Adaptively Timed Learning

This chapter explains how humans and other animals learn to adaptively time their behaviors to match external environmental constraints. It hereby explains how nerve cells learn to bridge big time intervals of hundreds of milliseconds or even several seconds, and thereby associate events that are separated in time. This is accomplished by a spectrum of cells that each respond in overlapping time intervals and whose population response can bridge intervals much larger than any individual cell can. Such spectral timing occurs in circuits that include the lateral entorhinal cortex and hippocampal cortex. Trace conditioning, in which CS and US are separated in time, requires the hippocampus, whereas delay conditioning, in which they overlap, does not. The Weber law observed in trace conditioning naturally emerges from spectral timing dynamics, as later confirmed by data about hippocampal time cells. Hippocampal adaptive timing enables a cognitive-emotional resonance to be sustained long enough to become conscious of its feeling and its causal event, and to support BDNF-modulated memory consolidation. Spectral timing supports balanced exploratory and consummatory behaviors whereby restless exploration for immediate gratification is replaced by adaptively timed consummation. During expected disconfirmations of reward, orienting responses are inhibited until an adaptively timed response is released. Hippocampally-mediated incentive motivation supports timed responding via the cerebellum. mGluR regulates adaptive timing in hippocampus, cerebellum, and basal ganglia. Breakdowns of mGluR and dopamine modulation cause symptoms of autism and Fragile X syndrome. Inter-personal circular reactions enable social cognitive capabilities, including joint attention and imitation learning, to develop.

How do different language typologies influence causal event conceptualizations?

This study investigated whether crosslinguistic differences in the expression of causality influence causal conceptualization of observed events in 3- to 4-year-old Swiss-German-learners and Turkish-learners. In Swiss-German, causality is mainly expressed lexically (e.g., schniidä “to cut”). In Turkish, causality is expressed both lexically, and morphologically with a verbal suffix (e.g., yemek “to eat” vs. yeDIRmek “to feed”). Moreover, unlike Swiss-German, Turkish allows argument ellipsis (e.g. “Mary pushed”). We used pseudo-verbs to test if and how well Swiss children inferred a causal meaning from lexical constructions compared to Turkish children tested in three conditions: lexical, morphological, and morphological constructions with object ellipsis. Swiss children and Turkish children in all three conditions reliably inferred causal meanings, and did so to a similar extent. The findings suggest that children as young as age 3 make use of the specific features of how their native language expresses causality to infer causal meanings.

Temporal Binding in Multisensory and Motor-Sensory Contexts: Toward a Unified Model

Our senses receive a manifold of sensory signals at any given moment in our daily lives. For a coherent and unified representation of information and precise motor control, our brain needs to temporally bind the signals emanating from a common causal event and segregate others. Traditionally, different mechanisms were proposed for the temporal binding phenomenon in multisensory and motor-sensory contexts. This paper reviews the literature on the temporal binding phenomenon in both multisensory and motor-sensory contexts and suggests future research directions for advancing the field. Moreover, by critically evaluating the recent literature, this paper suggests that common computational principles are responsible for the temporal binding in multisensory and motor-sensory contexts. These computational principles are grounded in the Bayesian framework of uncertainty reduction rooted in the Helmholtzian idea of unconscious causal inference.

Chromatin and transcriptomic profiling uncover dysregulation of the Tip60 HAT/HDAC2 epigenomic landscape in the neurodegenerative brain

ABSTRACTDisruption of histone acetylation mediated gene control is a critical step in Alzheimer’s Disease (AD), yet chromatin analysis of antagonistic histone acetyltransferases (HATs) and histone deacetylases (HDACs) causing these alterations remains uncharacterized. We report the first Tip60 HAT versus HDAC2 chromatin and transcriptional profiling study in Drosophila brains that model early human AD. We find Tip60 and HDAC2 predominantly recruited to identical neuronal genes. Moreover, AD brains exhibit robust genome-wide early alterations that include enhanced HDAC2 and reduced Tip60 binding and transcriptional dysregulation. Orthologous human genes to co-Tip60/HDAC2 Drosophila neural targets exhibit conserved disruption patterns in AD patient hippocampi. Notably, we discovered distinct transcription factor (TF) binding sites within Tip60/HDAC2 co-peaks in neuronal genes, implicating them in co-enzyme recruitment. Increased Tip60 protects against transcriptional dysregulation and enhanced HDAC2 enrichment genome-wide. We advocate Tip60 HAT/HDAC2 mediated epigenetic neuronal gene disruption as a genome-wide initial causal event in AD.

Can Language Direct Speakers' Attention in Causal Events?: An Empirical Study between Japanese and English Speakers

This thesis sheds lights on the relationship between descriptions of causal events and their effects on speakers’ memory. English and Japanese are similar in that speakers can use the same constructions when describing intentional events – both comfortably use transitive sentences. However, they are different when describing non-intentional events. English speakers can use the same construction as intentional events, while Japanese speakers prefer to mark that the event is accidental. They tend to add accidental markers to cancel the agent’s intention frequently. In Experiment 1, I confirm differences in describing causal events between these two languages. Then, Japanese speakers are expected to remember event nature (i.e., intentional or non-intentional) more accurately than English speakers. However, Experiment 2 fails to support the hypothesis. I present two possible reasons why language effects are not observed. First, marking non-intentionality is not obligatory but only preferred by Japanese speakers. Thus, language effects are not strong enough to affect speakers’ memory. Second, language does not affect speakers’ memory, especially in causal-event descriptions, even though it does in other domains, such as color terminology.

Can Language Direct Speakers' Attention in Causal Events?: An Empirical Study between Japanese and English Speakers

This thesis sheds lights on the relationship between descriptions of causal events and their effects on speakers’ memory. English and Japanese are similar in that speakers can use the same constructions when describing intentional events – both comfortably use transitive sentences. However, they are different when describing non-intentional events. English speakers can use the same construction as intentional events, while Japanese speakers prefer to mark that the event is accidental. They tend to add accidental markers to cancel the agent’s intention frequently. In Experiment 1, I confirm differences in describing causal events between these two languages. Then, Japanese speakers are expected to remember event nature (i.e., intentional or non-intentional) more accurately than English speakers. However, Experiment 2 fails to support the hypothesis. I present two possible reasons why language effects are not observed. First, marking non-intentionality is not obligatory but only preferred by Japanese speakers. Thus, language effects are not strong enough to affect speakers’ memory. Second, language does not affect speakers’ memory, especially in causal-event descriptions, even though it does in other domains, such as color terminology.