Functional Maps in Primary Visual Cortex

The basic structure of receptive fields and functional maps in primary visual cortex is established without exposure to normal sensory experience and before the onset of the critical period

two-photon microscopy, is now yielding a first look at the organization of functional maps with cellular resolution.

EPIdata quality

A representative example of raw EPI (echoplanar imaging) data normalized to MNI space is shown in a coronar (MNI y = −7 mm) and axial (MNI z = −20 mm) section. The axial section corresponds approx. to the sections shown in [51]. The example represents the average across all EPI volumes acquired during the experimental session of one subject. The outline of the amygdala is shown (red line), enclosing the area with at least 50% probability of belonging to the amygdala (according to the probabilistic maps from [26]). The extent of the laterobasal (LB) group of the amygdala (LB, > = 80% probability) is shown in blue, the superficial group (SF) in green, and the centromedial group (CM) in magenta. In addition, the outline of the segmentation mask enclosing the area with sufficient signal for application of point spread function (PSF) based EPI distortion correction (see reference [39] for further details) is shown in yellow. In all subjects, the whole analyzed extent of the amygdala was within the segmentation mask and therefore distortion correction was possible in this region. Good EPI signal quality in the amygdala region was achieved in all subjects investigated.

The extent of the amygdala sub-regions LB, SF, and CM defined by maximum-probability maps (MPMs, [28]) are rendered in blue, green, and magenta, respectively, on a coronal section. Regions with significant (p<0.05, corrected for multiple comparisons in the search volume) music-related responses are shown in red. The BOLD percentage signal change (PSC) of each of the three activation sites in the four music conditions (1: dissonant slow, 2: consonant slow, 3: dissonant fast, 4: consonant fast) is presented as mean and standard error. The fifth PSC value refers to the time period during which subjects evaluated the emotional effect evoked by the preceding musical piece, compared with rest. In the left amygdala, a cluster with positive responses to all music conditions was mainly located in LB and a cluster with negative responses was mainly found in SF and CM. A smaller cluster with consistently positive responses was also found in the right amygdala approximately in the mirror position to the positively responding left cluster.