What is deviant about deviant smooth pursuit eye movements in schizophrenia?

Smooth pursuit eye movements of schizophrenic, hospitalized nonpsychotic, and normal control subjects (18 per group) were measured in low and high target information conditions. A computer method for measuring saccade frequency and velocity was used. The results indicated that the frequency of saccades was significantly greater in both tracking conditions for schizophrenic than for hospitalized nonpsychotic or normal subjects. Consistent with our earlier finding, the reduction in saccade frequency with high information was greatest for schizophrenic subjects. The results also yielded a unique finding: the velocity of saccades within smooth pursuit records was significantly greater for schizophrenic than for hospitalized nonpsychotic or normal subjects. Greater saccade velocity was not a result of increased saccade size; there was no significant difference in the size of saccades for normal and schizophrenic subjects. Yet, the duration of saccades was significantly less for schizophrenics than for other subjects. Target information affected the frequency, duration and size, yet not the velocity of saccades emitted by all subjects. In contrast to earlier interpretations of deviant smooth pursuit eye movements in schizophrenia, the results may provide the first evidence of differences in the functioning of the saccadic eye movement systems of schizophrenic and normal subjects.     

Relatives of unipolar and bipolar patients have normal pursuit

Impaired smooth pursuit eye movements are significantly less prevalent among the first-degree relatives of patients who have major affective disorders than among the first-degree relatives of schizophrenics. The distribution of normal and abnormal smooth pursuit among the relatives of unipolar and bipolar patients does not differ from that of normal individuals having no family history of major psychosis. Smooth pursuit impairment is thus specific to relatives of schizophrenic patients and is not characteristic of relatives of patients with major affective disorders.     

Periparabigeminal and adjoining mesencephalic tegmental field projections to the dorsolateral periaqueductal grey in cat - a possible role for oculomotor input in the defensive system

The dorsolateral column of the mesencephalic periaqueductal grey (PAGdl) differs from its adjacent columns in terms of afferent and efferent connections and the distribution pattern of different histochemical substances. Functionally, PAGdl is associated with aversive and defensive behaviours, but in an earlier study of this laboratory [E.M. Klop et al. (2005) J. Comp. Neurol., 492, 303-322], it was found that PAGdl specifically receives input from the nucleus prepositus hypoglossi, which plays a role in oculomotor control. In search for other oculomotor-related brainstem structures projecting to PAGdl we studied the projections from the parabigeminal nucleus (PBGN) and its medially adjoining periparabigeminal area (PPBGA). In three cats, injections of wheatgerm agglutinin-horseradish peroxidase involving PAGdl did not, or to only a very limited extent, result in retrogradely labelled neurons in PBGN. When the peripheral parts of PAGdl were involved in the injection site, labelled neurons were located in PPBGA, while after an injection involving only the more central parts of PAGdl they were located in the tegmentum medial to the PPBGA. An anterograde tracing study using [3H]-leucine and biotinylated dextran amine affirmed that neurons in PPBGA project to more peripheral parts of PAGdl, while neurons located in the tegmentum medial to PPBGA project mainly to its central parts. These results provide further evidence for the existence of two different subdivisions of PAGdl. We hypothesize that PAGdl is alerted by sudden changes in the visual field, and that the PAGdl defensive system is inhibited when these changes are caused by eye movements.     

Development of fixation and pursuit eye movements in human infants

Visual fixation and pursuit abilities of human infants were tested during their first year of life. Eye as well as head position was measured. Results show that the fixation of visual targets is accomplished by a head rotation accompanied by a series of small eye saccades. The number of these saccades increases with target eccentricity but progressively decreases with age. Pursuit of a moving visual target is performed by a smooth eye and head movement only if the target velocity is low. The maximum speed of pursuit progressively increases with age. The results are compatible with the relatively late development of the fovea.     

A Female Case with the Kleine-Levin Syndrome and Its Physiopathologic Aspects

Abstract: A female case with the Kleine-Levin syndrome (KLS), which first occurred at the age of 19, was discussed in relation to the following four characteristics: 1) a female case, 2) a loss of memory and the appearance of slow waves in the pathosis, 3) the abnormal pattern of growth hormone (GH) secretion during sleep in the pathosis, and 4) a prolonged latency between the peaks of III and V in the auditory brainstem response (ABR) in both the pathosis and nonpathosis. These characteristics may suggest that there is a slight disturbance of consciousness in the pathosis, and that there is a functional disturbance in the hypothalamus.     

Lesch-Nyhan syndrome with delayed onset of self-mutilation: hyperactivity of interneurons at the brainstem and blink reflex

We studied a case of Lesch-Nyhan syndrome with delayed onset of self-mutilation. Athetotic cerebral palsy and mental retardation were diagnosed at 1 year old, but the disease was not suspected until age 8 years when he began biting his lips and fingers. There was no obvious alteration of catecholamine in urine and CSF. We attempted to induce a series of blink reflexes by electric, mechanical and photic procedures. The R1 amplitude increased and the latency of the R2 shortened compared with controls. This shows that not only orbicularis motoneuron itself, but also uncrossed interneurons, are in a state of hyperexcitability. The contralateral R2 was poor which was in favour of hypoexcitability of the crossed interneurons at the brainstem. The significant large response was obtained by photic procedure which was in favour of hyperexcitability of the motoneurons. Therefore, it is demonstrated that a thorough examination of blink reflexes provides a useful method for examination of a state of the underlying neural activity.     

Smooth pursuit eye movements of patients with schizophrenia and affective disorder during clinical treatment

Background Smooth pursuit eye movement dysfunctions are considered a biological indicator for vulnerability to schizophrenia. This study examines test-retest stability of specific eye movement variables such as velocity gain and different saccadic categories. Methods Smooth pursuit eye movements of 27 schizophrenic patients and 30 patients with major depression were examined three times during clinical treatment using high-resolution infrared oculography. Forty-one normal controls were retested after four weeks. Results Intraclass correlation coefficients as a measure for retest-stability were highly significant in each group for all time-points, except for anticipatory saccades in schizophrenics. No significant correlations were found between psychopathological status, neuroleptic medication and eye movement variables. Conclusions Our results indicate that the most important measures of eye tracking performance in psychiatric patients are not significantly influenced by neuroleptic medication or clinical state and are stable across time. Received: 15 May 2001 / Accepted: 17 December 2001     

Gaze is driven by an internal goal trajectory in a visuomotor task

When we make hand movements to visual targets, gaze usually leads hand position by a series of saccades to task‐relevant locations. Recent research suggests that the slow smooth pursuit eye movement system may interact with the saccadic system in complex tasks, suggesting that the smooth pursuit system can receive non‐retinal input. We hypothesise that a combination of saccades and smooth pursuit guides the hand movements towards a goal in a complex environment, using an internal representation of future trajectories as input to the visuomotor system. This would imply that smooth pursuit leads hand position, which is remarkable, as the general idea is that smooth pursuit is driven by retinal slip. To test this hypothesis, we designed a video‐game task in which human subjects used their thumbs to move two cursors to a common goal position while avoiding stationary obstacles. We found that gaze led the cursors by a series of saccades interleaved with ocular fixation or pursuit. Smooth pursuit was correlated with neither cursor position nor cursor velocity. We conclude that a combination of fast and slow eye movements, driven by an internal goal instead of a retinal goal, led the cursor movements, and that both saccades and pursuit are driven by an internal representation of future trajectories of the hand. The lead distance of gaze relative to the hand may reflect a compromise between exploring future hand (cursor) paths and verifying that the cursors move along the desired paths.     

Responses of Neurons of the Nucleus of the Optic Tract and the Dorsal Terminal Nucleus of the Accessory Optic Tract in the Awake Monkey

The nucleus of the optic tract (NOT) and the dorsal terminal nucleus of the accessory optic tract (DTN) are essential nuclei for the generation of slow-phase eye movements during horizontal optokinetic nystagmus. We recorded from 101 neurons (all directionally selective) in four NOT/DTN of three trained and behaving rhesus monkeys. Neuronal activity increased when stimuli moved ipsiversively with respect to the recording site and decreased below spontaneous activity when stimuli moved contraversively. While the monkey fixated a small spot, some NOT/DTN neurons did not respond at all to the retinal image slip of a whole-field random dot pattern; others showed a monotonic increase of activity to increasing velocities of that stimulus. The velocity range tested was up to 100°/s. During the execution of optokinetic nystagmus, 39 of 73 cells tested showed a velocity-tuned response with an average optimum at 21°/s retinal image slip. Following saccades during optokinetic nystagmus (quick phases), the NOT/DTN neuronal activity briefly attained the level of spontaneous activity, as predicted from the velocity selectivity during optokinetic nystagmus. Immediately upon cessation of optokinetic stimulation in the preferred direction, NOT/DTN activity returned to the spontaneous level and did not reflect the ongoing optokinetic afternystagmus in darkness. Most NOT/DTN neurons displayed direction selectivity also during smooth pursuit. Twenty-one of 50 cells tested (42%) always responded to the retinal slip of the target (target velocity cells), 16 cells (32%) responded to the retinal slip of the background (background velocity cells), and 13 cells (26%) did not respond at all during smooth pursuit. We conclude from our results that the NOT/DTN is an essential structure for the processing of the direction and speed of retinal image slip. This information is then used for the generation and maintenance of slow eye movements, preferentially during horizontal optokinetic nystagmus but also during pursuit eye movements.     

Behavioural relevance modulates access to spatial working memory in humans

Neurophysiological studies in monkeys suggest selective representation of behaviourally relevant information in working memory. So far, no behavioural evidence for this has been reported for humans. Here, we investigated the role of behavioural relevance for access to human visuospatial working memory by using delayed oculomotor response tasks. Subjects were presented two successive visual cues in different and unpredictable locations while fixating on a central fixation point. After a delay, an unpredictable auditory signal (one beep or two beeps) sounded and the central fixation point was turned off, initiating the oculomotor response (i.e. memory-guided saccade) phase. Two groups of 10 subjects each were studied in two conditions: in the 'relevant' condition, subjects were instructed to memorize both visual cues and to move the eyes to the remembered position of the first cue (one beep) or the second cue (two beeps). The same stimuli were used in the 'irrelevant' condition, but subjects were instructed to memorize and move the eyes to the position of the first cue only, regardless of the second cue and the auditory signal. In the 'relevant' condition, we found a significant increase in errors of memory-guided saccades to the first cue, when the second cue was located between central fixation point and first cue. This spatially selective interference effect disappeared in the 'irrelevant' condition, despite identical stimuli. On a behavioural level, these results show for the first time the significance of behavioural relevance for access to human spatial working memory. These findings complement recent single-neuron studies in monkeys, showing that the neuronal substrates of working memory selectively represent behaviourally relevant perceptual information.     

Abnormal antisaccades and smooth pursuit eye movements in patients with Wilson's disease

Neurological symptoms in Wilson's disease (WD) may include oculomotor abnormalities. However, to date, eye movements in WD patients were rarely investigated and the data concerning this issue are sparse. The purpose of this study was to evaluate reflexive and voluntary eye movements in WD patients. We examined horizontal saccadic and smooth pursuit eye movements using infra‐red oculography in 50 WD patients, including 29 neurologically symptomatic (WDn) and 21 asymptomatic ones (WDa), and in 29 healthy controls. We found statistically significant increase in mean antisaccadic latency (378 ms) and in mean antisaccadic error rate (22.5) in the WDn group, when compared with WDa group (317 ms and 9.1, respectively) and controls (318 ms and 9.7, respectively). In contrast, there were no statistically significant differences in mean latency of prosaccades and in size of the gap effect. Patients with neurological manifestations had also abnormal smooth pursuit—increased number of saccadic intrusions (mean: 8.6) and decreased gain (mean: 0.69) comparing with WDa patients (4.1 and 0.83, respectively) and controls (2.2 and 0.91, respectively). The data suggest that WD is associated both with impairment of voluntary control of saccades and with disturbed smooth pursuit eye movements while reflexive saccades seem to be preserved. © 2008 Movement Disorder Society     

Pentobarbital-induced changes in the mouse brainstem auditory evoked potential as a function of click repetition rate and time postdrug

The effects of pentobarbital (80 mg/kg, i.p.) and saline injections on the BAEP were studied in 10 adult female BDF1 mice. Pentobarbital anesthesia induced statistically significant increases in the amplitudes and latencies of various BAEP components relative to preinjection and saline control values. These pentobarbital-induced changes were maximal shortly after drug administration and dissipated over time in a pattern similar to a drug elimination curve. Since pentobarbital and fast stimulus repetition rates are considered to be 'synaptic stressors', it was predicted that pentobarbital anesthesia and click repetition rate would have combined effects on the BAEP. This prediction was partially supported in that pentobarbital-induced changes in P4 amplitude and latency were significantly dependent on click repetition rate. The pentobarbital-induced effects on earlier BAEP components, however, proved to be largely independent of click rate. Pentobarbital-associated changes in the BAEP were not due to such factors as core temperature changes, circadian variations, and stress. The importance of anesthetic-induced changes in the BAEP for clinical and experimental studies is discussed.     

Neural mechanisms of smooth pursuit eye movements in schizotypy

Patients with schizophrenia as well as individuals with high levels of schizotypy are known to have deficits in smooth pursuit eye movements (SPEM). Here, we investigated, for the first time, the neural mechanisms underlying SPEM performance in high schizotypy. Thirty‐one healthy participants [N = 19 low schizotypes, N = 12 high schizotypes (HS)] underwent functional magnetic resonance imaging at 3T with concurrent oculographic recording while performing a SPEM task with sinusoidal stimuli at two velocities (0.2 and 0.4 Hz). Behaviorally, a significant interaction between schizotypy group and velocity was found for frequency of saccades during SPEM, indicating impairments in HS in the slow but not the fast condition. On the neural level, HS demonstrated lower brain activation in different regions of the occipital lobe known to be associated with early sensory and attentional processing and motion perception (V3A, middle occipital gyrus, and fusiform gyrus). This group difference in neural activation was independent of target velocity. Together, these findings replicate the observation of altered pursuit performance in highly schizotypal individuals and, for the first time, identify brain activation patterns accompanying these performance changes. These posterior activation differences are compatible with evidence of motion processing deficits from the schizophrenia literature and, therefore, suggest overlap between schizotypy and schizophrenia both on cognitive‐perceptual and neurophysiological levels. However, deficits in frontal motor areas observed during pursuit in schizophrenia were not seen here, suggesting the operation of additional genetic and/or illness‐related influences in the clinical disorder. Hum Brain Mapp, 36:340–353, 2015. © 2014 Wiley Periodicals, Inc.     

Auditory brainstem responses in 10 inbred strains of mice

The auditory brainstem response (ABR) is an evoked potential response of auditory activity in the auditory nerve and subsequent fiber tracts and nuclei within the auditory brainstem pathways. The threshold, amplitude, and latency analysis of the ABR provides information on the peripheral hearing status and the integrity of brainstem pathways. In this study, we compared the threshold, amplitude, and latency of ABRs recorded from 149 mice of 10 commonly used inbred strains (BALB/cJ, C3HeB/FeJ, C3H/HeJ, CAST/EiJ, CBA/CaJ, CBA/J, FVB/NJ, MRL/MpJ, NZB/BlNJ, and SJL/J) using clicks of different intensities. The ABR thresholds of these strains ranged from 32 to 43 dB SPL. The amplitude of both waves I and IV of ABRs, which increased monotonically with click intensity in most strains, differed significantly among different strains at each intensity tested. Moreover, the amplitude of both waves was inversely correlated with the body weight of each strain at most intensities tested. In general, the amplitude of wave IV was smaller than that of wave I resulting in the IV/I amplitude ratio of <1.0 in all strains. The peak latency of both waves I and IV decreased significantly with click intensity in each strain. However, this intensity-dependent decrease was greater for wave IV than for wave I such that the wave I-IV inter-peak latency also decreased significantly with increasing intensity. I-IV inter-peak latencies for MRL/MpJ, C3HeB/FeJ, NZB/BlNJ, and C3H/HeJ strains are longer than FVB/NJ, SJL/J, or CAST/EiJ. This work is the first step to study the genetic basis underlying strain-related differences in auditory pathway.     

Gaze-evoked nystagmus and smooth pursuit deficits: Their relationship studied in 52 patients

Gaze-evoked nystagmus occurs with cerebellar and brain-stem lesions and reflects a deficiency of the so-called common neural integrator. Experimental data show that loss of the neural integrator also abolishes slow conjugate eye movements, i.e. smooth pursuit eye movements and the vestibulo-ocular reflex (VOR). Since the smooth pursuit system has its own premotor circuits, a smooth pursuit deficit can be either the result of a premotor smooth pursuit lesion or the consequence of a gaze-holding deficit. To study this question DC eye movement recordings of 52 patients with horizontal gaze-evoked nystagmus and/or smooth pursuit deficits were studied in detail. It was found that the majority (71 %) had a combined smooth pursuit and gaze-holding deficit. Thirteen patients (25%) had a smooth pursuit deficit only. Only 2 patients (4%) had an isolated gaze-evoked nystagmus, which was comparatively weak. Thus a major finding is that each substantial gaze-evoked nystagmus is combined with a smooth pursuit deficit; the two deficits are well correlated (coefficientr =0.81). In all patients with a smooth pursuit deficit, visual suppression of the VOR was similarly impaired, when comparing the groups with and without gaze-evoked nystagmus. It is argued here that, although gaze-holding and smooth pursuit deficits are well correlated, the gaze-holding deficits seen in patients are not severe enough to explain the smooth pursuit deficit solely as a consequence of the gaze-holding deficit. Rather it probably reflects the close anatomical vicinity of gaze-holding and smooth pursuit mechanisms in the floccular region, the vestibular nuclei/nucleus prepositus complex and its connecting pathways.     

听性脑干反应在婴幼儿分泌性中耳炎中的诊断价值

目的 分析听性脑干反应(auditory brainstem response,ABR)在婴幼儿分泌性中耳炎(otitis media with effusion,OME)中的临床应用价值.方法 收集2017 年1 月至2019 年12 月在驻马店市第一人民医院神经电生理室进行常规筛查ABR 的2 177 例婴幼儿资料...     

Brainstem involvement in multiple sclerosis: a clinical and electrophysiological study

ABSTRACT – A major aim of this study was to determine the diagnostic value of 4 electrophysiological tests in MS, and particularly their effectiveness in detecting signs of brainstem involvement. Therefore, auditory brainstem evoked response (ABER), somatosensory evoked response (SSER), blink reflex and electronystagmographic (ENG) investigative methods were applied to a group of 89 patients with definite, probable or possible multiple sclerosis (MS).
The 4 methods yielded interdependent data, especially where the brainstem function was concerned, thus it can be concluded that a single demyelinating lesion may cause a combination of electrophysiological disorders within a small structure such as the brainstem.
ENG recordings were found to reveal the highest number of asymptomatic abnormalities. The combination of ABER and ENG tests revealed electrophysiological disorders in 81% of all patients. The blink reflex and the SSER tests gave hardly supplementary information.     

Auditory startle response in cervical dystonia.

The excitability of brainstem neurons is abnormally enhanced in patients with cervical dystonia (CD), but the extend of such abnormality is not known. We examined whether patients with CD showed abnormalities in the auditory startle response (ASR), a brainstem reflex elicited by an unexpected loud stimulus. Thirteen patients with CD were investigated 3 months after botulinum toxin treatment. Thirteen healthy volunteers served as controls. ASRs were elicited by binaural high-intensity auditory stimuli. Reflex electromyographic (EMG) activity was recorded simultaneously with surface electrodes bilaterally from masseter, orbicularis oculi, sternocleidomastoid, and biceps brachii muscles. We found that ASR onset latencies were similar for patients and controls. CD patients had significantly lower ASR probabilities than controls (P = 0.007). ASR area under the curve was significantly smaller in CD patients (P = 0.017). Similar to controls, patients showed a significant habituation of ASR (P < 0.001, each); however, CD patients showed a prolonged tonic or phasic EMG activity after the initial ASR that was not observed in controls. Normal latencies and recruitment pattern indicate a preserved organization of intrinsic neural pathways mediating ASR in CD. Reduced ASR probability and magnitude as well as prolonged EMG activity after the proper startle response corroborate and extend previous findings on brainstem dysfunction in CD.     

Characteristic findings of auditory brainstem response and otoacoustic emission in the Bronx waltzer mouse

Auditory brainstem responses (ABRs) and distortion product otoacoustic emissions (DPOAEs) were evaluated serially from 1 to 22 months in Bronx waltzer homozygotes (bv/bv), heterozygotes (+/bv) and control (+/+) mice, which were differentiated by means of PCR of marker DNA (D5Mit209). The wave IV threshold of the click-evoked ABR was higher than the DPOAE threshold with the DP growth method in each bv/bv, although the two thresholds were almost the same in the +/+ group. The DP value at 2f₁ − f₂ in the bv/bv showed an apparent decrease at 2 to 3 months of age with 80 dB SPL stimulation using f₂ frequency 7996 Hz and frequency ratio f₂/f₁ = 1.22, compared to control or heterozygote mice. It was characteristic that the 2f₂ − f₁ DP signal-to-noise ratio (SNR) value was more preserved from 80 to 60 dB SPL than the 2f₁ − f₂ DP value at f₂ frequency 7996 Hz in most bv/bv, however, control mice showed almost the same levels of 2f₁ − f₂ and 2f₂ − f₁ SNR value at both f₂ frequencies of 6006 and 7996 Hz. The preservation of a substantial 2f₂ − f₁ DP suggested that it would be generated basal to the primary-tone place on the basilar membrane and there might be a reflection of the unique function of the remaining outer hair cells in the Bronx waltzer mice. These findings suggest that combination of ABR with DPOAE could offer useful information about differentiating the mechanism of hair cell dysfunction of the hereditary hearing impairment in the clinical fields.