Co-Planar Stereotaxic Atlas of the Human Brain—3-Dimensional Proportional System: An Approach to Cerebral Imaging, J. Talairach, P. Tournoux. Georg Thieme Verlag, New York (1988), 122 pp., 130 figs. DM 268

Information about the basal ganglia has accumulated at a prodigious pace over the past decade, necessitating major revisions in our concepts of the structural and functional organization of these nuclei. From earlier data it had appeared that the basal ganglia served primarily to integrate diverse inputs from the entire cerebral cortex and to "funnel" these influences, via the ventrolateral thalamus, to the motor cortex (Allen & Tsukahara 1974, Evarts & Thach 1969, Kemp & Powell 1971). In particular, the basal

/pdf/parallel-organization-of-functionally-segregated-circuits-159qr6wgp1.pdf

Parallel Organization of Functionally Segregated Circuits Linking Basal Ganglia and Cortex

Information processing in the cerebral cortex involves interactions among distributed areas. Anatomical connectivity suggests that certain areas form local hierarchical relations such as within the visual system. Other connectivity patterns, particularly among association areas, suggest the presence of large-scale circuits without clear hierarchical relations. In this study the organization of networks in the human cerebrum was explored using resting-state functional connectivity MRI. Data from 1,000 subjects were registered using surface-based alignment. A clustering approach was employed to identify and replicate networks of functionally coupled regions across the cerebral cortex. The results revealed local networks confined to sensory and motor cortices as well as distributed networks of association regions. Within the sensory and motor cortices, functional connectivity followed topographic representations across adjacent areas. In association cortex, the connectivity patterns often showed abrupt transitions between network boundaries. Focused analyses were performed to better understand properties of network connectivity. A canonical sensory-motor pathway involving primary visual area, putative middle temporal area complex (MT+), lateral intraparietal area, and frontal eye field was analyzed to explore how interactions might arise within and between networks. Results showed that adjacent regions of the MT+ complex demonstrate differential connectivity consistent with a hierarchical pathway that spans networks. The functional connectivity of parietal and prefrontal association cortices was next explored. Distinct connectivity profiles of neighboring regions suggest they participate in distributed networks that, while showing evidence for interactions, are embedded within largely parallel, interdigitated circuits. We conclude by discussing the organization of these large-scale cerebral networks in relation to monkey anatomy and their potential evolutionary expansion in humans to support cognition.

The organization of the human cerebral cortex estimated by intrinsic functional connectivity

As humans, we perceive feelings from our bodies that relate our state of well-being, our energy and stress levels, our mood and disposition. How do we have these feelings? What neural processes do they represent? Recent functional anatomical work has detailed an afferent neural system in primates and in humans that represents all aspects of the physiological condition of the physical body. This system constitutes a representation of 'the material me', and might provide a foundation for subjective feelings, emotion and self-awareness.

How do you feel? Interoception: the sense of the physiological condition of the body.

Magnetoencephalography (MEG) is a noninvasive technique for investigating neuronal activity in the living human brain. The time resolution of the method is better than 1 ms and the spatial discrimination is, under favorable circumstances, 2-3 mm for sources in the cerebral cortex. In MEG studies, the weak 10 fT-1 pT magnetic fields produced by electric currents flowing in neurons are measured with multichannel SQUID (superconducting quantum interference device) gradiometers. The sites in the cerebral cortex that are activated by a stimulus can be found from the detected magnetic-field distribution, provided that appropriate assumptions about the source render the solution of the inverse problem unique. Many interesting properties of the working human brain can be studied, including spontaneous activity and signal processing following external stimuli. For clinical purposes, determination of the locations of epileptic foci is of interest. The authors begin with a general introduction and a short discussion of the neural basis of MEG. The mathematical theory of the method is then explained in detail, followed by a thorough description of MEG instrumentation, data analysis, and practical construction of multi-SQUID devices. Finally, several MEG experiments performed in the authors' laboratory are described, covering studies of evoked responses and of spontaneous activity in both healthy and diseased brains. Many MEG studies by other groups are discussed briefly as well.

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Magnetoencephalography—theory, instrumentation, and applications to noninvasive studies of the working human brain

T2*/susceptibility-weighted (T2*SW) MRI enables diagnosis of cerebral venous thrombosis (CVT) by clot visualization as an area of hypointensity.1 This sequence also contributes to the diagnosis of …

https://n.neurology.org/content/neurology/63/9/1698.full.pdf

T2*-weighted MRI in cortical venous thrombosis

Crossed cortical projections to the superior colliculus of the cat were demonstrated by unilateral superior colliculus injections of horseradish per-oxidase (HRP) and by cortical injections of radioactive amino acids.



This crossed corticotectal projection originates in the lateral bank of the middle suprasylvian sulcus and in both banks of the posterior suprasylvian sulcus. The site of termination of the contralateral corticotectal projection is restricted to the anterior margin of the superior colliculus (SC) while the ipsilateral projection spreads over the whole SC. The contralateral terminal areas are restricted to the superficial tectal layers. The projection fibers reach the contralateral superior colliculus by crossing the collicular commissure.



The existence of such a connection may help to explain certain elec-trophysiological observations.

A crossed corticotectal projection from the lateral suprasylvian area in the cat

Early secondary somatosensory area (SII) SEPs. Data from intracerebral recordings in humans.

In this study we aimed to assess the brain distribution of 5-HT1A receptors in migraine patients without aura. Ten female migraine patients and 24 female healthy volunteers underwent magnetic resonance imaging and positron emission tomography using a radioligand antagonist of 5-HT1A receptors [4-(2'-methoxyphenyl)-1-[2'-(N-2-pirydynyl)-p-fluorobenzamido]-ethylpiperazine (18F-MPPF)]. A simplified reference tissue model was used to generate parametric images of 5-HT1A receptor binding potential (BP) values. Statistical Parametrical Mapping (SPM) analysis showed increased MPPF BP in posterior cortical areas and hippocampi bilaterally in patients compared with controls. Region of interest (ROI) analysis showed a non-significant trend in favour of a BP increase patients in cortical regions identified by the SPM analysis except in hippocampi, left parietal areas and raphe nuclei. During the interictal period of migraine patients without aura, the increase of MPPF BP in posterior cortical and limbic areas could ...

Interictal brain 5-HT1A receptors binding in migraine without aura: a 18F-MPPF-PET study.

Opsoclonus–myoclonus syndrome (OMS) is a rare condition that includes chaotic multidirectional saccadic eye movements associated with myoclonus and ataxia. In adults, it is usually considered to be an autoimmune disease occurring either in a paraneoplastic context or after central nervous system infection. We report the case of a patient who presented with the classic features of OMS as a manifestation of acute Borrelia burgdorferi infection that was shown both on serum and cerebrospinal fluid examination. The outcome was favourable after prolonged antibiotic treatment. Lyme disease could be added to the list of aetiologies to be screened in OMS, as it would allow effective treatment and avoidance of unnecessary investigations.

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François Mauguière

Papers

T2*-weighted MRI in cortical venous thrombosis

A crossed corticotectal projection from the lateral suprasylvian area in the cat

Early secondary somatosensory area (SII) SEPs. Data from intracerebral recordings in humans.

Interictal brain 5-HT1A receptors binding in migraine without aura: a 18F-MPPF-PET study.

Opsoclonus–myoclonus as a manifestation of Lyme disease