Emotional learning promotes perceptual predictions by remodeling stimulus representation in visual cortex

Toward reframing brain-social dynamics: current assumptions and future challenges

Evolutionary analyses suggest that the human social brain and sociality appeared together. The two fundamental tools that accelerated the concurrent emergence of the social brain and sociality include learning and plasticity. The prevailing core idea is that the primate brain and the cortex in particular became reorganised over the course of evolution to facilitate dynamic adaptation to ongoing changes in physical and social environments. Encouraged by computational or survival demands or even by instinctual drives for living in social groups, the brain eventually learned how to learn from social experience via its massive plastic capacity. A fundamental framework for modeling these orchestrated dynamic responses is that social plasticity relies upon neuroplasticity. In the present article, we first provide a glimpse into the concepts of plasticity, experience, with emphasis on social experience. We then acknowledge and integrate the current theoretical concepts to highlight five key intertwined assumptions within social neuroscience that underlie empirical approaches for explaining the brain-social dynamics. We suggest that this epistemological view provides key insights into the ontology of current conceptual frameworks driving future research to successfully deal with new challenges and possible caveats in favour of the formulation of novel assumptions. In the light of contemporary societal challenges, such as global pandemics, natural disasters, violent conflict, and other human tragedies, discovering the mechanisms of social brain plasticity will provide new approaches to support adaptive brain plasticity and social resilience.

Emotional Arousal and Valence Jointly Modulate the Auditory Response: A 40-Hz ASSR Study

Emotion is defined as a response to external stimuli and internal mental representations. It has been characterized as a multidimensional concept, primarily comprising two dimensions: valence and arousal. Existing studies have demonstrated that emotional experience exerts a powerful impact on auditory processing in terms of valence. However, it has also been shown that while negative emotion can improve auditory perception in healthy subjects, patients with depression show deficits in auditory perception. We thus speculated that both arousal and valence jointly modulate auditory perception. To examine the emotion-driven effects on the auditory response, we induced positive, negative, and neutral emotional states in healthy subjects and collected auditory steady-state response (ASSR) evoked by a 40-Hz chirp sound. We calculated peak-to-peak amplitude (PPA) and event-related spectral perturbation (ERSP) of evoked ASSRs and observed that the positive emotions significantly enhanced brain responses to auditory stimuli (p < 0.001), but that ASSRs in a negative state were not significantly enhanced compared with the neutral state. Subsequently, regression analysis showed a significant positive multiple linear relationship between the PPA and ratings of two emotional dimensions, indicating that arousal and valence jointly regulated the auditory cortex's synchronous oscillation, rather than the valence in isolation, offering the potential to clarify the conflicting results surrounding the role of negative emotions in auditory responses. Because depression is generally characterized by low arousal and low valence in actual life, whereas the negative emotion evoked under laboratory conditions is always with low valence but high arousal.

Memory guidance of value-based decision making at an abstract level of representation

Value-based decisions about alternatives we have never experienced can be guided by associations between current choice options and memories of prior reward. A critical question is how similar memories need to be to the current situation to effectively guide decisions. We address this question in the context of associative learning of faces using a sensory preconditioning paradigm. We find that memories of reward spread along established associations between faces to guide decision making. While memory guidance is specific for associated facial identities, it does not only occur for the specific images that were originally encountered. Instead, memory guidance generalizes across different images of the associated identities. This suggests that memory guidance does not rely on a pictorial format of representation but on a higher, view-invariant level of abstraction. Thus, memory guidance operates on a level of representation that neither over- nor underspecifies associative relationships in the context of obtaining reward.

Ocular dominance plasticity: Molecular mechanisms revisited

Ocular dominance plasticity (ODP) is a type of cortical plasticity operating in visual cortex of mammals that are endowed with binocular vision based on the competition-driven disparity. Earlier, a molecular mechanism was proposed that catecholamines play an important role in the maintenance of ODP in kittens. Having survived the initial test, the hypothesis was further advanced to identify noradrenaline (NA) as a key factor that regulates ODP in the immature cortex. Later, the ODP-promoting effect of NA is extended to the adult with age-related limitations. Following the enhanced NA availability, the chain events downstream lead to the β-adrenoreceptor-induced cAMP accumulation, which in turn activates the protein kinase A. Eventually, the protein kinase translocates to the cell nucleus to activate cAMP responsive element binding protein (CREB). CREB is a cellular transcription factor that controls the transcription of various genes, underpinning neuronal plasticity and long-term memory. In the advent of molecular genetics in that various types of new tools have become available with relative ease, ODP research has lightly adopted in the rodent model the original concepts and methodologies. Here, after briefly tracing the strategic maturation of our quest, the review moves to the later development of the field, with the emphasis placed around the following issues: (a) Are we testing ODP per se? (b) What does monocular deprivation deprive of the immature cortex? (c) The critical importance of binocular competition, (d) What is the adult plasticity? (e) Excitation-Inhibition balance in local circuits, and (f) Species differences in the animal models.