. In each trial, the target was automatically selected using a pseudorandom algorithm. The heart rate was recorded during the picture presentation. In the first experiment, a statistically significant heart rate increment associated with targets with respect to nontargets was observed. The replication experiment with 12 new subjects confirmed the data obtained in the main experiment. These findings support the hypothesis that heart rate is related not only to conscious but also to unconscious cognitive activity such as that involved in intuitive tasks, giving convergent evidence for the models describing human intuitive cognitive activity as a double, partially independent information processing system.

Cooling for Newborns with Hypoxic Ischemic Encephalopathy

adverse effects of cooling and ‘early’ indicators of neurodevelopmental outcome. Data Collection and Analysis: Four review authors independently selected, assessed the quality of and extracted data from the included studies. Study authors were contacted for further information. Meta-analyses were performed using risk ratios (RR) and risk differences (RD) for dichotomous data, and weighted mean difference for continuous data with 95% confidence intervals (CI). Main Results: We included 11 randomized controlled trials in this updated review, comprising 1,505 term and late preterm infants with moderate/severe encephalopathy and evidence of intrapartum asphyxia. Therapeutic hypothermia resulted in a statistically significant and clinically important reduction in the combined outcome of mortality or major neurodevelopmental disability to 18 months of age (typical RR 0.75 (95% CI 0.68–0.83); typical RD –0.15, 95% CI –0.20 to –0.10); number needed to treat for an additional beneficial outcome (NNTB) 7 (95% CI 5–10) (8 studies, 1,344 infants). Cooling also resulted in statistically significant reductions in mortality (typical RR 0.75 (95% CI 0.64–0.88), typical RD –0.09 (95% CI –0.13 to –0.04); NNTB 11 (95% CI 8–25) (11 studies, 1,468 infants) and in neurodevelopmental disability in survivors (typical RR 0.77 (95% CI 0.63–0.94), typical RD –0.13 (95% CI –0.19 to –0.07); NNTB 8 (95% CI 5–14) (8 studies, 917 infants). Some adverse effects of hypothermia included an increase sinus bradycardia and a significant increase in thrombocytopenia. Cochrane Abstract

Control of hand shaping in response to object shape perturbation

This study assessed how hand shaping responds to a perturbation of object shape. In blocked trials (80% of total), subjects were instructed to reach, to grasp and lift a concave or a convex object. In perturbed trials (20% of total), a rotating device allowed for the rapid change from the concave to the convex object or vice versa. In this situation subjects grasped the last presented object. Flexion/extension at the metacarpal-phalangeal and proximal interphalangeal joints of all digits was measured by resistive sensors embedded in a glove. In the blocked condition we found that most joints of the fingers were modulated by the type of the to-be-grasped object during the reach. When object shape was perturbed, reach duration was longer and angular excursion of all fingers differed with respect to blocked trials. For the ‘convex → concave’ perturbation, a greater degree of finger extension was found than during the blocked ‘concave’ trials. In contrast, for the ‘concave → convex’ perturbation, fingers were more flexed than for the blocked ‘convex’ trials. The thumb reacted to the perturbation showing a similar pattern (i.e., over-flexion with respect to the blocked trials) regardless the ‘direction’ of the perturbation. The present results suggest that applying an object shape perturbation during a reach-to-grasp action determines a reorganization of all digits. This pattern is suggestive of a control strategy, which assigns to opposing digits different roles.

Subliminally Perceived Odours Modulate Female Intrasexual Competition: An Eye Movement Study

BACKGROUND Evidence suggests that subliminal odorants influence human perception and behavior. It has been hypothesized that the human sex-steroid derived compound 4,16-androstadien-3-one (androstadienone) functions as a human chemosignal. The most intensively studied steroid compound, androstadienone is known to be biologically relevant since it seems to convey information about male mate quality to women. It is unclear if the effects of androstadienone are menstrual cycle related. METHODOLOGY/PRINCIPAL FINDINGS In the first experiment, heterosexual women were exposed to androstadienone or a control compound and asked to view stimuli such as female faces, male faces and familiar objects while their eye movements were recorded. In the second experiment the same women were asked to rate the level of stimuli attractiveness following exposure to the study or control compound. The results indicated that women at high conception risk spent more time viewing the female than the male faces regardless of the compound administered. Women at a low conception risk exhibited a preference for female faces only following exposure to androstadienone. CONCLUSIONS/SIGNIFICANCE We contend that a womans level of fertility influences her evaluation of potential competitors (e.g., faces of other women) during times critical for reproduction. Subliminally perceived odorants, such as androstadienone, might similarly enhance intrasexual competition strategies in women during fertility phases not critical for conception. These findings offer a substantial contribution to the current debate about the effects that subliminally perceived body odors might have on behavior.

Functional Neuroimaging of Breastfeeding Analgesia by Multichannel Near-Infrared Spectroscopy

Background: Newborns perceive pain, and several non-pharmacologic analgesic methods have been used during painful procedures. Activation of the neonatal somatosensory cortex, in association with a painful procedure without analgesia, has been demonstrated by two-channel near-infrared spectroscopy (NIRS). Objectives: To evaluate both cortical and behavioural responses of healthy term newborns to a painful procedure during two non-pharmacologic analgesic interventions, i.e. glucose solution and breastfeeding. Methods: The effects of glucose and breastfeeding on pain-associated neonatal cortical activity were studied in two groups (n = 30) by multichannel NIRS during a heel prick. Cortical activation was identified by variations in oxygenated haemoglobin. Neonatal pain expression was assessed by a validated scale. Results: No significant variations in cortical activity emerged using glucose solution, whereas breastfed newborns showed widespread cortical activation. Breastfed neonates showed significantly less behavioural pain expression. Conclusions: Glucose is associated with no significant cortical activation and may interfere with pain-associated response at the cortical level. Conversely, breastfeeding analgesia is associated with generalized cortical activation and may act by multisensory stimulation, possibly overwhelming pain perception.

Effects of Prone and Supine Position on Cerebral Blood Flow in Preterm Infants

We evaluated the effect of prone and supine position on cerebral blood flow (CBF) in stable preterm infants. CBF, PO(2), and PCO(2) were measured in the two positions. Peripheral oxygenation increased and CBF decreased in prone position. We speculate that CBF autoregulation may compensate for increased peripheral oxygenation, by decreasing CBF.

Breaking the flow of an action

The present study was aimed at investigating whether the execution of a sequential action changes when the temporal contiguity between the motor steps composing it is altered. Participants were requested to reach and grasp an object and pour its contents into a container under two conditions: a ‘fluent pouring’ condition in which participants were instructed to execute the action fluently and an ‘interrupted pouring’ condition in which participants were instructed to reach and grasp the object, wait for an acoustic signal and then complete the pouring action. A ‘control’ condition in which participants were requested to reach and grasp the object without performing any subsequent action was also administered. Results indicate that movement duration and hand kinematics varied depending on the temporal relationship between the reach-to-grasp and the lift-to-pour phases. When a delay at object contact was introduced, reach duration was longer and the thumb/index abduction angle was greater than when such a delay was not introduced. These results are interpreted in light of ‘internal model’ theories suggesting that a strict temporal contiguity between the motor steps composing an action is a prerequisite for a skilful movement to be planned and executed.

Non-invasive assessment of hemispheric language dominance by optical topography during a brief passive listening test: A pilot study

Summary Background The Wada test is usually used for pre-surgical assessment of language lateralization. Considering its invasiveness and risk of complications, alternative methods have been proposed but they are not always applicable to non-cooperative patients. In this study we explored the possibility of using optical topography (OT) – a multichannel near-infrared system – for non-invasive assessment of hemispheric language dominance during passive listening. Material/Methods Cortical activity was monitored in a sample of healthy, adult Italian native speakers, all right-handed. We assessed changes in oxy-haemoglobin concentration in temporal, parietal and posterior frontal lobes during a passive listening of bi-syllabic words and vowel-consonant-vowel syllables lasting less then 3 minutes. Activated channels were identified by t tests. Results Left hemisphere showed significant activity only during the passive listening of bi-syllabic words. Specifically, the superior temporal gyrus, the supramarginal gyrus and the posterior inferior parietal lobe were activated. Conclusions During passive listening of bi-syllabic words, right handed healthy adults showed a significant activation in areas already known to be involved in speech comprehension. Although more research is needed, OT proved to be a promising alternative to the Wada test for non-invasive assessment of hemispheric language lateralization, even if using a particularly brief trial, which has been designed for future applications with non-cooperative subjects.

Motion-induced blindness measured objectively

During central fixation, a moving pattern of nontargets induces repeated temporary blindness to even salient peripheral targets: motion-induced blindness (MIB). Hitherto, behavioral measures of MIB have relied on subjective judgments. Here, we offer an objective alternative that builds on earlier findings regarding the effects of MIB on the detectability of physical target offsets. We propose a small modification of regular MIB displays: Following a variable duration (lead time), one of the targets is physically removed. Subjects are to respond immediately afterward. We hypothesize that illusory target offsets, caused by MIB, are mistaken for physical target offsets and that errors should thus increase with lead time. Indeed, for both nonsalient and salient targets, we found that detection accuracy for physical target offsets dramatically decreased with lead time. We conclude that target offset detection accuracy is a valid objective measure of MIB. With our method, effects of guessing are minimal, and the fitting of psychometric functions is straightforward. In principle, a staircase extension—for more efficient data collection—is also possible.