Reviewed Medium: book
 Authors: Bruno Nettl
 Year: 2005
 Pages: 440
 Publisher: University of Illinois Press
 ISBN: 0-252-03033-8 (hard cover). Prices: $50.00 USD(hard cover).

The Study of Ethnomusicology: Thirty-One Issues and Concepts

The dorsal and ventral visual pathways represent both visual and conceptual object properties. Yet the relative contribution of these two factors in the representational content of visual areas is unclear. Indeed, research investigating brain category representations rarely dissociate visual and semantic properties of objects. We present a human event-related fMRI study with a two-factorial stimulus set with 54 images that explicitly dissociates shape from category to investigate their independent contribution as well as their interactions through representational similarity analyses. Results reveal a contribution from each dimension in both streams, with a transition from shape to category along the posterior-to-anterior anatomical axis. The nature of category representations differs in the two pathways: ventral areas represent object animacy and dorsal areas represent object action properties. Furthermore, information about shape evolved from low-level pixel-based to high-level perceived shape following a posterior-to-anterior gradient similar to the shape-to-category emergence. To conclude, results show that representations of shape and category independently coexist, but at the same time they are closely related throughout the visual hierarchy. SIGNIFICANCE STATEMENT Research investigating visual cortex conceptual category representations rarely takes into account visual properties of objects. In this report, we explicitly dissociate shape from category and investigate independent contributions and interactions of these two highly correlated dimensions.

https://www.jneurosci.org/content/jneuro/36/2/432.full.pdf

Dissociations and Associations between Shape and Category Representations in the Two Visual Pathways.

‘What’ Is Happening in the Dorsal Visual Pathway

System comprised of a portable medical device and method for registering at least one of electrocardiographic (ECG), magnetocardiographic (MCG), physical activity, body position, respiration, temperature, blood pressure, vasomotor activity, blood flow, neural activity, and other physiological, and health data, extracting and representing the most significant parameters from time series (trends) of said data. The system achieves the necessary sensitivity (signal-to-noise ratio) in order to miniaturize the device by collecting data of at least one fiducial point in a cardiac complex over a period of at least one, and preferably, several seconds, and extracting the underlying typical patterns from these data. Due to the miniaturization (pocket-size), the system can be implemented in a shape of a pen (or another miniature shape) that can be worn in a pocket.

Measurement and analysis of trends in physiological and/or health data

The interocular suppression technique termed continuous flash suppression (CFS) has become an immensely popular tool for investigating visual processing outside of awareness. The emerging picture from studies using CFS is that extensive processing of a visual stimulus, including its semantic and affective content, occurs despite suppression from awareness of that stimulus by CFS. However, the current implementation of CFS in many studies examining processing outside of awareness has several drawbacks that may be improved upon for future studies using CFS. In this paper, we address some of those shortcomings, particularly ones that affect the assessment of unawareness during CFS, and ones to do with the use of "visible" conditions that are often included as a comparison to a CFS condition. We also discuss potential biases in stimulus processing as a result of spatial attention and feature-selective suppression. We suggest practical guidelines that minimize the effects of those limitations in using CFS to study visual processing outside of awareness.

/pdf/on-the-use-of-continuous-flash-suppression-for-the-study-of-9w8dii8swn.pdf

On the use of continuous flash suppression for the study of visual processing outside of awareness

Previously, Almeida et al. (2008) used a technique called Continuous Flash Suppression to show that human dorsal stream cortical areas specifically responded to a “tool category.” Here, we used the same technique to clarify what attributes of tools are processed in the dorsal stream. We examined surface attributes and shape. A significant priming effect was found when we removed surface attributes by using line drawings instead of photographs. In a second experiment, we manipulated shape and we found that there were no significant priming effects when we used nonelongated tool pictures as tool prime stimuli. To better clarify the effect of shape attributes on priming effects, we conducted a further experiment using elongated stick-like rectangles as prime stimuli and found that elongated shapes significantly shortened the reaction time to the tool pictures as target stimuli. Additionally, when elongated vegetables were used as prime stimuli, the reaction time to the tool pictures as target stimuli was also significantly shortened, but there was no effect when stubby vegetables were used. Finally, when we controlled for orientation by presenting rotated elongated stick-like rectangles, diamond shapes, and cut circles as prime stimuli, we found that rectangles replicated the same significant priming effect as previous experiments, but the others did not. These results suggest that the dorsal stream processes elongated shapes but does not process the tool category specifically.

https://www.jneurosci.org/content/jneuro/32/11/3949.full.pdf

Does the Human Dorsal Stream Really Process a Category for Tools

An apparatus for measuring bio-magnetic fields includes a plurality of magnetometers for detecting magnetic fields generated from a live body; a driving circuit for driving the magnetometers; a computer for collecting output signals of the driving circuit in the form of data representing at least one waveform of the magnetic fields generated from the live body and for performing an arithmetic processing on the data representing the waveform of magnetic fields; a display unit; at least one signal processing circuit for processing output signals of the driving circuit; a signal generator for generating high-frequency AC current to be applied to the live animal body; and an electric wire for transmitting the high-frequency AC current from the signal generator to the live body via a plurality of electrodes to be attached to a plurality of points on the live body. The computer further performs an arithmetic processing of first-order differentiation on the waveform of the magnetic fields in a z direction (generally perpendicular to the front surface of the live body) with respect to time which is the output signals of the signal processing circuit so as to generate at least one first-order differential waveform of the magnetic fields to be displayed on the display unit. The apparatus can also detect mechanical movement which occurs as blood flows in organs and organs move.

Apparatus for measuring bio-magnetic fields

Group musical improvisation is thought to be akin to conversation, and therapeutically has been shown to be effective at improving communicativeness, sociability, creative expression, and overall psychological health. To understand these therapeutic effects, clarifying the nature of brain activity during improvisational cognition is important. Some insight regarding brain activity during improvisational music cognition has been gained via functional magnetic resonance imaging (fMRI) and electroencephalography (EEG). However, we have found no reports based on magnetoencephalography (MEG). With the present study, we aimed to demonstrate the feasibility of improvisational music performance experimentation in MEG. We designed a novel MEG-compatible keyboard, and used it with experienced musicians (N = 13) in a music performance paradigm to spectral-spatially differentiate spontaneous brain activity during mental imagery of improvisational music performance. Analyses of source activity revealed that mental imagery of improvisational music performance induced greater theta (5-7 Hz) activity in left temporal areas associated with rhythm production and communication, greater alpha (8-12 Hz) activity in left premotor and parietal areas associated with sensorimotor integration, and less beta (15-29 Hz) activity in right frontal areas associated with inhibition control. These findings support the notion that musical improvisation is conversational, and suggest that creation of novel auditory content is facilitated by a more internally-directed, disinhibited cognitive state.

/pdf/spectral-spatial-differentiation-of-brain-activity-during-3zqhpsa7zw.pdf

Spectral-Spatial Differentiation of Brain Activity During Mental Imagery of Improvisational Music Performance Using MEG.

A new type of SQUID gradiometer, a direct‐feedback gradiometer, is introduced in this paper. It is an axial gradiometer made of thin superconductive films. It consists of two magnetometers: a ‘‘cancellation magnetometer’’ and a ‘‘sensing magnetometer.’’ The feedback flux of the cancellation magnetometer is applied to both pickup coils of these magnetometers by connecting their feedback coils in a series. Environmental magnetic noise applied to the sensing magnetometer is cancelled by the magnetic flux measured by the cancellation magnetometer, when the two magnetometers are connected with normal conductive wires. The gradiometer has been fabricated and operated in a moderate magnetically shielded room. The capability to reduce environmental noise and thus to measure auditory evoked fields from the human brain has been confirmed.

Design and fabrication of direct‐feedback gradiometer: Axial gradiometer made of superconductive films and SQUIDs

https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/50987/1/Matsunaga_text_final.pdf

Koichi Yokosawa

Papers

Does the Human Dorsal Stream Really Process a Category for Tools

Apparatus for measuring bio-magnetic fields

Spectral-Spatial Differentiation of Brain Activity During Mental Imagery of Improvisational Music Performance Using MEG.

Design and fabrication of direct‐feedback gradiometer: Axial gradiometer made of superconductive films and SQUIDs

Magnetoencephalography evidence for different brain subregions serving two musical cultures.