scholarly journals Memory-Guided Saccades in Psychosis: Effects of Medication and Stimulus Location

2021 ◽  
Vol 11 (8) ◽  
pp. 1071
Author(s):  
Eleanor S. Smith ◽  
Trevor J. Crawford
Keyword(s):  
Target Location ◽  
Bipolar Affective Disorder ◽  
Gain Control ◽  
Stimulus Location ◽  
Group Differences ◽  
Diagnostic Classification ◽  
Eye Position ◽  
Peripheral Target ◽  
Auditory Cue ◽  
Saccade Task

The memory-guided saccade task requires the remembrance of a peripheral target location, whilst inhibiting the urge to make a saccade ahead of an auditory cue. The literature has explored the endophenotypic deficits associated with differences in target laterality, but less is known about target amplitude. The data presented came from Crawford et al. (1995), employing a memory-guided saccade task among neuroleptically medicated and non-medicated patients with schizophrenia (n = 31, n = 12), neuroleptically medicated and non-medicated bipolar affective disorder (n = 12, n = 17), and neurotypical controls (n = 30). The current analyses explore the relationships between memory-guided saccades toward targets with different eccentricities (7.5° and 15°), the discernible behaviour exhibited amongst diagnostic groups, and cohorts distinguished based on psychotic symptomatology. Saccade gain control and final eye position were reduced among medicated-schizophrenia patients. These metrics were reduced further among targets with greater amplitudes (15°), indicating greater deficit. The medicated cohort exhibited reduced gain control and final eye positions in both amplitudes compared to the non-medicated cohort, with deficits markedly observed for the furthest targets. No group differences in symptomatology (positive and negative) were reported, however, a greater deficit was observed toward the larger amplitude. This suggests that within the memory-guided saccade paradigm, diagnostic classification is more prominent in characterising disparities in saccade performance than symptomatology.

scholarly journals Cross-modal orienting of exogenous attention results in visual-cortical facilitation, not suppression

2020 ◽  
Author(s):  
Jonathan M. Keefe ◽  
Emilia Pokta ◽  
Viola S. Störmer
Keyword(s):  
Neural Activity ◽  
Target Location ◽  
Visual Target ◽  
Cortical Activity ◽  
Exogenous Attention ◽  
Peripheral Target ◽  
Behavioral Performance ◽  
Auditory Cue ◽  
Visual Cortical

AbstractAttention may be oriented exogenously (i.e., involuntarily) to the location of salient stimuli, resulting in improved perception. However, it is unknown whether exogenous attention improves perception by facilitating processing of attended information, suppressing processing of unattended information, or both. To test this question, we measured behavioral performance and cue-elicited neural changes in the electroencephalogram as participants (N = 19) performed a task in which a spatially non-predictive auditory cue preceded a visual target. Critically, this cue was either presented at a peripheral target location or from the center of the screen, allowing us to isolate spatially specific attentional activity. We find that both behavior and attention-mediated changes in visual-cortical activity are enhanced at the location of a cue prior to the onset of a target, but that behavior and neural activity at an unattended target location are equivalent to that following a central cue that does not direct attention (i.e., baseline). These results suggest that exogenous attention operates solely via facilitation of information at an attended location.

scholarly journals Cross-modal orienting of exogenous attention results in visual-cortical facilitation, not suppression

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jonathan M. Keefe ◽  
Emilia Pokta ◽  
Viola S. Störmer
Keyword(s):  
Neural Activity ◽  
Target Location ◽  
Visual Target ◽  
Cortical Activity ◽  
Exogenous Attention ◽  
Peripheral Target ◽  
Behavioral Performance ◽  
Auditory Cue ◽  
Visual Cortical

AbstractAttention may be oriented exogenously (i.e., involuntarily) to the location of salient stimuli, resulting in improved perception. However, it is unknown whether exogenous attention improves perception by facilitating processing of attended information, suppressing processing of unattended information, or both. To test this question, we measured behavioral performance and cue-elicited neural changes in the electroencephalogram as participants (N = 19) performed a task in which a spatially non-predictive auditory cue preceded a visual target. Critically, this cue was either presented at a peripheral target location or from the center of the screen, allowing us to isolate spatially specific attentional activity. We find that both behavior and attention-mediated changes in visual-cortical activity are enhanced at the location of a cue prior to the onset of a target, but that behavior and neural activity at an unattended target location is equivalent to that following a central cue that does not direct attention (i.e., baseline). These results suggest that exogenous attention operates via facilitation of information at an attended location.

scholarly journals Pre-Movement Cortico-Muscular Dynamics Underlying Improved Parkinson Gait Initiation after Instructed Arm Swing

2020 ◽  
Vol 10 (4) ◽  
pp. 1675-1693
Author(s):  
Joyce B. Weersink ◽  
Silvano R. Gefferie ◽  
Teus van Laar ◽  
Natasha M. Maurits ◽  
Bauke M. de Jong
Keyword(s):  
Muscle Activity ◽  
Motor Program ◽  
Group Differences ◽  
Gait Initiation ◽  
Movement Onset ◽  
Arm Swing ◽  
Auditory Cue ◽  
Eeg Changes ◽  
Motor Initiation ◽  
Spectral Perturbation

Background: The supplementary motor area (SMA) is implicated in both motor initiation and stereotypic multi-limb movements such as walking with arm swing. Gait in Parkinson’s disease exhibits starting difficulties and reduced arm swing, consistent with reduced SMA activity. Objective: We tested whether enhanced arm swing could improve Parkinson gait initiation and assessed whether increased SMA activity during preparation might facilitate such improvement. Methods: Effects of instructed arm swing on cortical activity, muscle activity and kinematics were assessed by ambulant EEG, EMG, accelerometers and video in 17 Parkinson patients and 19 controls. At baseline, all participants repeatedly started walking after a simple auditory cue. Next, patients started walking at this cue, which now meant starting with enhanced arm swing. EEG changes over the putative SMA and leg motor cortex were assessed by event related spectral perturbation (ERSP) analysis of recordings at Fz and Cz. Results: Over the putative SMA location (Fz), natural PD gait initiation showed enhanced alpha/theta synchronization around the auditory cue, and reduced alpha/beta desynchronization during gait preparation and movement onset, compared to controls. Leg muscle activity in patients was reduced during preparation and movement onset, while the latter was delayed compared to controls. When starting with enhanced arm swing, these group differences virtually disappeared. Conclusion: Instructed arm swing improves Parkinson gait initiation. ERSP normalization around the cue indicates that the attributed information may serve as a semi-internal cue, recruiting an internalized motor program to overcome initiation difficulties.

Combination of Hand and Gaze Signals During Reaching: Activity in Parietal Area 7m of the Monkey

1997 ◽  
Vol 77 (2) ◽  
pp. 1034-1038 ◽  
Author(s):  
S. Ferraina ◽  
P. B. Johnson ◽  
M. R. Garasto ◽  
A. Battaglia-Mayer ◽  
L. Ercolani ◽  
...  
Keyword(s):  
Visual Angle ◽  
Cell Activity ◽  
Target Localization ◽  
Hand Position ◽  
Eye Position ◽  
Peripheral Target ◽  
Central Target ◽  
The Third ◽  
Parietal Area

Ferraina, S., P. B. Johnson, M. R. Garasto, A. Battaglia-Mayer, L. Ercolani, L. Bianchi, F. Lacquaniti, and R. Caminiti. Combination of hand and gaze signals during reaching: activity in parietal area 7m of the monkey. J. Neurophysiol. 77: 1034–1038, 1997. The role of area 7m has been studied by recording the activity of single neurons of monkeys trained to fixate and reach toward peripheral targets. The target was randomly selected from eight possible locations on a virtual circle, of radius 30° visual angle from a central target. Three tasks were employed to dissociate hand- from eye-related contributions. In the first task, animals looked and reached to the peripheral target. In a second task, the animal reached to the peripheral target while maintaining fixation on the central target. In the third task, the monkey maintained fixation on peripheral targets that were spatially coincident with those of the reaching tasks. The results show that cell activity in area 7m relates, for some cells to eye position, for others to hand position and movement, and for the majority of cells to a combination of visuomanual and oculomotor information. This area, therefore, seems to perform an early combination of information in the processing leading from target localization to movement generation.

Visual Remapping by Vector Subtraction: Analysis of Multiplicative Gain Field Models

2007 ◽  
Vol 19 (9) ◽  
pp. 2353-2386 ◽  
Author(s):  
Carlos R. Cassanello ◽  
Vincent P. Ferrera
Keyword(s):  
Target Location ◽  
Target Position ◽  
Saccadic Eye Movements ◽  
Neural Mechanism ◽  
Spatial Modulation ◽  
Eye Position ◽  
Retinal Position ◽  
Population Activity ◽  
Firing Rates ◽  
The Brain

Saccadic eye movements remain spatially accurate even when the target becomes invisible and the initial eye position is perturbed. The brain accomplishes this in part by remapping the remembered target location in retinal coordinates. The computation that underlies this visual remapping is approximated by vector subtraction: the original saccade vector is updated by subtracting the vector corresponding to the intervening eye movement. The neural mechanism by which vector subtraction is implemented is not fully understood. Here, we investigate vector subtraction within a framework in which eye position and retinal target position signals interact multiplicatively (gain field). When the eyes move, they induce a spatial modulation of the firing rates across a retinotopic map of neurons. The updated saccade metric can be read from the shift of the peak of the population activity across the map. This model uses a quasi-linear (half-rectified) dependence on the eye position and requires the slope of the eye position input to be negatively proportional to the preferred retinal position of each neuron. We derive analytically this constraint and study its range of validity. We discuss how this mechanism relates to experimental results reported in the frontal eye fields of macaque monkeys.

Dynamic Representation of Eye Position in the Parieto-Occipital Sulcus

1999 ◽  
Vol 81 (5) ◽  
pp. 2374-2385 ◽  
Author(s):  
K. Nakamura ◽  
H. H. Chung ◽  
M.S.A. Graziano ◽  
C. G. Gross
Keyword(s):  
Eye Movement ◽  
Target Location ◽  
Visual Stimulation ◽  
Eye Position ◽  
Restricted Range ◽  
Fixation Light ◽  
Dynamic Representation ◽  
Target Locations ◽  
Field Area ◽  
Stimulation Of

Dynamic representation of eye position in the parieto-occipital sulcus. Area V6A, on the anterior bank of the parieto-occipital sulcus of the monkey brain, contains neurons sensitive both to visual stimulation and to the position and movement of the eyes. We examined the effects of eye position and eye movement on the activity of V6A neurons in monkeys trained to saccade to and fixate on target locations. Forty-eight percent of the neurons responded during these tasks. The responses were not caused by the visual stimulation of the fixation light because extinguishing the fixation light had no effect. Instead the neurons responded in relation to the position of the eye during fixation. Some neurons preferred a restricted range of eye positions, whereas others had more complex and distributed eye-position fields. None of these eye-related neurons responded before or during saccades. They all responded postsaccadically during fixation on the target location. However, the neurons did not simply encode the static position of the eyes. Instead most (88%) responded best after the eye saccaded into the eye-position field and responded significantly less well when the eye made a saccade that was entirely contained within the eye-position field. Furthermore, for many eye-position cells (45%), the response was greatest immediately after the eye reached the preferred position and was significantly reduced after 500 ms of fixation. Thus these neurons preferentially encoded the initial arrival of the eye into the eye-position field rather than the continued presence or the movement of the eye within the eye-position field. Area V6A therefore contains a representation of the position of the eye in the orbit, but this representation appears to be dynamic, emphasizing the arrival of the eye at a new position.

scholarly journals Predictive encoding of moving target trajectory by neurons in the parabigeminal nucleus

2013 ◽  
Vol 109 (8) ◽  
pp. 2029-2043 ◽  
Author(s):  
Rui Ma ◽  
He Cui ◽  
Sang-Hun Lee ◽  
Thomas J. Anastasio ◽  
Joseph G. Malpeli
Keyword(s):  
Moving Objects ◽  
Target Location ◽  
Dynamic Range ◽  
Target Position ◽  
Eye Position ◽  
Position Information ◽  
Target Trajectory ◽  
Parabigeminal Nucleus ◽  
Predictor Corrector ◽  
The Relationship

Intercepting momentarily invisible moving objects requires internally generated estimations of target trajectory. We demonstrate here that the parabigeminal nucleus (PBN) encodes such estimations, combining sensory representations of target location, extrapolated positions of briefly obscured targets, and eye position information. Cui and Malpeli (Cui H, Malpeli JG. J Neurophysiol 89: 3128–3142, 2003) reported that PBN activity for continuously visible tracked targets is determined by retinotopic target position. Here we show that when cats tracked moving, blinking targets the relationship between activity and target position was similar for ON and OFF phases (400 ms for each phase). The dynamic range of activity evoked by virtual targets was 94% of that of real targets for the first 200 ms after target offset and 64% for the next 200 ms. Activity peaked at about the same best target position for both real and virtual targets. PBN encoding of target position takes into account changes in eye position resulting from saccades, even without visual feedback. Since PBN response fields are retinotopically organized, our results suggest that activity foci associated with real and virtual targets at a given target position lie in the same physical location in the PBN, i.e., a retinotopic as well as a rate encoding of virtual-target position. We also confirm that PBN activity is specific to the intended target of a saccade and is predictive of which target will be chosen if two are offered. A Bayesian predictor-corrector model is presented that conceptually explains the differences in the dynamic ranges of PBN neuronal activity evoked during tracking of real and virtual targets.

Saccade-Related Activity in the Parietal Reach Region

2000 ◽  
Vol 83 (2) ◽  
pp. 1099-1102 ◽  
Author(s):  
Lawrence H. Snyder ◽  
Aaron P. Batista ◽  
Richard A. Andersen
Keyword(s):  
Posterior Parietal Cortex ◽  
Cross Coupling ◽  
Delay Period ◽  
Frame Of Reference ◽  
Eye Position ◽  
Related Activity ◽  
Position Information ◽  
Posterior Parietal ◽  
Saccade Task ◽  
Hand Coordination

In previous experiments, we showed that cells in the parietal reach region (PRR) in monkey posterior parietal cortex code intended reaching movements in an eye-centered frame of reference. These cells are more active when an arm compared with an eye movement is being planned. Despite this clear preference for arm movements, we now report that PRR neurons also fire around the time of a saccade. Of 206 cells tested, 29% had perisaccadic activity in a delayed-saccade task. Two findings indicate that saccade-related activity does not reflect saccade planning or execution. First, activity is often peri- or postsaccadic but seldom presaccadic. Second, cells with saccade-related activity were no more likely to show strong saccadic delay period activity than cells without saccade-related activity. These findings indicate that PRR cells do not take part in saccade planning. Instead, the saccade-related activity in PRR may reflect cross-coupling between reach and saccade pathways that may be used to facilitate eye-hand coordination. Alternatively, saccade-related activity may reflect eye position information that could be used to maintain an eye-centered representation of intended reach targets across eye movements.

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