It has been suggested that learning is associated with a transient and highly selective increase in brain gray matter in healthy young volunteers. It is not clear whether and to what extent the aging brain is still able to exhibit such structural plasticity. We built on our original study, now focusing on healthy senior citizens. We observed that elderly persons were able to learn three-ball cascade juggling, but with less proficiency compared with 20-year-old adolescents. Similar to the young group, gray-matter changes in the older brain related to skill acquisition were observed in area hMT/V5 (middle temporal area of the visual cortex). In addition, elderly volunteers who learned to juggle showed transient increases in gray matter in the hippocampus on the left side and in the nucleus accumbens bilaterally.

Motor compensation after stroke is a behavior in which the non-paretic limb performs tasks normally accomplished by the paretic limb. For example, stroke survivors with right hemiparesis often bear weight exclusively on the left leg when rising from a c...

The action observation network(AON) is comprised of motor regions (inferior frontal gyrus, ventral premotor cortex, and posterior parietal cortex) that are active when we make an action and when we see someone else make a similar action. Previous studie...

This study investigated the neural plasticity associated with perceptual learning of a cochlear implant (CI) simulation. Normal-hearing listeners were trained with vocoded and spectrally shifted speech simulating a CI while cortical responses were measured with functional magnetic resonance imaging (fMRI). A condition in which the vocoded speech was spectrally inverted provided a control for learnability and adaptation. Behavioral measures showed considerable individual variability both in the ability to learn to understand the degraded speech, and in phonological working memory capacity. Neurally, left-lateralized regions in superior temporal sulcus and inferior frontal gyrus (IFG) were sensitive to the learnability of the simulations, but only the activity in prefrontal cortex correlated with interindividual variation in intelligibility scores and phonological working memory. A region in left angular gyrus (AG) showed an activation pattern that reflected learning over the course of the experiment, and co...

Multiple Sclerosis (MS) results in visual cortex (VC) dysfunction, even in the absence of ophthalmic pathologies. The precise mechanism of this dysfunction remains elusive. Our previous studies have shown an association between white-matter microstructu...

Transcranial magnetic stimulation (TMS) is widely used for understanding brain function in neurologically intact subjects and for the treatment of various disorders. However, the precise neurophysiological effects of TMS at the site of stimulation remain poorly understood. The local effects of TMS can be studied using concurrent TMS-functional magnetic resonance imaging (fMRI), a technique where TMS is delivered during fMRI scanning. However, although concurrent TMS-fMRI was developed over 20 years ago and dozens of studies have used this technique, there is still no consensus on whether TMS increases blood oxygen level-dependent (BOLD) activity at the site of stimulation. To address this question, here we review all previous concurrent TMS-fMRI studies that reported analyses of BOLD activity at the target location. We find evidence that TMS increases local BOLD activity when stimulating the primary motor (M1) and visual (V1) cortices but that these effects are likely driven by the downstream consequences ...

This study utilized functional MRI to evaluate the early stages of a kainic acid induced seizure in a fully conscious rat. Seizure activity was confirmed by EEG, and blood oxygen level dependant (BOLD) signal was temporally consistent with this activity. Male SD rats where anesthetized using medetomidine (Pfizer) and ketamine and EEG electrodes were implanted. The animal was then placed into a special animal restraint/Rf coil system (Insight Neuroimaging systems). This system was put into a 4.7T MRI (Bruker) and the animal was awoken with atipamizole (Pfizer). Physiologic parameters were recorded for the entire duration of the experiment. Anatomical images were acquired before and after the seizure. A 45 repetition functional sequence was acquired with 14 baseline repetitions (3 minutes) followed by an IP injection of kainic acid (10mg/kg). Seizure activity was noted via EEG within a minute. The anatomical images were subtracted to confirm that the awake animal remained immobile during the experiment. All ...

Major sequelae of mild traumatic brain injury (mTBI) in adolescence include attention deficit hyperactivity disorder (ADHD) symptoms and cognitive deficits. As cognitive deficits are linked to abnormal dopamine (DA) function in the brain, we aimed to ex...

Using functional magnetic resonance imaging, we found that cortical visual motion area MT+/V5 responded to auditory motion in two rare subjects who had been blind since early childhood and whose vision was partially recovered in adulthood. Visually normal control subjects did not show similar auditory responses. These auditory responses in MT+ were specific to motion compared with other complex auditory stimuli including frequency sweeps and speech. Thus, MT+ developed motion-specific responses to nonvisual input, suggesting that cross-modal plasticity can be influenced by the normal functional specialization of a cortical region. Regarding sight recovery after early blindness, our results further demonstrate that cross-modal responses coexist with regained visual responses within the visual cortex.

Previous research from our laboratory demonstrated that volumes of mesial temporal lobe structures such as the entorhinal cortex and hippocampus are sensitive markers of incident Alzheimer’s disease (AD). In addition, older people with amnestic mild cog...