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Peter B Mack

Publications and source records attributed to Peter B Mack.

2 recordsLinked to original sources

Faces evoke spatially differentiated patterns of BOLD activation and deactivation.

Using fMRI techniques sensitive to blood oxygen-level dependent (BOLD) contrast, we measured brain activity in participants (n=8) as they viewed images of faces presented periodically within a continuously changing montage of common objects. Consistent with prior studies, we identified regions of ventral extrastriate cortex, primarily in the fusiform and inferior temporal gyri and nearby cortex, that were activated by faces as measured by an increase in BOLD signal. In addition, we made the novel observation that faces deactivated other areas of ventral extrastriate cortex, primarily in the lingual and parahippocampal gyri and medial to activations. These deactivated regions, identified by a decrease in BOLD signal, may reflect populations of neurons that decrease their activity when faces appear, possibly as a consequence of category-specific inhibition.

Adult↗

Perceiving patterns in random series: dynamic processing of sequence in prefrontal cortex.

We demonstrate that regions within human prefrontal cortex develop moment-to-moment models for patterns of events occurring in the sensory environment. Subjects viewed a random binary sequence of images, each presented singly and each requiring a different button press response. Patterns occurred by chance within the presented series of images. Using functional magnetic resonance imaging (fMRI), we identified activity evoked by viewing a stimulus that interrupted a pattern. Prefrontal activation was evoked by violations of both repeating and alternating patterns, and the amplitude of this activation increased with increasing pattern length. Violations of repeating patterns, but not of alternating patterns, activated the basal ganglia.

Adolescent↗