The study of decision making spans such varied fields as neuroscience, psychology, economics, statistics, political science, and computer science. Despite this diversity of applications, most decisions share common elements including deliberation and commitment. Here we evaluate recent progress in understanding how these basic elements of decision formation are implemented in the brain. We focus on simple decisions that can be studied in the laboratory but emphasize general principles likely to extend to other settings.

/pdf/the-neural-basis-of-decision-making-2p5agsty56.pdf

The Neural Basis of Decision Making

Technology and applications for the rendering of virtual acoustic spaces are reviewed. Chapter 1 deals with acoustics and psychoacoustics. Chapters 2 and 3 cover cues to spatial hearing and review psychoacoustic literature. Chapter 4 covers signal processing and systems overviews of 3-D sound systems. Chapter 5 covers applications to computer workstations, communication systems, aeronautics and space, and sonic arts. Chapter 6 lists resources. This TM is a reprint of the 1994 book from Academic Press.

/pdf/3-d-sound-for-virtual-reality-and-multimedia-jq7hovdm4r.pdf

3-D sound for virtual reality and multimedia

By Fourier's theorem1, signals can be decomposed into a sum of sinusoids of different frequencies. This is especially relevant for hearing, because the inner ear performs a form of mechanical Fourier transform by mapping frequencies along the length of the cochlear partition. An alternative signal decomposition, originated by Hilbert2, is to factor a signal into the product of a slowly varying envelope and a rapidly varying fine time structure. Neurons in the auditory brainstem3,4,5,6 sensitive to these features have been found in mammalian physiological studies. To investigate the relative perceptual importance of envelope and fine structure, we synthesized stimuli that we call ‘auditory chimaeras’, which have the envelope of one sound and the fine structure of another. Here we show that the envelope is most important for speech reception, and the fine structure is most important for pitch perception and sound localization. When the two features are in conflict, the sound of speech is heard at a location determined by the fine structure, but the words are identified according to the envelope. This finding reveals a possible acoustic basis for the hypothesized ‘what’ and ‘where’ pathways in the auditory cortex7,8,9,10.

/pdf/chimaeric-sounds-reveal-dichotomies-in-auditory-perception-4ck9rp9e96.pdf

Chimaeric sounds reveal dichotomies in auditory perception

Joris, P. X., C. E. Schreiner, and A. Rees. Neural Processing of Amplitude-Modulated Sounds. Physiol Rev 84: 541–577, 2004; 10.1152/physrev.00029.2003.—Amplitude modulation (AM) is a temporal featu...

https://www.physiology.org/doi/pdf/10.1152/physrev.00029.2003

Neural processing of amplitude-modulated sounds.

The ability to determine the location of a sound source is fundamental to hearing. However, auditory space is not represented in any systematic manner on the basilar membrane of the cochlea, the sensory surface of the receptor organ for hearing. Understanding the means by which sensitivity to spatial cues is computed in central neurons can therefore contribute to our understanding of the basic nature of complex neural representations. We review recent evidence concerning the nature of the neural representation of auditory space in the mammalian brain and elaborate on recent advances in the understanding of mammalian subcortical processing of auditory spatial cues that challenge the "textbook" version of sound localization, in particular brain mechanisms contributing to binaural hearing.

Mechanisms of Sound Localization in Mammals

Observers can detect interaural delays in three component stimuli produced by sinusoidally modulating the amplitude of a sinusoidal carrier. Interaural delays are detected in stimuli confined to a high‐frequency region even in the presence of an intense, low‐pass filtered noise. With 300‐Hz modulation of a 3900‐Hz carrier, detection of interaural delay is equally good when either the entire stimulus or just the envelope of the stimulus is delayed. In either case performance is as good as with a 300‐Hz pure tone.

Detectability of interaural delay in high-frequency complex waveforms.

Some experiments bearing on the hypothesis that the visual system analyses spatial patterns in independent bands of spatial frequency.

http://www.cvrl.org/people/Henning/pubs/DHnBVisR_93.pdf

Discriminating the direction of second-order motion at short stimulus durations

The detectability of a sinusoidal grating was measured in a standard two-interval forced-choice experiment against backgrounds of noise gratings of the same orientation as the signal. The noise gratings were either spatially high-pass or low-pass filtered and were either unchanged in each observation interval (static) or flickering at a rate that depended on their cutoff frequency (dynamic). Spatial-frequency-selective mechanisms are inferred from the data and their characteristics shown to depend on assumptions concerning the detection process thought to follow the spatial-frequency-selective device.

/pdf/effects-of-different-hypothetical-detection-mechanisms-on-58uvz0zjd5.pdf

Effects of different hypothetical detection mechanisms on the shape of spatial-frequency filters inferred from masking experiments: I. noise masks

The ability of human observers to discriminate frequencies of tones between 1000–15 000 cps was measured in a temporal two‐alternative forced‐choice discrimination experiment. On each trial, one of the test tones, selected at random, was attenuated by a random amount ranging from 8 to 20 dB in 2‐dB steps. Comparison of the results of this experiment with those of previous experiments in which fixed‐amplitude tones were used, indicates little difference between the observers' abilities to discriminate frequencies of fixed‐ and random‐amplitude tones at 1000 cps. Discrimination with random‐amplitude tones becomes relatively poorer, however, as frequency is increased. For example, the classical data show a frequency just‐noticeable difference (jnd) of 40 cps at 10 000 cps; in the present experiment, with random‐amplitude signals, the observers were unable to achieve 75% correct responses until ΔF was 300 cps.

G. Bruce Henning

Papers

Detectability of interaural delay in high-frequency complex waveforms.

Some experiments bearing on the hypothesis that the visual system analyses spatial patterns in independent bands of spatial frequency.

Discriminating the direction of second-order motion at short stimulus durations

Effects of different hypothetical detection mechanisms on the shape of spatial-frequency filters inferred from masking experiments: I. noise masks

Frequency Discrimination of Random-Amplitude Tones