Recent evidence suggests that adult neurogenesis contributes to the pathophysiology of different psychiatric disorders, including depressive disorder, anxiety disorder, and schizophrenia. Seasonal affective disorder (SAD) is a specific form of recurrent depressive disorder that can be induced by shortened light period. It is unclear yet whether neurogenesis is affected in SAD or under altered l...

BACKGROUND Melancholic depression, described also as endogenous depression, is a mood disorder with distinctive specific psychopathological features and biological homogeneity, including anhedonia, circadian variation of mood, psychomotor activation, weight loss, diurnal cortisol changes, and sleep disturbances. Although several hypotheses have been proposed, the etiology of this disorder is st...

Visual experience before eye-opening is not usually thought to have any developmental significance. Here we show that naturalistic visual stimuli presented through unopened eyelids robustly activate neurons in the ferret dorsal lateral geniculate nucleus. Further, dark-rearing prior to natural eye-opening has striking effects upon geniculate physiology. Receptive field maps after dark-rearing s...

In this study, we mainly investigated the visual selectivity of hand-manipulation-related neurons in the anterior intraparietal area (area AIP) while the animal was grasping or fixating on three-dimensional (3D) objects of different geometric shapes, sizes, and orientations. We studied the activity of 132 task-related neurons during the hand-manipulation tasks in the light and in the dark, as w...

The retina is the gateway to the visual system. To understand visual signal processing mechanisms, we investigate retinal neural network functions. Retinal neurons in the network comprise of numerous subtypes. More than 10 subtypes of bipolar cells, ganglion cells, and amacrine cells have been identified by morphological studies. Multiple subtypes of retinal neurons are thought to encode distin...

To efficiently detect a wide range of light-intensity changes, visual neurons must adapt to ambient luminance. However, how neurons in the primary visual cortex (V1) code the distribution of luminance remains unknown. We designed stimuli that represent rapid changes in luminance under different luminance distributions and investigated V1 neuron responses to these novel stimuli. We demonstrate t...

Most vertebrates process visual information using elaborately structured photosensory tissues, including the eyes and pineal. However, there is strong evidence that other tissues can detect and respond to photic stimuli. Many reports suggest that photosensitive elements exist within the brain itself and influence physiology and behavior; however, a long-standing puzzle has been the identity of ...

The circadian pacemaker of the suprachiasmatic nuclei (SCN) contains a major pacemaker for 24 h rhythms that is synchronized to the external light-dark cycle. In response to a shift in the external cycle, neurons of the SCN resynchronize with different pace. We performed electrical activity recordings of the SCN of rats in vitro following a 6 hour delay of the light-dark cycle and observed a bi...

The spatial arrangement of luminance increments (ON) and decrements (OFF) falling on the retina provides a wealth of information used by central visual pathways to construct coherent representations of visual scenes. But how the polarity of luminance change is represented in the activity of cortical circuits remains unclear. Using wide-field epifluorescence and two-photon imaging we demonstrate...

Microglia are thought to play important roles in the maintenance of neuronal circuitry and the regulation of behavior. We found that the cortical microglia contain an intrinsic molecular clock and exhibit a circadian expression of cathepsin S (CatS), a microglia-specific lysosomal cysteine protease in the brain. The genetic deletion of CatS causes mice to exhibit hyperlocomotor activity and rem...