Face-Selective Responses Present in Multiple Regions of the Human Infant Brain

Faces are a rich source of social information. How does the infant brain develop the ability to recognize faces and identify potential social partners? We collected functional magnetic neuroimaging (fMRI) data from 49 awake human infants (aged 2.5-9.7 months) while they watched movies of faces, bodies, objects, and scenes. Face-selective responses were observed not only in ventral temporal cortex (VTC) but also in superior temporal sulcus (STS), and medial prefrontal cortex (MPFC). Face responses were also observed (but not fully selective) in the amygdala and thalamus. We find no evidence that face-selective responses develop in visual perception regions (VTC) prior to higher order social perception (STS) or social evaluation (MPFC) regions. We suggest that face-selective responses may develop in parallel across multiple cortical regions. Infants’ brains could thus simultaneously process faces both as a privileged category of visual images, and as potential social partners.

Biochemical profile of human infant cerebrospinal fluid in intraventricular hemorrhage and post-hemorrhagic hydrocephalus of prematurity

Background Intraventricular hemorrhage (IVH) and post-hemorrhagic hydrocephalus (PHH) have a complex pathophysiology involving inflammatory response, ventricular zone and cell–cell junction disruption, and choroid-plexus (ChP) hypersecretion. Increased cerebrospinal fluid (CSF) cytokines, extracellular matrix proteins, and blood metabolites have been noted in IVH/PHH, but osmolality and electrolyte disturbances have not been evaluated in human infants with these conditions. We hypothesized that CSF total protein, osmolality, electrolytes, and immune cells increase in PHH. Methods CSF samples were obtained from lumbar punctures of control infants and infants with IVH prior to the development of PHH and any neurosurgical intervention. Osmolality, total protein, and electrolytes were measured in 52 infants (18 controls, 10 low grade (LG) IVH, 13 high grade (HG) IVH, and 11 PHH). Serum electrolyte concentrations, and CSF and serum cell counts within 1-day of clinical sampling were obtained from clinical charts. Frontal occipital horn ratio (FOR) was measured for estimating the degree of ventriculomegaly. Dunn or Tukey’s post-test ANOVA analysis were used for pair-wise comparisons. Results CSF osmolality, sodium, potassium, and chloride were elevated in PHH compared to control (p = 0.012 − < 0.0001), LGIVH (p = 0.023 − < 0.0001), and HGIVH (p = 0.015 − 0.0003), while magnesium and calcium levels were higher compared to control (p = 0.031) and LGIVH (p = 0.041). CSF total protein was higher in both HGIVH and PHH compared to control (p = 0.0009 and 0.0006 respectively) and LGIVH (p = 0.034 and 0.028 respectively). These differences were not reflected in serum electrolyte concentrations nor calculated osmolality across the groups. However, quantitatively, CSF sodium and chloride contributed 86% of CSF osmolality change between control and PHH; and CSF osmolality positively correlated with CSF sodium (r, p = 0.55,0.0015), potassium (r, p = 0.51,0.0041), chloride (r, p = 0.60,0.0004), but not total protein across the entire patient cohort. CSF total cells (p = 0.012), total nucleated cells (p = 0.0005), and percent monocyte (p = 0.016) were elevated in PHH compared to control. Serum white blood cell count increased in PHH compared to control (p = 0.042) but there were no differences in serum cell differential across groups. CSF total nucleated cells also positively correlated with CSF osmolality, sodium, potassium, and total protein (p = 0.025 − 0.0008) in the whole cohort. Conclusions CSF osmolality increased in PHH, largely driven by electrolyte changes rather than protein levels. However, serum electrolytes levels were unchanged across groups. CSF osmolality and electrolyte changes were correlated with CSF total nucleated cells which were also increased in PHH, further suggesting PHH is a neuro-inflammatory condition.

A novel probiotics therapy for aging-related leaky gut and inflammation

Inflammaging characterized with increased low grade inflammation in older adults is common determinant of unhealthy aging; and is a major risk factor of morbidity and mortality in older adults. The precise origin of inflammation in older adults is not known, however, emerging evidence indicate that increased intestinal epithelial permeability (leaky gut) and abnormal (dysbiotic) gut microbiota could be one of the key source. However, no preventive and treatment therapies are available to reverse the leaky gut and microbiome dysbiosis in older adults. Here, we presented the evidence that a human-origin probiotics cocktail containing 5 Lactobacillus and 5 Enterococcus strains isolated from healthy human infant gut can ameliorate aging-related metabolic, physical and cognitive dysfunctions in older mice. We show that the Feeding this probiotic cocktail prevented high-fat diet–induced (HFD-induced) abnormalities in glycose metabolism and physical functions in older mice and reduced microbiota dysbiosis, leaky gut, inflammation. Probiotic-modulated gut microbiota reduced leaky gut by increasing tight junctions on intestinal epithelia, which in turn reduced inflammation. Mechanistically, probiotics increased bile salt hydrolase activity in older microbiota, which in turn increased taurine deconjugation from bile acids to increase free taurine abundance in the gut. We further show that taurine stimulated tight junctions and suppressed gut leakiness. Further, taurine increased life span, reduced adiposity and leaky gut, and enhanced physical function in Caenorhabditis elegans. Whether this novel human origin probiotic therapy could prevent or treat aging-related leaky gut and inflammation in the elderly by reversing microbiome dysbiosis requires evaluation.

Numerosity, Abstraction, and the Emergence of Symbolic Thinking

In this paper we tentatively propose that one of the feral cognitive bases for modern symbolic thinking may be numerosity, that is, the ability to appreciate and understand numbers. We proffer that numerosity appears to be an inherently abstractive process, which is supported by numerous human infant and monkey studies. We also review studies that demonstrate that the neurological substrate for numerosity is primarily the intraparietal sulcus of the parietal lobes, the angular and supramarginal gyri in the inferior parietal lobes, and areas of the prefrontal cortex. We also speculate that the lower level of abstraction involved in numerosity may serve as a basis for higher-level symbolic thinking, such as number and letter symbolism and sequencing. We further speculate that these two levels of abstraction may give rise to highly sophisticated characteristics of modern human language, such as analogizing and metaphorizing.

Biochemical Profile of Human Infant Cerebrospinal Fluid in Intraventricular Hemorrhage and Post-hemorrhagic Hydrocephalus of Prematurity

BACKGROUND Intraventricular hemorrhage (IVH) and post-hemorrhagic hydrocephalus (PHH) have complex pathophysiology involving inflammatory response, ventricular zone and cell-cell junction disruption, and choroid-plexus (ChP) hypersecretion. Increased cerebrospinal fluid (CSF) cytokines, extracellular matrix proteins, and blood metabolites have been noted in IVH/PHH, but osmolality and electrolyte disturbances have not been evaluated in human infants with these conditions. We hypothesized that CSF total protein, osmolality, electrolytes, and immune cells increase in PHH. METHODS CSF samples were obtained from lumbar punctures in control infants and infants with IVH prior to development of PHH and any neurosurgical intervention. Osmolality, total protein, and electrolytes were measured in 52 infants (18 controls, 10 low grade (LG) IVH, 13 high grade (HG) IVH, and 11 PHH). Serum electrolyte concentrations, and CSF and serum cell counts within 1-day of clinical sampling were obtained from clinical charts. Dunn or Tukey’s post-test ANOVA analysis were used for pair-wise comparisons. RESULTS CSF osmolality, sodium, potassium, and chloride were elevated in PHH compared to control (p=0.012 - <0.0001), LGIVH (p=0.023 - <0.0001), and HGIVH (p=0.015 - 0.0003), while magnesium and calcium levels were higher compared to control (p=0.031) and LGIVH (p=0.041). CSF total protein was higher in both HGIVH and PHH compared to control (p=0.0009 and 0.0006 respectively) and LGIVH (p=0.034 and 0.028 respectively). These differences were not reflected in serum electrolyte concentrations nor calculated osmolality across the groups. However, quantitatively, CSF sodium and chloride contributed 86% of CSF osmolality change between control and PHH; and CSF osmolality positively correlated with CSF sodium (r,p=0.55,0.0015), potassium (r,p=0.51,0.0041), chloride (r,p=0.60,0.0004), but not total protein across the entire patient cohort. CSF total cells (p=0.012), total nucleated cells (p=0.0005), and percent monocyte (p=0.016) were elevated in PHH compared to control. Serum white blood cell count increased in PHH compared to control (p=0.042) but there were no differences in serum cell differential across groups. CSF total nucleated cells also positively correlated with CSF osmolality, sodium, potassium, and total protein (p=0.025-0.0008) in the whole cohort. CONCLUSIONS CSF osmolality increased in PHH, largely driven by electrolyte changes rather than protein levels. However, serum electrolytes levels were unchanged across groups. CSF osmolality and electrolyte changes were correlated with CSF total nucleated cells which were also increased in PHH, further suggesting PHH is a neuro-inflammatory condition.

Endogenous and social factors influencing infant vocalizations as fitness signals

This dissertation evaluated the role of social and endogenous prelinguistic vocalizations as vocal fitness signals in human development. It consists of three studies. The first investigated the saliency of infant vocal imitation using listener judgments regarding the degree of imitativeness in parent-infant vocal turn pairs. Participating listeners demonstrated moderate to high intra- and inter-rater agreement, suggesting vocal imitation has the potential to be used as a signal of fitness to caregivers in early development. The work also showed that vocal imitation in infancy is rare. The second study sought to quantify the extent to which infants produce vocalizations socially (directed to a caregiver) vs endogenously (not directed to a caregiver) in laboratory settings where parents either attempted to engage them or talked with another adult. The infants produced three times as many vocalizations endogenously as socially in both settings. High rates of endogenously produced sounds may result from evolutionary pressures to signal wellness to caregivers through vocalization. Extensive independent vocal play may offer infants the opportunity to explore sensorimotor characteristics of the vocal system and provide the raw material that parents can use in face-to-face interactions. The third study examined social and endogenous motivations in the emergence of advanced vocal forms. Specifically, it compared canonical babbling ratios of infants at low- and high-risk for autism across high and low levels of both vocal turn-taking and vocal play. Both groups showed a tendency to produce more canonical babbling during high turn-taking and high vocal play. The findings highlight a potentially robust internal social motivation for vocalization, even in the presence of likely social-cognitive differences such as risk for autism. High rates of endogenously produced canonical syllables in high-risk infants support the idea of robust evolutionary pressures for infants to signal fitness through vocalization. Furthermore, differences in vocal production across settings can inform our understanding of the importance of both vocal interaction and independent infant exploration of vocalization. This dissertation offers perspective on the ways in which social and endogenous factors reveal natural selection pressures on fitness signaling in the human infant.

Measurement and Analysis of Human Infant Crawling for Rehabilitation: A Narrative Review

When a child shows signs of potential motor developmental disorders, early diagnosis of central nervous system (CNS) impairment is beneficial. Known as the first CNS-controlled mobility for most of infants, mobility during crawling usually has been used in clinical assessments to identify motor development disorders. The current clinical scales of motor development during crawling stage are relatively subjective. Objective and quantitative measures of infant crawling afford the possibilities to identify those infants who might benefit from early intervention, as well as the evaluation of intervention progress. Thus, increasing researchers have explored objective measurements of infant crawling in typical and atypical developing infants. However, there is a lack of comprehensive review on infant-crawling measurement and analysis toward bridging the gap between research crawling analysis and potential clinical applications. In this narrative review, we provide a practical overview of the most relevant measurements in human infant crawling, including acquisition techniques, data processing methods, features extraction, and the potential value in objective assessment of motor function in infancy; meanwhile, the possibilities to develop crawling training as early intervention to promote the locomotor function for infants with locomotor delays are also discussed.

Effect of pitch range on dogs’ response to conspecific vs. heterospecific distress cries

Distress cries are emitted by many mammal species to elicit caregiving attention. Across taxa, these calls tend to share similar acoustic structures, but not necessarily frequency range, raising the question of their interspecific communicative potential. As domestic dogs are highly responsive to human emotional cues and experience stress when hearing human cries, we explore whether their responses to distress cries from human infants and puppies depend upon sharing conspecific frequency range or species-specific call characteristics. We recorded adult dogs’ responses to distress cries from puppies and human babies, emitted from a loudspeaker in a basket. The frequency of the cries was presented in both their natural range and also shifted to match the other species. Crucially, regardless of species origin, calls falling into the dog call-frequency range elicited more attention. Thus, domestic dogs’ responses depended strongly on the frequency range. Females responded both faster and more strongly than males, potentially reflecting asymmetries in parental care investment. Our results suggest that, despite domestication leading to an increased overall responsiveness to human cues, dogs still respond considerably less to calls in the natural human infant range than puppy range. Dogs appear to use a fast but inaccurate decision-making process to determine their response to distress-like vocalisations.

Protophones, the precursors to speech, dominate the human infant vocal landscape

Human infant vocalization is viewed as a critical foundation for vocal learning and language. All apes share distress sounds (shrieks and cries) and laughter. Another vocal type, speech-like sounds, common in human infants, is rare but not absent in other apes. These three vocal types form a basis for especially informative cross-species comparisons. To make such comparisons possible we need empirical research documenting the frequency of occurrence of all three. The present work provides a comprehensive portrayal of these three vocal types in the human infant from longitudinal research in various circumstances of recording. Recently, the predominant vocalizations of the human infant have been shown to be speech-like sounds, or ‘protophones’, including both canonical and non-canonical babbling. The research shows that protophones outnumber cries by a factor of at least five based on data from random-sampling of all-day recordings across the first year. The present work expands on the prior reports, showing the protophones vastly outnumber both cry and laughter in both all-day and laboratory recordings in various circumstances. The data provide new evidence of the predominance of protophones in the infant vocal landscape and illuminate their role in human vocal learning and the origin of language. This article is part of the theme issue ‘Vocal learning in animals and humans’.