LABORATORY OF VISUAL PERCEPTION

| Head: Prof. Andrzej MICHALSKI, Ph.D., D.Sc. E-mail: a.michalski@nencki.gov.pl Staff: Kalina BURNAT, Ph.D. Grażyna NIEWIADOMSKA, Ph.D. Maciej STASIAK, Ph.D., D.Sc. Irena ŁAPIŃSKA Wojciech BORKOWSKI Ph.D. students: Marta BAKSALERSKA-PAZERA Ewa ROJEK Rafał MILNER

Laboratory of Visual Perception is the traditional name that originates from the early days of the Nencki Institute and is linked with the memories of its founders prof. Żernicki and prof. Konorski. We keep this name in spite of the fact that the profiles of research conducted in the laboratory have branched out in time pretty far from the original domain. Nowadays, four lines of research are pursued in the laboratory.

1. Human long latency, event-related potentials. Most of the experiments concern the visual system, although other modalities are used incidentally. For many years, the research focused on the effects of pain and stress on processing the non-emotional, every day stimuli. It showed that the alterations of event-related responses to discrete, non-emotional stimuli could be used as the indicators of pain, stress and possibly even such emotional states as being successful or not. The continuation of this line of studies is the presently conducted research on the electrophysiological correlates of humor. The other presently conducted line of experiments concerns the general mechanisms of the selection of important information and the rejection of irrelevant inputs. Most of the research is done on the visual system. The paradigm includes the use of P300 component of event-related potential as an indicator of important stimulus and the analysis of cortical responsiveness with the ‘probe’ stimuli. Results of these experiments indicate that cortical responsiveness is reduced within the specific time window after the advent of important stimulus. Perhaps the more intriguing outcome is that these inhibitory effects seem to be different in cortical fields that represent the different stages of information processing.

2. Effects of sensory deprivation in the early period of life.

Binocular deprivation from the visual input in cats. Experiments demonstrated that binocularly deprived cats were impaired in the behavioral tests that required the perception of global motion, such as moving random dot pattern. At the same time, the deprivation did not produce any deficit in the detection of relative movement of visual patterns such as squares. We concluded that the effects of deprivation could be revealed better with the global motion stimulus whereas the relative motion can be detected probably using positional cues. At present we examine the effects of the deprivation on the detection of visual patterns that should eliminate such cues.

Early deprivation in gustatory system. His experiments address a severe and long-lasting controversy regarding the influence of early experience with a specific food on later food preference, that is, the controversy between ‘the primacy effect’ and ‘the novelty effect’. His results show that the deprivation of a variety of food tastes in early life influences later instrumental food conditioning. The deprivation can reveal the potential or inborn palatability of a specific food, potential food preference, and the potential food reward value. The experiments, originally done on cats are now extended on omnivorous animals.

3. Processes of aging. Using neurochemical methods, we study the degeneration processes in the basal forebrain neurons of the aging rats. We focus on the impairment of the uptake and retrograde transport of the nerve growth factor (NGF). After injection of fluorescent tracers into the neocortex and the hippocampus of young and aged rats we analyze the numbers of retrogradely labeled neurons in different subdivisions of the basal forebrain. In the same experiment, we evaluate the expression level of proteins associated with microtubule apparatus using immunostaining methods. These experiments show that transport of NGF to basal forebrain is impaired in aged animals. This is accompanied by changes in the level of expression and phosphorylation of microtubule binding Tau proteins as well as their redistribution within the main neuronal compartments. These could evidence of disorder in mechanisms of axonal transport. Our results suggest that Tau-dependent breakdown in cytoskeleton may cause a diminished transport of target-derived NGF leading to selective vulnerability of cholinergic neurons in aged animals.

Selected Publications:

1. Burnat K., Vandenbussche E., Żernicki B. Global motion detection is impaired in cats deprived early of pattern vision. Behavioral Brain Research 134: 59-65 (2002).

2. Niewiadomska, G., Komorowski, S. and Baksalerska-Pazera, M. Amelioration of cholinergic neurons dysfunction in aged rats by NGF depends on the continuous supply of the trophic factor. Neurobiology of Aging 23: 601-613 (2002).

3. Stasiak M. The development of food preferences in cats: the new direction. Nutritional Neuroscience 5: 221- 228 (2002).

4. Michalski A. Interactions between P300 and passive probe responses differ in different cortical areas. Acta Neurobiologiae Experimentalis 61: 93-104 (2001).

5. Stasiak M. The effect of early specific feeding on food conditioning in cats. Developmental Psychobiology 39: 205-215 (2001).

6. Michalski A. Effect of accomplishment and failure on P300 potentials evoked by neutral stimuli. Neuropsychologia 37: 413-420 (1999).