The brain in time: insights from neuromagnetic recordings

Hari, Riitta; Parkkonen, Lauri; Nangini, Cathy

doi:10.1111/j.1749-6632.2010.05438.x

Cited by 88 publications

(65 citation statements)

References 155 publications

(251 reference statements)

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“…parallel pathways | visual system | sleep-wake cycles | anesthesia | epilepsy T he thalamus is central to brain networks that generate slow rhythmic neural activity in sleep-wake cycles, anesthesia, and epilepsy (1)(2)(3)(4)(5). However, the thalamus also provides parallel pathways to cerebral cortex for conscious sensation.…”

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confidence: 99%

Slow intrinsic rhythm in the koniocellular visual pathway

Cheong

Tailby

Martin

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Slow rhythmic changes in nerve-cell activity are characteristic of unconscious brain states and also may contribute to waking brain function by coordinating activity between cortical and subcortical structures. Here we show that slow rhythms are exhibited by the koniocellular (K) pathway, one of three visual pathways beginning in the eye and projecting through the lateral geniculate visual relay nucleus to the cerebral cortex. We recorded activity in pairs and ensembles of neurons in the lateral geniculate nucleus of anesthetized marmoset monkeys. We found slow rhythms are common in K cells but are rare in parvocellular and magnocellular cell pairs. The time course of slow K rhythms corresponds to subbeta (<10 Hz) EEG frequencies, and high spike rates in K cells are associated with low power in the theta and delta EEG bands. By contrast, spontaneous activity in the parvocellular and magnocellular pathways is neither synchronized nor strongly linked to EEG state. These observations suggest that parallel visual pathways not only carry different kinds of visual signals but also contribute differentially to brain circuits at the first synapse in the thalamus. Differential contribution of sensory streams to rhythmic brain circuits also raises the possibility that sensory stimuli can be tailored to modify brain rhythms.parallel pathways | visual system | sleep-wake cycles | anesthesia | epilepsy T he thalamus is central to brain networks that generate slow rhythmic neural activity in sleep-wake cycles, anesthesia, and epilepsy (1-5). However, the thalamus also provides parallel pathways to cerebral cortex for conscious sensation. These two aspects of thalamic function are not independent, as shown, for example, when repetitive visual stimuli induce epileptic seizures (6). Anatomical studies of the dorsal lateral geniculate nucleus (LGN) show preferential inputs to the LGN koniocellular (K) layers from midbrain centers regulating eye movements and vigilance state (1, 2, 7-9), suggesting that activity in the K system is concerned with brain state as well as with faithful transmission of retinal signals. We found evidence supporting this idea from an unexpected observation on K cells. Results During extracellular recordings fromLGN in anesthetized marmoset monkeys (Fig.1 A-D), we found that in the absence of patterned visual stimuli the spike rate of K cells showed slow fluctuations over the course of several seconds to minutes. An example of these slow intrinsic rhythms in three simultaneously recorded K cells is shown in Fig. 1E. By contrast the spike rate of parvocellular (P) cells (Fig. 1F) and magnocellular (M) cells (Fig. 1G) was stable in the absence of patterned visual stimulus. Retinal ganglion cell inputs to K, P, and M layers show low variation in steady discharges at frequencies below 3 Hz (10); this fact implies that the fluctuations do not arise in the retina. Frequency analysis of maintained spike rates showed that below 1 Hz, K-cell spike rates (n = 56) on average were 33% more variable than P-cell spike ...

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confidence: 99%

Slow intrinsic rhythm in the koniocellular visual pathway

Cheong

Tailby

Martin

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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“…While these characteristics make the "Puffer system" easier to administer in young children than functional MRI, ERP does not provide the same degree of spatial resolution 24 . Caution should be used in attributing ERP signal sources to underlying structures, even in the case of well-studied somatosensory potentials 25 .…”

Section: Discussionmentioning

confidence: 99%

Quantitative Assessment of Cortical Auditory-tactile Processing in Children with Disabilities

Maitre

Key

2014

JoVE

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Objective and easy measurement of sensory processing is extremely difficult in nonverbal or vulnerable pediatric patients. We developed a new methodology to quantitatively assess children's cortical processing of light touch, speech sounds and the multisensory processing of the 2 stimuli, without requiring active subject participation or causing children discomfort. To accomplish this we developed a dual channel, time and strength calibrated air puff stimulator that allows both tactile stimulation and sham control. We combined this with the use of event-related potential methodology to allow for high temporal resolution of signals from the primary and secondary somatosensory cortices as well as higher order processing. This methodology also allowed us to measure a multisensory response to auditory-tactile stimulation. Video LinkThe video component of this article can be found at

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“…Expressive language tasks in the MEG are less common because the artefacts and trial-bytrial variability of speech production have been problematic for the small neuromagnetic signals (Hari, et al, 2010). Some groups have found creative approaches to these problems (e.g., Breier and Papanicolaou, 2008).…”

Section: Introductionmentioning

confidence: 99%

An MEG study of the spatiotemporal dynamics of bilingual verb generation

Pang

MacDonald

2012

Brain Research

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Studies of first (L1) and second (L2) language representation in the brain have not identified the timing and locations of neural regions involved in L1 and L2 processing. Magnetoencephalography offers high spatial and temporal resolution and can be employed to disentangle subtle timing and neural control differences between L1 and L2 use. We tested bilingual adults in the MEG as they completed a picture verb generation task in L1 and L2. We found the expected progression of activation from occipital to temporal to inferior frontal areas. We also observed the following differences. A sustained insula and early cingulate event-related desynchrony was observed only with L2; the fMRI literature suggests that the former reflects an activation, and the latter an inhibition, sub-process for language selection. L2 processes exhibited a lag and were bilateral compared to L1 processes. Finally, L1 and L2 activated adjacent language control in dorsolateral pre-frontal cortex.

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The brain in time: insights from neuromagnetic recordings

Cited by 88 publications

References 155 publications

Slow intrinsic rhythm in the koniocellular visual pathway

Slow intrinsic rhythm in the koniocellular visual pathway

Quantitative Assessment of Cortical Auditory-tactile Processing in Children with Disabilities

An MEG study of the spatiotemporal dynamics of bilingual verb generation

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