Biology subjects

Jafari, Z.

Publications and source records attributed to Jafari, Z..

4 recordsLinked to original sources

bioRxiv2022

Functional organization of mouse auditory cortex in response to stimulus complexity and brain state

The functional organization of sensory cortices is modulated by both extrinsic events and intrinsic states. The present study aimed to assess the mouse auditory cortex (AC) responses under varying conditions of stimulus complexity and brain state. Using wide-field calcium imaging, our results suggest a complete outline of topographic maps of frequency and FM rate as well as highly responsive regions to mouse ultrasonic vocalizations (USVs) in both awake and anesthetized states. Three new regions responsive to high-frequency tones and four new gradients responsive to frequency modulations (FMs) were identified. These maps are highly replicable across weeks and between animals. In awake versus anesthetized states, cortical responsiveness to pure tones was stronger, and regions that preferentially responded to slow rate FMs were smaller. In both states, fast FM regions showed the greatest contribution to the processing of USVs. Finally, our modeling of how best tone frequency or FM rate changes as a function of distance along a topographic gradient resulted in a sigmoid function. Together, our findings provide a better understanding of mouse AC functional organization and how this organization is modulated by changes in stimulus complexity and brain state. The function of newly identified regions in higher-order auditory/vocal processing and animal behavior should be considered in future research.

neuroscience↗

bioRxiv2022

Tactile Stimulation Improves Cognition, Motor, and Anxiety-Like Behaviours and Attenuates the AD Pathology in Adult APP NL-G-F/NL-G-F mice

Alzheimers Disease (AD) is one of the largest health crises in the world. There are, however, limited but expensive pharmaceutical interventions to treat AD and most of the treatment options are not for cure or prevention, but to slow down the progression of the disease. The aim of this study was to examine the effect of tactile stimulation on AD-like symptoms and pathology in APP NL-G-F/NL-G-F mice, a mouse model of AD. The results show that tactile stimulation improves the AD-like symptoms on tests of cognition, motor, and anxiety-like behaviours and these improvements are associated with reduced AD pathology in APP mice.

neuroscience↗

bioRxiv2022

Early Tactile Stimulation Influences the Development of Alzheimer Disease in Gestationally Stressed APPNL-G-F/ NL-G-F Adult mice

Alzheimer Disease (AD) is associated with cerebral plaques and tangles, reduced synapse number, and shrinkage in several brain areas and these morphological effects are associated with the onset of compromised cognitive, motor, and anxiety-like behaviours. The focus of this study was to examine the effect of neonatal tactile stimulation on AD-like behavioural and neurological symptoms on APP NL-G-F/NL-G-F mice, a mouse model of AD. Our findings indicate that neonatal tactile stimulation improves cognition, motor skills, and anxiety-like symptoms in both gestationally stressed and non-stressed adult APP mice and that these alterations are associated with reduced A{beta} plaque formation. Thus, tactile stimulation appears to be a promising non-invasive preventative strategy for slowing the onset of dementia in aging animals.

neuroscience↗

bioRxiv2020

Prenatal Stress Dysregulates Resting-State Functional Connectivity and Sensory Motifs

Prenatal stress (PS) can impact fetal brain structure and function and contribute to higher vulnerability to neurodevelopmental and neuropsychiatric disorders. To understand how PS alters evoked and spontaneous neocortical activity and intrinsic brain functional connectivity, mesoscale voltage imaging was performed in adult C57BL/6NJ mice that had been exposed to auditory stress on gestational days 12-16, the age at which neocortex is developing. PS mice had a four-fold higher basal corticosterone level and reduced amplitude of cortical sensory-evoked responses to visual, auditory, whisker, forelimb, and hindlimb stimuli. Relative to control animals, PS also led to a general reduction of resting-state functional connectivity, as well as reduced inter-modular connectivity, enhanced intra-modular connectivity, and altered frequency of auditory and forelimb spontaneous sensory motifs. These resting-state changes resulted in a cortical connectivity pattern featuring disjoint but tight modules and a decline in network efficiency. The findings demonstrate that cortical connectivity is sensitive to PS and exposed offspring may be at risk for adult stress-related neuropsychiatric disorders.

neuroscience↗