scholarly journals Revealing the neural fingerprints of a missing hand

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Sanne Kikkert ◽  
James Kolasinski ◽  
Saad Jbabdi ◽  
Irene Tracey ◽  
Christian F Beckmann ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Sensory Input ◽  
Life Experience ◽  
Primary Somatosensory Cortex ◽  
Neural Signals ◽  
Ultra High Field ◽  
Fine Grained ◽  
Arm Amputation ◽  
Main Input ◽  
Hand Area

The hand area of the primary somatosensory cortex contains detailed finger topography, thought to be shaped and maintained by daily life experience. Here we utilise phantom sensations and ultra high-field neuroimaging to uncover preserved, though latent, representation of amputees’ missing hand. We show that representation of the missing hand’s individual fingers persists in the primary somatosensory cortex even decades after arm amputation. By demonstrating stable topography despite amputation, our finding questions the extent to which continued sensory input is necessary to maintain organisation in sensory cortex, thereby reopening the question what happens to a cortical territory once its main input is lost. The discovery of persistent digit topography of amputees’ missing hand could be exploited for the development of intuitive and fine-grained control of neuroprosthetics, requiring neural signals of individual digits.

scholarly journals Locating primary somatosensory cortex in human brain stimulation studies: systematic review and meta-analytic evidence

2019 ◽  
Vol 121 (1) ◽  
pp. 152-162 ◽  
Author(s):  
Nicholas Paul Holmes ◽  
Luigi Tamè
Keyword(s):  
Somatosensory Cortex ◽  
Primary Motor Cortex ◽  
Primary Somatosensory Cortex ◽  
Similar Data ◽  
Indirect Methods ◽  
Gold Standard Method ◽  
Systematic Assessment ◽  
Stereotactic Navigation ◽  
Scalp Location ◽  
Hand Area

Transcranial magnetic stimulation (TMS) over human primary somatosensory cortex (S1), unlike over primary motor cortex (M1), does not produce an immediate, objective output. Researchers must therefore rely on one or more indirect methods to position the TMS coil over S1. The “gold standard” method of TMS coil positioning is to use individual functional and structural magnetic resonance imaging (f/sMRI) alongside a stereotactic navigation system. In the absence of these facilities, however, one common method used to locate S1 is to find the scalp location that produces twitches in a hand muscle (e.g., the first dorsal interosseus, M1-FDI) and then move the coil posteriorly to target S1. There has been no systematic assessment of whether this commonly reported method of finding the hand area of S1 is optimal. To do this, we systematically reviewed 124 TMS studies targeting the S1 hand area and 95 fMRI studies involving passive finger and hand stimulation. Ninety-six TMS studies reported the scalp location assumed to correspond to S1-hand, which was on average 1.5–2 cm posterior to the functionally defined M1-hand area. Using our own scalp measurements combined with similar data from MRI and TMS studies of M1-hand, we provide the estimated scalp locations targeted in these TMS studies of the S1-hand. We also provide a summary of reported S1 coordinates for passive finger and hand stimulation in fMRI studies. We conclude that S1-hand is more lateral to M1-hand than assumed by the majority of TMS studies.

scholarly journals Fine-Grained Nociceptive Maps in Primary Somatosensory Cortex

2012 ◽  
Vol 32 (48) ◽  
pp. 17155-17162 ◽  
Author(s):  
F. Mancini ◽  
P. Haggard ◽  
G. D. Iannetti ◽  
M. R. Longo ◽  
M. I. Sereno
Keyword(s):  
Somatosensory Cortex ◽  
Primary Somatosensory Cortex ◽  
Fine Grained

scholarly journals Localization of Palatal Area in Human Somatosensory Cortex

2007 ◽  
Vol 86 (3) ◽  
pp. 265-270 ◽  
Author(s):  
H. Bessho ◽  
Y. Shibukawa ◽  
M. Shintani ◽  
Y. Yajima ◽  
T. Suzuki ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Hard Palate ◽  
Three Dimensional ◽  
Posterior Wall ◽  
Primary Somatosensory Cortex ◽  
Central Sulcus ◽  
Precise Location ◽  
Greater Palatine Foramen ◽  
Hand Area ◽  
Stimulation Of

To determine the ’hard palate representing’ area in the primary somatosensory cortex, we recorded somatosensory-evoked magnetic fields from the cortex in ten healthy volunteers, using magnetoencephalography. Following electrical stimulation of 3 sites on the hard palate (the first and third transverse palatine ridges, and the greater palatine foramen), magnetic responses showed peak latencies of 15, 65, and 125 ms. Equivalent current dipoles for early magnetic responses were found along the posterior wall of the inferior part of the central sulcus. These dipoles were localized anterior-inferiorly, compared with locations for the hand area in the cortex. However, there were no significant differences in three-dimensional locations among the 3 selected regions for hard palate stimulation. These results demonstrated the precise location of palatal representation in the primary somatosensory cortex, the actual area being small.

scholarly journals Layer-specific activation of sensory input and predictive feedback in the human primary somatosensory cortex

2019 ◽  
Vol 5 (5) ◽  
pp. eaav9053 ◽  
Author(s):  
Yinghua Yu ◽  
Laurentius Huber ◽  
Jiajia Yang ◽  
David C. Jangraw ◽  
Daniel A. Handwerker ◽  
...  
Keyword(s):  
Somatosensory Cortex ◽  
Sensory Input ◽  
Specific Activity ◽  
Predictive Coding ◽  
Somatosensory System ◽  
Middle Layer ◽  
Predictive Processing ◽  
Primary Somatosensory Cortex ◽  
Imaging Data ◽  
Deep Layers

When humans perceive a sensation, their brains integrate inputs from sensory receptors and process them based on their expectations. The mechanisms of this predictive coding in the human somatosensory system are not fully understood. We fill a basic gap in our understanding of the predictive processing of somatosensation by examining the layer-specific activity in sensory input and predictive feedback in the human primary somatosensory cortex (S1). We acquired submillimeter functional magnetic resonance imaging data at 7T (n = 10) during a task of perceived, predictable, and unpredictable touching sequences. We demonstrate that the sensory input from thalamic projects preferentially activates the middle layer, while the superficial and deep layers in S1 are more engaged for cortico-cortical predictive feedback input. These findings are pivotal to understanding the mechanisms of tactile prediction processing in the human somatosensory cortex.

scholarly journals Within-finger maps of tactile and nociceptive input in the human parietal cortex

2019 ◽  
Author(s):  
Flavia Mancini ◽  
Martin I. Sereno ◽  
Min-Ho Lee ◽  
Giandomenico D Iannetti ◽  
Irene Tracey
Keyword(s):  
Somatosensory Cortex ◽  
Functional Mri ◽  
Parietal Cortex ◽  
High Field ◽  
Spatial Representation ◽  
Primary Somatosensory Cortex ◽  
Fine Grained ◽  
Tactile Input ◽  
Somatosensory Input ◽  
Nociceptive Input

AbstractThe spatial representation of nociceptive input in the human parietal cortex is not fully understood. For instance, it is known that the primary somatosensory cortex (S1) contains a representation of nociceptive-selective input to different fingers, but it is unclear whether S1 subdivisions contain finer-grained, within-finger maps of nociceptive input. It is also unknown whether within-finger maps of somatosensory input exist in intraparietal regions. Therefore, we used high-field 7T functional MRI to reveal within-finger maps of nociceptive and tactile inputs in the human parietal cortex. Although we replicated the previous findings of between-finger maps of nociceptive input spanning S1 subdivisions, we found weak and inconsistent evidence for within-finger maps of nociceptive input in S1 subdivisions. In the same subjects, we found mirrored, within-finger maps of tactile input in areas 3a, 3b, and 1. Importantly, we discovered a within-finger map of nociceptive input, but not of tactile input, in the human intraparietal area 1 (hIP1). In conclusion, our study indicates that the spatial representation of nociceptive input in the parietal cortex partly differs from that of tactile input and reports the discovery of a within-finger map of nociceptive input in hIP1.New & NoteworthyWe report the discovery of a fine-grained map of nociceptive input to finger segments in the human intraparietal area 1.

scholarly journals Locating primary somatosensory cortex in human brain stimulation studies: experimental evidence

2019 ◽  
Vol 121 (1) ◽  
pp. 336-344 ◽  
Author(s):  
Nicholas Paul Holmes ◽  
Luigi Tamè ◽  
Paisley Beeching ◽  
Mary Medford ◽  
Mariyana Rakova ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Human Brain ◽  
Somatosensory Cortex ◽  
Brain Stimulation ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Primary Somatosensory Cortex ◽  
Indirect Methods ◽  
Scalp Location ◽  
Hand Area

Transcranial magnetic stimulation (TMS) over human primary somatosensory cortex (S1) does not produce immediate outputs. Researchers must therefore rely on indirect methods for TMS coil positioning. The “gold standard” is to use individual functional and structural magnetic resonance imaging (MRI) data, but the majority of studies don’t do this. The most common method to locate the hand area of S1 (S1-hand) is to move the coil posteriorly from the hand area of primary motor cortex (M1-hand). Yet, S1-hand is not directly posterior to M1-hand. We localized the index finger area of S1-hand (S1-index) experimentally in four ways. First, we reanalyzed functional MRI data from 20 participants who received vibrotactile stimulation to their 10 digits. Second, to assist the localization of S1-hand without MRI data, we constructed a probabilistic atlas of the central sulcus from 100 healthy adult MRIs and measured the likely scalp location of S1-index. Third, we conducted two experiments mapping the effects of TMS across the scalp on tactile discrimination performance. Fourth, we examined all available neuronavigation data from our laboratory on the scalp location of S1-index. Contrary to the prevailing method, and consistent with systematic review evidence, S1-index is close to the C3/C4 electroencephalography (EEG) electrode locations on the scalp, ~7–8 cm lateral to the vertex, and ~2 cm lateral and 0.5 cm posterior to the M1-hand scalp location. These results suggest that an immediate revision to the most commonly used heuristic to locate S1-hand is required. The results of many TMS studies of S1-hand need reassessment. NEW & NOTEWORTHY Noninvasive human brain stimulation requires indirect methods to target particular brain areas. Magnetic stimulation studies of human primary somatosensory cortex have used scalp-based heuristics to find the target, typically locating it 2 cm posterior to the motor cortex. We measured the scalp location of the hand area of primary somatosensory cortex and found that it is ~2 cm lateral to motor cortex. Our results suggest an immediate revision of the prevailing method is required.

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