scholarly journals Exploring the cortical evidence of a sensory–discrimination process

2002 ◽  
Vol 357 (1424) ◽  
pp. 1039-1051 ◽  
Author(s):  
Ranulfo Romo ◽  
Adrián Hernández ◽  
Antonio Zainos ◽  
Carlos Brody ◽  
Emilio Salinas
Keyword(s):  
Working Memory ◽  
Somatosensory Cortex ◽  
Memory Trace ◽  
Premotor Cortex ◽  
Neural Representation ◽  
Mechanical Vibrations ◽  
Sensory Discrimination ◽  
Secondary Somatosensory Cortex ◽  
The Difference ◽  
A Chain

Humans and monkeys have similar abilities to discriminate the difference in frequency between two consecutive mechanical vibrations applied to their fingertips. This task can be conceived as a chain of neural operations: encoding the two consecutive stimuli, maintaining the first stimulus in working memory, comparing the second stimulus with the memory trace left by the first stimulus and communicating the result of the comparison to the motor apparatus. We studied this chain of neural operations by recording and manipulating neurons from different areas of the cerebral cortex while monkeys performed the task. The results indicate that neurons of the primary somatosensory cortex (S1) generate a neural representation of vibrotactile stimuli which correlates closely with psychophysical performance. Discrimination based on microstimulation patterns injected into clusters of S1 neurons is indistinguishable from that produced by natural stimuli. Neurons from the secondary somatosensory cortex (S2), prefrontal cortex and medial premotor cortex (MPC) display at different times the trace of the first stimulus during the working–memory component of the task. Neurons from S2 and MPC appear to show the comparison between the two stimuli and correlate with the behavioural decisions. These neural operations may contribute to the sensory–discrimination process studied here.

scholarly journals Finger representations in primary somatosensory cortex are modulated during vibrotactile working memory

2021 ◽  
Author(s):  
Finn Rabe ◽  
Sanne Kikkert ◽  
Nicole Wenderoth
Keyword(s):  
Working Memory ◽  
Somatosensory Cortex ◽  
Pattern Analysis ◽  
Blood Oxygen Level Dependent ◽  
Brain Regions ◽  
Delay Period ◽  
Blood Oxygen Level ◽  
Secondary Somatosensory Cortex ◽  
Analysis Technique ◽  
Hand Area

It is well-established that vibrotactile stimulations elicit Blood-oxygen-level-dependent (BOLD) responses in somatotopically organized brain regions. Whether these somatotopic maps are modulated by working memory (WM) is still unknown. In our WM experiment, participants had to compare frequencies that were separated by a delay period. Vibrotactile stimuli were sequentially applied to either their right index or little finger. Using functional MRI, we investigated whether vibrotactile WM modulated neural activity in primary somatosensory (S1), an area that is known to contain individual finger representations. Our mass-univariate results revealed the well-described network of brain regions involved in WM. Interestingly, our mass-univariate results did not demonstrate S1 to be part of this network. However, when we parametrically modulated the time-binned regressors in our GLM we found that the delay activity in S1 and secondary somatosensory cortex (S2) was reflected in a U-shaped manner. Using multi-voxel pattern analysis (MVPA), an analysis technique that is more sensitive to subtle activity differences, we found finger-specific patterns of activation in the S1 hand area during the WM delay period. These results indicate that processes underlying WM modulate finger-specific representations during our discrimination task.

scholarly journals Neocortical substrates of feelings evoked with music in the ACC, insula, and somatosensory cortex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stefan Koelsch ◽  
Vincent K. M. Cheung ◽  
Sebastian Jentschke ◽  
John-Dylan Haynes
Keyword(s):  
Somatosensory Cortex ◽  
Premotor Cortex ◽  
Activity Patterns ◽  
Cingulate Cortex ◽  
Brain Regions ◽  
Anterior Cingulate ◽  
Independent Experiment ◽  
Subjective Feeling ◽  
Secondary Somatosensory Cortex ◽  
Feeling States

AbstractNeurobiological models of emotion focus traditionally on limbic/paralimbic regions as neural substrates of emotion generation, and insular cortex (in conjunction with isocortical anterior cingulate cortex, ACC) as the neural substrate of feelings. An emerging view, however, highlights the importance of isocortical regions beyond insula and ACC for the subjective feeling of emotions. We used music to evoke feelings of joy and fear, and multivariate pattern analysis (MVPA) to decode representations of feeling states in functional magnetic resonance (fMRI) data of n = 24 participants. Most of the brain regions providing information about feeling representations were neocortical regions. These included, in addition to granular insula and cingulate cortex, primary and secondary somatosensory cortex, premotor cortex, frontal operculum, and auditory cortex. The multivoxel activity patterns corresponding to feeling representations emerged within a few seconds, gained in strength with increasing stimulus duration, and replicated results of a hypothesis-generating decoding analysis from an independent experiment. Our results indicate that several neocortical regions (including insula, cingulate, somatosensory and premotor cortices) are important for the generation and modulation of feeling states. We propose that secondary somatosensory cortex, which covers the parietal operculum and encroaches on the posterior insula, is of particular importance for the encoding of emotion percepts, i.e., preverbal representations of subjective feeling.

Learning Increases Stimulus Salience in Anterior Inferior Temporal Cortex of the Macaque

2001 ◽  
Vol 86 (1) ◽  
pp. 290-303 ◽  
Author(s):  
Bharathi Jagadeesh ◽  
Leonardo Chelazzi ◽  
Mortimer Mishkin ◽  
Robert Desimone
Keyword(s):  
Working Memory ◽  
Temporal Cortex ◽  
Poor Response ◽  
Neural Representation ◽  
Inferior Temporal Cortex ◽  
Neuronal Responses ◽  
Recording Session ◽  
Baseline Activity ◽  
Incorrect Stimulus ◽  
The Difference

With experience, an object can become behaviorally relevant and thereby quickly attract our interest when presented in a visual scene. A likely site of these learning effects is anterior inferior temporal (aIT) cortex, where neurons are thought to participate in the filtering of irrelevant information out of complex visual displays. We trained monkeys to saccade consistently to one of two pictures in an array, in return for a reward. The array was constructed by pairing two stimuli, one of which elicited a good response from the cell when presented alone (“good” stimulus) and the other of which elicited a poor response (“poor” stimulus). The activity of aIT cells was recorded while monkeys learned to saccade to either the good or poor stimulus in the array. We found that neuronal responses to the array were greater (before the saccade occurred) when training reinforced a saccade to the good stimulus than when training reinforced a saccade to the poor stimulus. This difference was not present on incorrect trials, i.e., when saccades to the incorrect stimulus were made. Thus the difference in activity was correlated with performance. The response difference grew over the course of the recording session, in parallel with the improvement in performance. The response difference was not preceded by a difference in the baseline activity of the cells, unlike what was found in studies of cued visual search and working memory in aIT cortex. Furthermore, we found similar effects in a version of the task in which any of 10 possible pairs of stimuli, prelearned before the recording session, could appear on a given trial, thereby precluding a working memory strategy. The results suggest that increasing the behavioral significance of a stimulus through training alters the neural representation of that stimulus in aIT cortex. As a result, neurons responding to features of the relevant stimulus may suppress neurons responding to features of irrelevant stimuli.

scholarly journals Transdiagnostic comparison of visual working memory capacity in bipolar disorder and schizophrenia

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Catherine V. Barnes-Scheufler ◽  
Caroline Passow ◽  
Lara Rösler ◽  
Jutta S. Mayer ◽  
Viola Oertel ◽  
...  
Keyword(s):  
Bipolar Disorder ◽  
Working Memory ◽  
Visual Working Memory ◽  
Effect Size ◽  
Working Memory Capacity ◽  
Memory Capacity ◽  
Medium Effect ◽  
Full Spectrum ◽  
Small Effect Size ◽  
The Difference

Abstract Background Impaired working memory is a core cognitive deficit in both bipolar disorder and schizophrenia. Its study might yield crucial insights into the underpinnings of both disorders on the cognitive and neurophysiological level. Visual working memory capacity is a particularly promising construct for such translational studies. However, it has not yet been investigated across the full spectrum of both disorders. The aim of our study was to compare the degree of reductions of visual working memory capacity in patients with bipolar disorder (PBD) and patients with schizophrenia (PSZ) using a paradigm well established in cognitive neuroscience. Methods 62 PBD, 64 PSZ, and 70 healthy controls (HC) completed a canonical visual change detection task. Participants had to encode the color of four circles and indicate after a short delay whether the color of one of the circles had changed or not. We estimated working memory capacity using Pashler’s K. Results Working memory capacity was significantly reduced in both PBD and PSZ compared to HC. We observed a small effect size (r = .202) for the difference between HC and PBD and a medium effect size (r = .370) for the difference between HC and PSZ. Working memory capacity in PSZ was also significantly reduced compared to PBD with a small effect size (r = .201). Thus, PBD showed an intermediate level of impairment. Conclusions These findings provide evidence for a gradient of reduced working memory capacity in bipolar disorder and schizophrenia, with PSZ showing the strongest degree of impairment. This underscores the importance of disturbed information processing for both bipolar disorder and schizophrenia. Our results are compatible with the cognitive manifestation of a neurodevelopmental gradient affecting bipolar disorder to a lesser degree than schizophrenia. They also highlight the relevance of visual working memory capacity for the development of both behavior- and brain-based transdiagnostic biomarkers.

scholarly journals Persistent recruitment of somatosensory cortex during active maintenance of hand images in working memory

NeuroImage ◽  
2018 ◽  
Vol 174 ◽  
pp. 153-163 ◽  
Author(s):  
A. Galvez-Pol ◽  
B. Calvo-Merino ◽  
A. Capilla ◽  
B. Forster
Keyword(s):  
Working Memory ◽  
Somatosensory Cortex ◽  
Active Maintenance

scholarly journals XXIII.—On the Disruptive Discharge of Electricity: An Experimental Thesis for the Degree of Doctor of Science, Department A

1878 ◽  
Vol 28 (2) ◽  
pp. 633-671 ◽  
Author(s):  
Alexander Macfarlane
Keyword(s):  
Copper Wire ◽  
Late Summer ◽  
The Other ◽  
Straight Line ◽  
Summer Session ◽  
The Difference ◽  
A Chain ◽  
The One ◽  
Metallic Parts ◽  
The University

The experiments to which I shall refer were carried out in the physical laboratory of the University during the late summer session. I was ably assisted in conducting the experiments by three students of the laboratory,—Messrs H. A. Salvesen, G. M. Connor, and D. E. Stewart. The method which was used of measuring the difference of potential required to produce a disruptive discharge of electricity under given conditions, is that described in a paper communicated to the Royal Society of Edinburgh in 1876 in the names of Mr J. A. Paton, M. A., and myself, and was suggested to me by Professor Tait as a means of attacking the experimental problems mentioned below.The above sketch which I took of the apparatus in situ may facilitate tha description of the method. The receiver of an air-pump, having a rod capable of being moved air-tight up and down through the neck, was attached to one of the conductors of a Holtz machine in such a manner that the conductor of the machine and the rod formed one conducting system. Projecting from the bottom of the receiver was a short metallic rod, forming one conductor with the metallic parts of the air-pump, and by means of a chain with the uninsulated conductor of the Holtz machine. Brass balls and discs of various sizes were made to order, capable of being screwed on to the ends of the rods. On the table, and at a distance of about six feet from the receiver, was a stand supporting two insulated brass balls, the one fixed, the other having one degree of freedom, viz., of moving in a straight line in the plane of the table. The fixed insulated ball A was made one conductor with the insulated conductor of the Holtz and the rod of the receiver, by means of a copper wire insulated with gutta percha, having one end stuck firmly into a hole in the collar of the receiver, and having the other fitted in between the glass stem and the hollow in the ball, by which it fitted on to the stem tightly. A thin wire similarly fitted in between the ball B and its insulating stem connected the ball with the insulated half ring of a divided ring reflecting electrometer.

Neural representation of binding lexical signs and words in the episodic buffer of working memory

2007 ◽  
Vol 45 (10) ◽  
pp. 2258-2276 ◽  
Author(s):  
Mary Rudner ◽  
Peter Fransson ◽  
Martin Ingvar ◽  
Lars Nyberg ◽  
Jerker Rönnberg
Keyword(s):  
Working Memory ◽  
Neural Representation ◽  
Episodic Buffer
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