Effect of optic nerve stimulation on neurons in pericruciate cortex of cats (original) (raw)
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Journal of neurophysiology, 1988
1. We recorded intracellularly from X and Y cells of the cat's lateral geniculate nucleus and measured the postsynaptic potentials (PSPs) evoked from electrical stimulation of the optic chiasm. We used an in vivo preparation and computer averaged the PSPs to enhance their signal-to-noise ratio. 2. The vast majority (46 of 50) of our sample of X and Y cells responded to stimulation of the optic chiasm with an excitatory postsynaptic potential (EPSP) followed by an inhibitory postsynaptic potential (IPSP); these were tentatively identified as relay cells. We quantified several parameters of these PSPs, including amplitude, latency, time to peak (i.e., rise time), and duration. 3. Among the relay cells, the latencies of both the EPSP and action potential evoked by optic chiasm stimulation were shorter in Y cells than in X cells. Furthermore, the difference between the latencies of the EPSP and action potential was shorter for Y cells than for X cells. This means that the EPSPs gene...
The effect of reticular stimulation on spontaneous and evoked activity in the cat visual cortex
Brain Research, 1976
The mesencephalic reticular formation (MRF) of cats anesthetized with NeO was stimulated electrically, and the effects of this stimulation on activity in the striate cortex were studied. The variations of intra-and extracellularly recorded unit activity and the changes in the extracellular potassium concentration were investigated. At all levels of analysis the prevailing effect of MRF stimulation was facilitation. Half of the cells reacted with brief bursts of activity to reticular stimuli. A decrease of resting activity was rare. The cells activated by MRF stimulation had in common: (l) to show a high degree of excitatory convergence from extrinsic and intrinsic afferents, (2) to possess often corticofugal axons, and (3) to have preferentially complex receptive fields. In the large majority of cortical cells MRF stimulation facilitated responses evoked by stimulation of the optic radiation or by light stimuli. This facilitation could lead to a loss of orientation and direction selectivity. Reticular activation further led to a large increase of the extracellular potassium concentration, whereas stimulation of specific afferents led to a decrease.
Visual response properties and afferents of nucleus of the optic tract in the ferret
Experimental Brain Research, 1990
Basic properties of responses to visual stimulation with large moving random dot patterns were studied in ferret nucleus of the optic tract. Retinal input to NOT was assessed by orthodromic electrical stimulation of the optic chiasm and optic nerves. Presence of an input from visual cortex was tested by orthodromic electrical stimulation of ipsilateral area 17. All 51 NOT neurons studied displayed a non-habituating, clearly directionspecific response: discharge rate strongly increased with the stimulus pattern moving horizontally in ipsiversive direction (motion directed towards the recorded hemisphere) and decreased with contraversive stimulus motion. Most latencies to visual stimulation ranged from 80 to 100 ms. Velocity tuning was studied using stimulus velocities between 4 deg/s and 100 deg/s. Discharge rates were most effectively modulated at a stimulus velocity of 20 deg/s. A large portion of the cells studied (91%) could be binocularly activated, although for almost all neurons the contralateral eye was dominant. Through stimulation of the optic chiasm 46 out of 51 NOT neurons could be electrically activated with a latency of 5.42~:0.66 ms (mean 4-SD). For 15 fibers stimulated from both optic chiasm and contralateral optic nerve, conduction velocities between 2.5 and 8.9 m/s, with a mean of 5.1 m/s, were obtained. A major direct input from the ipsilateral retina was not found. Furthermore, 65% of all neurons could be activated through electrical stimulation of visual cortex with a mean latency of 3.7:t: 1.5 ms, indicating a strong cortical projection to ferret NOT. The functional relevance of response properties of ferret NOT neurons for horizontal optokinetic nystagmus is discussed. Parameters that could be related to formation of a corticopretectal projection in mammals are considered.
Experimental Brain Research, 1986
Experiments were performed to examine the responses of cortical neurons in the pericruciate cortex to cutaneous afferent input from the distal forepaw. Ninty-nine cortical ncurons responding to electrical stimulation of the forepaw were recorded from four cats. Their response latencies ranged from 6 to 23 ms. The units had cutandous receptive fields which ranged in size from those restricted to one digit to those extending over the whole forelimb. They were recorded from area 4 and area 3. Intracortical microstimulation at the recording sitcs activated either the distal or proximal musculature of the forelimb. When the charactcristics obtained from cach recording site were examined as a group of features, a uniform population emerged which was significantly different from the rest of the sample. These units had 1) the shortest latency responses to distal forepaw electrical stimulation, 2) the shortest duration of evoked discharge, 3) the smallest distal cutaneous receptive fields. Such units were recorded at the border between areas 3 and 4, at sites which on microstimulation resulted in movements of the distal forepaw musculature.
Brain Research, 1973
(20-25 m/sec). The minority of collicular cells responded with very short latencies after optic chlasm stimulation indicating that they are activated by the fastest optic tract axons, which are the axons of Y-cells in the retina. Most colhcular cells are activated with very long latencies (6 msec) after stimulation in the optic chlasm, i.e. retinal axons running to the colliculus seem to be very slowly conducting (< 15 m/sec), even more slowly than X-cell axons. To demonstrate the existence of substantial numbers of retinal ganglion cells with slow axons projecting to the colhculus, we conducted two kinds of experiments. (l) A large number of cells were recorded m the colhculus and stimulation was apphed along the retlno-tectal pathway at 3 sites: optic disc, optic chmsm and optic tract close to the LGN. From the latency differences recorded in the same cell for the 3 sites, we calculated the conduction velocities in the optic nerve of fibres running to the colliculus. We found two groups: very fast Y-fibres and very slowly conducting fibres which we termed W-axons. (2) Retinal ganglion cells were recorded and electrical stimulation was applied at the optic chmsm, optic tract and superior colhculus. X-and Y-cells in the retina could be antidromically stimulated from the optic chlasm and optic tract just below LGN. This, of course, is in agreement with the finding that X-and Y-axons from the retina terminate on X-and Y-type cells in the LGN. Wand Y-cells in the retina, but no X-cells, could be antldromlcally activated from the superior colhculus. The conduction velocities measured antldromically Ill the retina for W-axons are in agreement with the conduction velocity of the majority of the retinal fibres running to the superior colliculus. Retinal ganglion cells with &fferent receptive field types and conduction velocities of their axons have separate central destinations. The axons of Y-cells bifurcate m the optic tract sending one branch into the LGN and the other into the superior colliculus. The axons of X-cells terminate m the LGN but not in the colliculus, and the axons of W-cells terminate in the colhculus and presumably not m LGN. On the effect of reticular stimulation and saccadic eye movements on transmission in cat lateral geniculate nucleus
Visual classification of X and Y perigeniculate neurons of the cat
Experimental brain research, 1994
The spike activity of perigeniculate cells evoked by small light spots flashing along the axes of their receptive fields was recorded and presented in response planes. This method allowed the investigated neurons to be grouped into two classes characterized by (1) large receptive fields and phasic-like responses and (2) small fields and tonic responses. The latency measurements for stimulation of the optic chiasma and visual cortex revealed that the cells from the first group are excited by fast, Y fibers and the second by slow, X axons. The spatial tuning curves of the second harmonic component, as measured from the responses of the cells from the two groups for slowly moving square gratings, are also different. We conclude that the X and Y systems of the visual pathway are segregated at the level of the perigeniculate nucleus.
Modulation of synaptic transmission in cat's superior colliculus by saccadic eye movements
Brain Research, 1974
In the search for neurophysiological correlates for saccadic suppressionT, 15,16, the findings have been reported that visually evoked responses of the lateral geniculate body (LGB) 1,6 and visual cortex (VC) 1,a,9 are more or less suppressed during eye movements. The present study was undertaken for the same purpose. Observations were made on responses of the superior colliculus (SC) to electrical stimulation of the peripheral visual pathway in awake cats carrying chronically implanted electrodes.
Visual responses of neurons in the Clare-Bishop area of the cat
PubMed, 1975
Single unit responses in the Clare-Bishop area of the pretrigeminal cat were analyzed using stationary and moving visual stimuli. Of the units responding, 80 percent could be influenced by a 0.5 s diffuse flash, most displaying inhibition or excitation to both "on" and "off". In most units responses to stationary shapes were not very specific. Responses to moving stimuli were strong and directional preference was usually present. For the majority of cells the optimal speed of movement was in the range from 100 to 800 deg/s, and some cells preserved their direction preferences when the speed was over 1,500 deg/s. The direction preference could be reversed depending on the speed of movement, location in the receptive field or the shape of stimulus.
Temporal distribution of the ganglion cell volleys in the normal rat optic nerve
Proceedings of The National Academy of Sciences, 2000
We describe experiments on behaving rats with electrodes implanted on the cornea, in the optic chiasm, and on the visual cortex; in addition, two red light-emitting diodes (LED) are permanently attached to the skull over the left eye. Recordings timelocked to the LED flashes reveal both the local events at each electrode site and the orderly transfer of visual information from retina to cortex. The major finding is that every stimulus, regardless of its luminance, duration, or the state of retinal light adaptation, elicits an optic nerve volley with a latency of about 10 ms and a duration of about 300 ms. This phenomenon has not been reported previously, so far as we are aware. We conclude that the retina, which originates from the forebrain of the developing embryo, behaves like a typical brain structure: it translates, within a few hundred milliseconds, the chemical information in each pattern of bleached photoreceptors into a corresponding pattern of ganglion cell neuronal information that leaves via the optic nerve. The attributes of each rat ganglion cell appear to include whether the retinal neuropile calls on it to leave after a stimulus and, if so when, within a 300-ms poststimulus epoch. The resulting retinal analysis of the scene, on arrival at the cortical level, is presumed to participate importantly in the creation of visual perceptual experiences.
Pericruciate fibres to the red nucleus and to the medial bulbar reticular formation
Neuroscience, 1994
Extracellular single activity was recorded from pericruciate neurons in anaesthetized, paralysed, artificially ventilated cats. A total of 455 neurons were classified antidromically according to their sites of termination along the corticospinal tract and whether they sent collateral branches to the ipsilateral red nucleus and/or to the contralateral nucleus reticularis gigantocellularis. It was found that the majority of the branching fibres that reached the most caudal segments of the cord were fast conducting, while the slower branching axons tended to terminate at more rostra1 levels of the corticospinal tract. Most of the branching fibres terminated al bulbar and cervical levels (153/182: 84%), and the remaining ended at thoracic (21/182: 11.5%) and at lumbar (8/182: 4.4%) segments of the cord. The non-corticospinal, pyramidal tract fibres branched more (56%) than the corticospinal fibres (26.6%). Within the corticospinal neurons, the degree of branching decreased with distance along the spinal cord. While 57.5% of the pericruciate fibres that projected only as far as the pyramidal tract were slow conducting, the majority of the corticospinal neurons were fast conducting (74.6%). Both pyramidal tract and corticospinal neurons that sent branches to one or to the two sites tested were significantly faster conducting than the neurons which did not branch. A total of 101 corticorubral and corticobulbar neurons which did not respond to pyramidal tract stimulation was also recorded.