Marek Wypych - Academia.edu (original) (raw)

Papers by Marek Wypych

Research paper thumbnail of Sorting functional classes of evoked potentials by wavelets

Research paper thumbnail of Standardized F1 – A consistent measure of strength of modulation of visual responses to sine-wave drifting gratings

Vision Research, 2012

The magnitude of spike-responses of neurons in the mammalian visual system to sine-wave luminance... more The magnitude of spike-responses of neurons in the mammalian visual system to sine-wave luminance-contrast-modulated drifting gratings is modulated by the temporal frequency of the stimulation. However, there are serious problems with consistency and reliability of the traditionally used methods of assessment of strength of such modulation. Here we propose an intuitive and simple tool for assessment of the strength of modulations in the form of standardized F1 index, zF1. We define zF1 as the ratio of the difference between the F1 (component of amplitude spectrum of the spike-response at temporal frequency of stimulation) and the mean value of spectrum amplitudes to standard deviation along all frequencies in the spectrum. In order to assess the validity of this measure, we have: (1) examined behavior of zF1 using spike-responses to optimized drifting gratings of single neurons recorded from four 'visual' structures (area V1 of primary visual cortex, superior colliculus, suprageniculate nucleus and caudate nucleus) in the brain of commonly used visual mammal - domestic cat; (2) compared the behavior of zF1 with that of classical statistics commonly employed in the analysis of steady-state responses; (3) tested the zF1 index on simulated spike-trains generated with threshold-linear model. Our analyses indicate that zF1 is resistant to distortions due to the low spike count in responses and therefore can be particularly useful in the case of recordings from neurons with low firing rates and/or low net mean responses. While most V1 and a half of caudate neurons exhibit high zF1 indices, the majorities of collicular and suprageniculate neurons exhibit low zF1 indices. We conclude that despite the general shortcomings of measuring strength of modulation inherent in the linear system approach, zF1 can serve as a sensitive and easy to interpret tool for detection of modulation and assessment of its strength in responses of visual neurons.

Research paper thumbnail of Basic Emotions in the Nencki Affective Word List (NAWL BE): New Method of Classifying Emotional Stimuli

PloS one, 2015

The Nencki Affective Word List (NAWL) has recently been introduced as a standardized database of ... more The Nencki Affective Word List (NAWL) has recently been introduced as a standardized database of Polish words suitable for studying various aspects of language and emotions. Though the NAWL was originally based on the most commonly used dimensional approach, it is not the only way of studying emotions. Another framework is based on discrete emotional categories. Since the two perspectives are recognized as complementary, the aim of the present study was to supplement the NAWL database by the addition of categories corresponding to basic emotions. Thus, 2902 Polish words from the NAWL were presented to 265 subjects, who were instructed to rate them according to the intensity of each of the five basic emotions: happiness, anger, sadness, fear and disgust. The general characteristics of the present word database, as well as the relationships between the studied variables are shown to be consistent with typical patterns found in previous studies using similar databases for different lan...

Research paper thumbnail of Nencki Affective Word List (NAWL): the cultural adaptation of the Berlin Affective Word List-Reloaded (BAWL-R) for Polish

Behavior research methods, Jan 15, 2015

In the present article, we introduce the Nencki Affective Word List (NAWL), created in order to p... more In the present article, we introduce the Nencki Affective Word List (NAWL), created in order to provide researchers with a database of 2,902 Polish words, including nouns, verbs, and adjectives, with ratings of emotional valence, arousal, and imageability. Measures of several objective psycholinguistic features of the words (frequency, grammatical class, and number of letters) are also controlled. The database is a Polish adaptation of the Berlin Affective Word List-Reloaded (BAWL-R; Võ et al., Behavior Research Methods 41:534-538, 2009), commonly used to investigate the affective properties of German words. Affective normative ratings were collected from 266 Polish participants (136 women and 130 men). The emotional ratings and psycholinguistic indexes provided by NAWL can be used by researchers to better control the verbal materials they apply and to adjust them to specific experimental questions or issues of interest. The NAWL is freely accessible to the scientific community for ...

Research paper thumbnail of Surprising relation between spatio-temporal receptive field structure and direction preference of neurons in cat's superior colliculus

Research paper thumbnail of W poszukiwaniu mechanizmów preferencji kierunku ruchu bodźca przez neurony wzrokowe górnych warstw wzgórków górnych

Research paper thumbnail of Modelling the neural network of the upper layers of the superior colliculus

Research paper thumbnail of Modele niejednorodnych procesów punktowych a kodowanie informacji w układzie wzrokowym

Research paper thumbnail of Stimulus dependent oscillations in visually evoked activity of cat's superior colliculus

Research paper thumbnail of Beyond the PSTH: point process modeling of spike trains

Research paper thumbnail of Identyfikacja stanu funkcjonalnego mózgu przy pomocy nowych metod analizy potencjałów wywołanych

Research paper thumbnail of A new method for identification of modulation in neural responses to drifting grating stimulation

Research paper thumbnail of Standardized F1–A consistent measure of strength of modulation of visual responses to sine-wave drifting gratings

Research paper thumbnail of Spatio-temporal visual properties in the ascending tectofugal system

Central European Journal of Biology, 2009

Ourstudycomparesthespatio-temporalvisualreceptivefieldpropertiesofdifferentsubcorticalstagesofthe... more Ourstudycomparesthespatio-temporalvisualreceptivefieldpropertiesofdifferentsubcorticalstagesoftheascendingtectofugal visualsystem.Extracellularsingle-cellrecordingswereperformedinthesuperficial(SCs)andintermediate(SCi)layersofthesuperior colliculus(SC),thesuprageniculatenucleus(Sg)oftheposteriorthalamusandthecaudatenucleus(CN)ofhalothane-anesthetized cats.Neuronalresponsestodriftinggratingsofvariousspatialandtemporalfrequencieswererecorded.Theneuronsofeachstructure responded optimally to low spatial and high temporal frequencies and displayed narrow spatial and temporal frequency tuning. ThedetailedstatisticalanalysisrevealedthataccordingtoitsstimuluspreferencestheSCshasmarkedlydifferentspatio-temporal propertiesfromthehomogeneousgroupformedbytheSCi,SgandCN.TheSCsneuronspreferredhigherspatialandlowertemporal frequenciesandhadbroaderspatialtuningthantheotherstructures.IncontrasttotheSCsthevisuallyactiveSCi,aswellastheSg andtheCNneuronspossessedconsequentlysimilarspatio-temporalpreferences.Thesedatasupportourhypothesisthatthevisually activeSCi,SgandCNneuronsformahomogeneousneuronalpopulationgivenasimilarspatio-temporalfrequencypreferenceanda commonfunctioninprocessingofdynamicvisualinformation. ©VersitaWarsawandSpringer-VerlagBerlinHeidelberg.

Research paper thumbnail of Temporal frequency modulation of neuronal activity in the suprageniculate nucleus of the posterior thalamus

Frontiers in Behavioral Neuroscience, 2009

ABSTRACT http://www.frontiersin.org/10.3389/conf.neuro.08.2009.09.351/event\_abstract

Research paper thumbnail of Zmienność i modele stochastyczne odpowiedzi wzrokowych neuronów wzgórka czworaczego górnego kota

Research paper thumbnail of Spectral Characteristics of Phase Sensitivity and Discharge Rate of Neurons in the Ascending Tectofugal Visual System

PLoS ONE, 2014

Drifting gratings can modulate the activity of visual neurons at the temporal frequency of the st... more Drifting gratings can modulate the activity of visual neurons at the temporal frequency of the stimulus. In order to characterize the temporal frequency modulation in the cat's ascending tectofugal visual system, we recorded the activity of single neurons in the superior colliculus, the suprageniculate nucleus, and the anterior ectosylvian cortex during visual stimulation with drifting sine-wave gratings. In response to such stimuli, neurons in each structure showed an increase in firing rate and/or oscillatory modulated firing at the temporal frequency of the stimulus (phase sensitivity). To obtain a more complete characterization of the neural responses in spatiotemporal frequency domain, we analyzed the mean firing rate and the strength of the oscillatory modulations measured by the standardized Fourier component of the response at the temporal frequency of the stimulus. We show that the spatiotemporal stimulus parameters that elicit maximal oscillations often differ from those that elicit a maximal discharge rate. Furthermore, the temporal modulation and discharge-rate spectral receptive fields often do not overlap, suggesting that the detection range for visual stimuli provided jointly by modulated and unmodulated response components is larger than the range provided by a one response component.

Research paper thumbnail of Standardized F1 – A consistent measure of strength of modulation of visual responses to sine-wave drifting gratings

Vision Research, 2012

The magnitude of spike-responses of neurons in the mammalian visual system to sine-wave luminance... more The magnitude of spike-responses of neurons in the mammalian visual system to sine-wave luminance-contrast-modulated drifting gratings is modulated by the temporal frequency of the stimulation. However, there are serious problems with consistency and reliability of the traditionally used methods of assessment of strength of such modulation. Here we propose an intuitive and simple tool for assessment of the strength of modulations in the form of standardized F1 index, zF1. We define zF1 as the ratio of the difference between the F1 (component of amplitude spectrum of the spike-response at temporal frequency of stimulation) and the mean value of spectrum amplitudes to standard deviation along all frequencies in the spectrum. In order to assess the validity of this measure, we have: (1) examined behavior of zF1 using spike-responses to optimized drifting gratings of single neurons recorded from four 'visual' structures (area V1 of primary visual cortex, superior colliculus, suprageniculate nucleus and caudate nucleus) in the brain of commonly used visual mammal - domestic cat; (2) compared the behavior of zF1 with that of classical statistics commonly employed in the analysis of steady-state responses; (3) tested the zF1 index on simulated spike-trains generated with threshold-linear model. Our analyses indicate that zF1 is resistant to distortions due to the low spike count in responses and therefore can be particularly useful in the case of recordings from neurons with low firing rates and/or low net mean responses. While most V1 and a half of caudate neurons exhibit high zF1 indices, the majorities of collicular and suprageniculate neurons exhibit low zF1 indices. We conclude that despite the general shortcomings of measuring strength of modulation inherent in the linear system approach, zF1 can serve as a sensitive and easy to interpret tool for detection of modulation and assessment of its strength in responses of visual neurons.

Research paper thumbnail of Variability of Visual Responses of Superior Colliculus Neurons Depends on Stimulus Velocity

Journal of Neuroscience, 2010

Visually responding neurons in the superficial, retinorecipient layers of the cat superior collic... more Visually responding neurons in the superficial, retinorecipient layers of the cat superior colliculus receive input from two primarily parallel information processing channels, Y and W, which is reflected in their velocity response profiles. We quantified the timedependent variability of responses of these neurons to stimuli moving with different velocities by Fano factor (FF) calculated in discrete time windows. The FF for cells responding to low-velocity stimuli, thus receiving W inputs, increased with the increase in the firing rate. In contrast, the dynamics of activity of the cells responding to fast moving stimuli, processed by Y pathway, correlated negatively with FF whether the response was excitatory or suppressive. These observations were tested against several types of surrogate data. Whereas Poisson description failed to reproduce the variability of all collicular responses, the inclusion of secondary structure to the generating point process recovered most of the observed features of responses to fast moving stimuli. Neither model could reproduce the variability of low-velocity responses, which suggests that, in this case, more complex time dependencies need to be taken into account. Our results indicate that Y and W channels may differ in reliability of responses to visual stimulation. Apart from previously reported morphological and physiological differences of the cells belonging to Y and W channels, this is a new feature distinguishing these two pathways.

Research paper thumbnail of Spectral receptive field properties of visually active neurons in the caudate nucleus

Neuroscience Letters, 2010

Recent studies stress the importance of the caudate nucleus in visual information processing. Alt... more Recent studies stress the importance of the caudate nucleus in visual information processing. Although the processing of moving visual signals depends upon the capability of a system to integrate spatial and temporal information, no study has investigated the spectral receptive field organization of the caudate nucleus neurons yet. Therefore, we tested caudate neurons of the feline brain by extracellular single-cell recording applying drifting sinewave gratings of various spatial and temporal frequencies, and reconstructed their spectral receptive fields by plotting their responsiveness as a function of different combinations of spatial and temporal frequencies. The majority of the caudate cells (74%) exhibited peak tuning, which means that their spatio-temporal frequency response profile had a characteristic region of increased activity with a single maximum in the spatio-temporal frequency domain. In one-quarter of the recorded caudate neurons ridge tuning was found, where the region of increased activity, forming an elongated ridge of maximal sensitivity parallel or angled to the spatial or the temporal frequency axis, indicating temporal (16%), spatial (5%) or speed (5%) tuning, respectively. The velocity preference of the ridge tuned caudate nucleus neurons is significantly lower than that of the peak tuned neurons. The peak tuned neuron could encode high velocities, while the ridge tuned neurons were responsible for the detection of moderate and lower velocities. Based upon our results, we suggest that the wide variety of spatio-temporal frequency response profiles might represent different functional neuronal groups within the caudate nucleus that subserve different behaviors to meet various environmental requirements.

Research paper thumbnail of Sorting functional classes of evoked potentials by wavelets

Research paper thumbnail of Standardized F1 – A consistent measure of strength of modulation of visual responses to sine-wave drifting gratings

Vision Research, 2012

The magnitude of spike-responses of neurons in the mammalian visual system to sine-wave luminance... more The magnitude of spike-responses of neurons in the mammalian visual system to sine-wave luminance-contrast-modulated drifting gratings is modulated by the temporal frequency of the stimulation. However, there are serious problems with consistency and reliability of the traditionally used methods of assessment of strength of such modulation. Here we propose an intuitive and simple tool for assessment of the strength of modulations in the form of standardized F1 index, zF1. We define zF1 as the ratio of the difference between the F1 (component of amplitude spectrum of the spike-response at temporal frequency of stimulation) and the mean value of spectrum amplitudes to standard deviation along all frequencies in the spectrum. In order to assess the validity of this measure, we have: (1) examined behavior of zF1 using spike-responses to optimized drifting gratings of single neurons recorded from four 'visual' structures (area V1 of primary visual cortex, superior colliculus, suprageniculate nucleus and caudate nucleus) in the brain of commonly used visual mammal - domestic cat; (2) compared the behavior of zF1 with that of classical statistics commonly employed in the analysis of steady-state responses; (3) tested the zF1 index on simulated spike-trains generated with threshold-linear model. Our analyses indicate that zF1 is resistant to distortions due to the low spike count in responses and therefore can be particularly useful in the case of recordings from neurons with low firing rates and/or low net mean responses. While most V1 and a half of caudate neurons exhibit high zF1 indices, the majorities of collicular and suprageniculate neurons exhibit low zF1 indices. We conclude that despite the general shortcomings of measuring strength of modulation inherent in the linear system approach, zF1 can serve as a sensitive and easy to interpret tool for detection of modulation and assessment of its strength in responses of visual neurons.

Research paper thumbnail of Basic Emotions in the Nencki Affective Word List (NAWL BE): New Method of Classifying Emotional Stimuli

PloS one, 2015

The Nencki Affective Word List (NAWL) has recently been introduced as a standardized database of ... more The Nencki Affective Word List (NAWL) has recently been introduced as a standardized database of Polish words suitable for studying various aspects of language and emotions. Though the NAWL was originally based on the most commonly used dimensional approach, it is not the only way of studying emotions. Another framework is based on discrete emotional categories. Since the two perspectives are recognized as complementary, the aim of the present study was to supplement the NAWL database by the addition of categories corresponding to basic emotions. Thus, 2902 Polish words from the NAWL were presented to 265 subjects, who were instructed to rate them according to the intensity of each of the five basic emotions: happiness, anger, sadness, fear and disgust. The general characteristics of the present word database, as well as the relationships between the studied variables are shown to be consistent with typical patterns found in previous studies using similar databases for different lan...

Research paper thumbnail of Nencki Affective Word List (NAWL): the cultural adaptation of the Berlin Affective Word List-Reloaded (BAWL-R) for Polish

Behavior research methods, Jan 15, 2015

In the present article, we introduce the Nencki Affective Word List (NAWL), created in order to p... more In the present article, we introduce the Nencki Affective Word List (NAWL), created in order to provide researchers with a database of 2,902 Polish words, including nouns, verbs, and adjectives, with ratings of emotional valence, arousal, and imageability. Measures of several objective psycholinguistic features of the words (frequency, grammatical class, and number of letters) are also controlled. The database is a Polish adaptation of the Berlin Affective Word List-Reloaded (BAWL-R; Võ et al., Behavior Research Methods 41:534-538, 2009), commonly used to investigate the affective properties of German words. Affective normative ratings were collected from 266 Polish participants (136 women and 130 men). The emotional ratings and psycholinguistic indexes provided by NAWL can be used by researchers to better control the verbal materials they apply and to adjust them to specific experimental questions or issues of interest. The NAWL is freely accessible to the scientific community for ...

Research paper thumbnail of Surprising relation between spatio-temporal receptive field structure and direction preference of neurons in cat's superior colliculus

Research paper thumbnail of W poszukiwaniu mechanizmów preferencji kierunku ruchu bodźca przez neurony wzrokowe górnych warstw wzgórków górnych

Research paper thumbnail of Modelling the neural network of the upper layers of the superior colliculus

Research paper thumbnail of Modele niejednorodnych procesów punktowych a kodowanie informacji w układzie wzrokowym

Research paper thumbnail of Stimulus dependent oscillations in visually evoked activity of cat's superior colliculus

Research paper thumbnail of Beyond the PSTH: point process modeling of spike trains

Research paper thumbnail of Identyfikacja stanu funkcjonalnego mózgu przy pomocy nowych metod analizy potencjałów wywołanych

Research paper thumbnail of A new method for identification of modulation in neural responses to drifting grating stimulation

Research paper thumbnail of Standardized F1–A consistent measure of strength of modulation of visual responses to sine-wave drifting gratings

Research paper thumbnail of Spatio-temporal visual properties in the ascending tectofugal system

Central European Journal of Biology, 2009

Ourstudycomparesthespatio-temporalvisualreceptivefieldpropertiesofdifferentsubcorticalstagesofthe... more Ourstudycomparesthespatio-temporalvisualreceptivefieldpropertiesofdifferentsubcorticalstagesoftheascendingtectofugal visualsystem.Extracellularsingle-cellrecordingswereperformedinthesuperficial(SCs)andintermediate(SCi)layersofthesuperior colliculus(SC),thesuprageniculatenucleus(Sg)oftheposteriorthalamusandthecaudatenucleus(CN)ofhalothane-anesthetized cats.Neuronalresponsestodriftinggratingsofvariousspatialandtemporalfrequencieswererecorded.Theneuronsofeachstructure responded optimally to low spatial and high temporal frequencies and displayed narrow spatial and temporal frequency tuning. ThedetailedstatisticalanalysisrevealedthataccordingtoitsstimuluspreferencestheSCshasmarkedlydifferentspatio-temporal propertiesfromthehomogeneousgroupformedbytheSCi,SgandCN.TheSCsneuronspreferredhigherspatialandlowertemporal frequenciesandhadbroaderspatialtuningthantheotherstructures.IncontrasttotheSCsthevisuallyactiveSCi,aswellastheSg andtheCNneuronspossessedconsequentlysimilarspatio-temporalpreferences.Thesedatasupportourhypothesisthatthevisually activeSCi,SgandCNneuronsformahomogeneousneuronalpopulationgivenasimilarspatio-temporalfrequencypreferenceanda commonfunctioninprocessingofdynamicvisualinformation. ©VersitaWarsawandSpringer-VerlagBerlinHeidelberg.

Research paper thumbnail of Temporal frequency modulation of neuronal activity in the suprageniculate nucleus of the posterior thalamus

Frontiers in Behavioral Neuroscience, 2009

ABSTRACT http://www.frontiersin.org/10.3389/conf.neuro.08.2009.09.351/event\_abstract

Research paper thumbnail of Zmienność i modele stochastyczne odpowiedzi wzrokowych neuronów wzgórka czworaczego górnego kota

Research paper thumbnail of Spectral Characteristics of Phase Sensitivity and Discharge Rate of Neurons in the Ascending Tectofugal Visual System

PLoS ONE, 2014

Drifting gratings can modulate the activity of visual neurons at the temporal frequency of the st... more Drifting gratings can modulate the activity of visual neurons at the temporal frequency of the stimulus. In order to characterize the temporal frequency modulation in the cat's ascending tectofugal visual system, we recorded the activity of single neurons in the superior colliculus, the suprageniculate nucleus, and the anterior ectosylvian cortex during visual stimulation with drifting sine-wave gratings. In response to such stimuli, neurons in each structure showed an increase in firing rate and/or oscillatory modulated firing at the temporal frequency of the stimulus (phase sensitivity). To obtain a more complete characterization of the neural responses in spatiotemporal frequency domain, we analyzed the mean firing rate and the strength of the oscillatory modulations measured by the standardized Fourier component of the response at the temporal frequency of the stimulus. We show that the spatiotemporal stimulus parameters that elicit maximal oscillations often differ from those that elicit a maximal discharge rate. Furthermore, the temporal modulation and discharge-rate spectral receptive fields often do not overlap, suggesting that the detection range for visual stimuli provided jointly by modulated and unmodulated response components is larger than the range provided by a one response component.

Research paper thumbnail of Standardized F1 – A consistent measure of strength of modulation of visual responses to sine-wave drifting gratings

Vision Research, 2012

The magnitude of spike-responses of neurons in the mammalian visual system to sine-wave luminance... more The magnitude of spike-responses of neurons in the mammalian visual system to sine-wave luminance-contrast-modulated drifting gratings is modulated by the temporal frequency of the stimulation. However, there are serious problems with consistency and reliability of the traditionally used methods of assessment of strength of such modulation. Here we propose an intuitive and simple tool for assessment of the strength of modulations in the form of standardized F1 index, zF1. We define zF1 as the ratio of the difference between the F1 (component of amplitude spectrum of the spike-response at temporal frequency of stimulation) and the mean value of spectrum amplitudes to standard deviation along all frequencies in the spectrum. In order to assess the validity of this measure, we have: (1) examined behavior of zF1 using spike-responses to optimized drifting gratings of single neurons recorded from four 'visual' structures (area V1 of primary visual cortex, superior colliculus, suprageniculate nucleus and caudate nucleus) in the brain of commonly used visual mammal - domestic cat; (2) compared the behavior of zF1 with that of classical statistics commonly employed in the analysis of steady-state responses; (3) tested the zF1 index on simulated spike-trains generated with threshold-linear model. Our analyses indicate that zF1 is resistant to distortions due to the low spike count in responses and therefore can be particularly useful in the case of recordings from neurons with low firing rates and/or low net mean responses. While most V1 and a half of caudate neurons exhibit high zF1 indices, the majorities of collicular and suprageniculate neurons exhibit low zF1 indices. We conclude that despite the general shortcomings of measuring strength of modulation inherent in the linear system approach, zF1 can serve as a sensitive and easy to interpret tool for detection of modulation and assessment of its strength in responses of visual neurons.

Research paper thumbnail of Variability of Visual Responses of Superior Colliculus Neurons Depends on Stimulus Velocity

Journal of Neuroscience, 2010

Visually responding neurons in the superficial, retinorecipient layers of the cat superior collic... more Visually responding neurons in the superficial, retinorecipient layers of the cat superior colliculus receive input from two primarily parallel information processing channels, Y and W, which is reflected in their velocity response profiles. We quantified the timedependent variability of responses of these neurons to stimuli moving with different velocities by Fano factor (FF) calculated in discrete time windows. The FF for cells responding to low-velocity stimuli, thus receiving W inputs, increased with the increase in the firing rate. In contrast, the dynamics of activity of the cells responding to fast moving stimuli, processed by Y pathway, correlated negatively with FF whether the response was excitatory or suppressive. These observations were tested against several types of surrogate data. Whereas Poisson description failed to reproduce the variability of all collicular responses, the inclusion of secondary structure to the generating point process recovered most of the observed features of responses to fast moving stimuli. Neither model could reproduce the variability of low-velocity responses, which suggests that, in this case, more complex time dependencies need to be taken into account. Our results indicate that Y and W channels may differ in reliability of responses to visual stimulation. Apart from previously reported morphological and physiological differences of the cells belonging to Y and W channels, this is a new feature distinguishing these two pathways.

Research paper thumbnail of Spectral receptive field properties of visually active neurons in the caudate nucleus

Neuroscience Letters, 2010

Recent studies stress the importance of the caudate nucleus in visual information processing. Alt... more Recent studies stress the importance of the caudate nucleus in visual information processing. Although the processing of moving visual signals depends upon the capability of a system to integrate spatial and temporal information, no study has investigated the spectral receptive field organization of the caudate nucleus neurons yet. Therefore, we tested caudate neurons of the feline brain by extracellular single-cell recording applying drifting sinewave gratings of various spatial and temporal frequencies, and reconstructed their spectral receptive fields by plotting their responsiveness as a function of different combinations of spatial and temporal frequencies. The majority of the caudate cells (74%) exhibited peak tuning, which means that their spatio-temporal frequency response profile had a characteristic region of increased activity with a single maximum in the spatio-temporal frequency domain. In one-quarter of the recorded caudate neurons ridge tuning was found, where the region of increased activity, forming an elongated ridge of maximal sensitivity parallel or angled to the spatial or the temporal frequency axis, indicating temporal (16%), spatial (5%) or speed (5%) tuning, respectively. The velocity preference of the ridge tuned caudate nucleus neurons is significantly lower than that of the peak tuned neurons. The peak tuned neuron could encode high velocities, while the ridge tuned neurons were responsible for the detection of moderate and lower velocities. Based upon our results, we suggest that the wide variety of spatio-temporal frequency response profiles might represent different functional neuronal groups within the caudate nucleus that subserve different behaviors to meet various environmental requirements.