Abstract #439, Date Monday, Jan 28 2002 1:00PM - 12:00PM Session K8 Auditory Cortex: Plasticity and Maturation
Representational Plasticity of Marmoset and Human Vocalizations in Rat Auditory Cortex
Pritesh K. Pandya, Navzer D. Engineer, Raluca Moucha, WeiWei Dai, Daniel L. Rathbun, Amanda Puckett, Jessica L. Vazquez, Cherie R. Percaccio, Michael P. Kilgard
We have recently reported that differential sensory experience with elemental tonal stimuli can substantially alter spatial and temporal responses in primary auditory cortex (A1) using a single paradigm that eliminates task-specific variables (Kilgard et al, 2001). A primary goal of our ongoing research is to extend these studies by documenting how experience with complex stimuli directs plasticity in A1. To accomplish this, we continue to employ activation of the basal forebrain to engage neural plasticity mechanisms. To extend our previous studies with simple stimuli, we are beginning to investigate how long-term experience with different spatiotemporal input patterns alters distributed cortical responses in rat A1. A marmoset twitter call (n=5 rats) and the human vocalization 'sash' (n=7 rats) were repeatedly paired with electrical activation of the basal forebrain ~300 times a day for one month and were compared to naïve controls (n=6 rats). The cortical representation of tones, modulated noise bursts, and vocalizations was obtained by mapping multiple unit responses from microelectrode penetrations in each animal during an acute experiment using barbiturate anesthesia. For each recording site (40-80 sites/rat), we determined the excitatory frequency-response area, repetition rate transfer functions, and the response to vocalizations. After extensive experience with vocalizations, population analysis suggests a temporal sharpening of the cortical responses. Our results support a learning hypothesis in which intensive and focused exposure to complex acoustic signals can increase the fidelity of neuronal representations and generate a more temporally coordinated distributed cortical neuronal network response.