Neuromagnetic fields were recorded from human subject as they listened selectively to sequences of rapidly presented tones in one ear while ignoring tones of a diferent pitch In the oppoite ear. in the interval 20-50 msec (the P20-50) was also found to be enlarged with attention (6, 7).These ERP results support the view that the flow of auditory sensory information can be altered by attention at a relatively early stage of processing. They do not specify, however, the brain structures in which this stimulus selection takes place. One approach to address this question is to study neuromagnetic recordings (ERFs), which offer an advantage over ERPs for localization of the anatomical sources of evoked brain activity in cortical sulci (e.g., auditory cortex on the supratemporal plane). This advantage is due to ERF recordings being selectively sensitive to activity from such sources and due to magnetic fields being less distorted by the skull (8, 9).Several studies have applied source localization techniques to ERF recordings and concluded that at least part of the enhanced activity elicited by attended sounds in the N100 latency range arises from the vicinity of auditory cortex (10, 11). However, the precise anatomical source(s) of this attention effect have yet to be verified by superposition of calculated source coordinates onto magnetic resonance (MR) images of the subjects' brains.11 Even less information is available regarding the neural generator(s) ofthe P20-50 ERP attention effect, as no magnetic counterpart ofthis very early ERP modulation has yet been reported.In the current study, neuromagnetic and MR imaging techniques were combined to localize the neuroanatomical origins of the early effects of attention on tone-evoked brain activity. The results provide evidence that focused auditory attention exerts selective control over early sensory processing in the auditory cortical areas on the supratemporal plane beginning at 20 msec poststimulus. METHODSSelective auditory attention was studied using the same fast-rate dichotic listening paradigm that we have used previously in ERP studies (6, IThere is considerable evidence that at least some of the "exogenous" tone-evoked activity (i.e., non-attention-related) in the 30-to 150-msec latency range arises from neural generators in the vicinity of the auditory cortex on the supratemporal plane (12)(13)(14)(15). Recent neuromagnetic studies have localized portions ofthis early sensoryevoked activity to the supratemporal-plane auditory cortex as visualized on subjects' MR scans (16-18). 8722

The objective of this study was to compare efficacy of two meditation protocols for treating patients with obsessive-compulsive disorder (OCD). Patients were randomized to two groups-matched for sex, age, and medication status-and blinded to the comparison protocol. They were told the trial would last for 12 months, unless one protocol proved to be more efficacious. If so, groups would merge, and the group that received the less efficacious treatment would also be afforded 12 months of the more effective one. The study was conducted at Children's Hospital, San Diego, Calif. Patients were selected according to Diagnostic and Statistical Manual of Mental Disorders, Third Edition-Revised (DSM-III-R) criteria and recruited by advertisements and referral. At baseline, Group 1 included 11 adults and 1 adolescent, and Group 2 included 10 adults. Group 1 employed a kundalini yoga meditation protocol and Group 2 employed the Relaxation Response plus Mindfulness Meditation technique. Baseline and 3-month interval testing was conducted using the Yale-Brown Obsessive Compulsive Scale (Y-BOCS), Symptoms Checklist-90-Revised Obsessive Compulsive (SCL-90-R OC) and Global Severity Index (SCL-90-R GSI) scales, Profile of Moods scale (POMS), Perceived Stress Scale (PSS), and Purpose in Life (PIL) test. Seven adults in each group completed 3 months of therapy. At 3 months, Group 1 demonstrated greater improvements (Student's independent groups t-test) on the Y-BOCS, SCL-90-R OC and GSI scales, and POMS, and greater but nonsignificant improvements on the PSS and PIL test. An intent-to-treat analysis (Y-BOCS) for the baseline and 3-month tests showed that only Group 1 improved. Within-group statistics (Student's paired t-tests) showed that Group 1 significantly improved on all six scales, but Group 2 had no improvements. Groups were merged for an additional year using Group 1 techniques. At 15 months, the final group (N=11) improved 71%, 62%, 66%, 74%, 39%, and 23%, respectively, on the Y-BOCS, SCL-90-R OC, SCL-90-R GSI, POMS, PSS, and PIL; P<0.003 (analysis of variance). This study demonstrates that kundalini yoga techniques are effective in the treatment of OCD.

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To validate the feasibility of precise noninvasive functional mapping in humans, a large-array biomagnetometer was used to map the somatosensory cortical locations corresponding to numerous distinct tactile sites on the fmgers, hand, arm, and face in different subjects. Source localizations were calculated by using a single equivalent current dipole (ECD) model. Dipole localizations were transposed upon the corresponding subject's magnetic resonance image (MRI) to resolve the anatomic locus of the individual dipoles within a given subject. Biomagnetic measurements demonstrated that (i) there were distinct separations between the ECD locations representing discrete sites on the face and hand; (u) the ECD localizations from facial sites clustered in a region inferior to ECD localizations from hand and digit sites; and (iii) there was clear spatial resolution of ECD locations representing closely spaced tactile sites on the hand and face. The ability of magnetoencephalography (MEG) to provide high-resolution spatial maps of the somatosensory system noninvasively in humans should make MEG a useful tool to defme the normal or pathological organization of the human somatosensory system and should provide an approach to the rapid detection of neuroplasticity.Functional mapping of the human somatosensory system has commonly used invasive surgical techniques which involve electrical stimulation of the brain (1), direct recordings of evoked potentials and electrical stimulation (2), somatosensory evoked responses (SERs) recorded on electrocorticography (ECoG) (3), or cortical surface recordings of somatosensory evoked potentials (SEP) during surgery (4, 5). The invasiveness of these approaches has limited the number of patients which may be studied and the types of questions which may be addressed. However, a variety of neuroimaging tools have been developed which may noninvasively study human mental functions. The human somatosensory cortex has been partially mapped using positron emission tomography (PET) (6), electroencephalography (EEG) (7-9), and magnetoencephalography (MEG) (10)(11)(12)(13)(14)(15)(16)(17)(18) METHODS Somatosensory stimulus-evoked magnetic brain activity generated by the left and right cortex in two neurologically normal undergraduate male subjects was recorded inside of a magnetically shielded room by using a Magnes 37-channel biomagnetometer (Biomagnetic Technologies, San Diego). The neuromagnetic field pattern was recorded over a 144-mm-diameter circular area above the parietotemporal cortex. Intrinsic noise in each channel was <10 ff/Hzl/2 in all but one channel.The biomagnetometer was placed over the contralateral hemisphere relative to the side being stimulated. Subjects were instructed to hold extremely still, and to count silently the number of stimuli.Tactile stimulators provided skin surface stimulation. The stimulators, which were circular rubber bladders of 1 cm diameter encased within a plastic outer shell, expanded with air during each time period corresponding to a single stim...