The role of neural tuning in quantity perception.

Perception of quantities, such as numerosity, timing, and size, is essential for behavior and cognition. Accumulating evidence demonstrates neurons processing quantities are tuned, that is, have a preferred quantity amount, not only for numerosity, but also other quantity dimensions and sensory modalities. We argue that quantity-tuned neurons are fundamental to understanding quantity perception. We illustrate how the properties of quantity-tuned neurons can underlie a range of perceptual phenomena. Furthermore, quantity-tuned neurons are organized in distinct but overlapping topographic maps. We suggest that this overlap in tuning provides the neural basis for perceptual interactions between different quantities, without the need for a common neural representational code.

Editorial note. Introduction to the Special Issue "Brain and Behavior: A Neuroscientific / Psychophysiological Approach", in honor and memory of Prof. Jesús Gómez Amor / Nota editorial. Introducción al tema monográfico “Cerebro y conducta: un enfoque neurocientífico/psicofisiológico”, en honor y recuerdo del Prof. Jesús Gómez Amor

Editorial note in which the special theme is presented and a brief comment is made on the articles that compose it.(AU)

Nota editorial en la que se presenta el monográfico y se hace un breve comentario de los artículos que lo componen.(AU)

Limitations Using Neuroimaging to Reconstruct Mental State After a Crime.

Neuroimaging offers great potential to clinicians and researchers for a host of mental and physical conditions. The use of imaging has been trumpeted for forensic psychiatric and psychological evaluations to allow greater insight into the relationship between the brain and behavior. The results of imaging certainly can be used to inform clinical diagnoses; however, there continue to be limitations in using neuroimaging for insanity cases due to limited scientific backing for how neuroimaging can inform retrospective evaluations of mental state. In making this case, this paper reviews the history of the insanity defense and explains how the use of neuroimaging is not an effective way of improving the reliability of insanity defense evaluations.

A perspective on brain-behavior relationships and effects of age and hearing using speech-in-noise stimuli.

Understanding speech in background noise is often more difficult for individuals who are older and have hearing impairment than for younger, normal-hearing individuals. In fact, speech-understanding abilities among older individuals with hearing impairment varies greatly. Researchers have hypothesized that some of that variability can be explained by how the brain encodes speech signals in the presence of noise, and that brain measures may be useful for predicting behavioral performance in difficult-to-test patients. In a series of experiments, we have explored the effects of age and hearing impairment in both brain and behavioral domains with the goal of using brain measures to improve our understanding of speech-in-noise difficulties. The behavioral measures examined showed effect sizes for hearing impairment that were 6-10 dB larger than the effects of age when tested in steady-state noise, whereas electrophysiological age effects were similar in magnitude to those of hearing impairment. Both age and hearing status influence neural responses to speech as well as speech understanding in background noise. These effects can in turn be modulated by other factors, such as the characteristics of the background noise itself. Finally, the use of electrophysiology to predict performance on receptive speech-in-noise tasks holds promise, demonstrating root-mean-square prediction errors as small as 1-2 dB. An important next step in this field of inquiry is to sample the aging and hearing impairment variables continuously (rather than categorically) - across the whole lifespan and audiogram - to improve effect estimates.

Diving into the world of alcohol teratogenesis: a review of zebrafish models of fetal alcohol spectrum disorder.

The term fetal alcohol spectrum disorder (FASD) refers to the entire suite of deleterious outcomes resulting from embryonic exposure to alcohol. Along with other reviews in this special issue, we provide insight into how animal models, specifically the zebrafish, have informed our understanding of FASD. We first provide a brief introduction to FASD. We discuss the zebrafish as a model organism and its strengths for alcohol research. We detail how zebrafish has been used to model some of the major defects present in FASD. These include behavioral defects, such as social behavior as well as learning and memory, and structural defects, disrupting organs such as the brain, sensory organs, heart, and craniofacial skeleton. We provide insights into how zebrafish research has aided in our understanding of the mechanisms of ethanol teratogenesis. We end by providing some relatively recent advances that zebrafish has provided in characterizing gene-ethanol interactions that may underlie FASD.

Speech and music shape the listening brain: evidence for shared domain-general mechanisms.

Are there bi-directional influences between speech perception and music perception? An answer to this question is essential for understanding the extent to which the speech and music that we hear are processed by domain-general auditory processes and/or by distinct neural auditory mechanisms. This review summarizes a large body of behavioral and neuroscientific findings which suggest that the musical experience of trained musicians does modulate speech processing, and a sparser set of data, largely on pitch processing, which suggest in addition that linguistic experience, in particular learning a tone language, modulates music processing. Although research has focused mostly on music on speech effects, we argue that both directions of influence need to be studied, and conclude that the picture which thus emerges is one of mutual interaction across domains. In particular, it is not simply that experience with spoken language has some effects on music perception, and vice versa, but that because of shared domain-general subcortical and cortical networks, experiences in both domains influence behavior in both domains.