Past events

Whether we are speaking, swimming, or playing the piano, we are crucially dependent on our brain?s capacity to step through sequences of neural states. Songbirds provide a marvelous animal model in which to study this phenomenon. Their stereotyped vocalizations have hierarchical temporal structure spanning two orders or magnitude in timescale ? from individual vocal gestures lasting ten milliseconds, to song syllables (~100 msec), to song motifs (~1 sec). Several brain areas have been proposed to control timing at these different timescales. By manipulating these circuits with temperature change and observing the effect on song structure, we have been able to localize a single ?clock? circuit in the premotor vocal pathway. Intracellular neuronal recordings during singing elucidate the mechanism by which this clock circuit operates. Our findings are consistent with the predictions of a synfire-chain model? a synaptically connected chain of neurons in HVC. Our findings are inconsistent with models in which subthreshold dynamics, such as ramps or oscillations, play a role in the control of timing.

Neuro-plasticity is one of the key processes in our brain's physiology. This process allows our brain to change itself, functionally and structurally, following the acquisition of a new skill or experience. While functional aspects of neuro-plasticity can be studied using non-invasive techniques such as fMRI, EEF and MEG, investigation of the structural tissue characteristics of neuro-plasticity requires invasive histological approaches. Long-term experience necessitates structural plasticity which, in the adult brain, is characterized by changes in the shape and number of the synapses (synaptogenesis) as well as other process (neurogenesis, gliogenesis and white matter plasticity). Structural MRI studies of brain plasticity reveal significant volumetric changes via voxel-based morphometry of T1 weighted scans. Yet, the micro-structure correlates of these changes are not well understood. Diffusion tensor imaging (DTI) became one of the most popular imaging techniques in neuroimaging and is regarded as a micro-structural probe. Recently, tract-based spatial statistics (TBSS) analysis of DTI scans before and after long-term motor coordination training (juggling) revealed regional fractional anisotropy (FA) increase in parietal pathways. In that study, FA changes were reported following few weeks of training. An open question is what happens at shorter term learning and memory processes? In a short term spatial navigation study performed both in humans and rodents, we found that diffusion MRI can detect structural changes in cell morphology induced by plasticity within mere hours. Both in humans and rodents, the micro-structural changes, as observed by MRI, were localized to the anticipated brain regions: hippocampus, para-hippocampus, visual cortex, cingulate cortex and insular cortex. Our results indicate that significant structural occur in the tissue within mere hours - an interesting result by itself from the neurophysiological point of view. However, by investigating the induced structural changes both by histology and MRI it is possible to elucidate the relations between tissue micro-structure and the diffusion MRI signal. Preliminary results of such comparison indicate that in gray matter tissue one of cellular correlates of diffusion MRI indices is the density and shape of astrocyte. Indeed more studies should be directed

: Sadé will talk about the relevance in collaboration between artists and scientists, and will introduce her recent art project: “Reconfiguring Memory”. Sadé collaborates with Professor Andre Fenton at NYU Neuroscience labs to develop art for the renovated Neuroscience labs at NYU. Her work with memory, time and light led to this collaboration and will result in art relating to the questions: How does the brain store experience as memories and how the expression of knowledge activates information that is relevant without activating what is irrelevant, and what visual methods can be used for recording the activity of memory, gain or loss.

Cognitive neuroscience experiments typically isolate human or animal subjects from their natural environment by placing them in a sealed quiet room where interactions occur solely with a computer screen. In everyday life, however, we spend most of our time interacting with other individuals. Using fMRI, we recently recorded the brain activity of a speaker telling an unrehearsed real-life story and the brain activity of a listener listening to a recording of the story. To make the study as ecological as possible, we instructed the speaker to speak as if telling the story to a friend. Next, we measured the brain activity of a listener hearing the recorded audio of the spoken story, thereby capturing the time-locked neural dynamics from both sides of the communication. Finally, we asked the listeners to complete a detailed questionnaire that assessed their level of comprehension. Our results indicate that during successful communication the speaker’s and listener’s brains exhibit joint, temporally coupled, response patterns. Such neural coupling substantially diminishes in the absence of communication, for instance, when listening to an unintelligible foreign language. In addition, more extensive speaker–listener neural couplings result in more successful communication. The speaker-listener neural coupling exposes a shared neural substrate that exhibits temporally aligned response patterns across communicators. The recording of the neural responses from both the speaker brain and the listener brain opens a new window into the neural basis of interpersonal communication, and may be used to assess verbal and non-verbal forms of interaction in both human and other model systems.