Yoram Gutfreund, PhD

Mechanisms of information processing and neural plasticity in the central auditory system

The main research interest in my laboratory is how information about the location of a sound source is represented in the brain, and how this representation is shaped by sensory experience. To this end, we are studying the central auditory system of the barn owl whose neural representation of auditory space is sharper than in any other studied species. This enables us to identify biological effects with high sensitivity and confidence. We use a variety of system neurobiological techniques that include acoustic stimulation, extracellular recording, microstimulation, neuropharmacology, and behavioral analysis. Specific projects in the laboratory are: 1) Effects of abnormal auditory experience on the development of the auditory space map. This project involves raising barn owls in various acoustic environments (different levels and protocols of background noise), and then studying the effects of the acoustic experience on the brain and on the auditory localization behavior. 2) Visual auditory interactions. When objects can be both seen and heard, the cooperative combination of visual and auditory signals increases the capacity to detect and locate stimuli under a wide range of difficult conditions. The integration of auditory and visual information is of special interest because it has been shown to play an important role in guiding auditory plasticity. We characterize visual and auditory responses in the barn owl’s brain to answer questions such as: Where do the interactions take place in the brain and what are the rules that govern these interactions? 

Figure 1:

We have identified two brain areas which combine visual and auditory information. One area is in the forebrain entopallium (E) and the other is in the thalamic nucleus rotondus (nRt). The figure shows a nissl-stained coronal section through the forebrain and midbrain of the barn owl in which the traces of a iontophoretic injection of fluorogold in the E and the retrograde labeled cell bodies in nRt can be seen. The two graphs show responses of a neuron in the E (green curves) to rare bimodal stimuli (stimuli which combine visual and auditory stimuli) compared with responses (blue curves) to the same bimodal stimuli but when they appear frequently 

Representative publications