Sensory and perceptual processes in early infancy

Remembering beloved objects from early childhood, middle childhood, and adolescence and the role of the five senses

ABSTRACTBeloved objects are cherished and valued possessions that we feel attached to. Previous research has demonstrated that the functions of beloved objects change across a lifespan. However, beloved objects may not only be appreciated because of their functions but also because of their sensory qualities. We hypothesised that the sensory experiences with beloved objects show a developmental trajectory and that the proximal senses (touch, taste, smell) become less important across childhood and adolescence, while the distant senses (vision, hearing) become more important. Moreover, we assumed that the observed changes in the sensory experiences are associated with the corresponding changes of functions across life stages. Building on the idea that those (perceptual) aspects of our environment that are particularly important to us are preferentially stored in memory, we hypothesised that this developmental trajectory would also be reflected in retrospective accounts. Hence, participants (N = 225) were asked to remember beloved objects from early childhood, middle childhood, and adolescence, to describe their functions and to answer questions regarding their sensory experiences with the objects. The mixed methods data analyses confirmed our hypotheses. Taken together, our study illustrates and underlines the importance of beloved objects for thinking, behaviour, memory, and identity.

Gene Therapy Restores Auditory Functions in an Adult Vglut3 Knockout Mouse Model

Adeno-associated virus (AAV)-based gene therapy has been demonstrated to be extremely effective for treating genetic hearing loss over the past several years. However, successful gene therapies for hereditary deafness have not been well-studied in adult mice. To explore the possibility of gene therapy after peripheral auditory maturity, we used AAV8 to express Vglut3 in the cochleae of 5 w, 8 w, and 20 w Vglut3KO mice. Results indicated that AAV8-Vglut3 could mediate the exogenous expression of Vglut3 in all inner hair cells (IHCs). Auditory function was successfully restored, and the hearing threshold remained stable for at least 12 weeks after rescue. Moreover, the results revealed that the number of synaptic ribbons, as well as their morphology, were significantly recovered after gene therapy, potentially indicating the glutamate-dependent plasticity of IHCs. Taken together, our data introduces the possibility of gene therapy in adult mice and advances our knowledge of the role of Vglut3 in presynaptic plasticity.

Characterization of promoters for adeno-associated virus mediated efficient Cas9 activation in adult Cas9 knock-in murine cochleae

CRISPR/Cas9 gene editing enables the treatment of hearing loss in congenitally deaf neonatal mice via both viral and non-viral delivery. While adeno-associated virus (AAV)-mediated gene delivery systems have been shown to be effective tools for gene replacement in the inner ear, application of the AAV-mediated CRISPR/Cas9 gene-editing approach for this purpose is yet to be documented. Based on our previous findings, we focused on the effects of several AAVs delivered via canalostomy injection in adult mice. Among the AAVs examined, AAV8 showed the greatest efficiency and specificity in transducing inner hair cells (IHC). The ability of Cre-expressing AAV8 to activate Cas9 in floxed-Cas9 knock-in (Cas9 KI) mice was further evaluated. We compared the effects of six different promoters (CMV, CAG, hSyn, CaMKIIa, GFAP, and ALB) of AAV8 delivered to the inner ear of adult Cas9 KI mice. Our findings showed that three AAV groups (CMV, CAG and hSyn promoters) infected the inner ear efficiently with different tropisms. Notably, AAVs with CMV, CAG, and hSyn promoters infected diverse cell types in mature murine cochleae, including IHCs. In particular, AAV8-hSyn showed high affinity to IHCs and spiral ganglion neurons (SGN). Neither the AAV8 virus itself (except AAV8-CAG) nor the surgical procedures used caused damage to HCs or impaired normal hearing. Our findings indicated that injection of AAV-Cre into mature inner ear efficiently induces Cas9 activation to achieve safe and efficient gene editing and different constituent promoters confer diverse infection patterns in cochlea, expanding the repertoire of gene-editing tools for regulating gene expression in target cells of the inner ear as part of the collective effort to rescue genetic hearing loss and develop effective gene therapy techniques.

Towards the optical cochlear implant: optogenetic approaches for hearing restoration

Cochlear implants (CIs) are considered the most successful neuroprosthesis as they enable speech comprehension in the majority of half a million CI users suffering from sensorineural hearing loss. By electrically stimulating the auditory nerve, CIs constitute an interface re-connecting the brain and the auditory scene, providing the patient with information regarding the latter. However, since electric current is hard to focus in conductive environments such as the cochlea, the precision of electrical sound encoding-and thus quality of artificial hearing-is limited. Recently, optogenetic stimulation of the cochlea has been suggested as an alternative approach for hearing restoration. Cochlear optogenetics promises increased spectral selectivity of artificial sound encoding, hence improved hearing, as light can conveniently be confined in space to activate the auditory nerve within smaller tonotopic ranges. In this review, we discuss the latest experimental and technological developments of cochlear optogenetics and outline the remaining challenges on the way to clinical translation.

Adeno-associated virus vector enables safe and efficient Cas9 activation in neonatal and adult Cas9 knockin murine cochleae

Adeno-associated virus (AAV)-mediated gene delivery systems have been shown to be effective tools for gene manipulation in the inner ear. For example, hair cells (HCs) and multiple other cell types can be transduced by the local injection of AAVs into the inner ear. However, application of the AAV-mediated CRISPR/Cas9 gene-editing approach to the inner ear in adult mice has not yet been studied. Based on our previous work, we investigated several AAV serotypes in neonatal and adult mice in parallel, and found that AAV8 had the top efficiency to transduce inner HCs. We then tested the ability of Cre-expressing AAV8 to activate Cas9 in floxed-Cas9 knockin mice, and observed significant Cas9 activation in the inner ear of both neonatal and adult animals. Neither the AAV8 virus itself nor the surgical procedures used to deliver it-cochleostomy for neonatal mice and canalostomy for adult mice-caused any damage to HCs or impaired normal hearing. Our studies indicate that the local injection of AAV8-Cre can induce Cas9 activation to perform safe and efficient gene editing in the inner ear, expanding the repertoire of gene-editing tools for regulating gene expression in the inner ear as a part of efforts to rescue genetic hearing loss, initiate regeneration of HCs, or develop gene therapy techniques.

Delivery of Adeno-Associated Virus Vectors in Adult Mammalian Inner-Ear Cell Subtypes Without Auditory Dysfunction

Hearing loss, including genetic hearing loss, is one of the most common forms of sensory deficits in humans with limited options of treatment. Adeno-associated virus (AAV)-mediated gene transfer has been shown to recover auditory functions effectively in mouse models of genetic deafness when delivered at neonatal stages. However, the mouse cochlea is still developing at those time points, whereas in humans, the newborn inner ears are already fully mature. For effective gene therapy to treat genetic deafness, it is necessary to determine whether AAV-mediated therapy can be equally effective in the fully mature mouse inner ear without causing damage to the inner ear. This study tested several AAV serotypes by canalostomy in adult mice. It is shown that most AAVs transduce the sensory inner hair cells efficiently, but are less efficient at transducing outer hair cells. A subset of AAVs also transduces non-sensory cochlear cell types. Neither the surgical procedure of canalostomy nor the AAV serotypes damage hair cells or impair normal hearing. The studies indicate that canalostomy can be a viable route for safe and efficient gene delivery, and they expand the repertoire of AAVs to target diverse cell types in the adult inner ear.

Neurodevelopmental care in the NICU

Neurodevelopmental care, which is any NICU intervention undertaken to improve neurodevelopmental outcome, includes NICU design, nursing routines, nursing care plans, management of pain, feeding methods and, most importantly, encouraging parental involvement with their NICU infant. Recognition that sensory stimulation can overwhelm preterm infants and increase physiologic signs of stress led to attempts to reduce sensory input. More recent approaches judiciously add back soothing sensory input (e.g., therapeutic touch, soft music). Circadian light/dark cycles and physical activity improve preterm growth. Attention to infant positioning and handling affects physiologic variables and joint mobility, if not functional motor abilities. A highly organized system of care for NICU infants is Als' NIDCAP (i.e., Neonatal Individualized Developmental Care and Assessment Program). Although NIDCAP may reduce need for respiratory support and hospital length of stay, it does not significantly influence neurodevelopmental outcome at 2-3 years. Pain management includes benign interventions (e.g., nonnutritive sucking, oral glucose), but the prolonged use of narcotics must be balanced against the consequences of sedation and dependency. The foremost challenge for NICUs remains parent disenfranchisement. Kangaroo care, which involves parent/infant skin-to-skin contact, improves preterm growth, decreases nosocomial infections and may shorten hospital length of stay. A great deal of work needs to be done to identify and demonstrate efficacy of specific interventions and changes that humanize the NICU, encourage parental involvement, support infant development and optimize preterm neurodevelopmental outcomes.

Parental touch of the neonate: encourage or condemn?

The available literature regarding parental touch and its use on premature infants indicates differing views on whether touch should be encouraged or condemned. Findings of this literature review indicate that touch can have a detrimental physical effect on the infant, however positive long-term benefits for parent and child. The absence of direct guidelines for nursing staff working in a neonatal intensive care unit make decisions about parental touch difficult. The result from this literature review suggests that guidelines for nursing staff need to be established, so that optimum care is provided for both infant and parent.

Helping foster children to mourn past relationships

In spite of the increasing number of foster children who have had pathological relationships with their biological parents, there are relatively few reports of intensive therapy with these children. This paper focuses on the psychoanalytic psychotherapy of two young foster children whose treatment began shortly after placement. The paper describes the children's developmental problems, their conflicts and defenses, and the therapeutic process utilized to enable them to resume progressive development. The children were helped to mourn their past objects and to form more appropriate attachments to their foster parents.

Early parental touch and preterm infants

Thirty-six parents were videotaped during visits with their preterm infants in a neonatal intensive care unit in order to describe some characteristics of parental touch. Parents most often touched infants' hands, backs, and heads, using stroke, hold, or contact actions of moderate intensity. Mothers and grandmothers provided more touch than fathers, and parents provided less touch to infants at or below a gestational age of 28 weeks. The results can be used as a basis for more controlled experimental studies evaluating preterm infants' physiologic responses to early parental touch.

Exploring internal and external worlds. Reflections on being curious

Curiosity is a complex function that is related to a number of other psychological functions such as motivation, arousal, attention, and novelty preference. This paper presents the thesis that curiosity represents a separate ego function which is closely tied to objects and is centrally organizing in all phases of development. It is an integrative function that regulates arousal, motivation, and affect, begins in infancy, has a neurobiological base, and is channeled by the child's social experience. Psychologically, curiosity may serve both libidinal and aggressive aims. Psychoanalytic views of curiosity are considered in light of data from studies of infants' and young children's exploratory activities and a model is presented for the developmental function of curiosity throughout the life-span.

Effects of early parent touch on preterm infants' heart rates and arterial oxygen saturation levels

A descriptive exploratory design was used in this study to evaluate the effects of early parent touch on the heart rates and arterial oxygen (O2) saturation levels of 36 preterm infants. The infants were between 27-33 weeks gestational age at birth, and were free of congenital defects. Infants were videotaped during parent visits on up to three separate occasions during the first month of life. Parents were encouraged to interact with their infants as they usually would, and data on the infants' heart rates and O2 saturation levels were recorded every 6 seconds on a portable computer that was interfaced with the infants' monitors. Mean O2 saturation levels were significantly lower during parent touch than during baseline periods on 45% of the visits, and significantly higher during parent touch periods on 19% of the visits. O2 saturation variability was greater during periods of parent touch, and there were more abnormal O2 saturation values during parent touch than during baseline periods. Mean heart rates during parent touch were significantly lower compared to baseline on 17% of the visits, and were higher during parent touch on 43% of the visits. There were no overall differences in mean heart rates between baseline, parent touch and post-visit classifications, although heart rate variability was greater during periods of parent touch. The results indicate that preterm infants' responses to early parent touch are variable, and suggest that blanket policies that limit parent touch during the early weeks of life may not be appropriate.(ABSTRACT TRUNCATED AT 250 WORDS)