Theta bandwidth determines human visual working memory capacity Human visual short term memory (VSTM) is capacity limited1. The neurophysiological basis for this limitation is, however, currently unknown. Here we apply the principle of efficient information transfer, derived from communications theory, to provide a mechanistic account of VSTM capacity. Shannon's information theory states that to increase the capacity of information encoded along a frequency axis, it is more efficient to expand the bandwidth than to increase the transmitted power for a given level of noise2. By applying Shannon's principles to human magnetoencephalography (MEG) recordings of oscillatory activity in the theta band during a VSTM task, we demonstrate that increasing memory load to capacity induces a parametric shift in theta frequency band during the delay period, from 4 to 8 Hz, in a right fronto-parietal network. Critically, we show that an individual's VSTM capacity is proportional to that parametric shift. Thus, the adherence of cortical neuronal oscillations to a fundamental principle of efficient information transfer appears to underlie the limited nature of visual representation in short-term memory.

NeuroImage ◽  
2009 ◽  
Vol 47 ◽  
pp. S144 ◽  
Author(s):  
R.J. Moran ◽  
B.A. Strange ◽  
P. Campo ◽  
R.J. Dolan
Keyword(s):  
Information Transfer ◽  
Short Term Memory ◽  
Memory Load ◽  
Working Memory Capacity ◽  
Fundamental Principle ◽  
Oscillatory Activity ◽  
Short Term ◽  
Term Memory ◽  
Communications Theory ◽  
Efficient Information

The Effects of Training on Cognitive Capacity Demands for Synthetic Speech

1994 ◽  
Vol 38 (18) ◽  
pp. 1229-1233 ◽  
Author(s):  
Catherine Connolly Gomez ◽  
Wayne Shebilske ◽  
J. Wesley Regian
Keyword(s):  
Cognitive Processing ◽  
Short Term Memory ◽  
Memory Load ◽  
Working Memory Capacity ◽  
Serial Order ◽  
Cognitive Capacity ◽  
Synthetic Speech ◽  
Short Term ◽  
Term Memory ◽  
Improved Performance

Previous studies have revealed that the perception and comprehension of synthetic speech may be attributed to increased processing demands in short-term memory as reflected in serial-order and preload paradigm tasks. Additionally, it has been consistently shown that the perception of synthetic speech improves with moderate amounts of training. The present study was conducted to determine if the increased perceptual effects of training for synthetic speech can be attributed to a reduction of short-term memory load. Two groups of subjects were tested with synthetic speech using the same comprehension and high cognitive processing tasks before and after training. One group was trained with synthetic speech and the other group acted as the control, receiving no training between the pretest and post-test interval. Results reveal similar increases in comprehension based on previous synthetic speech studies for the trained group. Moreover, these results suggest that training on synthetic speech promotes better allocation of attentional resources which result in improved performance on working memory capacity measures.

scholarly journals Visual short-term memory for 3D shapes reveals similar properties to simple 2D features

2019 ◽  
Author(s):  
Joel Robitaille ◽  
Stephen Emrich
Keyword(s):  
Short Term Memory ◽  
Memory Load ◽  
Memory Performance ◽  
Delayed Response ◽  
Short Term ◽  
Complex Objects ◽  
Term Memory ◽  
Visual Short Term Memory ◽  
2D And 3D ◽  
3D Shapes

In the past two decades, significant advances have been made to understand the psychophysical properties of visual short-term memory (VSTM). Most studies, however, make inferences based on memory for simple surface features of 2D shapes. Here, we examined the role of object complexity and dimensionality on the psychophysical properties of VSTM by comparing orientation memory for 2D lines and complex 3D objects in a delayed-response continuous report task, where memory load (Experiment 1) or axis of rotation (Experiment 2) was manipulated. In both experiments, our results demonstrate an overall cost of complexity that affected participants raw errors as well as their guess rate and response precision derived from mixture modelling. We also demonstrate that participants’ memory performance is correlated between stimulus types and that memory performance for both 2D and 3D shapes is better fit to the variable precision model of VSTM than to tested competing models. Interestingly, the ability to report complex objects is not consistent across axes of rotation. These results indicate that, despite the fact that VSTM shares similar properties for 2D and 3D shapes, VSTM is far from being a unitary process and is affected by stimulus properties such as complexity and dimensionality.

scholarly journals The Order of Information Transfer into Short- Term Memory from Visual Pathways with Different Spatial-Frequency Tunings

2020 ◽  
Vol 13 (2) ◽  
pp. 72-89
Author(s):  
D.S. Alekseeva ◽  
V.V. Babenko ◽  
D.V. Yavna
Keyword(s):  
Spatial Frequency ◽  
Information Transfer ◽  
Short Term Memory ◽  
Frequency Tuning ◽  
Visual Pathways ◽  
Input Image ◽  
Target Face ◽  
Short Term ◽  
Term Memory ◽  
Spatial Frequencies

Visual perceptual representations are formed from the results of processing the input image in parallel pathways with different spatial-frequency tunings. It is known that these representations are created gradually, starting from low spatial frequencies. However, the order of information transfer from the perceptual representation to short-term memory has not yet been determined. The purpose of our study is to determine the principle of entering information of different spatial frequencies in the short-term memory. We used the task of unfamiliar faces matching. Digitized photographs of faces were filtered by six filters with a frequency tuning step of 1 octave. These filters reproduced the spatial-frequency characteristics of the human visual pathways. In the experiment, the target face was shown first. Its duration was variable and limited by a mask. Then four test faces were presented. Their presentation was not limited in time. The observer had to determine the face that corresponds to the target one. The dependence of the accuracy of the solution of the task on the target face duration for different ranges of spatial frequencies was determined. When the target stimuli were unfiltered (broadband) faces, the filtered faces were the test ones, and vice versa. It was found that the short-term memory gets information about an unfamiliar face in a certain order, starting from the medium spatial frequencies, and this sequence does not depend on the processing method (holistic or featural).

FMRI and EEG in humans performing a delayed discrimination task: The effect of short-term memory load

NeuroImage ◽  
2001 ◽  
Vol 13 (6) ◽  
pp. 701
Author(s):  
David E.J. Linden ◽  
James A. Waltz ◽  
Lars Muckli ◽  
David Prvulovic ◽  
Rainer Goebel ◽  
...  
Keyword(s):  
Discrimination Task ◽  
Short Term Memory ◽  
Memory Load ◽  
Short Term ◽  
Term Memory

Working Memory: Models and Applications

2020 ◽  
Author(s):  
Stoo Sepp ◽  
Steven J. Howard ◽  
Sharon Tindall-Ford ◽  
Shirley Agostinho ◽  
Fred Paas
Keyword(s):  
Working Memory ◽  
Individual Differences ◽  
Short Term Memory ◽  
Working Memory Capacity ◽  
Memory Capacity ◽  
Long Term Memory ◽  
Auditory Information ◽  
Short Term ◽  
Term Memory

In 1956, Miller first reported on a capacity limitation in the amount of information the human brain can process, which was thought to be seven plus or minus two items. The system of memory used to process information for immediate use was coined “working memory” by Miller, Galanter, and Pribram in 1960. In 1968, Atkinson and Shiffrin proposed their multistore model of memory, which theorized that the memory system was separated into short-term memory, long-term memory, and the sensory register, the latter of which temporarily holds and forwards information from sensory inputs to short term-memory for processing. Baddeley and Hitch built upon the concept of multiple stores, leading to the development of the multicomponent model of working memory in 1974, which described two stores devoted to the processing of visuospatial and auditory information, both coordinated by a central executive system. Later, Cowan’s theorizing focused on attentional factors in the effortful and effortless activation and maintenance of information in working memory. In 1988, Cowan published his model—the scope and control of attention model. In contrast, since the early 2000s Engle has investigated working memory capacity through the lens of his individual differences model, which does not seek to quantify capacity in the same way as Miller or Cowan. Instead, this model describes working memory capacity as the interplay between primary memory (working memory), the control of attention, and secondary memory (long-term memory). This affords the opportunity to focus on individual differences in working memory capacity and extend theorizing beyond storage to the manipulation of complex information. These models and advancements have made significant contributions to understandings of learning and cognition, informing educational research and practice in particular. Emerging areas of inquiry include investigating use of gestures to support working memory processing, leveraging working memory measures as a means to target instructional strategies for individual learners, and working memory training. Given that working memory is still debated, and not yet fully understood, researchers continue to investigate its nature, its role in learning and development, and its implications for educational curricula, pedagogy, and practice.

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