Funding for Cognitive Imaging

磁共振成像（MRI）是一种强大的研究工具，可以在不给受试者带来风险的情况下研究人类大脑的解剖结构和功能。我们正在使用这种技术来研究三种常见疾病：左脑半球中风；轻度至中度阿尔茨海默病；还有一种慢性癫痫，叫做颞叶癫痫。我们正在调查左脑半球中风后出现沟通障碍（失语症）的患者。每年约有2.5万名患者在中风后患上持续性失语症。对这种情况的治疗还远远不够完美，在许多情况下，治疗的效果尚未得到证实。它主要采取行为再训练的形式，在言语和语言治疗师的监督下。一个特别困难的问题是预测将发生的自然恢复程度。这通常是最大的三个月，但恢复的量可以是非常可变的。中风的大小确实会影响结果。然而，似乎还涉及到其他因素，而这些因素是什么还不清楚。许多人认为语言恢复是因为语言从大脑的左半球“切换”到右半球，但这种情况发生的证据很少。有更好的证据表明，恢复是由于左半球未受损部分的广泛重组，我们的预测是，如果关键通路保持完整，那么恢复就会好得多。因此，我们招募了50名失语症中风后的患者，在第一阶段，我们评估他们在中风第一周内的语言能力。我们对语言产生特别感兴趣，因为患者发现表达能力受损是他们病情中最令人沮丧的方面。然后我们在三个月后对他们进行重新评估，这样我们就有了一个衡量他们恢复的“轨迹”：好、坏或一般。我们也做详细的核磁共振成像，在早期和晚期，以评估中风的边界，整个大脑的功能，当病人试图说话，以及整个大脑通路（白质束）的完整性。我们预测，这将对良好自然恢复的必要因素提供相当大的见解，并且这些知识将对改善未来的治疗策略至关重要。阿尔茨海默病阿尔茨海默病（AD）的主要特征是健忘，尤其是对口头信息的健忘。记住刚听过的话有三个阶段：记录信息（即注意说话人以理解所说的话）；将信息编码为更持久的记忆；然后在需要的时候提取记忆。这些不同的阶段依赖于大脑中非常不同的网络。大多数研究集中在编码和检索阶段。我们正在研究第一阶段，特别是注意力的作用。在AD的早期阶段，语言功能是完整的，所以理解言语不是问题。相反，我们认为是病人的注意力不集中。注意力依赖于右脑半球系统。我们正在使用功能性和解剖性MRI序列研究交流过程中的这个系统。我们还在观察用于缓解AD某些症状的药物是否对右半球系统有特别强的作用。一些癫痫患者通过手术来预防癫痫发作。一种常见的手术是切除大脑的前叶，即颞叶。令人惊讶的是，这对病人的高级心理功能的影响相对较小。我们正在研究一种假设，即患者一生中频繁的癫痫发作活动导致了颞叶网络的重组，从而保护患者在手术完成后免受重大缺陷的影响。这将告诉我们更多关于大脑的保护性“可塑性”。

Magnetic resonance imaging (MRI) is a powerful research tool, allowing both the anatomy and function of the human brain to be studied without risk to the subject. We are using this technique to study three common diseases: left cerebral hemisphere stroke; mild-to-moderate Alzheimer's disease; and a form of chronic epilepsy, know as temporal lobe epilepsy.StrokeWe are investigating patients who have impaired communication (aphasia) after a left cerebral hemisphere stroke. About 25,000 patients each year are left with persistent aphasia after stroke. Treatment for this condition is far from perfect, and in many instances largely of unproven benefit. It mostly takes the form of behavioural retraining, under the supervision of speech and language therapists. A particular difficulty is the problem of predicting the degree of natural recovery that will occur. This is usually maximal by three months, but the amount of recovery can be very variable. The size of the stroke does influence outcome. However, other factors seem to be involved, and what these are are not knowm. Many people believe that recovery is because language 'switches' from the left to the right cerebral hemisphere, but the evidence that this happens is slender. There is much better evidence that recovery is due to wide reorganisation of undamaged parts of the left hemisphere, and our prediction is that if critical pathways remain intact then recovery is much better. Therefore, we are recruiting 50 patients after aphasic stroke, and in the first phase we are assessing their language abilities within the first week of stroke. We are particularly interested in speech production, as patients find an impaired ability to express themselves the most frustrating aspect of their condition. We then reassess them at three months, and so we have a measure of their 'trajectory' of recovery: good, bad or indifferent. We also do detailed MRI, early and late, to assess the boundaries of the stroke, the function of the whole brain as the patients try to speak, and the integrity of pathways (white matter tracts) throughout the brain. We predict that this will give considerable insight into the factors necessary for good natural recovery, and this knowledge will be essential in informing improved future therapeutic strategies.Alzheimer's diseaseThe cardinal feature of Alzheimer's disease (AD) is forgetfulness, particularly for verbal information. There are three stages for remembering what one has just been told: registering the information (that is paying attention to the speaker to understand what is being said); encoding the information as a longer lasting memory; and then retrieving that memory when required. These different stages rely on very different networks in the the brain. Most research has concentrated on the encoding and retrieval stages. We are researching the first stage, and specifically the role of attention. In the early stages of AD, language functions are intact, so undertanding speech is not the problem. Rather, we argue, the patients are inattentive. Attention depends on a right cerebral hemisphere system. We are investigating this system during communication, using functional and anatomical MRI sequences. We are also observing whether the drugs used to alleviate some of the symptoms of AD have a particularly strong action on this right hemisphere system.EpislepsySome patients with epilepsy have surgery to prevent their attacks. One common operation is to remove the front pary of one lobe of the brain, the temporal lobe. Surprisingly, this has a relatively minor effect on the patient's higher mental functions. We are invetigating the hypothesis that frequent seizure activity throughot the lifetime of the patient has resulted in reorganisation of the temporal lobe networks, thus protecting the patient from a major deficity after the surgery has been completed. This will inform us more about the protective 'plasticity' of the brain.