Representation of Sound Categories in Auditory Cortical Maps

2004 ◽  
Vol 47 (1) ◽  
pp. 46-57 ◽  
Author(s):  
Frank H. Guenther ◽  
Alfonso Nieto-Castanon ◽  
Satrajit S. Ghosh ◽  
Jason A. Tourville
Keyword(s):  
Discrimination Training ◽  
Cortical Activation ◽  
Vowel Sound ◽  
Perceptual Distortion ◽  
Nonspeech Sounds ◽  
Acoustic Space ◽  
Sound Category ◽  
Cortical Representations ◽  
Training Discrimination ◽  
The Brain

Functional magnetic resonance imaging (fMRI) was used to investigate the representation of sound categories in human auditory cortex. Experiment 1 investigated the representation of prototypical (good) and nonprototypical (bad) examples of a vowel sound. Listening to prototypical examples of a vowel resulted in less auditory cortical activation than did listening to nonprototypical examples. Experiments 2 and 3 investigated the effects of categorization training and discrimination training with novel nonspeech sounds on auditory cortical representations. The 2 training tasks were shown to have opposite effects on the auditory cortical representation of sounds experienced during training: Discrimination training led to an increase in the amount of activation caused by the training stimuli, whereas categorization training led to decreased activation. These results indicate that the brain efficiently shifts neural resources away from regions of acoustic space where discrimination between sounds is not behaviorally important (e.g., near the center of a sound category) and toward regions where accurate discrimination is needed. The results also provide a straightforward neural account of learned aspects of perceptual distortion near sound categories: Sounds from the center of a category are more difficult to discriminate from each other than sounds near category boundaries because they are represented by fewer cells in the auditory cortical areas.

Greater Movement-Related Cortical Potential During Human Eccentric Versus Concentric Muscle Contractions

2001 ◽  
Vol 86 (4) ◽  
pp. 1764-1772 ◽  
Author(s):  
Yin Fang ◽  
Vlodek Siemionow ◽  
Vinod Sahgal ◽  
Fuqin Xiong ◽  
Guang H. Yue
Keyword(s):  
Muscle Activation ◽  
Onset Time ◽  
Muscle Contractions ◽  
Elbow Flexor ◽  
Movement Planning ◽  
Cortical Activation ◽  
Cortical Potential ◽  
Eeg Signals ◽  
Muscle Actions ◽  
The Brain

Despite abundant evidence that different nervous system control strategies may exist for human concentric and eccentric muscle contractions, no data are available to indicate that the brain signal differs for eccentric versus concentric muscle actions. The purpose of this study was to evaluate electroencephalography (EEG)-derived movement-related cortical potential (MRCP) and to determine whether the level of MRCP-measured cortical activation differs between the two types of muscle activities. Eight healthy subjects performed 50 voluntary eccentric and 50 voluntary concentric elbow flexor contractions against a load equal to 10% body weight. Surface EEG signals from four scalp locations overlying sensorimotor-related cortical areas in the frontal and parietal lobes were measured along with kinetic and kinematic information from the muscle and joint. MRCP was derived from the EEG signals of the eccentric and concentric muscle contractions. Although the elbow flexor muscle activation (EMG) was lower during eccentric than concentric actions, the amplitude of two major MRCP components—one related to movement planning and execution and the other associated with feedback signals from the peripheral systems—was significantly greater for eccentric than for concentric actions. The MRCP onset time for the eccentric task occurred earlier than that for the concentric task. The greater cortical signal for eccentric muscle actions suggests that the brain probably plans and programs eccentric movements differently from concentric muscle tasks.

scholarly journals Cortical activation in alexithymia as a response to emotional stimuli

2008 ◽  
Vol 192 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Hasse Karlsson ◽  
Petri Näätänen ◽  
Hanna Stenman
Keyword(s):  
Emotion Processing ◽  
Three Dimensional ◽  
Brain Regions ◽  
Physical Symptoms ◽  
Cortical Activation ◽  
Anterior Cingulate ◽  
Control Group ◽  
Emotional Stimuli ◽  
Healthy Women ◽  
The Brain

BackgroundAlexithymia has been shown to be related to many psychiatric and somatic illnesses. Aberrant emotion processing in the brain may underlie several psychiatric disorders. However, little is known about the neurobiological underpinnings of alexithymia.AimsTo determine the way in which the brain processes emotion in alexithymia.MethodThe participants were 10 healthy women with alexithymia and 11 healthy women without this condition, recruited into the study on the basis of their scores on the 20-item Toronto Alexithymia Scale. Four films were projected on a video screen to induce each of three emotional conditions (neutral, amusement, sadness). The brain areas activated during emotional stimuli in the alexithymia group were compared with those activated in the non-alexithymia group. Scans of the distribution of [15O]H2O were acquired using a positron emission tomography (PET) scanner operated in three-dimensional mode.ResultsIn response to emotional stimuli participants with alexithymia activated more parts of their sensory and motor cortices and insula, especially on the left side, and less of their anterior cingulate, compared with the control group.ConclusionsWomen with alexithymia seem to over-activate their ‘bodily’ brain regions, implying a different mode of emotion processing. This may be related to their tendency to experience physical symptoms.

scholarly journals How thalamic relays might orchestrate supervised deep training and symbolic computation in the brain

2018 ◽  
Author(s):  
Kenneth J. Hayworth ◽  
Adam H. Marblestone
Keyword(s):  
Symbolic Computation ◽  
Hebbian Learning ◽  
Declarative Memory ◽  
Connectionist Model ◽  
Sensory Inputs ◽  
Cortical Areas ◽  
Symbolic Reasoning ◽  
Stable Attractor ◽  
Cortical Representations ◽  
The Brain

AbstractThe thalamus appears to be involved in the flexible routing of information among cortical areas, yet the computational implications of such routing are only beginning to be explored. Here we create a connectionist model of how selectively gated cortico-thalamo-cortical relays could underpin both symbolic and sub-symbolic computations. We first show how gateable relays can be used to create a Dynamically Partitionable Auto-Associative Network (DPAAN) (Hayworth, 2012) consisting of a set of cross-connected cortical memory buffers. All buffers and relays in a DPAAN are trained simultaneously to have a common set of stable attractor states that become the symbol vocabulary of the DPAAN. We show via simulations that such a DPAAN can support operations necessary for syntactic rule-based computation, namely buffer-to-buffer copying and equality detection. We then provide each DPAAN module with a multilayer input network trained to map sensory inputs to the DPAAN’s symbol vocabulary, and demonstrate how gateable thalamic relays can provide recall and clamping operations to train this input network by Contrastive Hebbian Learning (CHL) (Xie and Seung, 2003). We suggest that many such DPAAN modules may exist at the highest levels of the brain’s sensory hierarchies and show how a joint snapshot of the contents of multiple DPAAN modules can be stored as a declarative memory in a simple model of the hippocampus. We speculate that such an architecture might first have been ‘discovered’ by evolution as a means to bootstrap learning of more meaningful cortical representations feeding the striatum, eventually leading to a system that could support symbolic computation. Our model serves as a bridging hypothesis for linking controllable thalamo-cortical information routing with computations that could underlie aspects of both learning and symbolic reasoning in the brain.

scholarly journals Transferring and Generalizing Deep-Learning-based Neural Encoding Models across Subjects

2017 ◽  
Author(s):  
Haiguang Wen ◽  
Junxing Shi ◽  
Wei Chen ◽  
Zhongming Liu
Keyword(s):  
Deep Learning ◽  
Learning Models ◽  
Neural Encoding ◽  
Natural Vision ◽  
Cortical Responses ◽  
Single Subjects ◽  
Visual Cortical ◽  
The Relationship ◽  
Cortical Representations ◽  
The Brain

Recent studies have shown the value of using deep learning models for mapping and characterizing how the brain represents and organizes information for natural vision. However, modeling the relationship between deep learning models and the brain (or encoding models), requires measuring cortical responses to large and diverse sets of natural visual stimuli from single subjects. This requirement limits prior studies to few subjects, making it difficult to generalize findings across subjects or for a population. In this study, we developed new methods to transfer and generalize encoding models across subjects. To train encoding models specific to a subject, the models trained for other subjects were used as the prior models and were refined efficiently using Bayesian inference with a limited amount of data from the specific subject. To train encoding models for a population, the models were progressively trained and updated with incremental data from different subjects. For the proof of principle, we applied these methods to functional magnetic resonance imaging (fMRI) data from three subjects watching tens of hours of naturalistic videos, while deep residual neural network driven by image recognition was used to model the visual cortical processing. Results demonstrate that the methods developed herein provide an efficient and effective strategy to establish subject-specific or populationwide predictive models of cortical representations of high-dimensional and hierarchical visual features.

scholarly journals Is Resting-State EEG Longitudinally Associated With Recovery of Clinical Neurological Impairments Early Poststroke? A Prospective Cohort Study

2020 ◽  
Vol 34 (5) ◽  
pp. 389-402 ◽  
Author(s):  
Mique Saes ◽  
Sarah B. Zandvliet ◽  
Aukje S. Andringa ◽  
Andreas Daffertshofer ◽  
Jos W. R. Twisk ◽  
...  
Keyword(s):  
Upper Limb ◽  
Resting State ◽  
Time Course ◽  
Time Window ◽  
Spectral Characteristics ◽  
Motor Recovery ◽  
National Institutes Of Health ◽  
Cortical Activation ◽  
Clinical Measures ◽  
The Brain

Background. The time course of cortical activation and its relation with clinical measures may elucidate mechanisms underlying spontaneous neurobiological recovery after stroke. Objective. We aimed to investigate (1) the time course of cortical activation as revealed by EEG-based spectral characteristics during awake rest and (2) the development of these spectral characteristics in relation to global neurological and upper-limb motor recovery in the first 6 months poststroke. Methods. Resting-state EEG was measured serially in 41 patients after a first-ever ischemic stroke, within 3 and at 5, 12, and 26 weeks poststroke. We computed the brain symmetry index (BSI) and directional BSI (BSIdir) over different frequency bands (1-25 Hz, delta, theta) and delta/alpha ratio (DAR). The National Institutes of Health Stroke Scale (NIHSS) and Fugl-Meyer motor assessment of the upper extremity (FM-UE) were determined as clinical reflections of spontaneous neurobiological recovery. Longitudinal changes in spectral characteristics and within- and between-subject associations with NIHSS and FM-UE were analyzed with linear mixed models. Results. Spectral characteristics showed a gradual normalization over time, within and beyond 12 weeks poststroke. Significant within- and between-subject associations with NIHSS were found for DAR of the affected hemisphere (DARAH) and BSIdirdelta. BSIdirdelta also demonstrated significant within- and between-subject associations with FM-UE. Conclusions. Changes in spectral characteristics are not restricted to the time window of recovery of clinical neurological impairments. The present study suggests that decreasing DARAH and BSIdirdelta reflect improvement of global neurological impairments, whereas BSIdirdelta was also specifically associated with upper-limb motor recovery early poststroke.

Assessment of neurofunctional activity in patients with vibration disease caused by combined effects of local and general vibration

2021 ◽  
Vol 61 (11) ◽  
pp. 726-733
Author(s):  
Oksana I. Shevchenko ◽  
Dina V. Rusanova ◽  
Oleg L. Lakhman
Keyword(s):  
Comparison Group ◽  
Cervical Spinal Cord ◽  
Cortical Activation ◽  
Combined Effects ◽  
Short Term ◽  
Afferent Pathways ◽  
Vibration Disease ◽  
Auditory Speech ◽  
Group I ◽  
The Brain

Introduction. The authors note insufficient knowledge of pathophysiological mechanisms, the cumulative role of cerebral functioning disorders in the formation of sensorineural deficit in vibration disease (VD). The study aims to identify changes in indicators characterizing neurofunctional activity in patients with VD due to the combined effects of local and general vibration. Materials and methods. The study involved 42 patients with VD (group I), 35 healthy men (comparison group). Researchers used methods of electroneuromyography, neuroenergic mapping, and neuropsychological testing. Results. In group I, when compared with the comparison group, we have detected an increase in latency N9, N10, N11, N13, N25, N30, the duration of the peak interval N10-N13 (p=0,002; 0,0001; 0,0002; 0,0001; 0,0023; 0,005; 0,01 respectively); an increase in local levels of constant potential (LCP) in the frontal, central, right parietal, occipital, right temporal parts of the brain (p=0.037; 0.0007; 0,0005; 0,01; 0,0004; 0,014; 0,029; 0,028; 0,001 respectively). Cognitive impairments in patients with VD correspond to an easily expressed disorder of analytical-synthetic and conceptual thinking, short-term (auditory-speech), visual imagery, long-term memory, dynamic praxis, joint coordination, impressive and expressive speech. The revealed conjugacy of the indicators of the LCP of the frontal left abduction, and the latency of the peak N30, duration N13-N20, and the hand of analytical and synthetic thinking (r=0.51, p=0.004; r=0.50, p=0.005, respectively) indicates the pathogenetic significance in the violation of neurofunctional activity of a decrease in cortical activation as a result of the arrival of a sensory message from the brain stem to the cortex, increased energy exchange in the frontal part of the left hemisphere. Conclusions. A sign of impaired neurofunctional activity in VB from the combined effects of local and general vibration is a decrease in the postsynaptic action of neurons, the time of signal passage through afferent pathways at the level of the cervical spinal cord, dynamic praxis, short-term (auditory-speech) memory, increased energy metabolism in the temporal right and left frontal brain.

Patterns of Cortical Activation When Using Concept Generation Techniques of Brainstorming, Morphological Analysis, and TRIZ

2018 ◽  
Author(s):  
Tripp Shealy ◽  
Mo Hu ◽  
John Gero
Keyword(s):  
Morphological Analysis ◽  
Brain Regions ◽  
Cognitive Effort ◽  
Cortical Activation ◽  
Generation Process ◽  
Concept Generation ◽  
Cognitive Differences ◽  
Solution Generation ◽  
Left Dlpfc ◽  
The Brain

This paper presents the results of an experimental study comparing cortical activation in the brain when generating solutions using brainstorming, morphological analysis, and TRIZ. Twelve engineering students were given the same three design tasks, respectively, using the three solution generation techniques. Students generated solutions while change in oxygenated blood along the prefrontal cortex (PFC) was measured using functional near-infrared spectroscopy. The results show that generating solutions using brainstorming, morphological analysis, and TRIZ leads to differences in cortical activation, specifically along the region of the brain associated with spatial working memory, cognitive flexibility, and abstract reasoning, called the left dorsolateral prefrontal cortex (left DLPFC). Brainstorming evokes a high average blood oxygenation level dependent (BOLD) response in the left DLPFC early during the solution generation process but this high response is not sustained. In comparison, morphological analysis and TRIZ evoke multiple high average BOLD responses across the solution generation process. Not only was the high average BOLD response sustained but the density of network coordination among brain regions across the PFC was greater for morphological analysis and TRIZ. Higher density is a proxy for higher cognitive effort. The brain regions most central to coordination also varied. During brainstorming the right hemisphere, in a region associated with memory encoding (right PFC), was most activated. During morphological analysis, the left hemisphere, the left DLPFC was most activated. During TRIZ, both the middle and left hemisphere included regions of high activation. These results indicate neuro-cognitive differences of activation patterns, cognitive effort over time, and brain regions central for coordination when using these three concept generation techniques. Future research can begin to explore neuro-cognitive differences as a result of these techniques over multiple uses and the effects of design education.

scholarly journals Constraint-Induced Movement Therapy for Individuals After Cerebral Hemispherectomy: A Case Series

2009 ◽  
Vol 89 (4) ◽  
pp. 361-369 ◽  
Author(s):  
Stella de Bode ◽  
Stacy L Fritz ◽  
Kristi Weir-Haynes ◽  
Gary W Mathern
Keyword(s):  
Brain Imaging ◽  
Upper Extremity ◽  
Case Series ◽  
Movement Therapy ◽  
Constraint Induced Movement Therapy ◽  
Before And After ◽  
Block Test ◽  
Cortical Representations ◽  
The Brain ◽  
Qualitative Changes

Background and PurposeThis case report describes the feasibility and efficacy of the use of constraint-induced movement therapy (CIMT) in 4 individuals (aged 12–22 years) who underwent cerebral hemispherectomy (age at time of surgery=4–10 years). The aims of this case series were: (1) to evaluate the feasibility of this therapeutic approach involving a shortened version of CIMT, (2) to examine improvements that occurred within the upper extremity of the hemiparetic side, (3) to investigate the feasibility of conducting brain imaging in individuals with depressed mental ages, and (4) to examine changes in the sensorimotor cortex following intervention.Case DescriptionThe patients received a shortened version of CIMT for 3 hours each day for a period of 10 days. In addition, a standard resting splint was used for the unimpaired hand for an 11-day period. Each patient was encouraged to wear the splint for 90% of his or her waking hours. The following outcome measures were used: the Actual Amount of Use Test (AAUT), the Box and Block Test (BBT), and the upper-extremity grasping and motor portions of the Fugl-Meyer Assessment of Motor Recovery (FM).OutcomesImmediately after therapy, improvements were found in AAUT and BBT scores, but no improvements were found in FM scores. Three patients underwent brain imaging before and after therapy and showed qualitative changes consistent with reorganization of sensorimotor cortical representations of both paretic and nonparetic hands in one isolated hemisphere.DiscussionThe findings suggest that CIMT may be a feasible method of rehabilitation in individuals with chronic hemiparesis, possibly leading to neuroplastic therapy–related changes in the brain.

Brain olfactory activation measured by near-infrared spectroscopy in humans

2006 ◽  
Vol 120 (8) ◽  
pp. 638-643 ◽  
Author(s):  
H Harada ◽  
M Tanaka ◽  
T Kato
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Cortical Activation ◽  
Olfactory Stimulation ◽  
Olfactory Test ◽  
Olfactory Stimuli ◽  
Preliminary Study ◽  
The Right ◽  
The Brain

In recent years, near-infrared spectroscopy (NIRS) has been used to study functional activation of various areas of the brain. This is based on the assumption that an increase in the recorded oxygenated haemoglobin (HbO2) concentration represents an increase in blood flow, which in turn reflects neuronal activation. The aim of this preliminary study was to use NIRS to monitor the activity of the olfactory cortex, as mirrored by the haemodynamic response, when subjects were exposed to olfactory stimuli.A NIRO 300 (Hamamatsu Photonics, Hamamatsu, Japan) device was used. The optodes were placed on the right forehead and right temporal, parietal and occipital regions. Changes in the concentration of HbO2 and deoxygenated haemoglobin during olfactory stimulation were monitored. Olfactory stimulation was performed with vanilla essence, strawberry essence and scatol.During olfactory stimulation, cerebral HbO2 concentration increased over the frontal region. However, in the temporal, parietal and occipital regions, little or no HbO2 changes were recorded.This study shows that human brain cortical activation following olfactory stimulation can be recorded by NIRS. This NIRS analysis may therefore provide the basis for future development of an objective olfactory test in humans.

scholarly journals Asymmetrical Body Perception

2009 ◽  
Vol 20 (11) ◽  
pp. 1373-1380 ◽  
Author(s):  
Sally A. Linkenauger ◽  
Jessica K. Witt ◽  
Jonathan Z. Bakdash ◽  
Jeanine K. Stefanucci ◽  
Dennis R. Proffitt
Keyword(s):  
Right Hemisphere ◽  
The Body ◽  
Neural Representation ◽  
Many Body ◽  
Body Perception ◽  
Left Handed ◽  
Naturally Occurring ◽  
The Right ◽  
Cortical Representations ◽  
The Brain

Perception of one's body is related not only to the physical appearance of the body, but also to the neural representation of the body. The brain contains many body maps that systematically differ between right- and left-handed people. In general, the cortical representations of the right arm and right hand tend to be of greater area in the left hemisphere than in the right hemisphere for right-handed people, whereas these cortical representations tend to be symmetrical across hemispheres for left-handers. We took advantage of these naturally occurring differences and examined perceived arm length in right- and left-handed people. When looking at each arm and hand individually, right-handed participants perceived their right arms and right hands to be longer than their left arms and left hands, whereas left-handed participants perceived both arms accurately. These experiments reveal a possible relationship between implicit body maps in the brain and conscious perception of the body.

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