What we remember affects how we see: Spatial working memory steers saccade programming

Relationships between visual attention, saccade programming, and visual working memory have been hypothesized for over a decade. Awh, Jonides, and Reuter-Lorenz (Journal of Experimental Psychology: Human Perception and Performance 24(3):780–90, 1998) and Awh et al. (Psychological Science 10(5):433–437, 1999) proposed that rehearsing a location in memory also leads to enhanced attentional processing at that location. In regard to eye movements, Belopolsky and Theeuwes (Attention, Perception & Psychophysics 71(3):620–631, 2009) found that holding a location in working memory affects saccade programming, albeit negatively. In three experiments, we attempted to replicate the findings of Belopolsky and Theeuwes (Attention, Perception & Psychophysics 71(3):620–631, 2009) and determine whether the spatial memory effect can occur in other saccade-cuing paradigms, including endogenous central arrow cues and exogenous irrelevant singletons. In the first experiment, our results were the opposite of those in Belopolsky and Theeuwes (Attention, Perception & Psychophysics 71(3):620–631, 2009), in that we found facilitation (shorter saccade latencies) instead of inhibition when the saccade target matched the region in spatial working memory. In Experiment 2, we sought to determine whether the spatial working memory effect would generalize to other endogenous cuing tasks, such as a central arrow that pointed to one of six possible peripheral locations. As in Experiment 1, we found that saccade programming was facilitated when the cued location coincided with the saccade target. In Experiment 3, we explored how spatial memory interacts with other types of cues, such as a peripheral color singleton target or irrelevant onset. In both cases, the eyes were more likely to go to either singleton when it coincided with the location held in spatial working memory. On the basis of these results, we conclude that spatial working memory and saccade programming are likely to share common overlapping circuitry.     

Electrical stimulation of the brain for psychiatric disorders

Despite advances in therapies, there remain psychiatric patients who are extremely ill and cannot be helped by classic psychiatric treatments, including psychotherapy and drug therapy. Certain of these patients may be helped by use of bilateral brain lesioning. The complication rate of standard stereotactic psychosurgery techniques is very low. The main rationale for the continued experimental use of deep brain stimulation (DBS) in neurosurgery for mental disorders is its reversibility. This reversibility is not an advantage in terms of the benefits obtained, but rather if side effects emerge. In addition, electrical stimulation may provide patients with some autonomy for their treatment. The first, very preliminary results of electrical stimulation for obsessive-compulsive disorder and for a small heterogeneous group of patients with other psychiatric disorders have been published. Electrical stimulation of the brain for psychiatric disorders may become a new treatment option for certain intractable psychiatric disorders. Nevertheless, the mechanism of action of DBS in psychiatric disorders is unknown, and the experience with this modality is extremely limited. The first results look promising, but this treatment option may prove unusable for some time because of a lack of knowledge of appropriate brain stimulation targets and technical problems such as the availability of sufficient current supply.     

Situating the self: understanding the effects of deep brain stimulation

The article proposes a theoretical model to account for changes in self due to Deep Brain Stimulation (DBS). First, we argue that most existing models postulate a very narrow conception of self, and thus fail to capture the full range of potentially relevant DBS-induced changes. Second, building on previous work by Shaun Gallagher, we propose a modified ‘pattern-theory of self’, which provides a richer picture of the possible consequences of DBS treatment.     

The psychological neuroscience of depression: implications for understanding effects of deep brain stimulation

In this article it is suggested that current psychological theories of depression presuppose that this condition will develop as a result of a vicious circle involving negatively biased communication between systems of emotional stress-/alarm-signaling, executive functions and mood regulation. These systems may from a neuroanatomical point of view be located in the limbic system, the orbitofrontal and lateral prefrontal cortex and the hypothalamus-pituitary-adrenal (HPA-) axis respectively. The theoretical and practical implications of this model for the understanding of pharmacological treatments of depression are briefly discussed and this theory is related to the catecholamine hypothesis of depression. The model is furthermore discussed in relation to deep brain stimulation (DBS) of treatment resistant major depression. Similarities and differences between this perspective and the one advocated by the "homeostatic theory" of depression are discussed. It is concluded that a topographical psychological theory may offer a useful heuristic in thinking about depression and that it offers several testable predictions about treatments of the disorder.     

Mechanisms and the current state of deep brain stimulation in neuropsychiatry

Deep brain stimulation (DBS) is established as a therapy for movement disorders, and it is an investigational treatment in other neurologic conditions. DBS precisely targets neuroanatomical targets deep within the brain that are proposed to be centrally involved in the pathophysiology of some neuropsychiatric illnesses. DBS is nonablative, offering the advantages of reversibility and adjustability. This might permit therapeutic effectiveness to be enhanced or side effects to be minimized. Preclinical and clinical studies have shown effects of DBS locally, at the stimulation target, and at a distance, via actions on fibers of passage or across synapses. Although its mechanisms of action are not fully elucidated, several effects have been proposed to underlie the therapeutic effects of DBS in movement disorders, and potentially in other conditions as well. The mechanisms of action of DBS are the focus of active investigation in a number of clinical and preclinical laboratories. As in severe movement disorders, DBS may offer a degree of hope for patients with intractable neuropsychiatric illness. It is already clear that research intended to realize this potential will require a very considerable commitment of resources, energy, and time across disciplines including psychiatry, neurosurgery neurology, neuropsychology, bioengineering, and bioethics. These investigations should proceed cautiously.     

Modulation of tremor amplitude during deep brain stimulation at different frequencies

Rest tremor was quantified in the index finger tip of 16 patients with Parkinson's disease (PD) receiving deep brain stimulation (DBS) of the ventro-intermediate nucleus (Vim) of the thalamus, the subthalamic nucleus (STN), or the internal part of the globus pallidus (GPi) while being off L-dopa for 12h. Clinically, without DBS, tremor amplitude varied from absent to high. Tremor was recorded continuously for about 5 min under three conditions of DBS repeated twice, namely, effective frequency (E), ineffective frequency (I), and no DBS (O). No changes in tremor were observed across conditions in subjects with little or no tremor. However, in subjects with moderate to large amplitude tremor, DBS decreased tremor amplitude to near normal values within a few seconds. Generally, transitions were progressive and occurred with a varying time delay. Occasionally, tremor escaped from control regardless of the stimulation condition considered. In some cases tremor amplitude in one condition appeared to depend on the preceding condition. Finally, the results were reproducible on two consecutive days. We conclude that tremor control with DBS follows specific dynamical rules, which must be compatible with the hypotheses proposed regarding the underlying mechanisms of DBS.     

Lessons learned in deep brain stimulation for movement and neuropsychiatric disorders

The introduction of deep brain stimulation (DBS) as a treatment for medication-refractory essential tremor in the late 1980s revealed, for the first time, that "chronically" implanted brain hardware had the potential to modulate neurologic function with surprisingly low morbidity. Over time, the therapeutic promise of DBS has become evident in Parkinson's disease and dystonia. In some experienced centers, complex tremor disorders, such as posttraumatic Holmes tremor and the tremor of multiple sclerosis, are being increasingly targeted. More recently, other indications, including obsessive-compulsive disorder, Tourette's syndrome, major depression, and chronic pain, have been proposed. As the field has expanded, our knowledge about potential cognitive side effects of DBS has also expanded. This article reviews the current knowledge regarding the impact of stimulation of the subthalamic nucleus, globus pallidus internus, and ventralis intermedius nucleus of the thalamus on symptoms in essential tremor, Parkinson's disease, and dystonia. Also discussed are the emerging targets, what is known about the cognitive sequelae of DBS, and what has been learned about the complications and therapeutic failures.     

Bottled memories: On how alcohol affects eyewitness recall

This study investigated how different doses of alcohol affected eyewitness recall. Participants (N = 126) were randomly assigned to three groups with different blood alcohol concentration (BAC), either a control group (mean BAC 0.00%, N = 42), a lower alcohol dose group (mean BAC 0.04%, N = 40), or a higher alcohol dose group (mean BAC 0.06%, N = 44). After consumption, participants witnessed a movie of a mock crime and were interviewed one week later. The main results showed that witnesses with the higher intoxication level recalled fewer details compared to witnesses with the lower intoxication level. The amount of alcohol consumed did not have an impact on the accuracy rate. No sex differences were found. The results are discussed in the light of past research. We conclude that more studies are needed before recommendations can be made to an applied setting.     

Regional brain catecholamines and memory: effects of footshock, amygdala implantation, and stimulation

Previous findings have revealed a correlation between post-training release of whole brain norepinephrine (NE) and later retention performance. The present experiment examined changes after a training footshock in NE levels, as well as the levels of the major central NE metabolite, 3-methoxy-4-hydroxyphenylglycol (MHPG), dopamine (DA), and epinephrine (EPI) in eight brain regions. Brain levels of these amines and the metabolite were assessed 10 min after training in a one-trial inhibitory (passive) avoidance task. The results indicate that NE levels decreased significantly in neocortex, neostriatum, hypothalamus, frontal pole, septum, and brainstem, but not in hippocampus or thalamus. The decreases in NE levels were generally accompanied by increases in MHPG; the MHPG/NE ratio increased significantly in all areas in which decreases in NE were observed. DA levels decreased in neostriatum and increased in neocortex and brainstem. Epinephrine levels decreased only in the brainstem sample. Thus, the effects of training on NE are widespread, probably reflecting the release of the amine in most brain regions. Such findings are consistent with the view that posttraining release of brain NE may modulate the storage of new information in many brain regions. One especially potent treatment for modulating memory storage is electrical stimulation of the amygdala. Therefore, we also examined the effects of amygdala implantation and stimulation on brain catecholamine levels to determine whether such changes might be correlated with the effects of amygdala stimulation on memory. The results indicate that electrode implantation into the amygdala results in pervasive changes in NE levels in most brain regions tested. Against this modified baseline, the results of training and electrical stimulation were region specific and very difficult to interpret. The major conclusion which can be derived from this portion of the experiment is that the amygdala damage produced by electrode implantation produces a brain which is substantially different from that of intact animals.     

Spatial memory: how egocentric and allocentric combine

Recent experiments indicate the need for revision of a model of spatial memory consisting of viewpoint-specific representations, egocentric spatial updating and a geometric module for reorientation. Instead, it appears that both egocentric and allocentric representations exist in parallel, and combine to support behavior according to the task. Current research indicates complementary roles for these representations, with increasing dependence on allocentric representations with the amount of movement between presentation and retrieval, the number of objects remembered, and the size, familiarity and intrinsic structure of the environment. Identifying the neuronal mechanisms and functional roles of each type of representation, and of their interactions, promises to provide a framework for investigation of the organization of human memory more generally.     

How generation affects source memory

Generation effects (better memory for self-produced items than for provided items) typically occur in item memory. Jurica and Shimamura (1999) reported a negative generation effect in source memory, but their procedure did not test participants on the items they had generated. In Experiment 1, participants answered questions and read statements made by a face on a computer screen. The target word was unscrambled, or letters were filled in. Generation effects were found for target recall and source recognition (which person did which task). Experiment 2 extended these findings to a condition in which the external sources were two different faces. Generation had a positive effect on source memory, supporting an overlap in the underlying mechanisms of item and source memory.     

Presentation modality affects false memory

Roediger and McDermott (1995) rejuvenated interest in Deese’s (1959) paradigm for producing reliable intrusions and false alarms. Using this paradigm in three experiments, we demonstrated that visual study presentation dramatically reduces the rate of false memories. Only auditory study presentation resulted in equal production of studied and critical items. Correct recall and recognition were unaffected. The suggestion that visual presentation provides a means for discriminating between false and true memories was supported by Experiment 3: Pleasantness rating of study items significantly reduced the creation of false memories regardless of modality.     

Be better or be merry: how mood affects self-control

In 6 studies, the authors tested whether the effect of mood on self-control success depends on a person's accessible goal. We propose that positive mood signals a person to adopt an accessible goal, whereas negative mood signals a person to reject an accessible goal; therefore, if a self-improvement goal is accessible, happy (vs. neutral or unhappy) people perform better on self-control tasks that further that goal. Conversely, if a mood management goal is accessible, happy people abstain from self-control tasks because the tasks are incompatible with this goal. This pattern receives consistent support across several self-control tasks, including donating to charity, demonstrating physical endurance, seeking negative feedback, and completing tests.     

A review of the treatment for refractory obsessive-compulsive disorder: from medicine to deep brain stimulation

This article provides an overview of the etiology, epidemiology, and first-line treatment options for obsessive-compulsive disorder (OCD). The subject of treatment-resistant and treatment-refractory OCD is then discussed, including a definition of these often-debated terms, and the latest treatment options delineated. This includes a review of the latest research concerning the pharmacological agents that have been studied as monotherapy or augmenting agents for the treatment of OCD, the use of experimental medications and procedures, treatment with reversible, minimally invasive procedures, such as vagal nerve stimulation and transcranial magnetic stimulation, invasive but the potentially reversible deep brain stimulation, and irreversible lesioning with ablative psychosurgery. A discussion of the role of psychotherapy in the treatment of OCD is also included.     

Vestibular stimulation affects optic-flow sensitivity

Typically, multiple cues can be used to generate a particular percept. Our area of interest is the extent to which humans are able to synergistically combine cues that are generated when moving through an environment. For example, movement through the environment leads to both visual (optic-flow) and vestibular stimulation, and studies have shown that non-human primates are able to combine these cues to generate a more accurate perception of heading than can be obtained with either cue in isolation. Here we investigate whether humans show a similar ability to synergistically combine optic-flow and vestibular cues. This was achieved by determining the sensitivity to optic-flow stimuli while physically moving the observer, and hence producing a vestibular signal, that was either consistent with the optic-flow signal, eg a radially expanding pattern coupled with forward motion, or inconsistent with it, eg a radially expanding pattern with backward motion. Results indicate that humans are more sensitive to motion-in-depth optic-flow stimuli when they are combined with complementary vestibular signals than when they are combined with conflicting vestibular signals. These results indicate that in humans, like in nonhuman primates, there is perceptual integration of visual and vestibular signals.