I much appreciate the honour of being invited to deliver the first Manson lecture, which, its founder has laid down, is to be devoted to the consideration of some subject of common interest to philosophy and medicine. I cannot think of anything which better fulfils that condition than the neurological approach to the problem of perception. The neurologist holds the bridge between body and mind. Every day he meets with examples of disordered perception and he learns from observing the effects (...) of lesions produced by disease, or by the physiologist's experiments, something of how the neural basis of perception is organized. It is possible to study perception as though this was largely irrelevant. How far that view is right will be for you to judge when I have finished. (shrink)

As philosophers of mind we seem to hold in common no very clear view about the relevance that work in psychology or the neurosciences may or may not have to our own favourite questions—even if we call the subject ‘philosophical psychology’. For example, in the literature we find articles on pain some of which do, some of which don't, rely more or less heavily on, for example, the work of Melzack and Wall; the puzzle cases used so extensively in discussions (...) of personal identity are drawn sometimes from the pleasant exercise of scientific fantasy, at times from surprising reports of scientific fact; and there are those who deny, as well as those who affirm, the importance of the discovery of rapid-eye-movement sleep to the philosophical treatment of dreaming. A general account of the relation between scientific, and philosophical, psychology is long overdue and of the first importance. Here I shall limit myself to just one area where the two seem to connect, discussing one type of neuropsychological research and its relevance to questions in the philosophy of mind and the philosophy of psychology. (shrink)

Falls are a leading cause of serious injury and restricted participation among persons with stroke (PwS). Reactive balance control is essential for fall prevention, however, only a few studies have explored the effects of lesion characteristics (location and extent) on balance control in PwS. We aimed to assess the impact of lesion characteristics on reactive and anticipatory balance capacity, gait, and hemiparetic lower limb function, in PwS. Forty-six subacute PwS were exposed to forward, backward, right and left unannounced horizontal surface (...) translations in 6 increasing intensities, while standing. Fall threshold (i.e., perturbation intensity that results in a fall into the harness system) was measured. In addition, the Berg Balance Scale (BBS), 6 Minute Walk Test (6MWT) and Lower Extremity Fugl-Meyer (LEFM) were measured. Lesion effects were analyzed separately for left- and right-hemisphere damaged (LHD, RHD) patients, using voxel-based lesion-symptom mapping (VLSM). Our results show that voxel clusters where damage exerted a significant impact on balance, gait and lower-limb function were found in the corticospinal tract, in its passage in the corona radiata and in the posterior limb of the internal capsule. Additional significant impact was found to lesions affecting the putamen and the external capsule. Balance, gait, and hemiparetic lower limb function showed much overlap of the corresponding ‘significant’ voxel clusters. Test scores of RHD and LHD patients were affected largely by damage to homologous regions, with the LHD group showing a wider distribution of ‘significant’ voxels. The study corroborates and extends previous findings by demonstrating that balance control, gait, and lower limb function are all affected mainly by damage to essentially the same brain structures, namely - the corticospinal tract and adjacent structures in the capsular-putaminal region. (shrink)

Deep Brain Stimulation is currently being investigated as an experimental treatment for patients suffering from treatment-refractory AN, with an increasing number of case reports and small-scale trials published. Although still at an exploratory and experimental stage, initial results have been promising. Despite the risks associated with an invasive neurosurgical procedure and the long-term implantation of a foreign body, DBS has a number of advantageous features for patients with SE-AN. Stimulation can be fine-tuned to the specific needs of the particular patient, (...) is relatively reversible, and the technique also allows for the crucial issue of investigating and comparing the effects of different neural targets. However, at a time when DBS is emerging as a promising investigational treatment modality for AN, lesioning procedures in psychiatry are having a renaissance. Of concern it has been argued that the two kinds of interventions should instead be understood as rivaling, yet “mutually enriching paradigms” despite the fact that lesioning the brain is irreversible and there is no evidence base for an effective target in AN. We argue that lesioning procedures in AN are unethical at this stage of knowledge and seriously problematic for this patient group, for whom self-control is particularly central to wellbeing. They pose a greater risk of major harms that cannot justify ethical equipoise, despite the apparent superiority in reduced short term surgical harms and lower cost. (shrink)

BackgroundFrontal brain dysfunction is a major challenge in neurorehabilitation. Neurofeedback (NF), as an EEG-based brain training method, is currently applied in a wide spectrum of mental health conditions, including traumatic brain injury.ObjectiveThis study aimed to explore the capacity of Infra-Low Frequency Neurofeedback (ILF-NF) to promote the recovery of brain function in patients with frontal brain injury.Materials and methodsTwenty patients hospitalized at a neurorehabilitation clinic in Switzerland with recently acquired, frontal and optionally other brain lesions were randomized to either receive (...) NF or sham-NF. Cognitive improvement was assessed using the Frontal Assessment Battery (FAB) and the Test of Attentional Performance (TAP) tasks regarding intrinsic alertness, phasic alertness and impulse control.ResultsWith respect to cognitive improvements, there was no significant difference between the two groups after 20 sessions of either NF or sham-NF. However, in a subgroup of patients with predominantly frontal brain lesions, the improvements measured by the FAB and intrinsic alertness were significantly higher in the NF-group.ConclusionThis is the first double-blind controlled study using NF in recovery from brain injury, and thus also the first such study of ILF NF. Although the result of the subgroup has limited significance because of the small number of participants, it accentuates the trend seen in the whole group regarding the FAB and intrinsic alertness (p = 0.068, p = 0.079, respectively). We therefore conclude that NF could be a promising candidate promoting the recoveryfrom frontal brain lesions. Further studies with larger numbers of patients and less lesion heterogeneity are needed to verify the usefulness of NF in the neurorehabilitation of patients with frontal brain injury (NCT02957695 ClinicalTrials.gov). (shrink)

Background: There is limited research on brain lesions in children with cerebral visual impairment of heterogeneous etiologies and according to associated subtyping and vision dysfunctions. This study was part of a larger project establishing data-driven subtypes of childhood CVI according to visual dysfunctions. Currently there is no consensus in relation to assessment, diagnosis and classification of CVI and more information about brain lesions may be of potential diagnostic value.Aim: This study aimed to investigate overall patterns of brain (...) class='Hi'>lesions and associations with level of visual dysfunction and to compare the patterns between the classification subgroups in children with CVI.Methods: School-aged children with CVI received ophthalmological and neuro-psychological/developmental assessments to establish CVI-related subtyping. Other pediatric information was collected from medical records. MRI scans were coded according to a semi-quantitative template including brain regions and summed for total scores. Non-parametric analyses were conducted.Results: 28 children had clinical brain MRI scans available [44% of total sample, Group A n = 16, Group B n = 12]. Total brain scores ranged between 0 and 18 and were widespread across regions. 71 per cent had post-geniculate visual pathway damage. The median total brain and hemisphere scores of Group B were higher than subgroup A but differences did not reach statistical significance. No statistically significant associations were found between brain scores and vision variables.Conclusion: This study found a spread of lesions across all regions on the brain scans in children with congenital CVI. The majority had damage in the postgeniculate visual pathways and visual cortex region suggesting this is an area of interest and potentially informative for diagnosis. However the subtyping classification did not show differences in number or region of lesions though the trend was higher toward Group B. This study confirms the complex diffuse and variable nature of brain lesions in children with congenital CVI, many of whom have other neurological impairments. (shrink)

According to higher-order theories of consciousness, a mental state is conscious only when represented by another mental state. Higher-order theories must predict there to be some brain areas (or networks of areas) such that, because they produce (the right kind of) higher-order states, the disabling of them brings about deficits in consciousness. It is commonly thought that the prefrontal cortex produces these kinds of higher-order states. In this paper, I first argue that this is likely correct, meaning that, if some (...) higher-order theory is true, prefrontal lesions should produce dramatic deficits in visual consciousness. I then survey prefrontal lesion data, looking for evidence of such deficits. I argue that no such deficits are to be found, and that this presents a compelling case against higher-order theories. (shrink)

The impact of stroke on motor functioning is analyzed at different levels. ‘Impairment’ denotes the loss of basic characteristics of voluntary movement. ‘Activity limitation’ denotes the loss of normal capacity for independent execution of daily activities. Recovery from impairment is accomplished by ‘restitution’ and recovery from activity limitation is accomplished by the combined effect of ‘restitution’ and ‘compensation.’ We aimed to unravel the long-term effects of variation in lesion topography on motor impairment of the hemiparetic lower limb (HLL), and gait (...) capacity as a measure of related activity limitation. Gait was assessed by the 3 m walk test (3MWT) in 67 first-event chronic stroke patients, at their homes. Enduring impairment of the HLL was assessed by the Fugl–Meyer Lower Extremity (FMA-LE) test. The impact of variation in lesion topography on HLL impairment and on walking was analyzed separately for left and right hemispheric damage (LHD, RHD) by voxel-based lesion-symptom mapping (VLSM). In the LHD group, HLL impairment tended to be affected by damage to the posterior limb of the internal capsule (PLIC). Walking capacity tended to be affected by a larger array of structures: PLIC and corona radiata, external capsule and caudate nucleus. In the RHD group, both HLL impairment and walking capacity were sensitive to damage in a much larger number of brain voxels. HLL impairment was affected by damage to the corona radiata, superior longitudinal fasciculus and insula. Walking was affected by damage to the same areas, plus the internal and external capsules, putamen, thalamus and parts of the perisylvian cortex. In both groups, voxel clusters have been found where damage affected FMA-LE and also 3MWT, along with voxels where damage affected only one of the measures (mainly 3MWT). In stroke, enduring ‘activity limitation’ is affected by damage to a much larger array of brain structures and voxels within specific structures, compared to enduring ‘impairment.’ Differences between the effects of left and right hemisphere damage are likely to reflect variation in motor-network organization and post-stroke re-organization related to hemispheric dominance. Further studies with larger sample size are required for the validation of these results. (shrink)

Higher-order thought (HOT) theory says that a mental state is conscious when and only when represented by a conceptual, belief-like mental state. Plausibly, HOT theory predicts the impairment of HOT-producing brain areas to cause significant deficits in consciousness. This means that HOT theory can be refuted by identifying those brain areas that are candidates for producing HOTs, then showing that damage to these areas never produces the expected deficits of consciousness. Building this refutation is a work-in-progress, with several key components (...) of it already existing in the literature (e.g., Boly et al. in J Neurosci 37(40):9603–9613, 2017; Kozuch in Mind Lang, 37(5):790–813, 2022). This article pulls together and supplements these earlier components so as to provide a comprehensive lesion-based argument against HOT theory, one which offers extra data and arguments in support of it, and which also addresses common objections. (shrink)

Data from published case and group studies bear on the trace deletion hypothesis. The deficit-lesion correlational literature does not support Grodzinsky's claim that lesions in and around Broca's area inevitably lead to comprehension deficits specifically related to coindexation of traces or his claim that other lesions spare this function.

Dual functional brain asymmetry refers to the notion that in most individuals the left cerebral hemisphere is specialized for language functions, whereas the right cerebral hemisphere is more important than the left for the perception, construction, and recall of stimuli that are difficult to verbalize. In the last twenty years there have been scattered reports of sex differences in degree of hemispheric specialization. This review provides a critical framework within which two related topics are discussed: Do meaningful sex differences in (...) verbal or spatial cerebral lateralization exist? and, if so, Is the brain of one sex more symmetrically organized than the other? Data gathered on right-handed adults are examined from clinical studies of patients with unilateral brain lesions; from dichotic listening, tachistoscopic, and sensorimotor studies of functional asymmetries in non-brain-damaged subjects; from anatomical and electrophysiological investigations, as well as from the developmental literature. Retrospective and descriptive findings predominate over prospective and experimental methodologies. Nevertheless, there is an impressive accummulation of evidence suggesting that the male brain may be more asymmetrically organized than the female brain, both for verbal and nonverbal functions. These trends are rarely found in childhood but are often significant in the mature organism. (shrink)

When cognitive neuropsychologists make inferences about the functional architecture of the normal mind from selective cognitive impairments they generally assume that the effects of brain damage are local, that is, that the nondamaged components of the architecture continue to function as they did before the damage. This assumption follows from the view that the components of the functional architecture are modular, in the sense of being informationally encapsulated. In this target article it is argued that this “locality” assumption is probably (...) not correct in general. Inferences about the functional architecture can nevertheless be made from neuropsychological data with an alternative set of assumptions, according to which human information processing is graded, distributed, and interactive. These claims are supported by three examples of neuropsychological dissociations and a comparison of the inferences obtained from these impairments with and without the locality assumption. The three dissociations are: selective impairments in knowledge of living things, disengagment of visual attention, and overt face recognition. In all three cases, the neuropsychological phenomena lead to more plausible inferences about the normal functional architecture when the locality assumption is abandoned. Also discussed are the relations between the locality assumption in neuropsychology and broader issues, including Fodor's modularity hypothesis and the choice between top-down and bottom-up research approaches. (shrink)

Dreams are a remarkable experiment in psychology and neuroscience, conducted every night in every sleeping person. They show that the human brain, disconnected from the environment, can generate an entire world of conscious experiences by itself. Content analysis and developmental studies have promoted understanding of dream phenomenology. In parallel, brain lesion studies, functional imaging and neurophysiology have advanced current knowledge of the neural basis of dreaming. It is now possible to start integrating these two strands of research to address fundamental (...) questions that dreams pose for cognitive neuroscience: how conscious experiences in sleep relate to underlying brain activity; why the dreamer is largely disconnected from the environment; and whether dreaming is more closely related to mental imagery or to perception. (shrink)

Study of symptoms with focal brain lesions reveals a microtemporal transition that elaborates the mind/brain state. The pattern of this transition corresponds with that of developmental growth , which can be characterized in terms of whole-part relations. This correspondence is interpreted as indicating that the cognitive process is an extension of growth trends in pre- and post-natal life. The continuum of ontogenetic growth into the cognitive process is a transition from exuberance of form to specificity or from generality to (...) precision, and conforms with the trajectory of the mind/brain state from categorical primitives at onset to definiteness at termination. A patterned sequence of brain activity corresponds to a patterned sequence of mental activity over the full processing sequence. This sustained whole-part transition begins in early brain structures and carries through to a neocortical end point. The process is epochal and modular, with overlapping replacement of mind/brain states. The specification of configurations in the brain is accompanied by the specification of categorical wholes: drive-categories partition to conceptual-feelings, then to images , finally to acts, words, and objects. A description of the process underlying the brain state is a description of the process underlying the mental state. This paper argues against a causal step from brain to mind, or the reverse, i.e. no one-way or two-way causation. (shrink)

PET studies using classical conditioning paradigms are reported. It is emphasized that PET studies show and not in learning paradigms. The importance of dissociating motor performance and learning deficits in human lesions studies is demonstrated in two exemplary studies. The different role of the cerebellum in adaptation of postural reflexes and learning of complex voluntary arm movements is discussed, [THACH].

Deep brain stimulation (DBS) is frequently described as a ‘reversible’ medical treatment, and the reversibility of DBS is often cited as an important reason for preferring it to brain lesioning procedures as a last resort treatment modality for patients suffering from treatment-refractory conditions. Despite its widespread acceptance, the claim that DBS is reversible has recently come under attack. Critics have pointed out that data are beginning to suggest that there can be non-stimulation-dependent effects of DBS. Furthermore, we lack long-term data (...) about other potential irreversible effects of neuromodulation. This has considerable normative implications for comparisons of DBS and brain lesioning procedures. Indeed, Devan Stahl and colleagues have recently argued that psychiatric DBS should be subject to the same legal safeguards as other forms of psychosurgery, supporting their position by forcibly criticising the claim that DBS is reversible. In this paper, I respond to these criticisms by first clarifying the descriptive and evaluative elements of the reversibility claim that supporters of DBS might invoke, and the different senses of ‘reversibility’ that we might employ in discussing the effects of medical procedures. I go on to suggest that it is possible to defend a nuanced version of the reversibility claim. To do so, I explain how DBS has some effects that are stimulation dependent in the short term, and argue that these effects can have significant normative implications for patient well-being and autonomy. I conclude that we should not abandon a nuanced version of the reversibility claim in the DBS debate. (shrink)

Over the past several years, the study of self-related cognition has garnered increasing interest amongst psychologists and cognitive neuroscientists. Concomitantly, lesion and neuroimaging studies have demonstrated the importance of intact cortico-cortical and cortico-subcortical connections for supporting high-level cognitive functions. Commissurotomy or “split-brain” patients provide unique insights into the role of the cerebral commissures in maintaining an individual’s sense of self, as well as into the unique self-representation capabilities of each cerebral hemisphere. Here we review empirical work examining the integrity of (...) self-related processes in patients with various disconnection syndromes, focusing on studies of self-recognition, ownership, and agency. Taken together, this body of work suggests that an intact corpus callosum enabling interhemispheric transfer is necessary for some, but not all types of self-representations. (shrink)

In the model proposed by Findlay & Walker, the programming of saccadic eye movements is achieved by two parallel processes, one dedicated to the coding of saccade metrics (Where) and the other controlling saccade initiation (When). One outcome of the “winner-take-all” characteristics of the salience map, the main node of the model, is an independence between the metrics and the latency of saccades. We report on some observations, made in the head-unrestrained cat under pathological conditions, of a correlation between accuracy (...) and latency of saccadic gaze shifts. To account for such a correlation, the link between metrics specification (Where) and saccade triggering (When) should be amended in the model. (shrink)

Deep brain stimulation of the subthalamic nucleus is an effective treatment for the motor symptoms of movement disorders including Parkinson's Disease. Despite its therapeutic benefits, STN-DBS has been associated with adverse effects on mood and cognition. Specifically, apathy, which is defined as a loss of motivation, has been reported to emerge or to worsen following STN-DBS. However, it is often challenging to disentangle the effects of STN-DBSper sefrom concurrent reduction of dopamine replacement therapy, from underlying PD pathology or from disease (...) progression. To this end, pre-clinical models allow for the dissociation of each of these factors, and to establish neural substrates underlying the emergence of motivational symptoms following STN-DBS. Here, we performed a systematic analysis of rodent studies assessing the effects of STN-DBS on reward seeking, reward motivation and reward consumption across a variety of behavioral paradigms. We find that STN-DBS decreases reward seeking in the majority of experiments, and we outline how design of the behavioral task and DBS parameters can influence experimental outcomes. While an early hypothesis posited that DBS acts as a “functional lesion,” an analysis of lesions and inhibition of the STN revealed no consistent pattern on reward-related behavior. Thus, we discuss alternative mechanisms that could contribute to the amotivational effects of STN-DBS. We also argue that optogenetic-assisted circuit dissection could yield important insight into the effects of the STN on motivated behavior in health and disease. Understanding the mechanisms underlying the effects of STN-DBS on motivated behavior-will be critical for optimizing the clinical application of STN-DBS. (shrink)

Grafting embryonic brain tissue into the brain of patients with visual field loss due to cerebral lesions may become a method to restore visual function. This method is not without risk, however, and will only be considered in cases of complete blindness after bilateral occipital lesions, when other, risk-free neuropsychological methods fail.

To fulfill their crucial duty of relieving suffering in their patients, physicians may have to administer palliative sedation when they implement treatment-limitation decisions such as the withdrawal of life-supporting interventions in patients with poor prognosis chronic severe brain injury. The issue of palliative sedation deserves particular attention in adults with serious brain injuries and in neonates with severe and irreversible brain lesions, who are unable to express pain or to state their wishes. In France, treatment limitation decisions for these (...) patients are left to the physicians. Treatment-limitation decisions are made collegially, based on the presence of irreversible brain lesions responsible for chronic severe disorders of consciousness. Before these decisions are implemented, they are communicated to the relatives. Because the presence and severity of pain cannot be assessed in these patients, palliative analgesia and/or sedation should be administered. However, palliative sedation is a complex strategy that requires safeguards to prevent a drift toward hastening death or performing covert euthanasia. In addition to the law on patients' rights at the end of life passed in France on April 22, 2005, a recent revision of Article 37 of the French code of medical ethics both acknowledges that treatment-limitation decisions and palliative sedation may be required in patients with severe brain injuries and provides legal and ethical safeguards against a shift towards euthanasia. This legislation may hold value as a model for other countries where euthanasia is illegal and for countries such as Belgium and Netherlands where euthanasia is legal but not allowed in patients incapable of asking for euthanasia but in whom a treatment limitation decision has been made. (shrink)

It has long been known that brain damage has important negative effects on one’s mental life and even eliminates one’s ability to have certain conscious experiences. It thus stands to reason that when all of one’s brain activity ceases upon death, consciousness is no longer possible and so neither is an afterlife. It seems clear that human consciousness is dependent upon functioning brains. This essay reviews some of the overall neurological evidence from brain damage studies and concludes that our argument (...) from brain damage has been vindicated by such overwhelming evidence. It also puts forth a more mature philosophical rationale against an afterlife and counters several replies to the argument. -/- 1. Philosophical Background -- 2. The Dependence of Consciousness on the Brain: Some Preliminary Evidence -- 3. Brain Damage, Lesion Studies, and the Localization of Mental Function - 3.1 Perception - 3.2 Awareness, Comprehension, and Recognition - 3.3 Memory - 3.4 Personality - 3.5 Language - 3.6 Emotion - 3.7 Decision-Making - 3.8 Social Cognition and Theory of Mind - 3.9 Moral Judgment and Empathy - 3.10 Neurological Disorders and Disease - 3.11 The Unity of Consciousness -- 4. Objections and Replies - 4.1 Souls, Minds, and Energy Fields - 4.2 The Instrument Theory - 4.3 The Embodied Soul Alone is Affected -- 5. Conclusion. (shrink)

BackgroundBilateral cerebral palsy is the most common type of CP in children and is often accompanied by different degrees of communication impairment. Several studies have attempted to identify children at high risk for communication impairment. However, most prediction factors are qualitative and subjective and may be influenced by rater bias. Individualized objective diagnostic and/or prediction methods are still lacking, and an effective method is urgently needed to guide clinical diagnosis and treatment. The aim of this study is to develop and (...) validate an objective, individual-based model for the prediction of communication impairment in children with BCP by the time they enter school.MethodsA multicenter prospective cohort study will be conducted in four Chinese hospitals. A total of 178 children with BCP will undergo advanced brain magnetic resonance imaging at baseline. At school entry, communication performance will be assessed by a communication function classification system. Three-quarters of children with BCP will be allocated as a training cohort, whereas the remaining children will be allocated as a test cohort. Multivariate lesion- and connectome-based approaches, which have shown good predictive ability of language performance in stroke patients, will be applied to extract features from MR images for each child with BCP. Multiple machine learning models using extracted features to predict communication impairment for each child with BCP will be constructed using data from the training cohort and externally validated using data from the test cohort. Prediction accuracy across models in the test cohort will be statistically compared.DiscussionThe findings of the study may lead to the development of several translational tools that can individually predict communication impairment in children newly diagnosed with BCP to ensure that these children receive early, targeted therapeutic intervention before they begin school.Trial registrationThe study has been registered with the Chinese Clinical Trial Registry. (shrink)

When the language-dominant hemisphere is damaged by a focal lesion, the brain may reorganize the language network through functional and structural changes known as adaptive plasticity. Adaptive plasticity is documented for triggers including ischemic, tumoral, and epileptic focal lesions, with effects in clinical practice. Many questions remain regarding language plasticity. Different lesions may induce different patterns of reorganization depending on pathologic features, location in the brain, and timing of onset. Neuroimaging provides insights into language plasticity due to its (...) non-invasiveness, ability to image the whole brain, and large-scale implementation. This review provides an overview of language plasticity on MRI with insights for patient care. First, we describe the structural and functional language network as depicted by neuroimaging. Second, we explore language reorganization triggered by stroke, brain tumors, and epileptic lesions and analyze applications in clinical diagnosis and treatment planning. By comparing different focal lesions, we investigate determinants of language plasticity including lesion location and timing of onset, longitudinal evolution of reorganization, and the relationship between structural and functional changes. (shrink)

The music and social bonding (MSB) hypothesis suggests that damage to brain regions in the proposed neurobiological model, including the ventromedial prefrontal cortex (vmPFC), would disrupt the social and emotional effects of music. This commentary evaluates prior research in persons with vmPFC damage in light of the predictions put forth by the MSB hypothesis.