Influence of White and Gray Matter Connections on Endogenous Human Cortical Oscillations

Hawasli, Ammar H.; Kim, Dohyun; Ledbetter, Noah M.; Dahiya, Sonika; Barbour, Dennis L.; Leuthardt, Eric C.

doi:10.3389/fnhum.2016.00330

Cited by 13 publications

(13 citation statements)

References 62 publications

(98 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The present study used a visual paradigm requiring timing judgements for the stimuli within the supra-second range. We propose that cognitively controlled timing processes engage a distributed brain network revolving around the right dorsolateral prefrontal and right intraparietal cortices as well as the AIC and BG (Lewiss and Miall, 2003 ; Teki, 2016 ). Introceptive signals processed mainly by the insula might construct the subjective present and add to the information supplied by the BG which might encode and maintain time intervals (Rao et al, 2001 ; Craig, 2009a , b ).…”

Section: Discussionmentioning

confidence: 99%

Neural Networks for Time Perception and Working Memory

Üstün

Kale

Çíçek

2017

Front. Hum. Neurosci.

View full text Add to dashboard Cite

Time is an important concept which determines most human behaviors, however questions remain about how time is perceived and which areas of the brain are responsible for time perception. The aim of this study was to evaluate the relationship between time perception and working memory in healthy adults. Functional magnetic resonance imaging (fMRI) was used during the application of a visual paradigm. In all of the conditions, the participants were presented with a moving black rectangle on a gray screen. The rectangle was obstructed by a black bar for a time period and then reappeared again. During different conditions, participants (n = 15, eight male) responded according to the instructions they were given, including details about time and the working memory or dual task requirements. The results showed activations in right dorsolateral prefrontal and right intraparietal cortical networks, together with the anterior cingulate cortex (ACC), anterior insula and basal ganglia (BG) during time perception. On the other hand, working memory engaged the left prefrontal cortex, ACC, left superior parietal cortex, BG and cerebellum activity. Both time perception and working memory were related to a strong peristriate cortical activity. On the other hand, the interaction of time and memory showed activity in the intraparietal sulcus (IPS) and posterior cingulate cortex (PCC). These results support a distributed neural network based model for time perception and that the intraparietal and posterior cingulate areas might play a role in the interface of memory and timing.

show abstract

Section: Discussionmentioning

confidence: 99%

Neural Networks for Time Perception and Working Memory

Üstün

Kale

Çíçek

2017

Front. Hum. Neurosci.

View full text Add to dashboard Cite

show abstract

“…There are some interesting similarities and differences between those studies and the current work. In the study performed by Hawasli et al white matter and gray matter disconnections were performed immediately adjacent to normal cortex in a temporal lobe (a region of the brain that was necessarily going to be resected to access a deeper pathology) (Hawasli et al, 2015). Thus, while the white and gray matter lesions were local (<1 cm from recorded cortical site) and the disconnected cortex was demonstrably normal for Hawasli et al in this experiment the disconnection is distant from the recorded cortex and the cortex is abnormal to varying degrees (peri-stroke cortex more normal, while the dysplastic cortex is quite abnormal).…”

Section: Discussionmentioning

confidence: 99%

“…This phenomenon has been implicated in neuronal firing, cortical activation, task completion, and alterations in consciousness (Canolty et al, 2006; Cardin et al, 2009; Breshears et al, 2010). Recent work challenges these notions (Hawasli et al, 2015) Hawasli et al report that when a one-centimeter region of normal cortex was circumferentially disconnected from adjacent cortex, the PAC was significantly increased. If PAC were a mechanism for cortico-cortical communication, PAC should to be reduced.…”

Section: Discussionmentioning

confidence: 99%

“…Phase-amplitude coupling signal analyses were performed to evaluate how low frequency oscillations phases modulate high frequency oscillation amplitudes, as previously described (Canolty et al, 2006; Tort et al, 2010; Daitch et al, 2013; Hawasli et al, 2015). Phase-amplitude coupling was assessed for every frequency pair in a 2-dimensional frequency space.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Electrophysiological Sequelae of Hemispherotomy in Ipsilateral Human Cortex

Hawasli

Chacko

Szrama

et al. 2017

Front. Hum. Neurosci.

Self Cite

View full text Add to dashboard Cite

Objectives: Hemispheric disconnection has been used as a treatment of medically refractory epilepsy and evolved from anatomic hemispherectomy to functional hemispherectomies to hemispherotomies. The hemispherotomy procedure involves disconnection of an entire hemisphere with limited tissue resection and is reserved for medically-refractory epilepsy due to diffuse hemispheric disease. Although it is thought to be effective by preventing seizures from spreading to the contralateral hemisphere, the electrophysiological effects of a hemispherotomy on the ipsilateral hemisphere remain poorly defined. The objective of this study was to evaluate the effects of hemispherotomy on the electrophysiologic dynamics in peri-stroke and dysplastic cortex.Methods: Intraoperative electrocorticography (ECoG) was recorded from ipsilateral cortex in 5 human subjects with refractory epilepsy before and after hemispherotomy. Power spectral density, mutual information, and phase-amplitude coupling were measured from the ECoG signals.Results: Epilepsy was a result of remote perinatal stroke in three of the subjects. In two of the subjects, seizures were a consequence of dysplastic tissue: one with hemimegalencephaly and the second with Rasmussen's encephalitis. Hemispherotomy reduced broad-band power spectral density in peri-stroke cortex. Meanwhile, hemispherotomy increased power in the low and high frequency bands for dysplastic cortex. Functional connectivity was increased in lower frequency bands in peri-stroke tissue but not affected in dysplastic tissue after hemispherotomy. Finally, hemispherotomy reduced band-specific phase-amplitude coupling in peristroke cortex but not dysplastic cortex.Significance: Disconnecting deep subcortical connections to peri-stroke cortex via a hemispherotomy attenuates power of oscillations and impairs the transfer of information from large-scale distributed brain networks to the local cortex. Hence, hemispherotomy reduces heterogeneity between neighboring cortex while impairing phase-amplitude coupling. In contrast, dysfunctional networks in dysplastic cortex lack the normal connectivity with distant networks. Therefore hemispherotomy does not produce the same effects.

show abstract

“…synchronization. 72 Hemispheric disconnection experiments have provided an understanding of the importance of long-range subcortical connections to local cerebral networks. Disconnecting deep subcortical connections through a hemispherotomy impairs the transfer of information from large-scale distributed brain networks to the local cortex, thereby increasing local mesoscale connectivity.…”

mentioning

confidence: 99%

Spinal Cord Injury Disrupts Resting-State Networks in the Human Brain

Hawasli

Rutlin

Roland

et al. 2018

Journal of Neurotrauma

Self Cite

View full text Add to dashboard Cite

Despite 253,000 spinal cord injury (SCI) patients in the United States, little is known about how SCI affects brain networks. Spinal MRI provides only structural information with no insight into functional connectivity. Resting-state functional MRI (RS-fMRI) quantifies network connectivity through the identification of resting-state networks (RSNs) and allows detection of functionally relevant changes during disease. Given the robust network of spinal cord afferents to the brain, we hypothesized that SCI produces meaningful changes in brain RSNs. RS-fMRIs and functional assessments were performed on 10 SCI subjects. Blood oxygen-dependent RS-fMRI sequences were acquired. Seed-based correlation mapping was performed using five RSNs: default-mode (DMN), dorsal-attention (DAN), salience (SAL), control (CON), and somatomotor (SMN). RSNs were compared with normal control subjects using false-discovery rate-corrected two way t tests. SCI reduced brain network connectivity within the SAL, SMN, and DMN and disrupted anti-correlated connectivity between CON and SMN. When divided into separate cohorts, complete but not incomplete SCI disrupted connectivity within SAL, DAN, SMN and DMN and between CON and SMN. Finally, connectivity changed over time after SCI: the primary motor cortex decreased connectivity with the primary somatosensory cortex, the visual cortex decreased connectivity with the primary motor cortex, and the visual cortex decreased connectivity with the sensory parietal cortex. These unique findings demonstrate the functional network plasticity that occurs in the brain as a result of injury to the spinal cord. Connectivity changes after SCI may serve as biomarkers to predict functional recovery following an SCI and guide future therapy.

show abstract

Influence of White and Gray Matter Connections on Endogenous Human Cortical Oscillations

Cited by 13 publications

References 62 publications

Neural Networks for Time Perception and Working Memory

Neural Networks for Time Perception and Working Memory

Electrophysiological Sequelae of Hemispherotomy in Ipsilateral Human Cortex

Spinal Cord Injury Disrupts Resting-State Networks in the Human Brain

Contact Info

Product

Resources

About