ROLE OF THE MEDIAL AMYGDALA IN FEAR POTENTIATED STARTLE AND SUCCESSIVE-CUE ODOR DISCRIMINATION Tracy Cheng, Catherine Elorette, Xiaotong Li, Nicholas Chiappini, Daniel Wei, Jane Wang, Dedeepya Konuthula, Christopher Marnell, Keerthana Krosuri, Sayantan Deb, Courtney Halgren, Susan Liao Susan

Pavlovian Fear Conditioning Associative Learning: Pairs a pre-occurring event or substance with a response Conditioned Stimulus (CS) + Unconditioned Stimulus (US) = Conditioned Fear Response (CR) Olfactory Stimulus + Foot Shock = Startle Dan

Acoustic Startle Neural Pathway Chris

The Amygdaloid Complex Fear Response Pathway Sayantan Blue=basolateral, red=medial, green=central

Purpose To determine the role of the medial amygdala in olfactory learning through: Fear conditioning Odor discrimination testing Courtney

Subjects Xiaotong Nineteen male Sprague-Dawley rats, 12 hr light cycle/ 12 hr dark cycle, Limited to 30min water per day but free access to food

Fear Potentiated Startle Tracy

Hypothesis Lesions to the medial amygdala will disrupt startle response Catherine, Supported by Walker, Paschall & Davis (2005)

Startle Chamber Nick

Startle Test Trial Type Duration ISI Odor? Shock? Sound Pulse? Matching 40 Pulses 30 s No Yes, 95 dB Baseline Yes, 75-105 dB Odor/Shock 6 Trials 4 min Yes Yes, .5 mA Odor/Pulse 70 Pulses 30 s (P) 2 min(O) Chris

Fear Potentiated Startle Susan

Conclusion No significant effect Keerthana

Odor Discrimination Tracy

Hypothesis Despite the lesions, the rats would still be able to detect and discriminate between the n-heptane and cineole Catherine, Supported by Cousens & Otto (1998)

Odor Discrimination Chamber Nick

Procedure Trial type 1 Trial type 2 Nose poke = water Trial type 2 Positive odor & entry = water + 2.5 s black-out Negative odor & entry = 9.5 s black-out Other results = 2.5 s black-out Rats were given only 30 min water every day to make them thirsty Tracy

Frequency of Response by Type Jane

Latencies Before Responses Jane

Conclusion No significant effect Keerthana

Discussion

Findings Fear conditioning No disruption of startle response   Fear conditioning No disruption of startle response Odor discrimination No effect of lesions on odor discrimination ability Latencies Percent correct response Sayantan

Inconsistencies Histology has not been performed Small number of rats Incomplete control of NMDA diffusion Small number of rats Innate preference for an odor Dedeepya

Our Team

Thank You! Dr. Cousens, Anna Toledano & Jill NJGSS Sponsors: John and Laura Overdeck, Novartis, Bristol-Myers Squibb, Jewish Communal Fund, Vanguard Charitable Endowment Program, The Ena Zucchi Charitable Trust, Village Veterinary Hospital, Fannie Mae Foundation, and NJGSS Alumnae and Parents 1984-2008 And everyone else who helped make this experience possible! 

YAY WATER!

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