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Activity of Caudate Nucleus Neurons in a Visual Fixation Paradigm in Behaving Cats.

Nagypál T, Gombkötő P, Barkóczi B, Benedek G, Nagy A - PLoS ONE (2015)

Bottom Line: The majority of the recorded units were insensitive to the direction of the optic flow, regardless of group, but a small number of direction-sensitive neurons were also found.Our results demonstrate that both the static and the dynamic components of the visual information are represented in the CN.Furthermore, these results provide the first piece of evidence on optic flow processing in the CN, which, in more general terms, indicates the possible role of this structure in dynamic visual information processing.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Faculty of Medicine, University of Szeged, Szeged, Hungary.

ABSTRACT
Beside its motor functions, the caudate nucleus (CN), the main input structure of the basal ganglia, is also sensitive to various sensory modalities. The goal of the present study was to investigate the effects of visual stimulation on the CN by using a behaving, head-restrained, eye movement-controlled feline model developed recently for this purpose. Extracellular multielectrode recordings were made from the CN of two cats in a visual fixation paradigm applying static and dynamic stimuli. The recorded neurons were classified in three groups according to their electrophysiological properties: phasically active (PAN), tonically active (TAN) and high-firing (HFN) neurons. The response characteristics were investigated according to this classification. The PAN and TAN neurons were sensitive primarily to static stimuli, while the HFN neurons responded primarily to changes in the visual environment i.e. to optic flow and the offset of the stimuli. The HFNs were the most sensitive to visual stimulation; their responses were stronger than those of the PANs and TANs. The majority of the recorded units were insensitive to the direction of the optic flow, regardless of group, but a small number of direction-sensitive neurons were also found. Our results demonstrate that both the static and the dynamic components of the visual information are represented in the CN. Furthermore, these results provide the first piece of evidence on optic flow processing in the CN, which, in more general terms, indicates the possible role of this structure in dynamic visual information processing.

No MeSH data available.


Related in: MedlinePlus

Autocorrelograms of the CN neurons.Neurons were classified on the basis of the shape of their autocorrelograms (at 100 ms and 1000 ms time resolutions), propISI>2sec and the background discharge rate in three big groups (PAN, HFN, TAN). Neurons belonging to each group have characteristic autocorrelogram. PANs are usually characterized by peaky autocorrelogram (A,B). HFNs have autocorrelograms with a blunt peak (C,D) and TANs are characterized by a deep gap in the autocorrelogram (E,F).
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pone.0142526.g002: Autocorrelograms of the CN neurons.Neurons were classified on the basis of the shape of their autocorrelograms (at 100 ms and 1000 ms time resolutions), propISI>2sec and the background discharge rate in three big groups (PAN, HFN, TAN). Neurons belonging to each group have characteristic autocorrelogram. PANs are usually characterized by peaky autocorrelogram (A,B). HFNs have autocorrelograms with a blunt peak (C,D) and TANs are characterized by a deep gap in the autocorrelogram (E,F).

Mentions: We intended to classify the CN neurons in functional groups by their electrophysiological properties. It is known from rat and primate studies that spontaneous activity, the proportion of the summed values over 2 seconds divided by the total session time in the interspike intervals (propISI>2sec), and the shape of the autocorrelogram at different time resolutions (100ms, 1000 ms) can be used to classify the CN neurons in different groups [16, 18]. The above mentioned electrophysiological parameters were calculated for each recorded CN unit. The spontaneous discharge rate of each neuron was calculated based on the last 3000 ms period of the intertrial intervals. In this way, the recorded neurons could be classified in three groups (Fig 2): PANs are characterized by peaky autocorrelogram and ISI values over 2 seconds. The propISI>2sec was usually higher than 0.5, and the spontaneous discharge rate was low, in most cases under 3 spikes/sec. The HFNs have autocorrelograms with a blunt peak, the propISI>2sec is lower than 0.5, and the spontaneous discharge rate is higher than 5 spikes/sec. Finally, TANs are characterized by a deep gap in the autocorrelogram, the propISI>2sec is lower than 0.5, and the spontaneous discharge rate is between 2 and 12 spikes/sec.


Activity of Caudate Nucleus Neurons in a Visual Fixation Paradigm in Behaving Cats.

Nagypál T, Gombkötő P, Barkóczi B, Benedek G, Nagy A - PLoS ONE (2015)

Autocorrelograms of the CN neurons.Neurons were classified on the basis of the shape of their autocorrelograms (at 100 ms and 1000 ms time resolutions), propISI>2sec and the background discharge rate in three big groups (PAN, HFN, TAN). Neurons belonging to each group have characteristic autocorrelogram. PANs are usually characterized by peaky autocorrelogram (A,B). HFNs have autocorrelograms with a blunt peak (C,D) and TANs are characterized by a deep gap in the autocorrelogram (E,F).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4636356&req=5

pone.0142526.g002: Autocorrelograms of the CN neurons.Neurons were classified on the basis of the shape of their autocorrelograms (at 100 ms and 1000 ms time resolutions), propISI>2sec and the background discharge rate in three big groups (PAN, HFN, TAN). Neurons belonging to each group have characteristic autocorrelogram. PANs are usually characterized by peaky autocorrelogram (A,B). HFNs have autocorrelograms with a blunt peak (C,D) and TANs are characterized by a deep gap in the autocorrelogram (E,F).
Mentions: We intended to classify the CN neurons in functional groups by their electrophysiological properties. It is known from rat and primate studies that spontaneous activity, the proportion of the summed values over 2 seconds divided by the total session time in the interspike intervals (propISI>2sec), and the shape of the autocorrelogram at different time resolutions (100ms, 1000 ms) can be used to classify the CN neurons in different groups [16, 18]. The above mentioned electrophysiological parameters were calculated for each recorded CN unit. The spontaneous discharge rate of each neuron was calculated based on the last 3000 ms period of the intertrial intervals. In this way, the recorded neurons could be classified in three groups (Fig 2): PANs are characterized by peaky autocorrelogram and ISI values over 2 seconds. The propISI>2sec was usually higher than 0.5, and the spontaneous discharge rate was low, in most cases under 3 spikes/sec. The HFNs have autocorrelograms with a blunt peak, the propISI>2sec is lower than 0.5, and the spontaneous discharge rate is higher than 5 spikes/sec. Finally, TANs are characterized by a deep gap in the autocorrelogram, the propISI>2sec is lower than 0.5, and the spontaneous discharge rate is between 2 and 12 spikes/sec.

Bottom Line: The majority of the recorded units were insensitive to the direction of the optic flow, regardless of group, but a small number of direction-sensitive neurons were also found.Our results demonstrate that both the static and the dynamic components of the visual information are represented in the CN.Furthermore, these results provide the first piece of evidence on optic flow processing in the CN, which, in more general terms, indicates the possible role of this structure in dynamic visual information processing.

View Article: PubMed Central - PubMed

Affiliation: Department of Physiology, Faculty of Medicine, University of Szeged, Szeged, Hungary.

ABSTRACT
Beside its motor functions, the caudate nucleus (CN), the main input structure of the basal ganglia, is also sensitive to various sensory modalities. The goal of the present study was to investigate the effects of visual stimulation on the CN by using a behaving, head-restrained, eye movement-controlled feline model developed recently for this purpose. Extracellular multielectrode recordings were made from the CN of two cats in a visual fixation paradigm applying static and dynamic stimuli. The recorded neurons were classified in three groups according to their electrophysiological properties: phasically active (PAN), tonically active (TAN) and high-firing (HFN) neurons. The response characteristics were investigated according to this classification. The PAN and TAN neurons were sensitive primarily to static stimuli, while the HFN neurons responded primarily to changes in the visual environment i.e. to optic flow and the offset of the stimuli. The HFNs were the most sensitive to visual stimulation; their responses were stronger than those of the PANs and TANs. The majority of the recorded units were insensitive to the direction of the optic flow, regardless of group, but a small number of direction-sensitive neurons were also found. Our results demonstrate that both the static and the dynamic components of the visual information are represented in the CN. Furthermore, these results provide the first piece of evidence on optic flow processing in the CN, which, in more general terms, indicates the possible role of this structure in dynamic visual information processing.

No MeSH data available.


Related in: MedlinePlus