Functional mechanisms that mediate stimulus-specific
adaptation in the
auditory brain
Manuel S. Malmierca
Auditory Neurophysiology Laboratory. Institute of Neuroscience of
Castilla y León, University of Salamanca Salamanca, Spain
C/ Pintor Fernando Gallego, 1
37007 Salamanca, Spain
Stimulus-specific adaptation (SSA) is the reduction in the responses to a common sound relative to
the same sound when rare. It has been described in auditory cortex (AC; Ulanovsky et al., 2003)
and in the auditory midbrain and thalamus (IC and MGB).
In this talk I will show our recent findings on recordings from single neurons in the IC and MGB
of rats to an oddball paradigm, as well as the effect of reversible cortical deactivation and the
manipulation at synaptic level as these responses.
Our data indicates: 1) Most neurons in the non-lemnical divisions of the IC and MGB show
strong SSA (Malmierca et al. 2009, Antunes et al., 2010); 2) the magnitude of adaptation in many
IC neurons increased proportionally with frequency contrast and low probability of occurrence for
deviant tones (Ayala and Malmierca, 2012). 3) SSA varies within the neuronal receptive field
(Duque et al., 2012). 4) GABAergic and/or glycinergic inhibition play a role in shaping SSA in
the IC (Pérez-González et al., 2012) and MGB (Duque et al., 2013). 5) AC modulates the
responses of neurons in a gain control manner but SSA in the IC (Anderson and Malmierca, 2013)
and MGB (Antunes et al., 2011) is not inherit from the AC (Antunes et al., 2011). Taken together
our results suggest that SSA can be generated in a bottom-up manner throughout the auditory
pathway and they are congruent with the notion that subcortical SSA can contribute upstream to
the generation of MMN.
In the future, we wish to know the cellular mechanisms that generate SSA and also to understand
how neurons that exhibit SSA code for other, more complex patterns of regularity beyond the
oddball paradigm such us expected and unexpected sounds in different context.
Financial support was provided by the Spanish MICINN (BFU2009-07286), MICINN-EU
Anderson LA, Malmierca MS (2013) The effect of auditory cortex deactivation on stimulusspecific adaptation in the inferior colliculus of the rat. The European journal of neuroscience
37 (1):52-62.
Antunes FM, Malmierca MS (2011) Effect of auditory cortex deactivation on stimulus-specific
adaptation in the medial geniculate body. The Journal of neuroscience 31 (47):17306-17316.
Antunes FM, Nelken I, Covey E, Malmierca MS (2010) Stimulus-specific adaptation in the
auditory thalamus of the anesthetized rat. PloS one 5 (11):e14071.
Ayala YA, Malmierca MS (2013) Stimulus-specific adaptation and deviance detection in the
inferior colliculus. Frontiers in neural circuits 6:89. doi:10.3389/fncir.2012.00089
Duque D, Malmierca MS, Caspary DM (2013) Modulation of stimulus-specific adaptation by
GABAA receptor activation or blockade in the medial geniculate body of the anesthetized rat.
J Physiol, 2013/10/09 edn. doi:jphysiol.2013.261941 [pii] 10.1113/jphysiol.2013.261941
Duque D, Perez-Gonzalez D, Ayala YA, Palmer AR, Malmierca MS (2012) Topographic
distribution, frequency, and intensity dependence of stimulus-specific adaptation in the
inferior colliculus of the rat. The Journal of neuroscience 32 (49):17762-17774.
Malmierca MS, Cristaudo S, Perez-Gonzalez D, Covey E (2009) Stimulus-specific adaptation in
the inferior colliculus of the anesthetized rat. The Journal of neuroscience 29 (17):5483-5493.
Perez-Gonzalez D, Hernandez O, Covey E, Malmierca MS (2012) GABA(A)-mediated inhibition
modulates stimulus-specific adaptation in the inferior colliculus. PloS one 7 (3):e34297.
Ulanovsky N, Las L, Nelken I (2003) Processing of low-probability sounds by cortical neurons.
Nature neuroscience 6 (4):391-398. doi:10.1038/nn1032

Neural responses in the auditory nervous system depend not only