Transcranial Doppler Ultrasonography Monitoring of Cerebral Hemodynamics During Performance of Cognitive Tasks: A Review

The examination of blood flow velocity (BFV) changes during the performance of mental tasks is one of the applications of transcranial Doppler (TCD) ultrasonography. The purpose of this review is to summarize the results of the functional TCD literature, to investigate the effects of methodological differences between studies, and to provide guidelines for future research. It is concluded that larger series of more homogeneous groups concerning age and handedness, and stricter criteria for subject selection and laboratory setting are required. The implication of quantitative and qualitative performance measures and psychological parameters (motivation, anxiety, and task anticipation) could also yield important information. We recommend future agreement upon a more standardized methodology. TCD promises to be a useful tool to provide further insight into the cerebral organization and temporal reactivity of the human brain.     

Cognitive neuroimaging: cognitive science out of the armchair

Cognitive scientists were not quick to embrace the functional neuroimaging technologies that emerged during the late 20th century. In this new century, cognitive scientists continue to question, not unreasonably, the relevance of functional neuroimaging investigations that fail to address questions of interest to cognitive science. However, some ultra-cognitive scientists assert that these experiments can never be of relevance to the study of cognition. Their reasoning reflects an adherence to a functionalist philosophy that arbitrarily and purposefully distinguishes mental information-processing systems from brain or brain-like operations. This article addresses whether data from properly conducted functional neuroimaging studies can inform and subsequently constrain the assumptions of theoretical cognitive models. The article commences with a focus upon the functionalist philosophy espoused by the ultra-cognitive scientists, contrasting it with the materialist philosophy that motivates both cognitive neuroimaging investigations and connectionist modelling of cognitive systems. Connectionism and cognitive neuroimaging share many features, including an emphasis on unified cognitive and neural models of systems that combine localist and distributed representations. The utility of designing cognitive neuroimaging studies to test (primarily) connectionist models of cognitive phenomena is illustrated using data from functional magnetic resonance imaging (fMRI) investigations of language production and episodic memory.     

On aims and methods in the neuroimaging of derived relations

Ingenious and seemingly powerful technologies have been developed recently that enable the visualization in some detail of events in the brain concomitant upon the ongoing behavioral performance of a human participant. Measurement of such brain events offers at the very least a new set of dependent variables in relation to which the independent variables familiarly manipulated in the operant laboratory may be explored. Two related paradigms in which a start has been made in such research concern the derivation of novel or emergent relations from a baseline set of trained relations, and include the phenomenon of transitive inference (TI), observed in studies of stimulus equivalence (SE) and serial learning (SL) or seriation. This paper reviews some published and forthcoming neuroimaging studies of these and related phenomena, and considers how this line of research both demands and represents a welcome synthesis between types of question and levels of explanation in behavioral science that often have been seen as antithetical.     

A comparison of masking by visual and transcranial magnetic stimulation: implications for the study of conscious and unconscious visual processing

Visual stimuli as well as transcranial magnetic stimulation (TMS) can be used: (1) to suppress the visibility of a target and (2) to recover the visibility of a target that has been suppressed by another mask. Both types of stimulation thus provide useful methods for studying the microgenesis of object perception. We first review evidence of similarities between the processes by which a TMS mask and a visual mask can either suppress the visibility of targets or recover such suppressed visibility. However, we then also point out a significant difference that has important implications for the study of the time course of unconscious and conscious visual information processing and for theoretical accounts of the processes involved. We present evidence and arguments showing: (a) that visual masking techniques, by revealing more detailed aspects of target masking and target recovery, support a theoretical approach to visual masking and visual perception that must take into account activities in two separate neural channels or processing streams and, as a corollary, (b) that at the current stage of methodological sophistication visual masks, by acting in more highly specifiable ways on these pathways, provide information about the microgenesis of form perception not available with TMS masks.     

Posttraining Electrical Stimulation of Vagal Afferents with Concomitant Vagal Efferent Inactivation Enhances Memory Storage Processes in the Rat

Peripherally administered or released substances that modulate memory storage, but do not freely enter the brain, may produce their effects on memory by activating peripheral receptors that send messages centrally through the vagus nerve. Indeed, vagus nerve stimulation enhances memory performance, although it is unclear whether this effect is due to the activation of vagal afferents or efferents. To eliminate the possible influence of descending fibers on memory storage processes, rats were implanted with cuff electrode/catheter systems along the left cervical vagus. Forty-eight hours following surgery, each animal received a 3.0-μl infusion (1.0 μl/min) of either lidocaine hydrochloride (75.0 mM) or isotonic saline below the point of stimulation. Animals were then trained 10 min later on an inhibitory-avoidance task with a 0.75-mA, 1.0-s foot shock. Sham stimulation or vagus nerve stimulation (0.5-ms biphasic pulses; 20.0 Hz; 30 s; 0.2, 0.4, or 0.8 mA) was administered immediately after training. Memory, tested 24 h later, was enhanced by stimulation whether descending vagus nerve fibers were inactivated or not. Both lidocaine- and saline-infused groups showed an intensity-dependent, inverted-U-shaped pattern of retention performance, with the greatest effect observed for 0.4 mA (U= 9,p< .05, andU= 7,p< .01, respectively). Additionally, animals that received lidocaine infusions, but no vagus nerve stimulation, showed impaired memory compared to the performance of saline-infused control animals (U= 11,p< .05). Together, these findings suggest that vagal afferents carry messages about peripheral states that lead to the modulation of memory storage and that the memory-enhancing effect produced by vagus nerve stimulation is not mediated via the activation of vagal efferents.     

Synergistic effects of ethanol and cocaine on brain stimulation reward.

The effects of two widely abused drugs, ethanol and cocaine, were examined alone and in combination on intracranial reward processes. In agreement with previous research, higher doses of both cocaine and ethanol alone produced facilitation of behavior maintained by brain stimulation reward. Low intraperitoneal doses of ethanol and cocaine, which alone did not affect performance, were found to reduce stimulation reward threshold and modestly increase response rate. The enhancement of brain stimulation reward by the combination of ethanol and cocaine suggests that both drugs may produce their rewarding effects through common neuronal substrates and that they may potentiate the abuse of each other.     

Histological data: Hollard and Davison (1971)

As Mogenson and Cioé (1977) have assumed that our electrodes aimed at the ectostriatum (Hollard and Davison, 1971) were actually located there, we feel that a presentation of the histological data is necessary. Following termination of further experiments (Hollard, 1974) the pigeons, numbered 93, 95, and 119, were sacrificed and perfused with saline followed by 10% formalin. Sections, 50 microns thick, were cut on a freezing microtome. Prints were made by mounting each unstained section of a microscope slide and placing them in a standard photographic enlarger. The electrode tips of Pigeons 93 and 119 were located in the paleostriatal complex. The sections of Pigeon 95 were damaged and precise localization was not possible. Further work in this laboratory has also found that, using the same coordinates, electrode tips tend to fall in the paleostriatum, rather than in the more dorsal ectostriatum at which they are aimed. The paleostriatal placements tended to sustain self-stimulation, whereas others located in the ectostriatum sustained relatively low or unstable rates.     

BEHAVIOR ANALYSIS OF MOTION CONTROL FOR PEDIATRIC NEUROIMAGING

Magnetic resonance imaging is a promising technological advance used for research and diagnosis of disease. The procedure has no risks, except when uncooperative patients require sedation. Four normal children participated in simulated scans to study the effects of (a) antecedent changes in the imaging environment and (b) operant conditioning of movement inhibition. Changing the environment can decrease movement, but operant contingencies were necessary to decrease movement to a level that, in most cases, would allow the procedure to occur without sedation.     

A double-blind,sham-controlled,trial of home-administered rhythmic 10-Hz median nerve stimulation for the reduction of tics,and suppression of the urge-to-tic,in individuals with Tourette syndrome and chronic tic disorder

Tourette syndrome (TS) and chronic tic disorder (CTD) are neurological disorders of childhood onset characterized by the occurrence of tics; repetitive, purposeless, movements or vocalizations of short duration which can occur many times throughout a day. Currently, effective treatment for tic disorders is an area of considerable unmet clinical need. We aimed to evaluate the efficacy of a home-administered neuromodulation treatment for tics involving the delivery of rhythmic pulse trains of median nerve stimulation (MNS) delivered via a wearable ‘watch-like’ device worn at the wrist. We conducted a UK-wide parallel double-blind sham-controlled trial for the reduction of tics in individuals with tic disorder. The device was programmed to deliver rhythmic (10 Hz) trains of low-intensity (1–19 mA) electrical stimulation to the median nerve for a pre-determined duration each day, and was intended to be used by each participant in their home once each day, 5 days each week, for a period of 4 weeks. Between 18th March 2022 and 26th September 2022, 135 participants (45 per group) were initially allocated, using stratified randomization, to one of the following groups; active stimulation; sham stimulation or to a waitlist (i.e. treatment as usual) control group. Recruited participants were individuals with confirmed or suspected TS/CTD aged 12 years of age or upward with moderate to severe tics. Researchers involved in the collection or processing of measurement outcomes and assessing the outcomes, as well as participants in the active and sham groups and their legal guardians were all blind to the group allocation. The primary outcome measure used to assess the ‘offline’ or treatment effect of stimulation was the Yale Global Tic Severity Scale–Total Tic Severity Score (YGTSS–TTSS) assessed at the conclusion of 4 weeks of stimulation. The primary outcome measure used to assess the ‘online’ effects of stimulation was tic frequency, measured as the number of tics per minute (TPM) observed, based upon blind analysis of daily video recordings obtained while stimulation was delivered. The results demonstrated that after 4-week stimulation, tic severity (YGTSS-TTSS) had reduced by 7.1 points (35 percentile reduction) for the active stimulation group compared to 2.13/2.11 points for the sham stimulation and waitlist control groups. The reduction in YGTSS–TTSS for the active stimulation group was substantially larger, clinically meaningful (effect size = .5) and statistically significant (p = .02) compared to both the sham stimulation and waitlist control groups, which did not differ from one another (effect size = −.03). Furthermore, blind analyses of video recordings demonstrated that tic frequency (tics per minute) reduced substantially (−15.6 TPM) during active stimulation compared to sham stimulation (−7.7 TPM). This difference represents a statistically significant (p < .03) and clinically meaningful reduction in tic frequency (>25 percentile reduction: effect size = .3). These findings indicate that home-administered rhythmic MNS delivered through a wearable wrist-worn device has the potential to be an effective community-based treatment for tic disorders.     

菜单界面设计的认知工效学研究方法

菜单研究是人 -计算机交互研究的重要内容之一。本文以研究方法的发展过程为主线 ,回顾了菜单界面认知工效学研究的历程 ,分别讨论了传统实验方法、系统仿真方法和眼动追踪方法在菜单界面设计研究中的应用