Retrograde degeneration of the thalamus following prefrontal lobotomy

Ventral targeted anterior capsulotomy for treatment-resistant depression and obsessive-compulsive disorder: A treatment method with cases

BACKGROUND

Ablative surgery using bilateral anterior capsulotomy (BAC) is an option for treatment resistant depression (TRD) and obsessive-compulsive disorder (TROCD). The location and extent of the lesion within anterior limb of the internal capsule (ALIC) remains uncertain. Accumulating evidence has suggested that the lesion should be located ventrally while limiting the dorsal extent. Our center is now targeting specific fiber tracts within the lower half of the ALIC.

METHOD

Presurgical diffusion tensor Magnetic Resonance Imaging (MRI) was used to identify individual fibre tracts within the ventral aspect of the ALIC in the last two patients who underwent BAC at our center. One patient had TRD and the other had both TROCD and TRD. Radiofrequency-induced thermal lesions were created in the identified targets with lesion volumes between 20 and 229 mm3 (average 95 mm3).

FINDINGS

Both patients were responders with neither experiencing significant side effects including compromised executive functions.

LIMITATIONS

The generalizability of our findings is limited because the outcome is based on two subjects.

CONCLUSION

This work suggests that BAC can be individually tailored and more limited to the ventral aspect of the ALIC and is effective and safe for TRD and TROCD. Accumulating data also suggests that to be clinically effective the length of the capsulotomy should be about 10mm. BAC's use may increase with the growing utilization and mastery of magnetic resonance guided focused ultrasound.

Thirty Years of Global Deep Brain Stimulation: "Plus ça change, plus c'est la même chose"?

BACKGROUND

The advent of deep brain stimulation (DBS) of the subthalamic nucleus (STN) for Parkinson's disease 30 years ago has ushered a global breakthrough of DBS as a universal method for therapy and research in wide areas of neurology and psychiatry. The literature of the last three decades has described numerous concepts and practices of DBS, often branded as novelties or discoveries. However, reading the contemporary publications often elicits a sense of déjà vu in relation to several methods, attributes, and practices of DBS. Here, we review various applications and techniques of the modern-era DBS and compare them with practices of the past.

SUMMARY

Compared with modern literature, publications of the old-era functional stereotactic neurosurgery, including old-era DBS, show that from the very beginning multidisciplinarity and teamwork were often prevalent and insisted upon, ethical concerns were recognized, brain circuitries and rational for brain targets were discussed, surgical indications were similar, closed-loop stimulation was attempted, evaluations of surgical results were debated, and controversies were common. Thus, it appears that virtually everything done today in the field of DBS bears resemblance to old-time practices, or has been done before, albeit with partly other tools and techniques. Movement disorders remain the main indications for modern DBS as was the case for lesional surgery and old-era DBS. The novelties today consist of the STN as the dominant target for DBS, the tremendous advances in computerized brain imaging, the sophistication and versatility of implantable DBS hardware, and the large potential for research.

KEY MESSAGES

Many aspects of contemporary DBS bear strong resemblance to practices of the past. The dominant clinical indications remain movement disorders with virtually the same brain targets as in the past, with one exception: the STN. Other novel brain targets - that are so far subject to DBS trials - are the pedunculopontine nucleus for gait freezing, the anteromedial internal pallidum for Gilles de la Tourette and the fornix for Alzheimer's disease. The major innovations and novelties compared to the past concern mainly the unmatched level of research activity, its high degree of sponsorship, and the outstanding advances in technology that have enabled multimodal brain imaging and the miniaturization, versatility, and sophistication of implantable hardware. The greatest benefit for patients today, compared to the past, is the higher level of precision and safety of DBS, and of all functional stereotactic neurosurgery.

José Manuel Rodríguez Delgado, Walter Freeman, and Psychosurgery: A Study in Contrasts

History has conflated the legacies of José Manuel Rodríguez Delgado and Walter Freeman, midcentury proponents of somatic therapies for neuropsychiatric conditions. Both gained notoriety: Delgado after he appeared on the front page of the New York Times having used his stimoceiver to stop a charging bull in Spain; Freeman as the proponent of lobotomy. Both were the object of critique by the antipsychiatry movement and those who felt that their methods and objectives posed a threat to personal liberty. Using archival sources, we demonstrate that this conflation is a misrepresentation of the historical record and that their methods, objectives, ethics, and philosophical commitments differed widely. Accurate knowledge about historical antecedents is a predicate for ethical analysis and becomes especially relevant information as neuroscience develops circuit-based treatments for conditions such as Parkinson disease, depression, and brain injury. Part of that corrective is to counter the conflation of Delgado's and Freeman's life and work. Appreciating their distinctive legacies can help guide neuropsychiatric research done today that might yet haunt future generations.

Human ventromedial prefrontal cortex lesions enhance the effect of expectations on pain perception

Pain is strongly modulated by expectations and beliefs. Across species, subregions of ventromedial prefrontal cortex (VMPFC) are implicated in a variety of functions germane to pain, predictions, and learning. Human fMRI studies show that VMPFC activity tracks expectations about pain and mediates expectancy effects on pain-related activity in other brain regions. Prior lesion studies suggest that VMPFC may instead play a more general role in generating affective responses to painful stimuli. To test whether VMPFC is required to generate affective responses to pain or is more specifically involved in expectancy-based pain modulation, we studied responses to heat stimuli in five adults with bilateral surgical lesions of VMPFC and twenty healthy adults without brain damage. All participants underwent a quantitative sensory testing procedure followed by a pain expectancy task in which cues predicting either low or high pain were followed by intermittent medium intensity heat stimuli. Compared to adults without brain damage, individuals with VMPFC lesions reported larger differences in expected pain based on predictive cues and failed to update expectations following the covert introduction of unexpected medium temperature stimuli. Consistent with observed expectancy differences, subjective pain unpleasantness ratings in the VMPFC lesion group were more strongly modulated by cue during thermal stimulation. We found no group differences in overall pain sensitivity, nor in relationships between pain and autonomic arousal, suggesting that VMPFC damage specifically enhances the effect of expectations on pain processing, likely driven by impaired integration of new sensory feedback to update expectations about pain. These results provide essential new data regarding the specific functional contribution of VMPFC to pain modulation.

Psychosurgery in the History of Stereotactic Functional Neurosurgery

The paper invites to reappraise the role of psychosurgery for and within the development of functional stereotactic neurosurgery. It highlights the significant and long-lived role of stereotactic neurosurgery in the treatment of severe and chronic mental disorders. Stereotactic neurosurgery developed out of psychosurgery. It was leucotomy for psychiatric disorders and chronic pain that paved the way for stereotactic dorsomedial thalamotomy in these indications and subsequently for stereotactic surgery in epilepsy and movement disorders. Through the 1960s stereotactic psychosurgery continued to progress in silence. Due to the increased applications of stereotactic surgery in psychiatric indications, psychosurgery's renaissance was proclaimed in the early 1970s. At the same time, however, a public fearing mind control started to discredit all functional neurosurgery for mental disorders, including stereotactic procedures. In writing its own history, stereotactic neurosurgery's identity as a neuropsychiatric discipline became subsequently increasingly redefined as principally a sort of "surgical neurology," cut off from its psychiatric origin.

Anatomical Correlates of Improvement After Leucotomy

Out of 95 leucotomy cases of which the brains and clinical records have been collected at this laboratory, 45 were cases with post-operative survival of over 5 months, and more than 20 of these showed some degree of clinical improvement. Such numbers now make worth while an attempt to ascertain whether or not any attribute common to the lesions is a prerequisite to clinical improvement; whether or not the degree of improvement tends to vary with any qualitative or quantitative feature of the lesions; and whether or not any such relationship between lesions and improvement which is revealed holds good in equal degree for each of the main types of functional-psychosis. Over 20 of the same 45 cases had a recorded post-operative change of personality, so that relationship of post-operative personality change to the leucotomy lesions can conveniently be investigated in the same group of cases. Only some general findings concerning the personality change will, however, be touched on in the present paper.

Some Reflections on the Nature of Affective Disorders, Arising from the Results of Prefrontal Leucotomy

For the use of the term “affective disorder” there is good literary warrant. Shakespeare, writing in the last decade of the sixteenth century, or just before it, uses the word thus:

Clinico-Anatomical Studies of Frontal Lobe Function Based on Leucotomy Material

The present paper is based upon the investigation of 95 brains of patients dying some time after leucotomy, and mainly, though not exclusively, upon the 45 cases in which the survival period was more than 5 months (up to 5 years). In a third of the total material and in about half of the 45 cases with survival longer than 5 months a full microscopical investigation has been carried out or is nearing completion. Eventually all the informative cases will have been so examined, but investigation by serial sections of considerable parts of the brain is a time-consuming undertaking. An unfortunately irremediable defect in our material is the unevenness and incompleteness of the clinical, physiological and psychological investigations of the patients. Obviously only limited correlation studies can be carried out on such material. Again, the number of fully recovered cases in our material is small, in fact only some four (Nos. 66, 71, 10 and 18) of the total could be classed as such. The reason for this is that fully recovered patients are likely to die from intercurrent disease outside mental hospitals, when it is difficult to procure a post-mortem.

Kochi: Recent topics in psychiatry and mental health in Japan

We intend to discuss recent developments in Japanese psychiatry and matters of major concern, i.e., psychiatric services following the amendment of Japan's Mental Health Law, schizophrenia, dementia and culture-specific problems to Japan.

Long-range connectomics

Decoding neural algorithms is one of the major goals of neuroscience. It is generally accepted that brain computations rely on the orchestration of neural activity at local scales, as well as across the brain through long-range connections. Understanding the relationship between brain activity and connectivity is therefore a prerequisite to cracking the neural code. In the past few decades, tremendous technological advances have been achieved in connectivity measurement techniques. We now possess a battery of tools to measure brain activity and connections at all available scales. A great source of excitement are the new in vivo tools that allow us to measure structural and functional connections noninvasively. Here, we discuss how these new technologies may contribute to deciphering the neural code.

Surgery of the mind and mood: a mosaic of issues in time and evolution

The prevalence and economic burden of neuropsychiatric disease are enormous. The surgical treatment of these psychiatric disorders, although potentially valuable, remains one of the most controversial subjects in medicine, as its concept and potential reality raises thorny issues of moral, ethical, and socioeconomic consequence. This article traces the roots of concept and surgical efforts in this turbulent area from prehistory to the 21st century. The details of the late 19th and 20th century evolution of approaches to the problem of intractable psychiatric diseases with scrutiny of the persona and contributions of the key individuals Gottlieb Burckhardt, John Fulton, Egas Moniz, Walter Freeman, James Watts, and William Scoville are presented as a foundation for the later, more logically refined approaches of Lars Leksell, Peter Lindstrom, Geoffrey Knight, Jean Talaraich, and Desmond Kelly. These refinements, characterized by progressive minimalism and founded on a better comprehension of underlying pathways of normal function and disease states, have been further explored with recent advances in imaging, which have allowed the emergence of less invasive and technology driven non-ablative surgical directives toward these problematical disorders of mind and mood. The application of therapies based on imaging comprehension of pathway and relay abnormalities, along with explorations of the notion of surgical minimalism, promise to serve as an impetus for revival of an active surgical effort in this key global health and socioeconomic problem. Eventual coupling of cellular and molecular biology and nanotechnology with surgical enterprise is on the horizon.

Tract identification by novel MRI signal changes following stereotactic anterior capsulotomy

BACKGROUND

Five patients underwent magnetic resonance imaging (MRI) following MRI-guided stereotactic bilateral anterior capsulotomy to detect lesion-related anatomic changes.

METHODS

Five disabled and treatment-resistant patients with major depression (n = 4) and obsessive-compulsive disorder (n = 1) underwent stereotactic bilateral anterior capsulotomy. All patients had postoperative MRI at 2 months and at 1-4 years after surgery. An additional patient who had a pure motor deficit following a spontaneous basal ganglia hemorrhagic stroke was imaged as a comparator.

RESULTS

The 2-month postcapsulotomy MRI showed a previously undescribed increase in T1-weighted signal within similar neural pathways for each patient. These pathways showed no changes in T2-weighted or fluid-attenuated inversion recovery sequences. The signal changes are different from the expected changes associated with anterograde Wallerian degeneration and identify retrograde changes in the proximal segment of the interrupted axon.

CONCLUSION

Previously undescribed T1-weighted signal alterations following stereotactic surgery identify retrograde non-Wallerian changes in interrupted axons and provide a new method in identifying and tracing lesioned pathways.

Depth electrode recorded cerebral responses with deep brain stimulation of the anterior thalamus for epilepsy

OBJECTIVE

We investigated the relation between anterior thalamic stimulation and the morphology of the evoked cerebral responses (CRs) using intracerebral depth electrodes in patients with intractable epilepsy undergoing deep brain stimulation (DBS) of the thalamus.

METHODS

Monopolar cathodic and bipolar stimuli were delivered at a rate of 2 or 1 Hz to the anterior nucleus (AN) and the dorsomedian nucleus (DM) of two patients using the programmable stimulation device (Medtronic ITREL II) or a GRASS stimulation device (S12). CRs were recorded from depth or DBS electrodes, situated bilaterally in mesial temporal (hippocampus, both patients), lateral temporal (one patient), orbitofrontal (Brodmann area 11, one patient) and anterior thalamic sites (one patient).

RESULTS

The distribution and morphology of the CRs depended primarily on the site of stimulation within the anterior thalamic region. Overall, monopolar cathodic and bipolar stimulation of the AN elicited CRs mainly in ipsilateral mesial temporal cortical areas, whereas stimulation of the DM evoked high-amplitude CRs predominantly in ipsilateral orbitofrontal areas. The amplitude of the CR was positively related to the strength of the stimulus and generally higher with monopolar than with bipolar stimulation. The differences between CRs elicited during wakefulness or slow wave sleep were minimal.

CONCLUSIONS

The distribution of the CRs corresponded with the intracerebral pathways of the involved structures and the findings are in good accordance with those of our previous study investigating the sources of CRs using statistical non-parametric mapping of low resolution electromagnetic tomography (LORETA) values.

SIGNIFICANCE

Our findings indicate a certain degree of point-to-point specificity within the thalamocortical circuitry, which may make optimal localization of DBS electrodes important in patients with epilepsy.

Permanent or transitory effects on neurocognitive components of the CNV complex induced by brain dysfunctions, lesions and ablations in humans

Since the mid-1960s, essentially using electrophysiological methods, our research group has examined the effects of different brain diseases in humans, both on first- and second-order conditioned responses and on some types of neurocognitive potentials of the CNV complex. This didactic lecture will focus on our various attempts to identify and understand the neuroanatomical and neurophysiological substrates involved in cognitive information processing followed by the conception and execution of sensory-motor and behavioural responses evoked by significant acoustic stimuli, in both pathological situations and normal control subjects. Great interest was, e.g. aroused in the early 1970s by the rare, fortunately unrepeatable, opportunity of examining the CNV patterns in various psychiatric patients treated with psychosurgical Freeman-Watts bilateral prefrontal 'radical' lobotomy, also with repeated recordings (The Responsive Brain (1976) 158; Multidisciplinary Perspectives in Event-Related Brain-Potentials Research (1978) 376) or bimedial bifrontal cingulotomy (Multidisciplinary Perspectives in Event-Related Brain Potential Research (1978) 383). In the same period, investigations into CNV activity recorded in patients submitted to complete callosotomy ('split brain': Attention and Performance, vol. IV (1972) 221; Electroenceph. Clin. Neurophysiol. Suppl. 33 (1973) 161) were also begun and were continued into the 1980s, also with regard to other types of ERP (Brain 111 (1988) 553; J. Cog. Neurosci. 2 (1990) 258). All these data furnished unique information about the sub-second dynamics of unilateral or bihemispheric cortico-cortical and cortico-subcortical interconnections in humans. In recent years, with a classic method of analysis based on sequential scalp-topographic bidimensional neuroelectric mapping and 21/19 electrodes connected to three different references, and binaural/monaural clicks as warning signals (S1), we have repeatedly examined the CNV activity of 11 selected patients submitted to complete ablation of the damaged cortical areas, with uni- or bilateral lesions restricted to the prefrontal or associative parieto-temporal areas. We have always used the standard CNV paradigm (S1-S2 motor-response) which evokes a complex of neurocognitive potentials, including the P300 from S1, which are well-known, since they are certainly among the most studied ERPs in the various ages and races of normal subjects, psychiatric patients and subjects with different brain diseases. The most important results have been, (1) In normal subjects the MRI and the latency differences of CNV component measurements along the bidirectional pathways functionally interconnecting ipsilateral distant associative cortical areas (e.g. the arcuate-superior longitudinal complex bundle) were accounted for by the transcortical conduction time, which varies in our scalp recordings from 1 cm/0.74 to 1.28 ms ( approximately 9.8 m/s). (2) Constantly, no true auditory S1-elicited N1a, b, c, P2, N2, P300 components or CNV slow waves (O- and E-wave) were recordable over the whole of the ablated cortical areas, but only clearly identifiable volume-conducted EP/ERPs generated in other hemispheric structures. (3) The post-S1 ERP/CNV complexes on the intact hemisphere were found to be within the normal limits. (4) Effects of severe disruption on the S1 ERP/CNV complexes evocable on the site and on remote ipsilateral apparently normal anatomo-functionally interconnected brain regions were observed in 5 patients, 4 of whom had extensive frontocortical ablations. In two of the latter the distant disruptive action on the CNV components over the neuroradiologically normal ipsilateral two-way connected post-rolandic sensory and association areas was seen to be partially reversible, showing aspects of a probable slowly evolving diaschisis-like effect. Similar deactivation of some ERP components was observed in reverse on the ipsilateral dorsolateral frontocortical region in the fifth patient with a large parieto-temporal cortex ablation. These data require confirmahese data require confirmation, and when this phenomenon is observable, it must be appropriately monitored with different methods of functional neuroimaging. This will serve not only for medical and neuropsychophysiological diagnosis purposes, but also particularly for a correct and really useful planning of neuro-rehabilitation activities in selected cases.

An autopsy case of the schizophrenic 32 years after lobotomy

An autopsy case is reported here of a 69-year-old patient with schizophrenia, who was known retrospectively to have had a prefrontal lobotomy 32 years previously. The patient was diagnosed as schizophrenic at the age of 24 and the lobotomy was undertaken 13 years later. The patient was recently found outside in a dehydrated condition and admitted to a general hospital, where he died of respiratory failure. Bilateral cystic lesions were found in the deep white matter of the frontal lobe. The cyst walls consisted of glial fibrous tissues, and severe demyelination with axonal destruction was diffusely observed in the white matter of the frontal lobe. In the thinner frontal cortex without arcuate fibers (U fibers) close to the cavities, cytoarchitectural abnormalities were observed. In the thalamic nuclei marked retrograde degeneration and astrocytic gliosis were observed. The detailed neuropathological findings of a lobotomized schizophrenic brain are reported here. It is proposed that one should be reminded of a lobotomized brain if bilateral cysts are found.

No deficit in total number of neurons in the prefrontal cortex in schizophrenics

The prefrontal cortex (PFC), defined as the cortical region which has the major reciprocal connections with the mediodorsal thalamic nucleus (MD), has often been implicated in schizophrenia. Morphometric studies have shown altered neuronal density and structure in parts of the PFC in schizophrenic brains. In addition, the MD and nucleus accumbens have shown a significant deficit in total neuron number. The purpose of the present study was to estimate the total neuron number in the PFC in schizophrenics and controls. Using a stereological design, the PFC was studied in eight brains from schizophrenic patients and 10 age-matched control brains. The bilateral average total number of neurons in the PFC was estimated to be 2.76 x 10(9) (CV=S.D./mean=0.15) in the schizophrenic brains whereas that of controls was a non-significantly different value of 3.11 x 10(9) (CV=0.22; P=0.23). Furthermore, no significant differences were found between the two groups in neuronal density (P=0.10) or volume of the PFC (P=0.49). It is of course possible that a neuronal deficit, which cannot be revealed when estimating the total global number of neurons in the whole PFC, might exist in a subregion of the PFC. In conclusion, uniform loss of neuronal soma in the PFC does not appear to constitute the neural substrate of the pathological process in schizophrenia.

Eye fields in the frontal lobes of primates

Two eye fields have been identified in the frontal lobes of primates: one is situated dorsomedially within the frontal cortex and will be referred to as the eye field within the dorsomedial frontal cortex (DMFC); the other resides dorsolaterally within the frontal cortex and is commonly referred to as the frontal eye field (FEF). This review documents the similarities and differences between these eye fields. Although the DMFC and FEF are both active during the execution of saccadic and smooth pursuit eye movements, the FEF is more dedicated to these functions. Lesions of DMFC minimally affect the production of most types of saccadic eye movements and have no effect on the execution of smooth pursuit eye movements. In contrast, lesions of the FEF produce deficits in generating saccades to briefly presented targets, in the production of saccades to two or more sequentially presented targets, in the selection of simultaneously presented targets, and in the execution of smooth pursuit eye movements. For the most part, these deficits are prevalent in both monkeys and humans. Single-unit recording experiments have shown that the DMFC contains neurons that mediate both limb and eye movements, whereas the FEF seems to be involved in the execution of eye movements only. Imaging experiments conducted on humans have corroborated these findings. A feature that distinguishes the DMFC from the FEF is that the DMFC contains a somatotopic map with eyes represented rostrally and hindlimbs represented caudally; the FEF has no such topography. Furthermore, experiments have revealed that the DMFC tends to contain a craniotopic (i.e., head-centered) code for the execution of saccadic eye movements, whereas the FEF contains a retinotopic (i.e., eye-centered) code for the elicitation of saccades. Imaging and unit recording data suggest that the DMFC is more involved in the learning of new tasks than is the FEF. Also with continued training on behavioural tasks the responsivity of the DMFC tends to drop. Accordingly, the DMFC is more involved in learning operations whereas the FEF is more specialized for the execution of saccadic and smooth pursuit eye movements.

Efferent connections of the anteromedial nucleus of the thalamus of the rat

The projections from the anteromedial nucleus of the thalamus (AM) were investigated using anterograde and retrograde tracing techniques. AM projects to nearly the entire rostrocaudal extent of limbic cortex and to visual cortex. Anteriorly, AM projects to medial orbital, frontal polar, precentral agranular, and infraradiata cortices. Posteriorly, AM projects to retrosplenial granular, entorhinal, perirhinal and presubicular cortices, and to the subiculum. Further, AM projects to visual cortical area 18b, and to the lateral and basolateral nuclei of the amygdala. AM projections are topographically organized, i.e., projections to different cortical areas arise from distinct parts of AM. The neurons projecting to rostral infraradiata cortex (IRalpha) are more caudally located in AM than the neurons projecting to caudal infraradiata cortex (IRbeta). The neuronal cell bodies that project to the terminal field in area 18b are located primarily in ventral and lateral parts of AM, whereas neurons projecting to perirhinal cortex and amygdala are more medially located in AM. Injections into the most caudal, medial part of AM (i.e., the interanteromedial [IAM] nucleus) label terminals in the rostral precentral agranular, caudal IRbeta, and caudal perirhinal cortices. Whereas most AM axons terminate in layers I and V-VI, exceptions to this pattern include area 18b (axons and terminals in layers I and IV-V), the retrosplenial granular cortex (axons and terminals in layers I and V), and the presubicular, perirhinal, and entorhinal cortices (axons and terminals predominantly in layer V). Together, these findings suggest that AM influences a widespread area of limbic cortex.

Frontopolar ictal epileptiform discharges on scalp electroencephalogram in temporal lobe epilepsy

We report 3 patients with medically intractable complex partial seizures (CPS) arising from the temporal lobe judged by surgical outcome, in whom scalp electroencephalogram (EEG) showed ictal epileptiform discharges at the frontopolar region. In all patients, results of cranial magnetic resonance imaging (MRI), positron emission tomography (PET), and ictal single photon emission computed tomography (SPECT) were consistent with those of temporal lobe epilepsy (TLE). The epileptogenic area was defined in the temporal lobe by chronic subdural recording in 2 patients. After surgical treatment (amygdalohippocampectomy, anterior temporal lobectomy, and temporal lesionectomy, respectively), all 3 patients became seizure-free and the interictal frontopolar epileptiform discharges on scalp EEG disappeared. Patients with TLE may show ictal scalp EEG with frontopolar onset. This is most likely explained by direction of dipolar orientation of epileptiform discharges in 1 of our patients; rapid spread of ictal activity to the frontopolar area can also be considered in the 2.

Psychosurgery: stereotactic subcaudate tractomy. An indispensable treatment

BACKGROUND

Stereotactic subcaudate tractotomy (SST) is the only type of psychosurgery performed at the Geoffrey Knight Unit, London, where nearly 1300 operations have been done since 1961. Statistically reliable data are not available to prove the effectiveness of SST. A detailed statement about contemporary psychosurgery is given.

METHOD

Relevant publications from the Unit and via Medline are discussed. The outcome figures are reviewed. The outcome is assessed at the Unit in global and clinical terms, associated with results of self-completed questionnaires.

RESULTS

SST allows 40-60% of patients to live normal or near-normal lives, perhaps with continuation of medication. A reduction in suicide rate to 1% post-operatively, from 15% in cases of uncontrolled affective disorders is seen.

CONCLUSION

As a treatment of last resort, no controlled trial against a comparable treatment is possible. It appears reasonable to offer SST to patients with suicidal and deluded depression or with frequently swinging moods, not responding to other treatments.

Leucotomized schizophrenics lose neurons in the mediodorsal thalamic nucleus

It has previously been shown that chronic schizophrenic patients have a 40-50% reduction in the total number of nerve and glia cells in the mediodorsal thalamic nucleus and the nucleus accumbens compared with controls, while the total neuron and glia number is the same in the two groups in the ventral pallidum. Using new stereological cell counting methods, neuron and glia cell numbers were estimated in the mediodorsal thalamic nucleus, the ventro-medial part of nucleus accumbens and the ventral pallidum in nine brains from leucotomized schizophrenics. This number was compared with counts from control cases and chronic schizophrenics without leucotomy. The results showed that the total number of nerve cells in the mediodorsal thalamic nucleus was statistically significantly reduced from 1.08 x 10(6) in chronic schizophrenics to 0.88 x 10(6) in leucotomized schizophrenics. Total neuron number was statistically significantly reduced in the ventro-medial part of the nucleus accumbens in schizophrenics without further reduction in leucotomized schizophrenics. The total neuron number in ventral pallidum was normal. With frontal leucotomy it is possible to investigate the consequences of disconnection of the prefrontal cortex to central regions in the human brain. The mediodorsal nucleus of thalamus represents a major efferent projection to the prefrontal cortex.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of the frontal lobes in the propagation of mesial temporal lobe seizures

The depth ictal electroencephalographic (EEG) propagation sequence accompanying 78 complex partial seizures of mesial temporal origin was reviewed in 24 patients (15 from the University of Pittsburgh Epilepsy Center and 9 from UCLA). All patients were monitored with bilateral mesial frontal and mesial temporal depth electrodes and later received anterior temporal lobectomy. Ictal EEG records were categorized according to sequence of spread from the temporal focus to the other regions. Although propagation patterns varied both within and between patients, certain features were notable: (a) It was very common for seizure activity to spread initially to the ipsilateral frontal lobe (observed in 22 of 24 patients). (b) The most common mode of spread (15 of 24 patients) was initiating temporal lobe----ipsilateral frontal lobe----contralateral frontal lobe----contralateral temporal lobe. (c) Occasionally, seizure discharges invaded the frontal lobes but failed to invade the contralateral temporal lobe (2 of 24 patients). (d) Seizure activity occasionally invaded the contralateral temporal lobe prior to invading the frontal lobes (2 of 24 patients). Other notable features included (i) a clear tendency for mesial temporal seizure discharges initially to invade orbitofrontal (as opposed to anterior cingulate) cortex and (ii) the emergence of a period of clear asymmetry in the frontal lobes during which high-amplitude, rapid discharges were present on the side ipsilateral to the initiating temporal lobe. These results suggest that the prefrontal region, especially the orbitofrontal cortex, is strongly influenced by mesial temporal ictal activity. This region appears to be frequently involved in the propagation of seizures initiated in the mesial temporal lobe and may play a role in the interhemispheric propagation of mesial temporal seizures.

Prefrontal projections to the mediodorsal nucleus of the thalamus in the rhesus monkey

The corticothalamic projections to the prefrontal cortex have been shown to be topographically organized. However, the underlying basis for this topography as it relates to the organization of the different architectonically defined areas of the prefrontal cortex has not been systematically studied. In the present investigation we have reassessed the thalamic projections from the different architectonic areas of the prefrontal cortex by using the technique of autoradiography in the rhesus monkey. The results show that the prefronto-mediodorsal projections are organized according to the architectonic differentiation of the prefrontal cortices. Thus architectonically less differentiated medial and orbital prefrontal regions project to the medial sector of the mediodorsal nucleus, the magnocellular subdivision. In contrast, highly differentiated prefrontal area 8 projects to the most lateral sector of the mediodorsal nucleus, the multiformis subdivision. Lateral prefrontal areas with intermediate architectonic features project to the central parvocellular sector of the mediodorsal nucleus. Additionally, these projections also reveal a dorsoventral topography. Thus areas in the medial and dorsolateral cortices project to the dorsal part of the mediodorsal nucleus. In contrast, areas in orbital and ventrolateral cortices project to the ventral part of the mediodorsal nucleus. The topographic organization of the corticothalamic connections described in this study corresponds to the progressive elaboration and differentiation of the architectonic features of the different prefrontal areas. This successive and dichotomous organization of prefrontothalamic connections may provide the basis for the observed differential functions of the prefrontal cortex and the mediodorsal nucleus.

The human cerebro-cerebellar system: its computing, cognitive, and language skills

In this review of the human cerebro-cerebellar system, the focus is on the possible contributions of the cerebellum to cognitive and language functions. The role of the cerebellum in these human functions has tended to be obscured by the traditional preoccupation with the motor functions of the cerebellum, which have been widely observed in other vertebrates as well. In the human brain, some phylogenetically new parts evolved and enlarged in the cerebellum, concomitantly with the enlargement of association areas in the cerebral cortex. Anatomical evidence and behavioral evidence combine to suggest that this enlarged cerebellum contributes not only to motor function but also to some sensory, cognitive, linguistic, and emotional aspects of behavior. The anatomical evidence derives from the modularity of the cerebellum, whose cortical nerve cells are organized into longitudinal micro-modules, which are arrayed perpendicular to the cortical surface and parallel to each other. The number of these micro-modules increased when the cerebellum enlarged, which enlarged the computing capabilities of the network. (From principles underlying the processing of information, it is known that when modules with modest processing capabilities are assembled in large numbers in parallel, the resulting network can achieve remarkably powerful computing capabilities.) Such cerebellar computing capabilities can be utilized in the different areas of the cerebral cortex to which the cerebellum sends signals. The cerebellar output connections convey signals through the thalamus to the cerebral cortex in segregated channels of communication, which preserve the modularity of the cerebellum. Through these channels, modules in the lateral cerebellum can send signals to new cognitive and language areas of the cerebral cortex, such as Broca's area in the prefrontal cortex. The anatomy of the human cerebro-cerebellar system therefore suggests that the cerebellum can contribute to the learning not only of motor skills but also of some cognitive and language skills. Supporting this anatomical evidence is the mounting behavioral evidence, obtained both in normal brains and in clinical studies, which indicates that the lateral cerebellum is indeed involved in some cognitive and language functions.

Topography of the projection from the central complex of the thalamus to the sensorimotor striatal territory in monkeys

The distribution of axons arising from the central complex (or centre médian-parafascicular complex) and terminating in the striatum was studied in seven macaques and one squirrel monkey. Deposits of anterograde tracers were made in the two lateral-most subdivisions of the central complex, i.e., the middle part (or pars media) and the lateral part (or pars paralateralis). All injections avoided the pars parafascicularis. The intrastriatal distribution of labeled axonal endings was mapped in relation to the standard ventricular (CA-CP) system of coordinates. Labeled endings were observed in the major posterior and dorsal parts of the putamen (excluding its anteromedial and ventral parts) and also in a restricted ventrolateral part of the caudate nucleus. The topography of the central territory of the striatum, defined as the striatal space receiving axons from the central complex, was found to correspond exactly to that of the cortical sensorimotor territory delineated after cortical injections. The termination pattern of the central axons within the striatum was patchy. Viewed as a whole, the irregular and hazy patches formed oblique streaks, parallel one with the other. The three-dimensional reconstructions of data from transverse sections revealed that the streaks were bi-dimensional pictures of three-dimensional parasagittal layers covering the whole anteroposterior extent of the cortical sensorimotor territory of the striatum. Our work shows that the pars media of the central complex, which receives selectively pallidal afferent axons (François et al., '88: Brain Res. 473:181-186), is the main source of the centroputaminal projection. The probable implication of this in a closed sensorimotor loop of the basal ganglia is discussed.

Mediodorsal nucleus: areal, laminar, and tangential distribution of afferents and efferents in the frontal lobe of rhesus monkeys

The terminal distribution of thalamic afferents in primate prefrontal cortex has never been examined in any detail. In the present study, WGA-HRP was injected into major subdivisions of the mediodorsal nucleus (MD) in the rhesus monkey in order to determine 1) The areal distribution of MD projections, 2) the layer(s) in which MD afferents terminate, 3) the tangential pattern of the MD axonal terminals, 4) the cells of origin of the reciprocal corticothalamic pathway, and 5) the degree of reciprocity between the corticothalamic and thalamocortical pathways in the different regions of the prefrontal cortex. As expected on the basis of retrograde degeneration and transport studies, injections centered in the magnocellular (MDmc) subnucleus of MD labeled cells and terminals in the ventral and medial prefrontal cortex. Injections involving ventral MDmc labeled the more lateral of these areas (Walker's areas 11 and 12); injections of the dorsal MDmc labeled the ventromedial regions (areas 13 and 14). In contrast, injections involving mainly the lateral, parvicellular (MDpc) moiety labeled cells and terminals in dorsolateral and dorsomedial areas (Walker's 46, 9, and 8B). Area 8A was labeled most prominently when injections included the multiform portion of MD (MDmf) and area 10 had connections with anterior portions of MD. A dorsal-ventral topography for MDpc exists with dorsal MDpc labeling dorsal and dorsomedial prefrontal areas and ventral MDpc labeling dorsolateral prefrontal cortex. Our findings with respect to MD are consistent with a nucleus-to-field organization of its thalamocortical projection system. Outside of the traditional boundaries of prefrontal cortex, lateral MD projections extended to the supplementary motor area (SMA) and the dorsal part of the anterior cingulate (AC) whereas the medial MD projection targeted the ventromedial cingulate cortex and spared SMA. In addition, a few labeled cells and sparse terminals were found in the inferior parietal lobule, the superior temporal sulcus, and the anterior part of the insula after injections that involved the medial part of MD. Labeled terminals were invariably confined to layer IV and adjacent deep layer III. No terminal label was ever observed in layers I, II, superficial III, V, or VI in any part of the cerebral cortex following injections confined to any part of MD.(ABSTRACT TRUNCATED AT 400 WORDS)

The primate mediodorsal (MD) nucleus and its projection to the frontal lobe

The frontal lobe projections of the mediodorsal (MD) nucleus of the thalamus were examined in rhesus monkey by transport of retrograde markers injected into one of nine cytoarchitectonic regions (Walker's areas 6, 8A, 9, 10, 11, 12, 13, 46, and Brodmann's area 4) located in the rostral third of the cerebrum. Each area of prefrontal, premotor, or motor cortex injected was found to receive a topographically unique thalamic input from clusters of cells in specific subdivisions within MD. All of the prefrontal areas examined also receive topographically organized inputs from other thalamic nuclei including, most prominently, the ventral anterior (VA) and medial pulvinar nuclei. Conversely, and in agreement with previous findings, MD projects to areas of the frontal lobe beyond the traditional borders of prefrontal cortex, such as the anterior cingulate and supplementary motor cortex. The topography of thalamocortical neurons revealed in coronal sections through VA, MD, and pulvinar is circumferential. In the medial part of MD, for example, thalamocortical neurons shift from a dorsal to a ventral position for cortical targets lying medial to lateral along the ventral surface of the lobe; neurons in the lateral MD move from a ventral to a dorsal position, for cortical areas situated lateral to medial on the convexity of the hemisphere. The aggregate evidence for topographic specificity is supported further by experiments in which different fluorescent dyes were placed in multiple areas of the frontal lobe in each of three cases. The results show that very few, if any, thalamic neurons project to more than one area of cortex. The widespread cortical targets of MD neurons together with evidence for multiple thalamic inputs to prefrontal areas support a revision of the classical hodological definition of prefrontal cortex as the exclusive cortical recipient of MD projections. Rather, the prefrontal cortex is defined by multiple specific relationships with the thalamus.

Intraaxonal transport of Herpes simplex virus in the rat central nervous system

Light and electron microscopic observation 3--4 days after microinjection of Herpes simplex virus (HSV) into the left neostriatum of rat demonstrated the following results. (1) Virus labeled nerve cells were found in the ipsilateral substantia nigra; a large number of infected neurons were in the zona compacta and some were in the zona reticulata. No virus infection was evident in the contralateral side. (2) Virus labeled neurons were found in the cortex, a greater number ipsilaterally than contralaterally, and in the dorsal raphé nuclei. Cortical microinjection of HSV led to infection of some cortical cells but no neostriatal cells. We conclude, therefore, that spread of the virus to the cortex, the substantia nigra and the dorsal raphé following neostriatal injection was by retrograde axonal transport. (3) The left neostriatum, where HSV was injected, showed a surprisingly small number of virus infected neurons. The infected neurons were mostly the large neurons; the majority of medium sized neurons were well preserved. There was massive degeneration of nerve terminals throughout the neuropil. Most of these degenerating nerve terminals are considered to be afferent fibers.

Organization of the thalamo-cortical connexions to the frontal lobe in the rhesus monkey

In 25 rhesus monkeys horseradish peroxidase was injected in different parts of the frontal cortex. The retrogradely labelled thalamic neurons formed longitudinal bands, some of which crossed the internal medullary lamina, and extended from one thalamic nucleus into another. On the basis of these findings the frontal cortex was subdivided into seven transverse cortical strips which receive afferents from seven longitudinal bands of thalamic neurons. The most rostral transverse strip receives afferents from the most medial thalamic band which is oriented vertically and extends through the most medial part of the MD into the medial pulvinar. Progressively more caudally located transverse strips receive afferents from progressively more laterally located thalamic bands which in part are situated in the VL and show an increasing tilt towards the horizontal. Moreover, those parts of the various bands which are situated along the dorsal and lateral margin of the thalamus project to the medial portions of the transverse cortical strips, i.e. along the medial margin of the frontal lobe, while the other parts situated ventromedially in the thalamus project to the lateral portions of these strips, i.e. along the lateral margin of the frontal lobe. These data provide an alternative view of the organization of the thalamus and suggest that this structure contains a matrix of longitudinal cell columns which in some cases extend across specific nuclear borders and may represent the basic thalamic building blocks in respect to the thalamo-cortical connexions.

Afferents to prefrontal cortex from the thalamic mediodorsal nucleus in the rhesus monkey

Thalamic afferents to Macaque prefrontal cortex from the mediodorsal nucleus were examined by techniques specific for anterograde degeneration and axoplasmic transport. The sampling procedure employed permits establishing the extent of topographic projections to cortex from subcortical foci for the same brain which was surveyed subsequently in tracing specific neuronal connections by electron microscopy. Topographic and general laminar distribution of thalamic terminals are presented in terms of 3 subareas of prefrontal cortex. The dorsolateral and ventral (orbital) surfaces of prefrontal cortex receive respectively projections from the lateral and medial subdivision of the mediodorsal nucleus. In addition, the medial wall of the frontal lobe, including the dorsomedial part of the lateral convexity, heretofore regarded as athalamic, receives input from the caudal-dorsomedial aspect of the mediodorsal nucleus. Preliminary evidence suggests that axons from the mediodorsal nucleus terminate in the head of caudate nucleus, as Sachs-81 described 65 years ago in the first orthograde study of thalamo-prefrontal cortex connections.