Biology subjects

Kimel, E.

Publications and source records attributed to Kimel, E..

3 recordsLinked to original sources

bioRxiv2020

Capacity of short-term memory in dyslexia is reduced due to less efficient utilization of items' long-term frequency

Dyslexia, defined as a specific impairment in decoding the written script, is the most widespread learning difficulty. However, individuals with dyslexia (IDDs) also consistently manifest reduced short-term memory (STM) capacity, typically measured by Digit Span or non-word repetition tasks. In this paper we report two experiments which test the effect of item frequency and the effect of a repeated sequence on the performance in STM tasks in good readers and in IDDs. IDDs performance benefited less from item frequency, revealing poor use of long-term single item statistics. This pattern suggests that the amply reported shorter verbal spans in dyslexia may in fact reflect their impaired sensitivity to items long-term frequency. For repeated sequence learning, we found no significant deficit among IDDs, even when a sensitive paradigm and a robust measure were used.

neuroscience↗

bioRxiv2019

Spans attributed to short-term memory are explained by sensitivity to long-term statistics in both musicians and individuals with dyslexia

Reduced short-term memory (STM) of individuals with dyslexia (IDDs) and enhanced STM of musicians are well documented, yet their causes are disputed. We hypothesized that their STMs reflect their sensitivities to accumulative long-term stimuli statistics. Indeed, when performing an STM task, IDDs had reduced benefit from syllable frequency, whereas musicians manifested an opposite effect, compared to controls. Interestingly, benefit from sequence-repetition did not significantly differ between groups, suggesting that it relies on different mechanisms. To test the generality of this separation across populations, we recruited a group of good-readers, whose native language contains a smaller fraction of the high-frequency syllables. Their span for these \"high-frequency\" syllables was small, yet their benefit from sequence-repetition was adequate. These experiments indicate that sensitivity to long-term stimuli distribution, and not to sequential repetition, is reduced in IDDs and enhanced in musicians, and this accounts for differences in their STM performance.

neuroscience↗

bioRxiv2017

Widespread shorter cortical adaptation in dyslexia

Studies of dyslexics performance on perceptual tasks suggest that their implicit inference of sound statistics is impaired. In a previous paper (Jaffe-Dax, Frenkel, & Ahissar, 2017), using 2-tone frequency discrimination, we found that the effect of previous trial frequencies on dyslexics judgments decayed faster than the effect on controls judgments, and that the adaptation of their ERP responses to tones recovered faster. Here, we show the cortical distribution of this abnormal dynamics of adaptation using fast acquisition fMRI. We find that dyslexics faster decay of adaptation is widespread, though the most significant effects are found in the left superior temporal lobe, including the auditory cortex. This broad distribution suggests that dyslexics faster decay of implicit memory is a general characteristic of their cortical dynamics, which also encompasses the sensory cortices.

neuroscience↗