Abnormal neuronal responses during evolution of a penicillin epileptic focus in cat visual cortex

1975 ◽  
Vol 38 (2) ◽  
pp. 250-256 ◽  
Author(s):  
J. S. Ebersole ◽  
R. A. Levine

After defining the receptive fields of single units in cortical area 17 of anesthetized cats, recurrent on-off stimulation with bars of light of optimal configuration win from a second micropipette; Progressively, three distinct alterations of neuronal activity developed. The most longlasting and usually the earliest abnormality was an increase in the number and frequency of spikes comprising a neuron's response to stimuli that were effective prior to iontophoresis. This enhanced physiologic response (EPR) could be elicited from a cell independently of the discharge activity of an induced focus, but only with stimuli appropriate for the cell's receptive field. With additional iontophoresis an entirely new response developed, which was consistent with an extracellular paroxysmal depolarization shift (PDS). This high-frequency burst of spikes appeared only in association with an ECoG interictal potential. It could be triggered, however, by stimuli which were previously effective or ineffective, as well as occur spontaneously. Characteristics which further distinguished the PDS from EPR included a longer and more-variable latency, a longer recovery period, and a different sensitivity to changes of stimulus intensity. A period of response inhibition also accompanied each interictal potential and persisted with a variable duration afterward. It was most noticeable as an interruption in the activity of tonically responding neurons and was often present before the cell began to generate PDSs. It was concluded that the EPR represents a direct effect of penicillin on the cell or its immediate synaptic connections, while the PDS appears dependent on the altered interactions within a population of such affected cells. The inhibitory phenomenon, in addition, seems a result of projected influences from cells more fully involved with the developing focus. A dynamic model of the EPR-PDS relationship is proposed.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Estefanía Hernandez-Martin ◽  
Enrique Arguelles ◽  
Yifei Zheng ◽  
Ruta Deshpande ◽  
Terence D. Sanger

AbstractHigh-frequency peripheral nerve stimulation has emerged as a noninvasive alternative to thalamic deep brain stimulation for some patients with essential tremor. It is not known whether such techniques might be effective for movement disorders in children, nor is the mechanism and transmission of the peripheral stimuli to central brain structures understood. This study was designed to investigate the fidelity of transmission from peripheral nerves to thalamic nuclei in children with dystonia undergoing deep brain stimulation surgery. The ventralis intermediate (VIM) thalamus nuclei showed a robust evoked response to peripheral high-frequency burst stimulation, with a greatest response magnitude to intra-burst frequencies between 50 and 100 Hz, and reliable but smaller responses up to 170 Hz. The earliest response occurred at 12–15 ms following stimulation onset, suggesting rapid high-fidelity transmission between peripheral nerve and thalamic nuclei. A high-bandwidth, low-latency transmission path from peripheral nerve to VIM thalamus is consistent with the importance of rapid and accurate sensory information for the control of coordination and movement via the cerebello-thalamo-cortical pathway. Our results suggest the possibility of non-invasive modulation of thalamic activity in children with dystonia, and therefore the possibility that a subset of children could have beneficial clinical response without the need for invasive deep brain stimulation.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Christiaan P. J. de Kock ◽  
Jean Pie ◽  
Anton W. Pieneman ◽  
Rebecca A. Mease ◽  
Arco Bast ◽  
...  

AbstractDiversity of cell-types that collectively shape the cortical microcircuit ensures the necessary computational richness to orchestrate a wide variety of behaviors. The information content embedded in spiking activity of identified cell-types remain unclear to a large extent. Here, we recorded spike responses upon whisker touch of anatomically identified excitatory cell-types in primary somatosensory cortex in naive, untrained rats. We find major differences across layers and cell-types. The temporal structure of spontaneous spiking contains high-frequency bursts (≥100 Hz) in all morphological cell-types but a significant increase upon whisker touch is restricted to layer L5 thick-tufted pyramids (L5tts) and thus provides a distinct neurophysiological signature. We find that whisker touch can also be decoded from L5tt bursting, but not from other cell-types. We observed high-frequency bursts in L5tts projecting to different subcortical regions, including thalamus, midbrain and brainstem. We conclude that bursts in L5tts allow accurate coding and decoding of exploratory whisker touch.


Science ◽  
2015 ◽  
Vol 350 (6256) ◽  
pp. 98-101 ◽  
Author(s):  
Masahiro Sawada ◽  
Kenji Kato ◽  
Takeharu Kunieda ◽  
Nobuhiro Mikuni ◽  
Susumu Miyamoto ◽  
...  

Motivation facilitates recovery after neuronal damage, but its mechanism is elusive. It is generally thought that the nucleus accumbens (NAc) regulates motivation-driven effort but is not involved in the direct control of movement. Using causality analysis, we identified the flow of activity from the NAc to the sensorimotor cortex (SMC) during the recovery of dexterous finger movements after spinal cord injury at the cervical level in macaque monkeys. Furthermore, reversible pharmacological inactivation of the NAc during the early recovery period diminished high-frequency oscillatory activity in the SMC, which was accompanied by a transient deficit of amelioration in finger dexterity obtained by rehabilitation. These results demonstrate that during recovery after spinal damage, the NAc up-regulates the high-frequency activity of the SMC and is directly involved in the control of finger movements.


2001 ◽  
Vol 204 (21) ◽  
pp. 3693-3702 ◽  
Author(s):  
Mark A. Frye

SUMMARYTo characterize the in vivo responses of the wing hinge stretch receptor of Manduca sexta, I recorded its activity and simultaneously tracked the up-and-down motion of the wing while the hawkmoth flew tethered in a wind tunnel. The stretch receptor fires a high-frequency burst of spikes near each dorsal stroke reversal. The onset of the burst is tightly tuned to a set-point in wing elevation, and the number of spikes contained within the burst encodes the maximal degree of wing elevation during the stroke. In an effort to characterize its mechanical encoding properties, I constructed an actuator that delivered deformations to the wing hinge and simultaneously recorded the resultant stretch and tension and the activity of the stretch receptor. Stimuli included stepwise changes in length as well as more natural dynamic deformation that was measured in vivo. Step changes in length reveal that the stretch receptor encodes the static amplitude of stretch with both phasic and tonic firing dynamics. In vivo sinusoidal deformation revealed (i) that the timing of stretch receptor activity is tightly phase-locked within the oscillation cycle, (ii) that the number of spikes per burst is inversely related to oscillation frequency and (iii) that the instantaneous frequency of the burst increases with oscillation rate. At all oscillation rates tested, the instantaneous frequency of the burst increases with amplitude.


2008 ◽  
Vol 100 (3) ◽  
pp. 1622-1634 ◽  
Author(s):  
Ling Qin ◽  
JingYu Wang ◽  
Yu Sato

Previous studies in anesthetized animals reported that the primary auditory cortex (A1) showed homogenous phasic responses to FM tones, namely a transient response to a particular instantaneous frequency when FM sweeps traversed a neuron's tone-evoked receptive field (TRF). Here, in awake cats, we report that A1 cells exhibit heterogeneous FM responses, consisting of three patterns. The first is continuous firing when a slow FM sweep traverses the receptive field of a cell with a sustained tonal response. The duration and amplitude of FM response decrease with increasing sweep speed. The second pattern is transient firing corresponding to the cell's phasic tonal response. This response could be evoked only by a fast FM sweep through the cell's TRF, suggesting a preference for fast FM. The third pattern was associated with the off response to pure tones and was composed of several discrete response peaks during slow FM stimulus. These peaks were not predictable from the cell's tonal response but reliably reflected the time when FM swept across specific frequencies. Our A1 samples often exhibited a complex response pattern, combining two or three of the basic patterns above, resulting in a heterogeneous response population. The diversity of FM responses suggests that A1 use multiple mechanisms to fully represent the whole range of FM parameters, including frequency extent, sweep speed, and direction.


2017 ◽  
Vol 138 ◽  
pp. 46-52 ◽  
Author(s):  
C.Á. Szabó ◽  
F.S. Salinas ◽  
A.M. Papanastassiou ◽  
J. Begnaud ◽  
M. Ravan ◽  
...  

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Bram-Ernst Verhoef ◽  
John HR Maunsell

Shifting attention among visual stimuli at different locations modulates neuronal responses in heterogeneous ways, depending on where those stimuli lie within the receptive fields of neurons. Yet how attention interacts with the receptive-field structure of cortical neurons remains unclear. We measured neuronal responses in area V4 while monkeys shifted their attention among stimuli placed in different locations within and around neuronal receptive fields. We found that attention interacts uniformly with the spatially-varying excitation and suppression associated with the receptive field. This interaction explained the large variability in attention modulation across neurons, and a non-additive relationship among stimulus selectivity, stimulus-induced suppression and attention modulation that has not been previously described. A spatially-tuned normalization model precisely accounted for all observed attention modulations and for the spatial summation properties of neurons. These results provide a unified account of spatial summation and attention-related modulation across both the classical receptive field and the surround.


2019 ◽  
Vol 11 (514) ◽  
pp. eaax7830 ◽  
Author(s):  
Su Liu ◽  
Josef Parvizi

Epileptic brain tissue is often considered physiologically dysfunctional, and the optimal treatment of many patients with uncontrollable seizures involves surgical removal of the epileptic tissue. However, it is unclear to what extent the epileptic tissue is capable of generating physiological responses to cognitive stimuli and how cognitive deficits ensuing surgical resections can be determined using state-of-the-art computational methods. To address these unknowns, we recruited six patients with nonlesional epilepsies and identified the epileptic focus in each patient with intracranial electrophysiological monitoring. We measured spontaneous epileptic activity in the form of high-frequency oscillations (HFOs), recorded stimulus-locked physiological responses in the form of physiological high-frequency broadband activity, and explored the interaction of the two as well as their behavioral correlates. Across all patients, we found abundant normal physiological responses to relevant cognitive stimuli in the epileptic sites. However, these physiological responses were more likely to be “seized” (delayed or missed) when spontaneous HFOs occurred about 850 to 1050 ms before, until about 150 to 250 ms after, the onset of relevant cognitive stimuli. Furthermore, spontaneous HFOs in medial temporal lobe affected the subjects’ memory performance. Our findings suggest that nonlesional epileptic sites are capable of generating normal physiological responses and highlight a compelling mechanism for cognitive deficits in these patients. The results also offer clinicians a quantitative tool to differentiate pathological and physiological high-frequency activities in epileptic sites and to indirectly assess their possible cognitive reserve function and approximate the risk of resective surgery.


2000 ◽  
Vol 83 (6) ◽  
pp. 3430-3452 ◽  
Author(s):  
H.H.L.M. Goossens ◽  
A. J. Van Opstal

Trigeminal reflex blinks evoked near the onset of a saccade cause profound spatial-temporal perturbations of the saccade that are typically compensated in mid-flight. This paper investigates the influence of reflex blinks on the discharge properties of saccade-related burst neurons (SRBNs) in intermediate and deep layers of the monkey superior colliculus (SC). Twenty-nine SRBNs, recorded in three monkeys, were tested in the blink-perturbation paradigm. We report that the air puff stimuli, used to elicit blinks, resulted in a short-latency (∼10 ms) transient suppression of saccade-related SRBN activity. Shortly after this suppression (within 10–30 ms), all neurons resumed their activity, and their burst discharge then continued until the perturbed saccade ended near the extinguished target. This was found regardless whether the compensatory movement was into the cell's movement field or not. In the limited number of trials where no compensation occurred, the neurons typically stopped firing well before the end of the eye movement. Several aspects of the saccade-related activity could be further quantified for 25 SRBNs. It appeared that 1) the increase in duration of the high-frequency burst was well correlated with the (two- to threefold) increase in duration of the perturbed movement. 2) The number of spikes in the burst for control and perturbed saccades was quite similar. On average, the number of spikes increased only 14%, whereas the mean firing rate in the burst decreased by 52%. 3) An identical number of spikes were obtained between control and perturbed responses when burst and postsaccadic activity were both included in the spike count. 4) The decrease of the mean firing rate in the burst was well correlated with the decrease in the velocity of perturbed saccades. 5) Monotonic relations between instantaneous firing rate and dynamic motor error were obtained for control responses but not for perturbed responses. And 6) the high-frequency burst of SRBNs with short-lead and long-lead presaccadic activity (also referred to as burst and buildup neurons, respectively) showed very similar features. Our findings show that blinking interacts with the saccade premotor system already at the level of the SC. The data also indicate that a neural mechanism, rather than passive elastic restoring forces within the oculomotor plant, underlies the compensation for blink-related perturbations. We propose that these interactions occur downstream from the motor SC and that the latter may encode the desired displacement vector of the eyes by sending an approximately fixed number of spikes to the brainstem saccadic burst generator.


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