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Abstract

Psycholinguistic investigations provide invaluable empirical utility in theorizing and typologizing phonological phenomena. Instrumental approaches to the sound structure of Turkish have proven to be no exception here, contributing independent and multi-faceted evidence towards theory building and testing. Two areas of Turkish phonology in relation to suprasegmental structure and prominence patterns, namely word-level prosody (Section 2) and prominence and rhythmic phenomena at the level of the sentence and beyond (Section 3) have particularly fueled psycholinguistically motivated empirical studies. This chapter will approach representational and processing-related issues in each of these and provide a review of pertinent perception and production studies, touching upon phonetic and developmental investigations insofar as they have implications for mental representations or processing.

Abstract

This study describes the sensory lexicon on the domains of colour, taste, shape, smell and touch of a rural sign language called Kata Kolok (KK). Taste was highly codable for Kata Kolok signers, who used a dedicated set of signs and facial expressions to indicate each of the taste stimuli. The second most codable perceptual domain was shape, for which signers often used classifiers and tracing gestures that reflected the shape of the object directly. Smell had a comparatively intermediate level of codability, but this was due, for the most part, to the use of evaluative terms. Although Kata Kolok has a dedicated set of colour signs, these leave large parts of the colour spectrum unnamed, resulting in low degrees of codability in this sensory domain. Unnamed colours were frequently described by iconic-indexical forms such as object labelling and pointing strategies. Touch was the least codable domain for Kata Kolok, which resulted in a wide range of iconically motivated constructions including a restricted set of domain-specific lexical signs, classifiers, tracing gestures, object labelling, and general evaluative terms.

Abstract

The Ghana-Togo Mountain languages are a typologically distinct group of languages within the Kwa branch of the Niger-Congo language family. Until recently, they have received very little documentary attention, and are still greatly under-described. Where there is information regarding the tense, aspect, and mood system, Ghana-Togo Mountain languages are described as tense and aspect prominent. In contrast, Kwa languages are typically aspect and mood prominent, with little to no grammatical tense marking. Is the apparent greater emphasis on tense one of the typological features that separates the Ghana- Togo Mountain languages from the other Kwa languages? Or has tense been overrepresented due to the lack of description? In the case of Avatime, it is the latter. Previous accounts have described Avatime with a strong focus on tense. However, when the semantics are considered in more detail, we see that none of the forms contains an inherent specification for tense. While there is often a default interpretation in the past, present or future, this default can easily be overridden. Thus, Avatime has a typical Kwa system with a focus on aspect and mood and no grammatical tense.

Abstract

Changes in the activity profile of cortical neurons are due to phenomena at the scale of local and long-range networks. Accordingly, the states of cortical neurons and their, often abrupt, transitions – a phenomenon known as Up/Down states – are attributed to variations in the afferent neurons’ activity. However, cellular physiology and morphology may also play a role. This study examines the impact of dendritic nonlinearities, in the form of voltage-gated NMDA receptors, on the response of cortical neurons to balanced excitatory/inhibitory synaptic inputs. Using a neuron model with two segregated dendritic compartments, we compare cells with and without dendritic nonlinearities. Our analysis shows that NMDA receptors boost somatic firing in the balanced condition and increase the correlation of membrane potentials across the three compartments of the neuron model. Then we introduce controlled fluctuations in excitatory inputs and quantify the ensuing bimodality of the somatic membrane potential. We show that dendritic nonlinearities are crucial for detecting these fluctuations and initiating Up-Down states whose shape and statistics closely resemble electrophysiological data. Our results provide new insights into the mechanisms underlying cortical bistability and highlight the complex interplay between dendritic integration and network dynamics in shaping neuronal behavior.

Significance statement In several physiological states, such as sleep or quiet wakefulness, the membrane of cortical cells shows a stereotypical bistability. The cell is either fully depolarized and ready to spike or in a silent, hyperpolarized state. This dynamics, known as Up-Down states, has often been attributed to changes in the network activity. However, whether cell-specific properties, such as dendritic nonlinearity, have a role in driving the neuron’s bistability remains unclear. This study examines the issue using a model of a pyramidal cell and reveals that the presence of dendritic NMDA receptors, drives the up-down states in response to small fluctuations in the network activity.