Global form perception in cats early deprived of pattern vision.

Recently, we showed that binocularly deprived cats are not able to detect global motion in a random dot pattern (Burnat et al., 2002). Here, we examined, in these animals, a global form discrimination task, that is, distinction of a square from a rectangle, matched for total surface.

Affective percept and voluntary action: a hypothesis.

I present a hypothesis concerning the neuronal, mental and behavioral effects of all kinds of affective (emotional) stimuli, i.e., of unpleasant and pleasant stimuli.

Global motion detection is impaired in cats deprived early of pattern vision.

We investigated global motion detection in binocularly deprived cats (BD cats) and control cats (C cats). The cats were trained in the two-choice free running apparatus for a food reward. The positive stimulus was a moving random-dot pattern with all dots moving in one direction, the negative stimulus was the same random-dot pattern but stationary.

Food conditioning is impaired in cats deprived of the taste of food in early life.

Cats were fed by stomach tube during the first 75 days of their life. Thus, they were deprived of the taste of food and the food reward. The cats were then trained to find food behind the gate.

Visual discrimination learning under switching procedure in visually deprived cats.

Previous studies have shown that fine visual discrimination learning is severely impaired in cats binocularly deprived in the early period of life (BD cats) and also somewhat in control cats reared with open eyes in the limited laboratory environment (C cats) compared with cats reared in a normal rural environment (N cats). It was concluded that visual deprivation impairs perceptual learning. In the present study discriminative stimuli were dissimilar and so the task was perceptually easy, but using a switching procedure made it associatively difficult.

EEG activity in cat's isolated brainstem.

Midbrain and pons were isolated together by two brainstem transections, at the junctions between midbrain and forebrain on one hand and the medulla and pons on the other hand. Low-voltage, high-frequency and high-voltage, low-frequency EEG activity were present in the isolated brainstem. This is in contrast to previous findings, showing that in the midbrain and pons separately isolated the EEG activity was greatly depressed, although accompanied by brisk single-unit spike activity.

Habituation of ocular following reflex requires corpus callosum for interhemispheric transfer.

In cats, unanesthetized following transection of the brainstem at a level precluding painful sensation, and limiting ocular motility to a vertically oriented course (the pretrigeminal preparation), habituation of the orienting reflex, consisting of ocular fixation and smooth pursuit, readily transferred between moving visual stimuli directed first at one and then the other cerebral hemisphere. Under the same conditions, when the corpus callosum had been transected 2 weeks prior to the habituation, interhemispheric transfer was absent. Thus, despite substantial brainstem involvement and bilateral coordination of ocular motility the neocortex plays an essential role in this habituation, just as it does in the interhemispheric transfer of visual discrimination learning.

Reversal of visual discrimination and visual acute extinction in cats with poor or limited early visual experience.

Transformation of visual instrumental conditioned reflexes rewarded with food was compared in cats binocularly deprived of pattern vision in the early period of life (BD cats), control cats reared also in the laboratory but with open eyes (C cats) and cats reared in normal environment (N cats). In Expt. I the cats were given 4 sequential reversal trainings of cross vs.

Direction discrimination learning in normal and visually deprived cats and the effects of lateral suprasylvian lesions.

We used 5 binocularly deprived cats (BD cats), 4 control cats reared also in the laboratory (C cats) and 4 cats reared in a normal environment (N cats). The cats were trained to discriminate an upward or downward-moving light spot versus a stationary spot (detection task) and then an upward versus a downward spot (direction task). The N and C cats learned slowly.

Object discrimination learning and object-pattern discrimination transfer in visually deprived cats.

We used binocularly deprived cats (BD cats), control cats reared in the laboratory with open eyes (C cats) and normal wild cats (N cats). In stage 1, the cats were trained to discriminate a black ping-pong ball and a 3-dimensional cross of the same size and color for food reward. The BD cats learned slower than N cats.

Visual neglect in pretrigeminal cats with lateral suprasylvian lesions.

Eleven cats with brain stem transected at the pretrigeminal level were used. The cortex of the middle suprasylvian sulcus was removed on the left side. The vertical following reflex was evoked by a slit of light (1 degree x 4 degrees) or a black bar (1 degree x 1 degree x 4 degrees) moving along the vertical meridian or parallel to it out to 40 degrees in the left or right hemifield.

Discrimination learning of grating orientation in visually deprived cats and the role of the superior colliculi.

Four cats deprived binocularly of pattern vision (BD cats), 4 control cats reared also in the laboratory (C cats), and 4 normal wild cats (N cats) were trained to discriminate gratings of progressively smaller difference in orientation. Differences in learning were found only in fine orientation discriminations. The stage of 15 degrees orientation difference was learned by 4 N cats, 2 C cats, and 1 BD cat.

Electrical activity of the acutely isolated pons in cats.

The cat's pons was isolated by two brainstem transections, at the junction of medulla and pons and at the junction of pons and midbrain. In the deafferented pons the EEG activity was virtually absent, whereas the spatial density of active units and the rate of their spontaneous spike activity were at a high level. In the pons of control preparations with brainstem transected only at the ponto-midbrain junction the EEG activity was present, while the single-unit activity was such as in the isolated pons.

Sleep-waking cycle in chronic rat preparations with brain stem transected at the caudopontine level.

The brain stem of rats was transected at the middle of the nucleus reticularis pontis caudalis. The preparations were maintained 2-9 days, and their EEG activity and behavior were studied. Maintained EEG activity and EEG arousal to visual and olfactory stimuli indicated the presence of sleep-waking cycle.

The contralateral impairment of the orienting ocular-following reflex after lesions of the lateral suprasylvian cortex in cats.

The cortex of the middle suprasylvian sulcus was removed unilaterally in cats with brain stem transected at the pretrigeminal level. The vertical following reflex was evoked by a slit of light (1 degree x 4 degrees) moving along the vertical meridian or parallel to it up to 40 degrees in the left or right hemifield. The reflexes from the contralateral hemified were greatly reduced.

Delayed response learning to auditory stimuli is impaired in cage-reared cats.

Four normal and eight cage-reared cats were used. Four of the cage-reared cats were visually deprived in the first 6 months of life. The cats were trained on a three-choice delayed response task to auditory stimuli.

Learning deficits in lab-reared cats.

Data obtained by the author and his colleagues on deficits in learning in cats reared in the lab breeding colony are reviewed. As compared with cats who lived free in a farm during the first 3-4 months of life, the lab-reared cats showed a dramatic impairment of delayed response learning to visual and auditory stimuli. They also showed some impairment of visual discrimination learning: they commited more errors than farm-reared cats when a discrimination apparatus had a partition between the stimuli, their reaction times were longer, and after lesions of the superior colliculus-pretectum complex their relearning was impaired.

Discrimination learning of the vertical and horizontal light spot oscillations in normal and visually deprived cats.

Three groups of cats were used: cats deprived binocularly of patterned vision from birth (BD cats), control cats reared in the laboratory with opened eyes (C cats) and cats reared in a rural environment during the first months of life (N cats). The cats were trained to discriminate vertical vs. horizontal oscillations of a light spot for food reward.

Hippocampal and cortical EEG activity in rats with transected hypothalamus.

The brain was transected in eight rats: the transection passed through the posterior pole of the superior colliculi and ended down at midhypothalamic level. The EEG activity in the dorsal hippocampus and cortex showed continuously slow, high amplitude waves. Thus the posterior hypothalamus is critical for the previously described hippocampal theta rhythm found in rats transected at the posthypothalamic level.

Brightness-discrimination learning in cats is influenced by early visual deprivation.

A two-choice apparatus for food reward was used. Normal and visually deprived cats were trained to discriminate white and black cards. After the animals had reached criterion, the contrast difference between the cards was diminished in steps.

Visual discrimination learning in binocularly deprived cats: 20 years of studies in the Nencki Institute.

Data obtained by the author and his colleagues on various forms of visual discrimination learning in cats binocularly deprived of pattern vision with cloth masks (BD cats) are reviewed. In these studies two comparison groups were used: controls reared also in the laboratory but with open eyes (C cats) and cats reared in normal environment outside the laboratory (N cats). Data from other laboratories on lid-sutured and dark-reared BD cats are also shortly reviewed.

Delayed response learning to visual stimuli in cats.

Six normally reared cats were trained on a three-choice delayed response task to visual stimuli. All cats mastered 1 min delay, three cats 2 min delay and one cat 6 min delay. Learning was much better than in previously studied cats reared in laboratory cages.

Partition between stimuli slows down greatly discrimination learning in binocularly deprived cats.

Pattern discrimination learning was compared in cats reared in a normal environment during the first months of life (N cats), control cats reared in the laboratory with opened eyes (C cats), and cats deprived binocularly of patterned vision from birth (BD cats). A two-choice apparatus was used for training. In Expt.

Some aspects of brain morphology of the chronic cat and kitten preparations with brain stem transected at the pretrigeminal level.

In two adult cats and in three kittens aged from 8 to 11 days the brain stem was transected at the pretrigeminal level. The preparations were maintained from 7 to 79 days and processed histologically together with nonoperated controls. In kitten preparations brain was underdeveloped as shown by less numerous secondary sulci on the surface of the cortex.